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Author name code: asplund
ADS astronomy entries on 2022-09-14
author:"Asplund, Martin" 

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Title: The Gaia-ESO Public Spectroscopic Survey: Motivation,
    implementation, GIRAFFE data processing, analysis, and final data
    products
Authors: Gilmore, G.; Randich, S.; Worley, C. C.; Hourihane, A.;
   Gonneau, A.; Sacco, G. G.; Lewis, J. R.; Magrini, L.; Francois, P.;
   Jeffries, R. D.; Koposov, S. E.; Bragaglia, A.; Alfaro, E. J.; Allende
   Prieto, C.; Blomme, R.; Korn, A. J.; Lanzafame, A. C.; Pancino, E.;
   Recio-Blanco, A.; Smiljanic, R.; Van Eck, S.; Zwitter, T.; Bensby, T.;
   Flaccomio, E.; Irwin, M. J.; Franciosini, E.; Morbidelli, L.; Damiani,
   F.; Bonito, R.; Friel, E. D.; Vink, J. S.; Prisinzano, L.; Abbas,
   U.; Hatzidimitriou, D.; Held, E. V.; Jordi, C.; Paunzen, E.; Spagna,
   A.; Jackson, R. J.; Maiz Apellaniz, J.; Asplund, M.; Bonifacio, P.;
   Feltzing, S.; Binney, J.; Drew, J.; Ferguson, A. M. N.; Micela, G.;
   Negueruela, I.; Prusti, T.; Rix, H. -W.; Vallenari, A.; Bergemann,
   M.; Casey, A. R.; de Laverny, P.; Frasca, A.; Hill, V.; Lind, K.;
   Sbordone, L.; Sousa, S. G.; Adibekyan, V.; Caffau, E.; Daflon, S.;
   Feuillet, D. K.; Gebran, M.; Gonzalez Hernandez, J. I.; Guiglion,
   G.; Herrero, A.; Lobel, A.; Merle, T.; Mikolaitis, S.; Montes, D.;
   Morel, T.; Ruchti, G.; Soubiran, C.; Tabernero, H. M.; Tautvaisiene,
   G.; Traven, G.; Valentini, M.; Van der Swaelmen, M.; Villanova, S.;
   Viscasillas Vazquez, C.; Bayo, A.; Biazzo, K.; Carraro, G.; Edvardsson,
   B.; Heiter, U.; Jofre, P.; Marconi, G.; Martayan, C.; Masseron, T.;
   Monaco, L.; Walton, N. A.; Zaggia, S.; Aguirre Borsen-Koch, V.; Alves,
   J.; Balaguer-Nunez, L.; Barklem, P. S.; Barrado, D.; Bellazzini, M.;
   Berlanas, S. R.; Binks, A. S.; Bressan, A.; Capuzzo-Dolcetta, R.;
   Casagrande, L.; Casamiquela, L.; Collins, R. S.; D'Orazi, V.; Dantas,
   M. L. L.; Debattista, V. P.; Delgado-Mena, E.; Di Marcantonio, P.;
   Drazdauskas, A.; Evans, N. W.; Famaey, B.; Franchini, M.; Fremat, Y.;
   Fu, X.; Geisler, D.; Gerhard, O.; Gonzalez Solares, E. A.; Grebel,
   E. K.; Gutierrez Albarran, M. L.; Jimenez-Esteban, F.; Jonsson, H.;
   Khachaturyants, T.; Kordopatis, G.; Kos, J.; Lagarde, N.; Ludwig,
   H. -G.; Mahy, L.; Mapelli, M.; Marfil, E.; Martell, S. L.; Messina,
   S.; Miglio, A.; Minchev, I.; Moitinho, A.; Montalban, J.; Monteiro,
   M. J. P. F. G.; Morossi, C.; Mowlavi, N.; Mucciarelli, A.; Murphy,
   D. N. A.; Nardetto, N.; Ortolani, S.; Paletou, F.; Palous, J.;
   Pickering, J. C.; Quirrenbach, A.; Re Fiorentin, P.; Read, J. I.;
   Romano, D.; Ryde, N.; Sanna, N.; Santos, W.; Seabroke, G. M.; Spina,
   L.; Steinmetz, M.; Stonkute, E.; Sutorius, E.; Thevenin, F.; Tosi,
   M.; Tsantaki, M.; Wright, N.; Wyse, R. F. G.; Zoccali, M.; Zorec,
   J.; Zucker, D. B.
2022arXiv220805432G    Altcode:
  The Gaia-ESO Public Spectroscopic Survey is an ambitious project
  designed to obtain astrophysical parameters and elemental abundances
  for 100,000 stars, including large representative samples of the
  stellar populations in the Galaxy, and a well-defined sample of 60
  (plus 20 archive) open clusters. We provide internally consistent
  results calibrated on benchmark stars and star clusters, extending
  across a very wide range of abundances and ages. This provides a
  legacy data set of intrinsic value, and equally a large wide-ranging
  dataset that is of value for homogenisation of other and future
  stellar surveys and Gaia's astrophysical parameters. This article
  provides an overview of the survey methodology, the scientific aims,
  and the implementation, including a description of the data processing
  for the GIRAFFE spectra. A companion paper (arXiv:2206.02901)
  introduces the survey results. Gaia-ESO aspires to quantify both
  random and systematic contributions to measurement uncertainties. Thus
  all available spectroscopic analysis techniques are utilised, each
  spectrum being analysed by up to several different analysis pipelines,
  with considerable effort being made to homogenise and calibrate the
  resulting parameters. We describe here the sequence of activities up to
  delivery of processed data products to the ESO Science Archive Facility
  for open use. The Gaia-ESO Survey obtained 202,000 spectra of 115,000
  stars using 340 allocated VLT nights between December 2011 and January
  2018 from GIRAFFE and UVES. The full consistently reduced final data set
  of spectra was released through the ESO Science Archive Facility in late
  2020, with the full astrophysical parameters sets following in 2022.

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Title: The Gaia-ESO Public Spectroscopic Survey: Implementation,
    data products, open cluster survey, science, and legacy
Authors: Randich, S.; Gilmore, G.; Magrini, L.; Sacco, G. G.; Jackson,
   R. J.; Jeffries, R. D.; Worley, C. C.; Hourihane, A.; Gonneau, A.;
   Viscasillas Vàzquez, C.; Franciosini, E.; Lewis, J. R.; Alfaro, E. J.;
   Allende Prieto, C.; Blomme, T. Bensby R.; Bragaglia, A.; Flaccomio, E.;
   François, P.; Irwin, M. J.; Koposov, S. E.; Korn, A. J.; Lanzafame,
   A. C.; Pancino, E.; Recio-Blanco, A.; Smiljanic, R.; Van Eck, S.;
   Zwitter, T.; Asplund, M.; Bonifacio, P.; Feltzing, S.; Binney, J.;
   Drew, J.; Ferguson, A. M. N.; Micela, G.; Negueruela, I.; Prusti,
   T.; Rix, H. -W.; Vallenari, A.; Bayo, A.; Bergemann, M.; Biazzo, K.;
   Carraro, G.; Casey, A. R.; Damiani, F.; Frasca, A.; Heiter, U.; Hill,
   V.; Jofré, P.; de Laverny, P.; Lind, K.; Marconi, G.; Martayan, C.;
   Masseron, T.; Monaco, L.; Morbidelli, L.; Prisinzano, L.; Sbordone,
   L.; Sousa, S. G.; Zaggia, S.; Adibekyan, V.; Bonito, R.; Caffau,
   E.; Daflon, S.; Feuillet, D. K.; Gebran, M.; González Hernández,
   J. I.; Guiglion, G.; Herrero, A.; Lobel, A.; Maíz Apellániz,
   J.; Merle, T.; Mikolaitis, S.; Montes, D.; Morel, T.; Soubiran,
   C.; Spina, L.; Tabernero, H. M.; Tautvaišienė, G.; Traven, G.;
   Valentini, M.; Van der Swaelmen, M.; Villanova, S.; Wright, N. J.;
   Abbas, U.; Aguirre Børsen-Koch, V.; Alves, J.; Balaguer-Núnez,
   L.; Barklem, P. S.; Barrado, D.; Berlanas, S. R.; Binks, A. S.;
   Bressan, A.; Capuzzo--Dolcetta, R.; Casagrande, L.; Casamiquela, L.;
   Collins, R. S.; D'Orazi, V.; Dantas, M. L. L.; Debattista, V. P.;
   Delgado-Mena, E.; Di Marcantonio, P.; Drazdauskas, A.; Evans, N. W.;
   Famaey, B.; Franchini, M.; Frémat, Y.; Friel, E. D.; Fu, X.; Geisler,
   D.; Gerhard, O.; González Solares, E. A.; Grebel, E. K.; Gutiérrez
   Albarrán, M. L.; Hatzidimitriou, D.; Held, E. V.; Jiménez-Esteban,
   F.; Jönsson, H.; Jordi, C.; Khachaturyants, T.; Kordopatis, G.; Kos,
   J.; Lagarde, N.; Mahy, L.; Mapelli, M.; Marfil, E.; Martell, S. L.;
   Messina, S.; Miglio, A.; Minchev, I.; Moitinho, A.; Montalban, J.;
   Monteiro, M. J. P. F. G.; Morossi, C.; Mowlavi, N.; Mucciarelli, A.;
   Murphy, D. N. A.; Nardetto, N.; Ortolani, S.; Paletou, F.; Palouus, J.;
   Paunzen, E.; Pickering, J. C.; Quirrenbach, A.; Re Fiorentin, P.; Read,
   J. I.; Romano, D.; Ryde, N.; Sanna, N.; Santos, W.; Seabroke, G. M.;
   Spagna, A.; Steinmetz, M.; Stonkuté, E.; Sutorius, E.; Thévenin,
   F.; Tosi, M.; Tsantaki, M.; Vink, J. S.; Wright, N.; Wyse, R. F. G.;
   Zoccali, M.; Zorec, J.; Zucker, D. B.; Walton, N. A.
2022arXiv220602901R    Altcode:
  In the last 15 years different ground-based spectroscopic surveys
  have been started (and completed) with the general aim of delivering
  stellar parameters and elemental abundances for large samples of
  Galactic stars, complementing Gaia astrometry. Among those surveys,
  the Gaia-ESO Public Spectroscopic Survey (GES), the only one performed
  on a 8m class telescope, was designed to target 100,000 stars using
  FLAMES on the ESO VLT (both Giraffe and UVES spectrographs), covering
  all the Milky Way populations, with a special focus on open star
  clusters. This article provides an overview of the survey implementation
  (observations, data quality, analysis and its success, data products,
  and releases), of the open cluster survey, of the science results and
  potential, and of the survey legacy. A companion article (Gilmore et
  al.) reviews the overall survey motivation, strategy, Giraffe pipeline
  data reduction, organisation, and workflow. The GES has determined
  homogeneous good-quality radial velocities and stellar parameters for a
  large fraction of its more than 110,000 unique target stars. Elemental
  abundances were derived for up to 31 elements for targets observed with
  UVES. Lithium abundances are delivered for about 1/3 of the sample. The
  analysis and homogenisation strategies have proven to be successful;
  several science topics have been addressed by the Gaia-ESO consortium
  and the community, with many highlight results achieved. The final
  catalogue has been released through the ESO archive at the end of
  May 2022, including the complete set of advanced data products. In
  addition to these results, the Gaia-ESO Survey will leave a very
  important legacy, for several aspects and for many years to come.

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Title: VizieR Online Data Catalog: (non-)existence of five sparse
    open clusters (Kos+, 2018)
Authors: Kos, J.; de Silva, G.; Buder, S.; Bland-Hawthorn, J.; Sharma,
   S.; Asplund, M.; D'Orazi, V.; Duong, L.; Freeman, K.; Lewis, G. F.;
   Lin, J.; Lind, K.; Martell, S. L.; Schlesinger, K. J.; Simpson, J. D.;
   Zucker, D. B.; Zwitter, T.; Bedding, T. R.; Cotar, K.; Horner, J.;
   Nordlander, T.; Stello, D.; Ting, Y. -S.; Traven, G.
2022yCat..74805242K    Altcode:
  Stars observed as a part of the GALAH survey are selected
  from the 2MASS catalogue (Skrutskie et al. 2006AJ....131.1163S,
  Cat. VII/233). Depending on the observing mode, all the stars in a
  1<SUP>°</SUP>radius field are in a magnitude range 12&lt;V&lt;14
  for regular fields and 9&lt;V&lt;12 for bright fields. Most of the
  data used in this work comes from the Gaia DR2 (Gaia Collaboration
  2018A&amp;A...616A...1G, Cat. I/345), which includes positions,
  G magnitudes, proper motions and parallaxes for more than 1.3
  billion stars. This part of the catalogue is essentially complete for
  12&lt;G&lt;17, which is the range where we expect to find most of the
  cluster stars discussed in this paper. There are, however, a few members
  of the four alleged clusters that are brighter than G=12 and are not
  included in Gaia DR2, but do not impact the results of this paper. We
  also disregarded all stars with the proper motion error&gt;0.5mas/yr
  or parallax error&gt;10 per cent. Radial velocities in Gaia DR2 are
  only given for 7.2 million stars down to G=13. Because the precision
  of radial velocities is significantly higher in the GALAH survey
  (Zwitter et al. 2018MNRAS.481..645Z) than the Gaia data release, we
  use GALAH values wherever available. Because GALAH has a more limited
  magnitude range than Gaia, there are many stars for which Gaia DR2
  radial velocities must be used. From the cluster stars used in this work
  that have radial velocity measured in both Gaia DR2 and GALAH we find
  no systematic differences larger than 0.2km/s between the two surveys,
  so we can use whichever velocity is available. <P />(7 data files).

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Title: VizieR Online Data Catalog: Thorium in solar twins (Botelho+,
    2019)
Authors: Botelho, R. B.; Milone, A. De C.; Melendez, J.; Bedell, M.;
   Spina, L.; Asplund, M.; Dos Santos, L.; Bean, J. L.; Ramirez, I.;
   Yong, D.; Dreizler, S.; Alves-Brito, A.; Yana Galarza, J.
2022yCat..74821690B    Altcode:
  The sample is composed of 67 solar twins (stars with effective
  temperature, surface gravity, and metallicity around the solar values
  within {+/-}100K in Teff and within {+/-}0.1dex in logg and [Fe/H]),
  which were recently analysed by Spina et al. (2018MNRAS.474.2580S) and
  Bedell et al. (2018ApJ...865...68B). Spina et al. (2018MNRAS.474.2580S)
  derived their photospheric parameters by applying a line-by-line
  differential spectroscopic analysis relative to the Sun through
  equivalent width (EW) measurements of FeI and FeII lines. The estimated
  typical errors in Teff, logg, [Fe/H], and {xi} (micro-turbulence
  velocity) are, respectively, 4K, 0.012, 0.004dex and 0.011km/s. High
  Accuracy Radial velocity Planet Searcher (HARPS) spectra are used
  in this work to extract Th abundances. HARPS is an ultra-stable
  echelle spectrograph installed on the 3.6m telescope of the European
  Southern Observatory (ESO) at La Silla Observatory in Chile (Mayor
  et al. 2003Msngr.114...20M). The HARPS spectra covers λ=3780-6910Å
  under a resolving power R=115000. Each one-dimensional spectrum comes
  from more than 50 stacked spectra that are previously Doppler-corrected
  and carefully continuum normalized. <P />(3 data files).

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Title: Combined APOGEE-GALAH stellar catalogues using the Cannon
Authors: Nandakumar, Govind; Hayden, Michael R.; Sharma, Sanjib; Buder,
   Sven; Asplund, Martin; Bland-Hawthorn, Joss; De Silva, Gayandhi M.;
   D'Orazi, Valentina; Freeman, Ken C.; Kos, Janez; Lewis, Geraint F.;
   Martell, Sarah L.; Schlesinger, Katharine J.; Lin, Jane; Simpson,
   Jeffrey D.; Zucker, Daniel B.; Zwitter, Tomaž; Nordlander, Thomas;
   Casagrande, Luca; Lind, Karin; Côtar, Klemen; Stello, Dennis;
   Wittenmyer, Robert A.; Tepper-Garcia, Thor
2022MNRAS.513..232N    Altcode: 2022MNRAS.tmp..866N
  APOGEE and GALAH are two high resolution multi-object spectroscopic
  surveys that provide fundamental stellar parameters and multiple
  elemental abundance estimates for about half a million stars in the
  Milky Way. Both surveys observe in different wavelength regimes and
  use different data reduction pipelines leading to significant offsets
  and trends in stellar parameters and abundances for the common stars
  observed in both surveys. Such systematic differences/offsets in stellar
  parameters and abundances make it difficult to effectively utilize
  them to investigate Galactic abundance trends in spite of the unique
  advantage provided by their complementary sky coverage and different
  Milky Way components they observe. Hence, we use the Cannon data-driven
  method selecting a training set of 4418 common stars observed by
  both surveys. This enables the construction of two catalogues, one
  with the APOGEE-scaled and the other with the GALAH-scaled stellar
  parameters. Using repeat observations in APOGEE and GALAH, we find
  high precision in metallicity (~0.02-0.4 dex) and alpha abundances
  (~0.02-0.03 dex) for spectra with good signal-to-noise ratio (SNR &gt;
  80 for APOGEE and SNR &gt; 40 for GALAH). We use open and globular
  clusters to validate our parameter estimates and find small scatter in
  metallicity (0.06 dex) and alpha abundances (0.03 dex) in APOGEE-scaled
  case. The final catalogues have been cross-matched with the Gaia EDR3
  catalogue to enable their use to carry out detailed chemo-dynamic
  studies of the Milky Way from perspectives of APOGEE and GALAH.

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Title: The internal rotation of the Sun and its link to the solar
    Li and He surface abundances
Authors: Eggenberger, P.; Buldgen, G.; Salmon, S. J. A. J.; Noels,
   A.; Grevesse, N.; Asplund, M.
2022NatAs...6..788E    Altcode: 2022NatAs.tmp..119E
  The Sun serves as a natural reference for the modelling of the various
  physical processes at work in stellar interiors. Helioseismology
  results, which inform us on the characterization of the interior of
  the Sun (such as, for example, the helium abundance in its envelope),
  are, however, at odds with heavy element abundances. Moreover,
  the solar internal rotation and surface abundance of lithium have
  always been challenging to explain. We present results of solar models
  that account for transport of angular momentum and chemicals by both
  hydrodynamic and magnetic instabilities. We show that these transport
  processes reconcile the internal rotation of the Sun, its surface
  lithium abundance, and the helioseismic determination of the envelope
  helium abundance. We also show that the efficiency of the transport of
  chemicals required to account for the solar surface lithium abundance
  also predicts the correct value of helium, independently from a specific
  transport process.

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Title: The GALAH Survey: dependence of elemental abundances on age
    and metallicity for stars in the Galactic disc
Authors: Sharma, Sanjib; Hayden, Michael R.; Bland-Hawthorn,
   Joss; Stello, Dennis; Buder, Sven; Zinn, Joel C.; Spina, Lorenzo;
   Kallinger, Thomas; Asplund, Martin; De Silva, Gayandhi M.; D'Orazi,
   Valentina; Freeman, Ken C.; Kos, Janez; Lewis, Geraint F.; Lin, Jane;
   Lind, Karin; Martell, Sarah L.; Schlesinger, Katharine J.; Simpson,
   Jeffrey D.; Zucker, Daniel B.; Zwitter, Tomaž; Chen, Boquan; Cotar,
   Klemen; Kafle, Prajwal R.; Khanna, Shourya; Tepper-Garcia, Thor;
   Wang, Purmortal; Wittenmyer, Rob A.
2022MNRAS.510..734S    Altcode: 2021MNRAS.tmp.3061S; 2020arXiv201113818S
  Using data from the GALAH survey, we explore the dependence of elemental
  abundances on stellar age and metallicity among Galactic disc stars. We
  find that the abundance of most elements can be predicted from age and
  [Fe/H] with an intrinsic scatter of about 0.03 dex. We discuss the
  possible causes for the existence of the abundance-age-metallicity
  relations. Using a stochastic chemical enrichment scheme that takes
  the volume of supernovae remnants into account, we show the intrinsic
  scatter is expected to be small, about 0.05 dex or even smaller if
  there is additional mixing in the ISM. Elemental abundances show
  trends with both age and metallicity and the relationship is well
  described by a simple model in which the dependence of abundance
  ([X/Fe]) on age and [Fe/H] are additively separable. Elements can be
  grouped based on the direction of their abundance gradient in the
  (age,[Fe/H]) plane and different groups can be roughly associated
  with three distinct nucleosynthetic production sites, the exploding
  massive stars, the exploding white dwarfs, and the AGB stars. However,
  the abundances of some elements, like Co, La, and Li, show large scatter
  for a given age and metallicity, suggesting processes other than simple
  Galactic chemical evolution are at play. We also compare the abundance
  trends of main-sequence turn-off (MSTO) stars against that of giants,
  whose ages were estimated using asteroseismic information from the K2
  mission. For most elements, the trends of MSTO stars are similar to
  that of giants. The existence of abundance relations implies that we
  can estimate the age and birth radius of disc stars, which is important
  for studying the dynamic and chemical evolution of the Galaxy.

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Title: Distances, extinctions, and stellar parameters for stars in
    SkyMapper DR3
Authors: Lin, Jane; Casagrande, Luca; Asplund, Martin
2022MNRAS.510..433L    Altcode: 2021MNRAS.tmp.3066L
  We present a Bayesian isochrone fitting machinery to derive distances,
  extinctions, and stellar parameters (T<SUB>eff</SUB>, log g, and $\rm
  [Fe/H]$) for stars in the SkyMapper data release 3 (DR3) survey. We
  complement the latter with photometry from Gaia, 2MASS, and AllWISE,
  in addition to priors on parallaxes and interstellar extinction. We
  find our results to be in agreement with smaller samples of literature
  values derived using spectroscopic/photometric method, with typical
  uncertainties of order 130 K in effective temperature and 0.2 dex
  in surface gravity and metallicity. We demonstrate the quality of
  our stellar parameters by benchmarking our results against various
  spectroscopic surveys. We highlight the potential that SkyMapper bears
  for stellar population studies showing how we are able to clearly
  differentiate metallicities along the Gaia red (~-0.4 dex) and blue
  (~-1.1 dex) sequences using both dwarf and giant stars.

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Title: The SAPP pipeline for the determination of stellar abundances
    and atmospheric parameters of stars in the core program of the
    PLATO mission
Authors: Gent, Matthew Raymond; Bergemann, Maria; Serenelli, Aldo;
   Casagrande, Luca; Gerber, Jeffrey M.; Heiter, Ulrike; Kovalev, Mikhail;
   Morel, Thierry; Nardetto, Nicolas; Adibekyan, Vardan; Silva Aguirre,
   Víctor; Asplund, Martin; Belkacem, Kevin; del Burgo, Carlos; Bigot,
   Lionel; Chiavassa, Andrea; Rodríguez Díaz, Luisa Fernanda; Goupil,
   Marie-Jo; González Hernández, Jonay I.; Mourard, Denis; Merle,
   Thibault; Mészáros, Szabolcs; Marshall, Douglas J.; Ouazzani,
   Rhita-Maria; Plez, Bertrand; Reese, Daniel; Trampedach, Regner;
   Tsantaki, Maria
2022A&A...658A.147G    Altcode: 2021arXiv211106666G
  We introduce the SAPP (Stellar Abundances and atmospheric Parameters
  Pipeline), the prototype of the code that will be used to determine
  parameters of stars observed within the core program of the PLATO
  space mission. The pipeline is based on the Bayesian inference and
  provides effective temperature, surface gravity, metallicity, chemical
  abundances, and luminosity. The code in its more general version has a
  much wider range of potential applications. It can also provide masses,
  ages, and radii of stars and can be used with stellar types not targeted
  by the PLATO core program, such as red giants. We validate the code on
  a set of 27 benchmark stars that includes 19 FGK-type dwarfs, 6 GK-type
  subgiants, and 2 red giants. Our results suggest that combining various
  observables is the optimal approach, as this allows the degeneracies
  between different parameters to be broken and yields more accurate
  values of stellar parameters and more realistic uncertainties. For the
  PLATO core sample, we obtain a typical uncertainty of 27 (syst.) ±
  37 (stat.) K for T<SUB>eff</SUB>, 0.00 ± 0.01 dex for log g, 0.02
  ± 0.02 dex for metallicity [Fe/H], −0.01 ± 0.03 R<SUB>⊙</SUB>
  for radii, −0.01 ± 0.05 M<SUB>⊙</SUB> for stellar masses, and
  −0.14 ± 0.63 Gyr for ages. We also show that the best results
  are obtained by combining the ν<SUB>max</SUB> scaling relation with
  stellar spectra. This resolves the notorious problem of degeneracies,
  which is particularly important for F-type stars.

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Title: Non-detection of <SUP>6</SUP>Li in Spite plateau stars with
    ESPRESSO
Authors: Wang, Ella Xi; Nordlander, Thomas; Asplund, Martin; Lind,
   Karin; Zhou, Yixiao; Reggiani, Henrique
2022MNRAS.509.1521W    Altcode: 2021MNRAS.tmp.2661W; 2021arXiv211003822E; 2021arXiv211003822W
  The detection of <SUP>6</SUP>Li in Spite plateau stars contradicts
  the standard big bang nucleosynthesis prediction, known as the
  second cosmological lithium problem. We measure the isotopic ratio
  <SUP>6</SUP>Li/<SUP>7</SUP>Li in three Spite plateau stars: HD
  84937, HD 140283, and LP 815-43. We use 3D non-local thermodynamic
  equilibrium radiative transfer and for the first time apply this to
  high-resolution, high signal-to-noise ratio data from the ultra-stable
  ESPRESSO/Very Large Telescope spectrograph. These are among the
  best spectra ever taken of any metal-poor stars. As the measurement
  of <SUP>6</SUP>Li/<SUP>7</SUP>Li is degenerate with other physical
  stellar parameters, we employ Markov chain Monte Carlo methods to find
  the probability distributions of measured parameters. As a test of
  systematics, we also use three different fitting methods. We do not
  detect <SUP>6</SUP>Li in any of the three stars, and find consistent
  results between our different methods. We estimate 2σ upper limits
  to <SUP>6</SUP>Li/<SUP>7</SUP>Li of 0.7, 0.6, and 1.7 per cent,
  respectively, for HD 84937, HD 140283, and LP 815-43. Our results
  indicate that there is no second cosmological lithium problem, as
  there is no evidence of <SUP>6</SUP>Li in Spite plateau stars.

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Title: The GALAH+ survey: a new library of observed stellar spectra
    improves radial velocities and hints at motions within M67
Authors: Zwitter, Tomaž; Kos, Janez; Buder, Sven; Čotar, Klemen;
   Asplund, Martin; Bland-Hawthorn, Joss; Casey, Andrew R.; De Silva,
   Gayandhi M.; D'Orazi, Valentina; Freeman, Ken C.; Hayden, Michael
   R.; Lewis, Geraint F.; Lin, Jane; Lind, Karin; Martell, Sarah L.;
   Schlesinger, Katharine J.; Sharma, Sanjib; Simpson, Jeffrey D.;
   Stello, Dennis; Zucker, Daniel B.; Beeson, Kevin L.; de Grijs, Richard;
   Nordlander, Thomas; Ting, Yuan-Sen; Traven, Gregor; Vogrinčič, Rok;
   Watson, Fred; Wittenmyer, Rob
2021MNRAS.508.4202Z    Altcode: 2020arXiv201212201Z; 2021MNRAS.tmp.2413Z
  GALAH+ is a magnitude-limited survey of high-resolution stellar spectra
  obtained by the HERMES spectrograph at the Australian Astronomical
  Observatory. Its third data release provides reduced spectra with
  new derivations of stellar parameters and abundances of 30 chemical
  elements for 584 015 dwarfs and giants, 88 per cent of them in the
  Gaia magnitude range 11 &lt; G &lt; 14. Here, we use these improved
  values of stellar parameters to build a library of observed spectra
  which is useful to study variations of individual spectral lines
  with stellar parameters. This and other improvements are used to
  derive radial velocities with uncertainties which are generally
  within 0.1 km s<SUP>-1</SUP> or ~25 per cent smaller than in the
  previous release. Median differences in radial velocities measured
  here and by the Gaia DR2 or APOGEE DR16 surveys are smaller than 30 m
  s<SUP>-1</SUP>, a larger offset is present only for Gaia measurements
  of giant stars. We identify 4483 stars with intrinsically variable
  velocities and 225 stars for which the velocity stays constant over
  ≥3 visits spanning more than a year. The combination of radial
  velocities from GALAH+ with distances and sky plane motions from
  Gaia enables studies of dynamics within streams and clusters. For
  example, we estimate that the open cluster M67 has a total mass of
  ~3300 M<SUB>⊙</SUB> and its outer parts seem to be expanding, though
  astrometry with a larger time-span than currently available from Gaia
  eDR3 is needed to judge if the latter result is real.

---------------------------------------------------------
Title: The solar carbon, nitrogen, and oxygen abundances from a 3D
    LTE analysis of molecular lines
Authors: Amarsi, A. M.; Grevesse, N.; Asplund, M.; Collet, R.
2021A&A...656A.113A    Altcode: 2021arXiv210904752A
  Carbon, nitrogen, and oxygen are the fourth, sixth, and third most
  abundant elements in the Sun. Their abundances remain hotly debated due
  to the so-called solar modelling problem that has persisted for almost
  20 years. We revisit this issue by presenting a homogeneous analysis
  of 408 molecular lines across 12 diagnostic groups, observed in the
  solar intensity spectrum. Using a realistic 3D radiative-hydrodynamic
  model solar photosphere and local thermodynamic equilibrium (LTE)
  line formation, we find log ϵ<SUB>C</SUB> = 8.47 ± 0.02, log
  ϵ<SUB>N</SUB> = 7.89 ± 0.04, and log ϵ<SUB>O</SUB> = 8.70 ±
  0.04. The stipulated uncertainties mainly reflect the sensitivity of
  the results to the model atmosphere; this sensitivity is correlated
  between the different diagnostic groups, which all agree with the
  mean result to within 0.03 dex. For carbon and oxygen, the molecular
  results are in excellent agreement with our 3D non-LTE analyses of
  atomic lines. For nitrogen, however, the molecular indicators give
  a 0.12 dex larger abundance than the atomic indicators, and our
  best estimate of the solar nitrogen abundance is given by the mean:
  7.83 dex. The solar oxygen abundance advocated here is close to our
  earlier determination of 8.69 dex, and so the present results do
  not significantly alleviate the solar modelling problem. <P />Full
  Table 2 is only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr/">cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/656/A113">http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/656/A113</A>

---------------------------------------------------------
Title: Erratum: The GALAH survey: Chemical homogeneity of the
    Orion complex
Authors: Kos, Janez; Bland-Hawthorn, Joss; Buder, Sven; Nordlander,
   Thomas; Spina, Lorenzo; Beeson, Kevin L.; Lind, Karin; Asplund,
   Martin; Freeman, Ken; Hayden, Michael R.; Lewis, Geraint F.; Martell,
   Sarah L.; Sharma, Sanjib; De Silva, Gayandhi; Simpson, Jeffrey D.;
   Zucker, Daniel B.; Zwitter, Tomaž; Čotar, Klemen; Horner, Jonti;
   Ting (丁源森), Yuan-Sen; Traven, Gregor
2021MNRAS.508.4969K    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Spectroscopy and Photometry of the Least Massive Type II
Globular Clusters: NGC 1261 and NGC 6934
Authors: Marino, A. F.; Milone, A. P.; Renzini, A.; Yong, D.; Asplund,
   M.; Da Costa, G. S.; Jerjen, H.; Cordoni, G.; Carlos, M.; Dondoglio,
   E.; Lagioia, E. P.; Jang, S.; Tailo, M.
2021ApJ...923...22M    Altcode: 2021arXiv210615978M
  Recent work has revealed two classes of globular clusters (GCs), dubbed
  Type I and Type II. Type II GCs are characterized by both a blue and a
  red red giant branch composed of stars with different metallicities,
  often coupled with distinct abundances in the slow neutron-capture
  elements (s-elements). Here we continue the chemical tagging of Type II
  GCs by adding the two least massive clusters of this class, NGC 1261 and
  NGC 6934. Based on both spectroscopy and photometry, we find red stars
  in NGC 1261 to be slightly enhanced in [Fe/H] by ~0.1 dex and confirm
  that red stars of NGC 6934 are enhanced in iron by ~0.2 dex. Neither
  NGC 1261 nor NGC 6934 show internal variations in the s-elements,
  which suggests a GC mass threshold for the occurrence of s-process
  enrichment. We found a significant correlation between the additional Fe
  locked in the red stars of Type II GCs and the present-day mass of the
  cluster. Nevertheless, most Type II GCs retained a small fraction of Fe
  produced by SNe II, lower than the 2%; NGC 6273, M54, and ω Centauri
  are remarkable exceptions. In the Appendix, we infer for the first time
  chemical abundances of lanthanum, assumed as representative of the
  s-elements, in M54, the GC located in the nucleus of the Sagittarius
  dwarf galaxy. Red-sequence stars are marginally enhanced in [La/Fe]
  by 0.10 ± 0.06 dex, in contrast with the large [La/Fe] spread of most
  Type II GCs. We suggest that different processes are responsible for the
  enrichment in iron and s-elements in Type II GCs. <SUP>*</SUP> Based
  on observations collected at the European Southern Observatory under
  ESO program 0101.D-0109(A), and the NASA/ESA Hubble Space Telescope,
  obtained at the Space Telescope Science Institute, which is operated
  by AURA, Inc., under NASA contract NAS 5-26555.

---------------------------------------------------------
Title: Chemical evolution of the Galactic bulge as traced by
    microlensed dwarf and subgiant stars. VIII. Carbon and oxygen
Authors: Bensby, T.; Gould, A.; Asplund, M.; Feltzing, S.; Meléndez,
   J.; Johnson, J. A.; Lucatello, S.; Udalski, A.; Yee, J. C.
2021A&A...655A.117B    Altcode: 2021arXiv210611314B
  Context. Next to H and He, carbon is, together with oxygen, the most
  abundant element in the Universe and widely used when modelling the
  formation and evolution of galaxies and their stellar populations. For
  the Milky Way bulge, there are currently essentially no measurements of
  carbon in un-evolved stars, hampering our abilities to properly compare
  Galactic chemical evolution models to observational data for this still
  enigmatic stellar population. <BR /> Aims: We aim to determine carbon
  abundances for our sample of 91 microlensed dwarf and subgiant stars
  in the Galactic bulge. Together with new determinations for oxygen
  this forms the first statistically significant sample of bulge stars
  that have C and O abundances measured, and for which the C abundances
  have not been altered by the nuclear burning processes internal to
  the stars. <BR /> Methods: Our analysis is based on high-resolution
  spectra for a sample of 91 dwarf and subgiant stars that were obtained
  during microlensing events when the brightnesses of the stars were
  highly magnified. Carbon abundances were determined through spectral
  line synthesis of six C I lines around 9100 Å, and oxygen abundances
  using the three O I lines at about 7770 Å. One-dimensional (1D) MARCS
  model stellar atmospheres calculated under the assumption of local
  thermodynamic equilibrium (LTE) were used, and non-LTE corrections were
  applied when calculating the synthetic spectra for both C and O. <BR />
  Results: Carbon abundances was possible to determine for 70 of the 91
  stars in the sample and oxygen abundances for 88 of the 91 stars in the
  sample. The [C/Fe] ratio evolves essentially in lockstep with [Fe/H],
  centred around solar values at all [Fe/H]. The [O/Fe]-[Fe/H] trend
  has an appearance very similar to that observed for other α-elements
  in the bulge, with the exception of a continued decrease in [O/Fe]
  at super-solar [Fe/H], where other α-elements tend to level out. When
  dividing the bulge sample into two sub-groups, one younger than 8 Gyr
  and one older than 8 Gyr, the stars in the two groups follow exactly
  the elemental abundance trends defined by the solar neighbourhood
  thin and thick disks, respectively. Comparisons with recent models
  of Galactic chemical evolution in the [C/O]-[O/H] plane show that the
  models that best match the data are the ones that have been calculated
  with the Galactic thin and thick disks in mind. <BR /> Conclusions: We
  conclude that carbon, oxygen, and the combination of the two support
  the idea that the majority of the stars in the Galactic bulge have a
  secular origin; that is, they are formed from disk material. We cannot
  exclude that a fraction of stars in the bulge could be classified as
  a classical bulge population, but it would have to be small. More
  dedicated and advanced models of the inner region of the Milky Way
  are needed to make more detailed comparisons to the observations. <P
  />Full Table 2 is only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr/">cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via<A
  href="http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/655/A117">http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/655/A117</A>
  <P />Based on data obtained with the European Southern Observatory
  telescopes (Proposal ID:s 87.B-0600, 88.B-0349, 89.B-0047, 90.B-0204,
  91.B-0289, 92.B-0626, 93.B-0700), the Magellan Clay telescope at the
  Las Campanas observatory, and the Keck I telescope at the W.M. Keck
  Observatory, which is operated as a scientific partnership among the
  California Institute of Technology, the University of California,
  and the National Aeronautics and Space Administration.

---------------------------------------------------------
Title: High-resolution spectroscopic follow-up of the most metal-poor
    candidates from SkyMapper DR1.1
Authors: Yong, D.; Da Costa, G. S.; Bessell, M. S.; Chiti, A.; Frebel,
   A.; Gao, X.; Lind, K.; Mackey, A. D.; Marino, A. F.; Murphy, S. J.;
   Nordlander, T.; Asplund, M.; Casey, A. R.; Kobayashi, C.; Norris,
   J. E.; Schmidt, B. P.
2021MNRAS.507.4102Y    Altcode: 2021MNRAS.tmp.1796Y; 2021arXiv210706430Y
  We present chemical abundances for 21 elements (from Li to Eu)
  in 150 metal-poor Galactic stars spanning -4.1 &lt; [Fe/H] &lt;
  -2.1. The targets were selected from the SkyMapper survey and
  include 90 objects with [Fe/H] ≤ -3 of which some 15 have [Fe/H]
  ≤ -3.5. When combining the sample with our previous studies, we find
  that the metallicity distribution function has a power-law slope of
  Δ(log N)/Δ[Fe/H] = 1.51 ± 0.01 dex per dex over the range -4 ≤
  [Fe/H] ≤ -3. With only seven carbon-enhanced metal-poor stars in the
  sample, we again find that the selection of metal-poor stars based
  on SkyMapper filters is biased against highly carbon-rich stars for
  [Fe/H] &gt; -3.5. Of the 20 objects for which we could measure nitrogen,
  11 are nitrogen-enhanced metal-poor (NEMP) stars. Within our sample,
  the high NEMP fraction (55 per cent ± 21 per cent) is compatible
  with the upper range of predicted values (between 12 per cent and 35
  per cent). The chemical abundance ratios [X/Fe] versus [Fe/H] exhibit
  similar trends to previous studies of metal-poor stars and Galactic
  chemical evolution models. We report the discovery of nine new r-I
  stars, four new r-II stars, one of which is the most metal-poor known,
  nine low-α stars with [α/Fe] ≤ 0.15 as well as one unusual star with
  [Zn/Fe] = +1.4 and [Sr/Fe] = +1.2 but with normal [Ba/Fe]. Finally, we
  combine our sample with literature data to provide the most extensive
  view of the early chemical enrichment of the Milky Way Galaxy.

---------------------------------------------------------
Title: Detailed elemental abundances of binary stars: searching for
    signatures of planet formation and atomic diffusion
Authors: Liu, Fan; Bitsch, Bertram; Asplund, Martin; Liu, Bei-Bei;
   Murphy, Michael T.; Yong, David; Ting, Yuan-Sen; Feltzing, Sofia
2021MNRAS.508.1227L    Altcode: 2021MNRAS.tmp.2246L; 2021arXiv210811001L
  Binary star systems are assumed to be co-natal and coeval, and thus to
  have identical chemical composition. In this work, we aim to test the
  hypothesis that there is a connection between observed element abundance
  patterns and the formation of planets using binary stars. Moreover,
  we also want to test how atomic diffusion might influence the observed
  abundance patterns. We conduct a strictly line-by-line differential
  chemical abundance analysis of seven binary systems. Stellar atmospheric
  parameters and elemental abundances are obtained with extremely
  high precision (&lt;3.5 per cent) using the high-quality spectra
  from Very Large Telescope/ultraviolet-visual Echelle spectrograph
  and Keck/high-resolution Echelle spectrometer. We find that four of
  seven binary systems show subtle abundance differences (0.01-0.03
  dex) without clear correlations with the condensation temperature,
  including two planet-hosting pairs. The other three binary systems
  exhibit similar degree of abundance differences correlating with the
  condensation temperature. We do not find any clear relation between
  the abundance differences and the occurrence of known planets in
  our systems. Instead, the overall abundance offsets observed in the
  binary systems (four of seven) could be due to the effects of atomic
  diffusion. Although giant planet formation does not necessarily imprint
  chemical signatures on to the host star, the differences in the observed
  abundance trends with condensation temperature, on the other hand,
  are likely associated with diverse histories of planet formation
  (e.g. formation location). Furthermore, we find a weak correlation
  between abundance differences and binary separation, which may provide
  a new constraint on the formation of binary systems.

---------------------------------------------------------
Title: The GALAH survey: effective temperature calibration from the
    InfraRed Flux Method in the Gaia system
Authors: Casagrande, Luca; Lin, Jane; Rains, Adam D.; Liu, Fan;
   Buder, Sven; Horner, Jonathan; Asplund, Martin; Lewis, Geraint F.;
   Martell, Sarah L.; Nordlander, Thomas; Stello, Dennis; Ting, Yuan-Sen;
   Wittenmyer, Robert A.; Bland-Hawthorn, Joss; Casey, Andrew R.; De
   Silva, Gayandhi M.; D'Orazi, Valentina; Freeman, Ken C.; Hayden,
   Michael R.; Kos, Janez; Lind, Karin; Schlesinger, Katharine J.;
   Sharma, Sanjib; Simpson, Jeffrey D.; Zucker, Daniel B.; Zwitter, Tomaž
2021MNRAS.507.2684C    Altcode: 2020arXiv201102517C; 2021MNRAS.tmp.2075C
  In order to accurately determine stellar properties, knowledge of
  the effective temperature of stars is vital. We implement Gaia and
  2MASS photometry in the InfraRed Flux Method and apply it to over
  360 000 stars across different evolutionary stages in the GALAH DR3
  survey. We derive colour-effective temperature relations that take
  into account the effect of metallicity and surface gravity over the
  range $4000\, \rm {K}\lesssim T_{\rm {eff}}\lesssim 8000\, \rm {K}$,
  from very metal-poor stars to supersolar metallicities. The internal
  uncertainty of these calibrations is of order 40-80 K depending
  on the colour combination used. Comparison against solar-twins,
  Gaia benchmark stars, and the latest interferometric measurements
  validates the precision and accuracy of these calibrations from F
  to early M spectral types. We assess the impact of various sources
  of uncertainties, including the assumed extinction law, and provide
  guidelines to use our relations. Robust solar colours are also derived.

---------------------------------------------------------
Title: VizieR Online Data Catalog: COMBS Survey. Metal-poor bulge
    stars (Lucey+, 2021)
Authors: Lucey, M.; Hawkins, K.; Ness, M.; Debattista, V. P.; Luna,
   A.; Asplund, M.; Bensby, T.; Casagrande, L.; Feltzing, S.; Freeman,
   K. C.; Kobayashi, C.; Marino, A. F.
2021yCat..75015981L    Altcode:
  Based on observations collected at the European Southern Observatory
  under ESO programme: 089.B-069 <P />(1 data file).

---------------------------------------------------------
Title: The GALAH survey: accreted stars also inhabit the Spite plateau
Authors: Simpson, Jeffrey D.; Martell, Sarah L.; Buder, Sven;
   Bland-Hawthorn, Joss; Casey, Andrew R.; de Silva, Gayandhi M.;
   D'Orazi, Valentina; Freeman, Ken C.; Hayden, Michael; Kos, Janez;
   Lewis, Geraint F.; Lind, Karin; Schlesinger, Katharine J.; Sharma,
   Sanjib; Stello, Dennis; Zucker, Daniel B.; Zwitter, Tomaž; Asplund,
   Martin; da Costa, Gary; Čotar, Klemen; Tepper-García, Thor; Horner,
   Jonathan; Nordlander, Thomas; Ting, Yuan-Sen; Wyse, Rosemary F. G.;
   Galah Collaboration
2021MNRAS.507...43S    Altcode: 2021MNRAS.tmp.1793S; 2020arXiv201102659S
  The European Space Agency (ESA) Gaia mission has enabled the
  remarkable discovery that a large fraction of the stars near the solar
  neighbourhood are debris from a single in-falling system, the so-called
  Gaia-Sausage-Enceladus (GSE). This discovery provides astronomers for
  the first time with a large cohort of easily observable, unevolved stars
  that formed in a single extragalactic environment. Here we use these
  stars to investigate the 'Spite plateau' - the near-constant lithium
  abundance observed in unevolved metal-poor stars across a wide range
  of metallicities (-3 &lt; [Fe/H] &lt; -1). Our aim is to test whether
  individual galaxies could have different Spite plateaus - e.g. the
  interstellar medium could be more depleted in lithium in a lower
  galactic mass system due to it having a smaller reservoir of gas. We
  identified 93 GSE dwarf stars observed and analysed by the GALactic
  Archaeology with HERMES (GALAH) survey as part of its Data Release
  3 (DR3). Orbital actions were used to select samples of GSE stars,
  and comparison samples of halo and disc stars. We find that the GSE
  stars show the same lithium abundance as other likely accreted stars
  and in situ Milky Way stars. Formation environment leaves no imprint
  on lithium abundances. This result fits within the growing consensus
  that the Spite plateau, and more generally the 'cosmological lithium
  problem' - the observed discrepancy between the amount of lithium in
  warm, metal-poor dwarf stars in our Galaxy, and the amount of lithium
  predicted to have been produced by big bang nucleosynthesis - is the
  result of lithium depletion processes within stars.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Carbon and oxygen in microlensed
    bulge dwarfs (Bensby+, 2021)
Authors: Bensby, T.; Gould, A.; Asplund, M.; Feltzing, S.; Melendez,
   J.; Johnson, J. A.; Lucatello, S.; Udalski, A.; Yee, J. C.
2021yCat..36550117B    Altcode:
  We perform a detailed analysis of C and O in 91 microlensed dwarf stars
  in the Galactic bulge. Abundances were determined through spectral
  line synthesis of three oxygen lines at 777nm and six carbon lines
  at 910nm. The stellar sample traces the evolution of the Galactic
  bulge, and is the same as previously analysed by Bensby et al. (2017,
  Cat. J/A+A/605/A89) where stellar parameters and ages were taken
  from. <P />For each star we give the NLTE corrected C and O abundances,
  and their uncertainties based on the same analysis but increasing
  and decreasing the stellar parameters (effective temperature, surface
  gravity, metallicity, microturbulence) with their uncertainties. The
  abundances have been normalised to the Sun, based on our analysis of
  the Sun, on a line-by-line basis. We also give the absolute abundances
  for individual lines. For each carbon line we give a flag (0, 1, or 2)
  depending on whether the spectral line is close to a telluric absorption
  line or not: 0 = not affected; 1 = closer than 0.03nm to a weak telluric
  line (depth smaller than 15% of the continuum level); 2 = closer than
  0.03 nm to a strong telluric line (depth greater than 15 % of the
  continuum level). <P />70 stars have the carbon abundance measured
  and 89 stars have the oxygen abundance measured. <P />(1 data file).

---------------------------------------------------------
Title: Fundamental relations for the velocity dispersion of stars
    in the Milky Way
Authors: Sharma, Sanjib; Hayden, Michael R.; Bland-Hawthorn, Joss;
   Stello, Dennis; Buder, Sven; Zinn, Joel C.; Kallinger, Thomas;
   Asplund, Martin; De Silva, Gayandhi M.; D'Orazi, Valentina; Freeman,
   Ken; Kos, Janez; Lewis, Geraint F.; Lin, Jane; Lind, Karin; Martell,
   Sarah; Simpson, Jeffrey D.; Wittenmyer, Rob A.; Zucker, Daniel B.;
   Zwitter, Tomaz; Chen, Boquan; Cotar, Klemen; Esdaile, James; Hon,
   Marc; Horner, Jonathan; Huber, Daniel; Kafle, Prajwal R.; Khanna,
   Shourya; Ting, Yuan-Sen; Nataf, David M.; Nordlander, Thomas; Saadon,
   Mohd Hafiz Mohd; Tepper-Garcia, Thor; Tinney, C. G.; Traven, Gregor;
   Watson, Fred; Wright, Duncan; Wyse, Rosemary F. G.
2021MNRAS.506.1761S    Altcode: 2020arXiv200406556S; 2021MNRAS.tmp.1513S
  We explore the fundamental relations governing the radial and vertical
  velocity dispersions of stars in the Milky Way, from combined studies
  of complementary surveys including GALAH, LAMOST, APOGEE, the NASA
  Kepler and K2 missions, and Gaia DR2. We find that different stellar
  samples, even though they target different tracer populations and
  employ a variety of age estimation techniques, follow the same set of
  fundamental relations. We provide the clearest evidence to date that,
  in addition to the well-known dependence on stellar age, the velocity
  dispersions of stars depend on orbital angular momentum L<SUB>z</SUB>,
  metallicity, and height above the plane |z|, and are well described
  by a multiplicatively separable functional form. The dispersions have
  a power-law dependence on age with exponents of 0.441 ± 0.007 and
  0.251 ± 0.006 for σ<SUB>z</SUB> and σ<SUB>R</SUB>, respectively,
  and the power law is valid even for the oldest stars. For the solar
  neighbourhood stars, the apparent break in the power law for older
  stars, as seen in previous studies, is due to the anticorrelation
  of L<SUB>z</SUB> with age. The dispersions decrease with increasing
  L<SUB>z</SUB> until we reach the Sun's orbital angular momentum,
  after which σ<SUB>z</SUB> increases (implying flaring in the outer
  disc) while σ<SUB>R</SUB> flattens. For a given age, the dispersions
  increase with decreasing metallicity, suggesting that the dispersions
  increase with birth radius. The dispersions also increase linearly with
  |z|. The same set of relations that work in the solar neighbourhood also
  work for stars between 3 &lt; R/kpc &lt; 20. Finally, the high-[α/Fe]
  stars follow the same relations as the low-[α/Fe] stars.

---------------------------------------------------------
Title: VizieR Online Data Catalog: The solar CNO abundances (Amarsi+,
    2021)
Authors: Amarsi, A. M.; Grevesse, N.; Asplund, M.; Collet, R.
2021yCat..36560113A    Altcode:
  Table 2 contains the parameters, measured equivalent widths, and
  abundances inferred from the different models, for the 408 lines used
  in the present analysis. <P />(1 data file).

---------------------------------------------------------
Title: The GALAH survey: Chemical homogeneity of the Orion complex
Authors: Kos, Janez; Bland-Hawthorn, Joss; Buder, Sven; Nordlander,
   Thomas; Spina, Lorenzo; Beeson, Kevin L.; Lind, Karin; Asplund,
   Martin; Freeman, Ken; Hayden, Michael R.; Lewis, Geraint F.; Martell,
   Sarah L.; Sharma, Sanjib; De Silva, Gayandhi; Simpson, Jeffrey D.;
   Zucker, Daniel B.; Zwitter, Tomaž; Čotar, Klemen; Horner, Jonti;
   Ting, Yuan-Sen; Traven, Gregor
2021MNRAS.506.4232K    Altcode: 2020arXiv201102485K; 2021MNRAS.tmp.1571K
  Due to its proximity, the Orion star forming region is often used as
  a proxy to study processes related to star formation and to observe
  young stars in the environment they were born in. With the release of
  Gaia DR2, the distance measurements to the Orion complex are now good
  enough that the 3D structure of the complex can be explored. Here we
  test the hypothesis that, due to non-trivial structure and dynamics,
  and age spread in the Orion complex, the chemical enrichment of
  youngest stars by early core-collapse supernovae can be observed. We
  obtained spectra of 794 stars of the Orion complex with the HERMES
  spectrograph at the Anglo Australian telescope as a part of the
  GALAH and GALAH-related surveys. We use the spectra of ~300 stars to
  derive precise atmospheric parameters and chemical abundances of 25
  elements for 15 stellar clusters in the Orion complex. We demonstrate
  that the Orion complex is chemically homogeneous and that there was
  no self-pollution of young clusters by core-collapse supernovae from
  older clusters; with a precision of 0.02 dex in relative alpha-elements
  abundance and 0.06 dex in oxygen abundance we would have been able to
  detect pollution from a single supernova, given a fortunate location of
  the SN and favourable conditions for ISM mixing. We estimate that the
  supernova rate in the Orion complex was very low, possibly producing
  no supernova by the time the youngest stars of the observed population
  formed (from around 21 to 8 Myr ago).

---------------------------------------------------------
Title: VizieR Online Data Catalog: The GALAH+ Survey DR3 (Buder+,
    2021)
Authors: Buder, S.; Sharma, S.; Kos, J.; Amarsi, A. M.; Nordlander,
   T.; Lind, K.; Martell, S. L.; Asplund, M.; Bland-Hawthorn, J.; Casey,
   A. R.; de Silva, G. M.; D'Orazi, V.; Freeman, K. C.; Hayden, M. R.;
   Lewis, G. F.; Lin, J.; Schlesinger, K. J.; Simpson, J. D.; Stello,
   D.; Zucker, D. B.; Zwitter, T.; Beeson, K. L.; Buck, T.; Casagrande,
   L.; Clark, J. T.; Cotar, K.; da Costa, G. S.; de Grijs, R.; Feuillet,
   D.; Horner, J.; Kafle, P. R.; Khanna, S.; Kobayashi, C.; Liu, F.;
   Montet, B. T.; Nandakumar, G.; Nataf, D. M.; Ness, M. K.; Spina, L.;
   Tepper-Garcia, T.; Ting, Y. -S.; Traven, G.; Vogrincic, R.; Wittenmyer,
   R. A.; Wyse, R. F. G.; Zerjal M. GALAH Collaboration
2021yCat..75060150B    Altcode:
  This is the third data release of the GALAH survey. Data for the
  GALAH survey are taken with the HERMES spectrograph on the 3.9-metre
  Anglo-Australian Telescope (AAT) at Siding Spring Observatory. HERMES
  is a fibre-fed high-resolution (R=28000) spectrograph optimized to do
  Galactic archaeology from a 4m class telescope, with four discrete
  optical wavelength channels covering 4713-4903Å, 5648-5873Å,
  6478-6737Å, 7585-7887Å. <P />(5 data files).

---------------------------------------------------------
Title: The GALAH+ survey: Third data release
Authors: Buder, Sven; Sharma, Sanjib; Kos, Janez; Amarsi, Anish M.;
   Nordlander, Thomas; Lind, Karin; Martell, Sarah L.; Asplund, Martin;
   Bland-Hawthorn, Joss; Casey, Andrew R.; de Silva, Gayandhi M.; D'Orazi,
   Valentina; Freeman, Ken C.; Hayden, Michael R.; Lewis, Geraint F.;
   Lin, Jane; Schlesinger, Katharine J.; Simpson, Jeffrey D.; Stello,
   Dennis; Zucker, Daniel B.; Zwitter, Tomaž; Beeson, Kevin L.; Buck,
   Tobias; Casagrande, Luca; Clark, Jake T.; Čotar, Klemen; da Costa,
   Gary S.; de Grijs, Richard; Feuillet, Diane; Horner, Jonathan; Kafle,
   Prajwal R.; Khanna, Shourya; Kobayashi, Chiaki; Liu, Fan; Montet,
   Benjamin T.; Nandakumar, Govind; Nataf, David M.; Ness, Melissa K.;
   Spina, Lorenzo; Tepper-García, Thor; Ting, Yuan-Sen; Traven, Gregor;
   Vogrinčič, Rok; Wittenmyer, Robert A.; Wyse, Rosemary F. G.; Žerjal,
   Maruša; Galah Collaboration
2021MNRAS.506..150B    Altcode: 2020arXiv201102505B; 2021MNRAS.tmp.1259B
  The ensemble of chemical element abundance measurements for stars,
  along with precision distances and orbit properties, provides
  high-dimensional data to study the evolution of the Milky Way. With
  this third data release of the Galactic Archaeology with HERMES (GALAH)
  survey, we publish 678 423 spectra for 588 571 mostly nearby stars
  (81.2 per cent of stars are within &lt;2 kpc), observed with the
  HERMES spectrograph at the Anglo-Australian Telescope. This release
  (hereafter GALAH+ DR3) includes all observations from GALAH Phase 1
  (bright, main, and faint survey, 70 per cent), K2-HERMES (17 per cent),
  TESS-HERMES (5 per cent), and a subset of ancillary observations (8
  per cent) including the bulge and &gt;75 stellar clusters. We derive
  stellar parameters T<SUB>eff</SUB>, log g, [Fe/H], v<SUB>mic</SUB>,
  v<SUB>broad</SUB>, and v<SUB>rad</SUB> using our modified version of
  the spectrum synthesis code Spectroscopy Made Easy (SME) and 1D MARCS
  model atmospheres. We break spectroscopic degeneracies in our spectrum
  analysis with astrometry from Gaia DR2 and photometry from 2MASS. We
  report abundance ratios [X/Fe] for 30 different elements (11 of which
  are based on non-LTE computations) covering five nucleosynthetic
  pathways. We describe validations for accuracy and precision, flagging
  of peculiar stars/measurements and recommendations for using our
  results. Our catalogue comprises 65 per cent dwarfs, 34 per cent
  giants, and 1 per cent other/unclassified stars. Based on unflagged
  chemical composition and age, we find 62 per cent young low-$\alpha$,
  9 per cent young high-$\alpha$, 27 per cent old high-$\alpha$, and 2
  per cent stars with [Fe/H] ≤ -1. Based on kinematics, 4 per cent are
  halo stars. Several Value-Added-Catalogues, including stellar ages and
  dynamics, updated after Gaia eDR3, accompany this release and allow
  chrono-chemodynamic analyses, as we showcase.

---------------------------------------------------------
Title: The chemical make-up of the Sun: A 2020 vision
Authors: Asplund, M.; Amarsi, A. M.; Grevesse, N.
2021A&A...653A.141A    Altcode: 2021arXiv210501661A
  Context. The chemical composition of the Sun is a fundamental
  yardstick in astronomy, relative to which essentially all cosmic
  objects are referenced. As such, having accurate knowledge of the
  solar elemental abundances is crucial for an extremely broad range
  of topics. <BR /> Aims: We reassess the solar abundances of all
  83 long-lived elements, using highly realistic solar modelling and
  state-of-the-art spectroscopic analysis techniques coupled with the
  best available atomic data and observations. <BR /> Methods: The
  basis for our solar spectroscopic analysis is a three-dimensional
  (3D) radiative-hydrodynamical model of the solar surface convection
  and atmosphere, which reproduces the full arsenal of key observational
  diagnostics. New complete and comprehensive 3D spectral line formation
  calculations taking into account of departures from local thermodynamic
  equilibrium (non-LTE) are presented for Na, Mg, K, Ca, and Fe using
  comprehensive model atoms with reliable radiative and collisional
  data. Our newly derived abundances for C, N, and O are based on a 3D
  non-LTE analysis of permitted and forbidden atomic lines as well as
  3D LTE calculations for a total of 879 molecular transitions of CH,
  C<SUB>2</SUB>, CO, NH, CN, and OH. Previous 3D-based calculations for
  another 50 elements are re-evaluated based on updated atomic data,
  a stringent selection of lines, improved consideration of blends,
  and new non-LTE calculations available in the literature. For elements
  where spectroscopic determinations of the quiet Sun are not possible,
  the recommended solar abundances are revisited based on complementary
  methods, including helioseismology (He), solar wind data from the
  Genesis sample return mission (noble gases), sunspot observations
  (four elements), and measurements of the most primitive meteorites
  (15 elements). <BR /> Results: Our new improved analysis confirms
  the relatively low solar abundances of C, N, and O obtained in
  our previous 3D-based studies: log ϵ<SUB>C</SUB> = 8.46 ± 0.04,
  log ϵ<SUB>N</SUB> = 7.83 ± 0.07, and log ϵ<SUB>O</SUB> = 8.69 ±
  0.04. Excellent agreement between all available atomic and molecular
  indicators is achieved for C and O, but for N the atomic lines imply
  a lower abundance than for the molecular transitions for unknown
  reasons. The revised solar abundances for the other elements also
  typically agree well with our previously recommended values, with only
  Li, F, Ne, Mg, Cl, Kr, Rb, Rh, Ba, W, Ir, and Pb differing by more
  than 0.05 dex. The here-advocated present-day photospheric metal mass
  fraction is only slightly higher than our previous value, mainly due
  to the revised Ne abundance from Genesis solar wind measurements:
  X<SUB>surface</SUB> = 0.7438 ± 0.0054, Y<SUB>surface</SUB> =
  0.2423 ± 0.0054, Z<SUB>surface</SUB> = 0.0139 ± 0.0006, and
  Z<SUB>surface</SUB>/X<SUB>surface</SUB> = 0.0187 ± 0.0009. Overall,
  the solar abundances agree well with those of CI chondritic meteorites,
  but we identify a correlation with condensation temperature such that
  moderately volatile elements are enhanced by ≈0.04 dex in the CI
  chondrites and refractory elements possibly depleted by ≈0.02 dex,
  conflicting with conventional wisdom of the past half-century. Instead,
  the solar chemical composition more closely resembles that of the
  fine-grained matrix of CM chondrites with the expected exception of the
  highly volatile elements. <BR /> Conclusions: Updated present-day solar
  photospheric and proto-solar abundances are presented for 83 elements,
  including for all long-lived isotopes. The so-called solar modelling
  problem - a persistent discrepancy between helioseismology and solar
  interior models constructed with a low solar metallicity similar to
  that advocated here - remains intact with our revised solar abundances,
  suggesting shortcomings with the computed opacities and/or treatment of
  mixing below the convection zone in existing standard solar models. The
  uncovered trend between the solar and CI chondritic abundances with
  condensation temperature is not yet understood but is likely imprinted
  by planet formation, especially since a similar trend of opposite sign
  is observed between the Sun and solar twins.

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Title: The GALAH survey: a census of lithium-rich giant stars
Authors: Martell, Sarah L.; Simpson, Jeffrey D.; Balasubramaniam,
   Adithya G.; Buder, Sven; Sharma, Sanjib; Hon, Marc; Stello, Dennis;
   Ting, Yuan-Sen; Asplund, Martin; Bland-Hawthorn, Joss; De Silva,
   Gayandhi M.; Freeman, Ken C.; Hayden, Michael; Kos, Janez; Lewis,
   Geraint F.; Lind, Karin; Zucker, Daniel B.; Zwitter, Tomaž; Campbell,
   Simon W.; Čotar, Klemen; Horner, Jonathan; Montet, Benjamin;
   Wittenmyer, Rob
2021MNRAS.505.5340M    Altcode: 2021MNRAS.tmp.1346M; 2020arXiv200602106M
  We investigate the properties of 1262 red giant stars with high
  photospheric abundances of lithium observed by the GALAH and K2-HERMES
  surveys, and discuss them in the context of proposed mechanisms for
  lithium enrichment and redepletion in giant stars. We confirm that
  Li-rich giants are rare, making up only 1.2 per cent of our giant star
  sample. We use stellar parameters from the third public data release
  from the GALAH survey and a Bayesian isochrone analysis to divide
  the sample into first-ascent red giant branch (RGB) and red clump
  (RC) stars, and confirm these classifications using asteroseismic
  data from K2. We find that RC stars are 2.5 times as likely to be
  lithium-rich as RGB stars, in agreement with other recent work. The
  probability for a star to be lithium-rich is affected by a number of
  factors, though the causality in those correlations is not entirely
  clear. We show for the first time that primary and secondary RC stars
  have distinctly different lithium enrichment patterns. The data set
  discussed here is large and heterogeneous in terms of evolutionary
  phase, metallicity, rotation rate, and mass. We expect that if the
  various mechanisms that have been proposed for lithium enrichment in
  evolved stars are in fact active, they should all contribute to this
  sample of lithium-rich giants at some level.

---------------------------------------------------------
Title: The GALAH Survey: using galactic archaeology to refine our
    knowledge of TESS target stars
Authors: Clark, Jake T.; Clerté, Mathieu; Hinkel, Natalie R.;
   Unterborn, Cayman T.; Wittenmyer, Robert A.; Horner, Jonathan; Wright,
   Duncan J.; Carter, Brad; Morton, Timothy D.; Spina, Lorenzo; Asplund,
   Martin; Buder, Sven; Bland-Hawthorn, Joss; Casey, Andy; De Silva,
   Gayandhi; D'Orazi, Valentina; Duong, Ly; Hayden, Michael; Freeman, Ken;
   Kos, Janez; Lewis, Geraint; Lin, Jane; Lind, Karin; Martell, Sarah;
   Sharma, Sanjib; Simpson, Jeffrey; Zucker, Dan; Zwitter, Tomaz; Tinney,
   Christopher G.; Ting, Yuan-Sen; Nordlander, Thomas; Amarsi, Anish M.
2021MNRAS.504.4968C    Altcode: 2020arXiv200805372C; 2021MNRAS.tmp.1044C
  An unprecedented number of exoplanets are being discovered by the
  Transiting Exoplanet Survey Satellite (TESS). Determining the orbital
  parameters of these exoplanets, and especially their mass and radius,
  will depend heavily upon the measured physical characteristics of
  their host stars. We have cross-matched spectroscopic, photometric, and
  astrometric data from GALAH Data Release 2, the TESS Input Catalog and
  Gaia Data Release 2, to create a curated, self-consistent catalogue of
  physical and chemical properties for 47 285 stars. Using these data,
  we have derived isochrone masses and radii that are precise to within
  5 per cent. We have revised the parameters of three confirmed, and
  twelve candidate, TESS planetary systems. These results cast doubt
  on whether CTOI-20125677 is indeed a planetary system, since the
  revised planetary radii are now comparable to stellar sizes. Our
  GALAH-TESS catalogue contains abundances for up to 23 elements. We
  have specifically analysed the molar ratios for C/O, Mg/Si, Fe/Si,
  and Fe/Mg, to assist in determining the composition and structure of
  planets with R<SUB>p</SUB> &lt; 4R<SUB>⊕</SUB>. From these ratios,
  36 per cent fall within 2$\sigma$ sigma of the Sun/Earth values,
  suggesting that these stars may host rocky exoplanets with geological
  compositions similar to planets found within our own Solar system.

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Title: r-Process elements from magnetorotational hypernovae
Authors: Yong, D.; Kobayashi, C.; Da Costa, G. S.; Bessell, M. S.;
   Chiti, A.; Frebel, A.; Lind, K.; Mackey, A. D.; Nordlander, T.;
   Asplund, M.; Casey, A. R.; Marino, A. F.; Murphy, S. J.; Schmidt, B. P.
2021Natur.595..223Y    Altcode: 2021arXiv210703010Y
  Neutron-star mergers were recently confirmed
  as sites of rapid-neutron-capture (r-process)
  nucleosynthesis<SUP>1-3</SUP>. However, in Galactic chemical
  evolution models, neutron-star mergers alone cannot reproduce
  the observed element abundance patterns of extremely metal-poor
  stars, which indicates the existence of other sites of r-process
  nucleosynthesis<SUP>4-6</SUP>. These sites may be investigated by
  studying the element abundance patterns of chemically primitive
  stars in the halo of the Milky Way, because these objects retain
  the nucleosynthetic signatures of the earliest generation of
  stars<SUP>7-13</SUP>. Here we report the element abundance pattern of
  the extremely metal-poor star SMSS J200322.54−114203.3. We observe
  a large enhancement in r-process elements, with very low overall
  metallicity. The element abundance pattern is well matched by the
  yields of a single 25-solar-mass magnetorotational hypernova. Such a
  hypernova could produce not only the r-process elements, but also
  light elements during stellar evolution, and iron-peak elements
  during explosive nuclear burning. Hypernovae are often associated with
  long-duration γ-ray bursts in the nearby Universe<SUP>8</SUP>. This
  connection indicates that similar explosions of fast-spinning strongly
  magnetized stars occurred during the earliest epochs of star formation
  in our Galaxy.

---------------------------------------------------------
Title: VizieR Online Data Catalog: GALAH survey. Galactic disc with
    open clusters (Spina+, 2021)
Authors: Spina, L.; Ting, Y. -S.; de Silva, G. M.; Frankel, N.; Sharma,
   S.; Cantat-Gaudin, T.; Joyce, M.; Stello, D.; Karakas, A. I.; Asplund,
   M. B.; Nordlander, T.; Casagrande, L.; D'Orazi, V.; Casey, A. R.;
   Cottrell, P.; Tepper-Garcia, T.; Baratella, M.; Kos, J.; Cotar, K.;
   Bland-Hawthorn, J.; Buder, S.; Freeman, K. C.; Hayden, M. R.; Lewis,
   G. F.; Lin, J.; Lind, K.; Martell, S. L.; Schlesinger, K. J.; Simpson,
   J. D.; Zucker, D. B.; Zwitter, T.
2021yCat..75033279S    Altcode:
  In this study, we make use of three data sets: Gaia DR2 (Gaia
  Collaboration, 2018A&amp;A...616A...1G, Cat. I/345), APOGEE DR16
  (Ahumada et al., 2020ApJS..249....3A) and GALAH+ (Wittenmyer et al.,
  2018AJ....155...84W; Sharma et al., 2018, Cat. J/MNRAS/473/2004,
  2019MNRAS.490.5335S; Buder et al., 2020, arXiv:2011.02505). <P />In
  this work, we used astrometric information from Gaia to identify the
  stellar members of the 226 open clusters that potentially fall in the
  footprints of the APOGEE or GALAH survey. <P />Stellar coordinates
  and astrometric solutions from Gaia are used for cluster membership
  analysis. Radial velocities (RVs) provided by either Gaia, APOGEE,
  or GALAH. <P />(3 data files).

---------------------------------------------------------
Title: The relationship between photometric and spectroscopic
    oscillation amplitudes from 3D stellar atmosphere simulations
Authors: Zhou, Yixiao; Nordlander, Thomas; Casagrande, Luca; Joyce,
   Meridith; Li, Yaguang; Amarsi, Anish M.; Reggiani, Henrique; Asplund,
   Martin
2021MNRAS.503...13Z    Altcode: 2021MNRAS.tmp..360Z; 2021arXiv210202135Z
  We establish a quantitative relationship between photometric and
  spectroscopic detections of solar-like oscillations using ab initio,
  3D, hydrodynamical numerical simulations of stellar atmospheres. We
  present a theoretical derivation as a proof of concept for our
  method. We perform realistic spectral line formation calculations to
  quantify the ratio between luminosity and radial velocity amplitude
  for two case studies: the Sun and the red giant ϵ Tau. Luminosity
  amplitudes are computed based on the bolometric flux predicted by
  3D simulations with granulation background modelled the same way as
  asteroseismic observations. Radial velocity amplitudes are determined
  from the wavelength shift of synthesized spectral lines with methods
  closely resembling those used in Birmingham Solar Oscillations
  Network (BiSON) and Stellar Oscillations Network Group (SONG)
  observations. Consequently, the theoretical luminosity to radial
  velocity amplitude ratios are directly comparable with corresponding
  observations. For the Sun, we predict theoretical ratios of 21.0
  and 23.7 ppm [m s<SUP>-1</SUP>]<SUP>-1</SUP> from BiSON and SONG,
  respectively, in good agreement with observations 19.1 and 21.6 ppm
  [m s<SUP>-1</SUP>]<SUP>-1</SUP>. For ϵ Tau, we predict K2 and SONG
  ratios of 48.4 ppm [m s<SUP>-1</SUP>]<SUP>-1</SUP>, again in good
  agreement with observations 42.2 ppm [m s<SUP>-1</SUP>]<SUP>-1</SUP>,
  and much improved over the result from conventional empirical scaling
  relations that give 23.2 ppm [m s<SUP>-1</SUP>]<SUP>-1</SUP>. This study
  thus opens the path towards a quantitative understanding of solar-like
  oscillations, via detailed modelling of 3D stellar atmospheres.

---------------------------------------------------------
Title: The GALAH Survey: No Chemical Evidence of an Extragalactic
    Origin for the Nyx Stream
Authors: Zucker, Daniel B.; Simpson, Jeffrey D.; Martell, Sarah
   L.; Lewis, Geraint F.; Casey, Andrew R.; Ting, Yuan-Sen; Horner,
   Jonathan; Nordlander, Thomas; Wyse, Rosemary F. G.; Zwitter, Tomaž;
   Bland-Hawthorn, Joss; Buder, Sven; Asplund, Martin; De Silva, Gayandhi
   M.; D'Orazi, Valentina; Freeman, Ken C.; Hayden, Michael R.; Kos,
   Janez; Lin, Jane; Lind, Karin; Schlesinger, Katharine J.; Sharma,
   Sanjib; Stello, Dennis
2021ApJ...912L..30Z    Altcode: 2021arXiv210408684Z
  The results from the ESA Gaia astrometric mission and deep photometric
  surveys have revolutionized our knowledge of the Milky Way. There are
  many ongoing efforts to search these data for stellar substructure to
  find evidence of individual accretion events that built up the Milky
  Way and its halo. One of these newly identified features, called Nyx,
  was announced as an accreted stellar stream traveling in the plane
  of the disk. Using a combination of elemental abundances and stellar
  parameters from the GALAH and Apache Point Observatory Galactic
  Evolution Experiment (APOGEE) surveys, we find that the abundances
  of the highest likelihood Nyx members are entirely consistent with
  membership of the thick disk, and inconsistent with a dwarf galaxy
  origin. We conclude that the postulated Nyx stream is most probably
  a high-velocity component of the Milky Way's thick disk. With the
  growing availability of large data sets including kinematics, stellar
  parameters, and detailed abundances, the probability of detecting
  chance associations increases, and hence new searches for substructure
  require confirmation across as many data dimensions as possible.

---------------------------------------------------------
Title: The GALAH survey: tracing the Galactic disc with open clusters
Authors: Spina, L.; Ting, Y. -S.; De Silva, G. M.; Frankel, N.; Sharma,
   S.; Cantat-Gaudin, T.; Joyce, M.; Stello, D.; Karakas, A. I.; Asplund,
   M. B.; Nordlander, T.; Casagrande, L.; D'Orazi, V.; Casey, A. R.;
   Cottrell, P.; Tepper-García, T.; Baratella, M.; Kos, J.; Čotar,
   K.; Bland-Hawthorn, J.; Buder, S.; Freeman, K. C.; Hayden, M. R.;
   Lewis, G. F.; Lin, J.; Lind, K.; Martell, S. L.; Schlesinger, K. J.;
   Simpson, J. D.; Zucker, D. B.; Zwitter, T.
2021MNRAS.503.3279S    Altcode: 2021MNRAS.tmp..491S; 2020arXiv201102533S
  Open clusters are unique tracers of the history of our own Galaxy's
  disc. According to our membership analysis based on Gaia astrometry,
  out of the 226 potential clusters falling in the footprint of
  the GALactic Archaeology with HERMES (GALAH) survey or the Apache
  Point Observatory Galactic Evolution Experiment (APOGEE) survey,
  we find that 205 have secure members that were observed by at least
  one of the surveys. Furthermore, members of 134 clusters have
  high-quality spectroscopic data that we use to determine their
  chemical composition. We leverage this information to study the
  chemical distribution throughout the Galactic disc of 21 elements,
  from C to Eu. The radial metallicity gradient obtained from our
  analysis is -0.076 ± 0.009 dex kpc<SUP>-1</SUP>, which is in
  agreement with previous works based on smaller samples. Furthermore,
  the gradient in the [Fe/H]-guiding radius (r<SUB>guid</SUB>) plane
  is -0.073 ± 0.008 dex kpc<SUP>-1</SUP>. We show consistently that
  open clusters trace the distribution of chemical elements throughout
  the Galactic disc differently than field stars. In particular, at the
  given radius, open clusters show an age-metallicity relation that has
  less scatter than field stars. As such scatter is often interpreted
  as an effect of radial migration, we suggest that these differences
  are due to the physical selection effect imposed by our Galaxy:
  clusters that would have migrated significantly also had higher
  chances to get destroyed. Finally, our results reveal trends in the
  [X/Fe]-r<SUB>guid</SUB>-age space, which are important to understand
  production rates of different elements as a function of space and time.

---------------------------------------------------------
Title: Exploring the Galaxy's halo and very metal-weak thick disc
    with SkyMapper and Gaia DR2
Authors: Cordoni, G.; Da Costa, G. S.; Yong, D.; Mackey, A. D.; Marino,
   A. F.; Monty, S.; Nordlander, T.; Norris, J. E.; Asplund, M.; Bessell,
   M. S.; Casey, A. R.; Frebel, A.; Lind, K.; Murphy, S. J.; Schmidt,
   B. P.; Gao, X. D.; Xylakis-Dornbusch, T.; Amarsi, A. M.; Milone, A. P.
2021MNRAS.503.2539C    Altcode: 2020arXiv201101189C; 2020MNRAS.tmp.3219C
  In this work, we combine spectroscopic information from the SkyMapper
  survey for Extremely Metal-Poor stars and astrometry from Gaia DR2 to
  investigate the kinematics of a sample of 475 stars with a metallicity
  range of $-6.5 \le \rm [Fe/H] \le -2.05$ dex. Exploiting the action map,
  we identify 16 and 40 stars dynamically consistent with the Gaia Sausage
  and Gaia Sequoia accretion events, respectively. The most metal poor
  of these candidates have metallicities of $\rm [Fe/H]=-3.31\, \mathrm{
  and }\, -3.74$ , respectively, helping to define the low-metallicity
  tail of the progenitors involved in the accretion events. We also find,
  consistent with other studies, that ∼21 per cent of the sample have
  orbits that remain confined to within 3 kpc of the Galactic plane, that
  is, |Z<SUB>max</SUB>| ≤ 3 kpc. Of particular interest is a subsample
  (∼11 per cent of the total) of low |Z<SUB>max</SUB>| stars with low
  eccentricities and prograde motions. The lowest metallicity of these
  stars has [Fe/H] = -4.30 and the subsample is best interpreted as the
  very low-metallicity tail of the metal-weak thick disc population. The
  low |Z<SUB>max</SUB>|, low eccentricity stars with retrograde orbits are
  likely accreted, while the low |Z<SUB>max</SUB>|, high eccentricity pro-
  and retrograde stars are plausibly associated with the Gaia Sausage
  system. We find that a small fraction of our sample (∼4 per cent
  of the total) is likely escaping from the Galaxy, and postulate that
  these stars have gained energy from gravitational interactions that
  occur when infalling dwarf galaxies are tidally disrupted.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Thick disc probability of GALAH
    stars (Duong+, 2018)
Authors: Duong, L.; Freeman, K. C.; Asplund, M.; Casagrande, L.; Buder,
   S.; Lind, K.; Ness, M.; Bland-Hawthorn, J.; de Silva, G. M.; D'Orazi,
   V.; Kos, J.; Lewis, G. F.; Lin, J.; Martell, S. L.; Schlesinger, K.;
   Sharma, S.; Simpson, J. D.; Zucker, D. B.; Zwitter, T.; Anguiano, B.;
   da Costa, G. S.; Hyde, E.; Horner, J.; Kafle, P. R.; Nataf, D. M.;
   Reid, W.; Stello, D.; Ting, Y. -S.; Wyse, R. F. G.
2021yCat..74765216D    Altcode:
  We present a data table listing the stars analysed in this work,
  their GALAH object ID, UCAC4 catalogue ID, coordinates, thick disc
  membership probability and distances. <P />(1 data file).

---------------------------------------------------------
Title: The COMBS Survey - II. Distinguishing the metal-poor bulge
    from the halo interlopers
Authors: Lucey, Madeline; Hawkins, Keith; Ness, Melissa; Debattista,
   Victor P.; Luna, Alice; Asplund, Martin; Bensby, Thomas; Casagrande,
   Luca; Feltzing, Sofia; Freeman, Kenneth C.; Kobayashi, Chiaki; Marino,
   Anna F.
2021MNRAS.501.5981L    Altcode: 2021MNRAS.tmp...42L; 2020arXiv200903886L
  The metal-poor stars in the bulge are important relics of the Milky
  Way's formation history, as simulations predict that they are some
  of the oldest stars in the Galaxy. In order to determine if they are
  truly ancient stars, we must understand their origins. Currently, it
  is unclear if the metal-poor stars in the bulge ([Fe/H] &lt; -1 dex)
  are merely halo interlopers, a unique accreted population, part of the
  boxy/peanut-shaped bulge, or a classical bulge population. In this work,
  we use spectra from the VLT/FLAMES spectrograph to obtain metallicity
  estimates using the Ca-II triplet of 473 bulge stars (187 of which have
  [Fe/H] &lt; -1 dex), targeted using SkyMapper photometry. We also use
  Gaia DR2 data to infer the Galactic positions and velocities along
  with orbital properties for 523 stars. We employ a probabilistic
  orbit analysis and find that about half of our sample has a &gt;50
  per cent probability of being bound to the bulge, and half are halo
  interlopers. We also see that the occurrence rate of halo interlopers
  increases steadily with decreasing metallicity across the full range of
  our sample (-3 &lt; [Fe/H] &lt; 0.5). Our examination of the kinematics
  of the confined compared to the unbound stars indicates the metal-poor
  bulge comprises at least two populations; those confined to the
  boxy/peanut bulge and halo stars passing through the inner galaxy. We
  conclude that an orbital analysis approach, as we have employed, is
  important to understand the composite nature of the metal-poor stars
  in the inner region.

---------------------------------------------------------
Title: Explosive nucleosynthesis of a metal-deficient star as the
    source of a distinct odd-even effect in the solar twin HIP 11915
Authors: Yana Galarza, Jhon; Meléndez, Jorge; Karakas, Amanda I.;
   Asplund, Martin; Lorenzo-Oliveira, Diego
2021MNRAS.502L.104Y    Altcode: 2021MNRAS.tmpL..11G; 2021arXiv210110182G
  The abundance patterns observed in the Sun and in metal-poor stars
  show a clear odd-even effect. An important question is whether the
  odd-even effect in solar-metallicity stars is similar to the Sun,
  or if there are variations that can tell us about different chemical
  enrichment histories. In this work, we report for the first time
  observational evidence of a differential odd-even effect in the solar
  twin HIP 11915, relative to the solar odd-even abundance pattern. The
  spectra of this star were obtained with high-resolving power (140 000)
  and signal-to-noise ratio (∼420) using the ESPRESSO spectrograph and
  the VLT telescope. Thanks to the high spectral quality, we obtained
  extremely precise stellar parameters (σ(T<SUB>eff</SUB>) = 2 K, $\sigma
  (\rm {[Fe/H]})$ = 0.003 dex, and σ(log g) = 0.008 dex). We determine
  the chemical abundance of 20 elements (Z ≤ 39) with high precision
  (∼0.01 dex), which shows a strong pattern of the odd-even effect
  even after performing galactic chemical evolution corrections. The
  odd-even effect is reasonably well-reproduced by a core-collapse
  supernova of 13 $\rm {M_{\odot }}$ and metallicity Z = 0.001 diluted
  into a metal-poor gas of 1 $\rm {M_{\odot }}$ . Our results indicate
  that HIP 11915 has an odd-even effect slightly different than the Sun,
  thus confirming a different supernova enrichment history.

---------------------------------------------------------
Title: From accurate stellar abundances to exoplanet structures
    and compositions
Authors: Wang, Haiyang; Quanz, Sascha; Yong, David; Asplund, Martin;
   Liu, Fan; Acuña, Lorena
2021cosp...43E.518W    Altcode:
  A major goal of exoplanet studies is to identify terrestrial
  exoplanets with similar (or otherwise distinct) bulk and interior
  properties to our Earth. Recent results have highlighted the urgent
  need to include devolatilization to reduce exoplanetary interior
  modelling degeneracies and to thereby achieve more accurate and
  reliable results. Devolatilization - i.e. depletion of volatiles from
  protoplanetary disks to planets - is crucial for obtaining accurate bulk
  compositions for terrestrial planets from their host stellar abundances,
  particularly for non-refractory elements (e.g. hydrogen, carbon, and
  oxygen). Our pioneering devolatilization approach was benchmarked with
  the proto-Sun and bulk Earth and other solar system rocky bodies. In
  this work, we studied a sample of 15 small-planet-hosting stars and
  obtained high-precision stellar parameters and chemical abundances for
  up to 18 elements using observations from the 10m Keck Telescope. For
  each planet host, we applied our devolatilization approach to obtain
  the bulk elemental composition of the hypothetical, habitable-zone
  terrestrial planets ("exo-Earths"). Our modelling shows that most
  of these exo-Earths would have an Earth-like structure while their
  mantle compositions would be rather diverse in terms of MgO:SiO$
  _{2}$:FeO ratios. We then applied the same approach to the Galactic
  Chemical Evolution (GCE)-corrected host stellar abundances and find
  that the exo-Earth mantles are more oxidized, resulting in relatively
  smaller core sizes compared to the previous modelling. We attribute this
  modelling discrepancy mainly to the lower C/O ratios in these stars when
  they (and the systems) were born. This work represents essential steps -
  high-precision and homogenous analysis of stellar chemical abundances,
  the application of GCE corrections, as well as the devolatilization
  process - towards studying the properties of terrestrial exoplanets.

---------------------------------------------------------
Title: Atomic data for the Gaia-ESO Survey
Authors: Heiter, U.; Lind, K.; Bergemann, M.; Asplund, M.; Mikolaitis,
   Š.; Barklem, P. S.; Masseron, T.; de Laverny, P.; Magrini, L.;
   Edvardsson, B.; Jönsson, H.; Pickering, J. C.; Ryde, N.; Bayo Arán,
   A.; Bensby, T.; Casey, A. R.; Feltzing, S.; Jofré, P.; Korn, A. J.;
   Pancino, E.; Damiani, F.; Lanzafame, A.; Lardo, C.; Monaco, L.;
   Morbidelli, L.; Smiljanic, R.; Worley, C.; Zaggia, S.; Randich, S.;
   Gilmore, G. F.
2021A&A...645A.106H    Altcode: 2020arXiv201102049H
  Context. We describe the atomic and molecular data that were used for
  the abundance analyses of FGK-type stars carried out within the Gaia-ESO
  Public Spectroscopic Survey in the years 2012 to 2019. The Gaia-ESO
  Survey is one among several current and future stellar spectroscopic
  surveys producing abundances for Milky-Way stars on an industrial
  scale. <BR /> Aims: We present an unprecedented effort to create a
  homogeneous common line list, which was used by several abundance
  analysis groups using different radiative transfer codes to calculate
  synthetic spectra and equivalent widths. The atomic data are accompanied
  by quality indicators and detailed references to the sources. The
  atomic and molecular data are made publicly available at the CDS. <BR
  /> Methods: In general, experimental transition probabilities were
  preferred but theoretical values were also used. Astrophysical gf-values
  were avoided due to the model-dependence of such a procedure. For
  elements whose lines are significantly affected by a hyperfine structure
  or isotopic splitting, a concerted effort has been made to collate the
  necessary data for the individual line components. Synthetic stellar
  spectra calculated for the Sun and Arcturus were used to assess
  the blending properties of the lines. We also performed adetailed
  investigation of available data for line broadening due to collisions
  with neutral hydrogen atoms. <BR /> Results: Among a subset of over
  1300 lines of 35 elements in the wavelength ranges from 475 to 685 nm
  and from 850 to 895 nm, we identified about 200 lines of 24 species
  which have accurate gf-values and are free of blends in the spectra of
  the Sun and Arcturus. For the broadening due to collisions with neutral
  hydrogen, we recommend data based on Anstee-Barklem-O'Mara theory, where
  possible. We recommend avoiding lines of neutral species for which these
  are not available. Theoretical broadening data by R.L. Kurucz should
  be used for Sc II, Ti II, and Y II lines; additionally, for ionised
  rare-earth species, the Unsöld approximation with an enhancement
  factor of 1.5 for the line width can be used. <BR /> Conclusions: The
  line list has proven to be a useful tool for abundance determinations
  based on the spectra obtained within the Gaia-ESO Survey, as well as
  other spectroscopic projects. Accuracies below 0.2 dex are regularly
  achieved, where part of the uncertainties are due to differences in
  the employed analysis methods. Desirable improvements in atomic data
  were identified for a number of species, most importantly Al I, S I,
  and Cr II, but also Na I, Si I, Ca II, and Ni I. <P />The atomic and
  molecular data are only available at the CDS via an anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/645/A106">http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/645/A106</A>

---------------------------------------------------------
Title: 3D NLTE spectral line formation of lithium in late-type stars
Authors: Wang, Ella Xi; Nordlander, Thomas; Asplund, Martin; Amarsi,
   Anish M.; Lind, Karin; Zhou, Yixiao
2021MNRAS.500.2159W    Altcode: 2020MNRAS.tmp.3205W; 2020MNRAS.500.2159W; 2020arXiv201015248W
  Accurately known stellar lithium abundances may be used to shed
  light on a variety of astrophysical phenomena such as big bang
  nucleosynthesis, radial migration, ages of stars and stellar clusters,
  and planet engulfment events. We present a grid of synthetic lithium
  spectra that are computed in non-local thermodynamic equilibrium (NLTE)
  across the STAGGER grid of three-dimensional (3D) hydrodynamic stellar
  atmosphere models. This grid covers three Li lines at 610.4, 670.8,
  and 812.6 nm for stellar parameters representative of FGK-type dwarfs
  and giants, spanning T<SUB>eff</SUB> = 4000-7000 K, log g = 1.5-5.0,
  $[\rm {Fe}/\rm {H}]= -4.0$ -0.5, and A(Li) = -0.5-4.0. We find that
  our abundance corrections are up to 0.15 dex more negative than in
  previous work, due to a previously overlooked NLTE effect of blocking
  of UV lithium lines by background opacities, which has important
  implications for a wide range of science cases. We derive a new 3D
  NLTE solar abundance of A(Li) = 0.96 ± 0.05, which is 0.09 dex lower
  than the commonly used value. We make our grids of synthetic spectra
  and abundance corrections publicly available through the BREIDABLIK
  package. This package includes methods for accurately interpolating
  our grid to arbitrary stellar parameters through methods based on
  Kriging (Gaussian process regression) for line profiles, and multilayer
  perceptrons (a class of fully connected feedforward neural networks)
  for NLTE corrections and 3D NLTE abundances from equivalent widths,
  achieving interpolation errors of the order of 0.01 dex.

---------------------------------------------------------
Title: Combined APOGEE-GALAH stellar catalogues using the Cannon
Authors: Nandakumar, Govind; Hayden, Michael R.; Sharma, Sanjib; Buder,
   Sven; Asplund, Martin; Bland-Hawthorn, Joss; De Silva, Gayandhi M.;
   D'Orazi, Valentina; Freeman, Ken C.; Kos, Janez; Lewis, Geraint F.;
   Martell, Sarah L.; Schlesinger, Katharine J.; Lin, Jane; Simpson,
   Jeffrey D.; Zucker, Daniel B.; Zwitter, Tomaz; Nordlander, Thomas;
   Casagrande, Luca; Lind, Karin; Cotar, Klemen; Stello, Dennis;
   Wittenmyer, Robert A.; Tepper-Garcia, Thor
2020arXiv201102783N    Altcode:
  APOGEE and GALAH are two high resolution multi-object spectroscopic
  surveys that provide fundamental stellar parameters and multiple
  elemental abundance estimates for about half a million stars in the
  Milky Way. Both surveys observe in different wavelength regimes and
  use different data reduction pipelines leading to significant offsets
  and trends in stellar parameters and abundances for the common stars
  observed in both surveys. Such systematic differences/offsets in
  stellar parameters and abundances make it difficult to effectively
  utilise them to investigate Galactic abundance trends in spite of
  the unique advantage provided by their complementary sky coverage
  and different Milky Way components they observe. Hence, we use the
  \textit{Cannon} data-driven method selecting a training set of 4418
  common stars observed by both surveys. This enables the construction
  of two catalogues, one with the APOGEE scaled and the other with the
  GALAH scaled stellar parameters. Using repeat observations in APOGEE
  and GALAH, we find high precision in metallicity (~ 0.02-0.4 dex) and
  alpha abundances (~ 0.02-0.03 dex) for spectra with good signal-to-noise
  ratio (SNR &gt; 80 for APOGEE, SNR &gt; 40 for GALAH). We use open and
  globular clusters to validate our parameter estimates and find small
  scatter in metallicity (0.06 dex) and alpha abundances (0.03 dex)
  in APOGEE scaled case. The final catalogues have been cross matched
  with the Gaia EDR3 catalogue to enable their use to carry out detailed
  chemo-dynamic studies of the Milky Way from perspectives of APOGEE
  and GALAH.

---------------------------------------------------------
Title: VizieR Online Data Catalog: TESS-HERMES Survey Data Release
    1 catalog (Sharma+, 2018)
Authors: Sharma, S.; Stello, D.; Buder, S.; Kos, J.; Bland-Hawthorn,
   J.; Asplund, M.; Duong, L.; Lin, J.; Lind, K.; Ness, M.; Huber, D.;
   Zwitter, T.; Traven, G.; Hon, M.; Kafle, P. R.; Khanna, S.; Saddon,
   H.; Anguiano, B.; Casey, A. R.; Freeman, K.; Martell, S.; de Silva,
   G. M.; Simpson, J. D.; Wittenmyer, R. A.; Zucker, D. B.
2020yCat..74732004S    Altcode:
  The observations were obtained with the 4-m AAT located at Siding Spring
  Observatory in Australia. We use the High Efficiency and Resolution
  Multi-Element Spectrograph (HERMES), which can obtain spectra of up
  to 360 science targets simultaneously. <P />We find that our catalogue
  of spectroscopic results is magnitude complete down to 12.1mag in the
  TESS band for stars hotter than 4800K. In addition to spectroscopic
  values, we also provide fundamental stellar properties inferred from
  the Bayesian isochrone-based scheme, BSTEP. <P />(1 data file).

---------------------------------------------------------
Title: VizieR Online Data Catalog: Planet-hosting stars chemical
    compositions (Liu+, 2020)
Authors: Liu, F.; Yong, D.; Asplund, M.; Wang, H. S.; Spina, L.;
   Acuna, L.; Melendez, J.; Ramirez, I.
2020yCat..74953961L    Altcode:
  We present a differential analysis of 16 planet-hosting stars and 68
  comparison objects using high-resolution, high S/N spectra. We obtained
  high-precision stellar parameters and relative chemical abundance
  ratios. Average uncertainties for Teff, logg, and [Fe/H] are 15K,
  0.034cm/s<SUP>2</SUP>, and 0.012dex, respectively. <P />(4 data files).

---------------------------------------------------------
Title: The GALAH Survey: Chemical Clocks
Authors: Hayden, Michael R.; Sharma, Sanjib; Bland-Hawthorn,
   Joss; Spina, Lorenzo; Buder, Sven; Asplund, Martin; Casey, Andrew
   R.; De Silva, Gayandhi M.; D'Orazi, Valentina; Freeman, Ken C.;
   Kos, Janez; Lewis, Geraint F.; Lin, Jane; Lind, Karin; Martell,
   Sarah L.; Schlesinger, Katharine J.; Simpson, Jeffrey D.; Zucker,
   Daniel B.; Zwitter, Tomaz; Chen, Boquan; Cotar, Klemen; Feuillet,
   Diane; Horner, Jonti; Joyce, Meridith; Nordlander, Thomas; Stello,
   Dennis; Tepper-Garcia, Thorsten; Ting, Yuan-sen; Wang, Purmortal;
   Wittenmyer, Rob
2020arXiv201113745H    Altcode:
  Previous studies have found that the elemental abundances of a star
  correlate directly with its age and metallicity. Using this knowledge,
  we derive ages for a sample of 250,000 stars taken from GALAH DR3
  using only their overall metallicity and chemical abundances. Stellar
  ages are estimated via the machine learning algorithm $XGBoost$, using
  main sequence turnoff stars with precise ages as our input training
  set. We find that the stellar ages for the bulk of the GALAH DR3
  sample are accurate to 1-2 Gyr using this method. With these ages,
  we replicate many recent results on the age-kinematic trends of the
  nearby disk, including the age-velocity dispersion relationship of
  the solar neighborhood and the larger global velocity dispersion
  relations of the disk found using $Gaia$ and GALAH. The fact that
  chemical abundances alone can be used to determine a reliable age for
  a star have profound implications for the future study of the Galaxy
  as well as upcoming spectroscopic surveys. These results show that the
  chemical abundance variation at a given birth radius is quite small,
  and imply that strong chemical tagging of stars directly to birth
  clusters may prove difficult with our current elemental abundance
  precision. Our results highlight the need of spectroscopic surveys to
  deliver precision abundances for as many nucleosynthetic production
  sites as possible in order to estimate reliable ages for stars directly
  from their chemical abundances. Applying the methods outlined in
  this paper opens a new door into studies of the kinematic structure
  and evolution of the disk, as ages may potentially be estimated for a
  large fraction of stars in existing spectroscopic surveys. This would
  yield a sample of millions of stars with reliable age determinations,
  and allow precise constraints to be put on various kinematic processes
  in the disk, such as the efficiency and timescales of radial migration.

---------------------------------------------------------
Title: The GALAH Survey: non-LTE departure coefficients for large
    spectroscopic surveys
Authors: Amarsi, A. M.; Lind, K.; Osorio, Y.; Nordlander, T.;
   Bergemann, M.; Reggiani, H.; Wang, E. X.; Buder, S.; Asplund, M.;
   Barklem, P. S.; Wehrhahn, A.; Skúladóttir, Á.; Kobayashi, C.;
   Karakas, A. I.; Gao, X. D.; Bland-Hawthorn, J.; de Silva, G. M.; Kos,
   J.; Lewis, G. F.; Martell, S. L.; Sharma, S.; Simpson, J. D.; Zucker,
   D. B.; Čotar, K.; Horner, J.; GALAH Collaboration
2020A&A...642A..62A    Altcode: 2020arXiv200809582A
  Massive sets of stellar spectroscopic observations are rapidly becoming
  available and these can be used to determine the chemical composition
  and evolution of the Galaxy with unprecedented precision. One of the
  major challenges in this endeavour involves constructing realistic
  models of stellar spectra with which to reliably determine stellar
  abundances. At present, large stellar surveys commonly use simplified
  models that assume that the stellar atmospheres are approximately
  in local thermodynamic equilibrium (LTE). To test and ultimately
  relax this assumption, we have performed non-LTE calculations for
  13 different elements (H, Li, C, N, O, Na, Mg, Al, Si, K, Ca, Mn,
  and Ba), using recent model atoms that have physically-motivated
  descriptions for the inelastic collisions with neutral hydrogen,
  across a grid of 3756 1D MARCS model atmospheres that spans 3000 ≤
  T<SUB>eff</SUB>/K ≤ 8000, - 0.5 ≤log g/cm s<SUP>-2</SUP> ≤ 5.5,
  and - 5 ≤ [Fe/H] ≤ 1. We present the grids of departure coefficients
  that have been implemented into the GALAH DR3 analysis pipeline in
  order to complement the extant non-LTE grid for iron. We also present
  a detailed line-by-line re-analysis of 50 126 stars from GALAH DR3. We
  found that relaxing LTE can change the abundances by between - 0.7 dex
  and + 0.2 dex for different lines and stars. Taking departures from
  LTE into account can reduce the dispersion in the [A/Fe] versus [Fe/H]
  plane by up to 0.1 dex, and it can remove spurious differences between
  the dwarfs and giants by up to 0.2 dex. The resulting abundance slopes
  can thus be qualitatively different in non-LTE, possibly with important
  implications for the chemical evolution of our Galaxy. The grids of
  departure coefficients are publicly available and can be implemented
  into LTE pipelines to make the most of observational data sets from
  large spectroscopic surveys. <P />Grids of departure coefficients can
  be found online (&lt;xref ref-type="bibr" rid="R3"&gt;http://Amarsi
  2020&lt;/xref&gt;http://) or by contacting the lead author directly.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Atomic data for the Gaia-ESO Survey
    (Heiter+, 2021)
Authors: Heiter, U.; Lind, K.; Bergemann, M.; Asplund, M.; Mikolaitis,
   S.; Barklem, P. S.; Masseron, T.; de Laverny, P.; Magrini, L.;
   Edvardsson, B.; Joensson, H.; Pickering, J. C.; Ryde, N.; Bayo Aran,
   A.; Bensby, T.; Casey, A. R.; Feltzing, S.; Jofre, P.; Korn, A. J.;
   Pancino, E.; Damiani, F.; Lanzafame, A.; Lardo, C.; Monaco, L.;
   Morbidelli, L.; Smiljanic, R.; Worley, C.; Zaggia, S.; Randich, S.;
   Gilmore, G. F.
2020yCat..36450106H    Altcode:
  In general experimental transition probabilities were preferred but
  theoretical values were also used. Astrophysical gf-values were avoided
  due to the model-dependence of such a procedure. Synthetic stellar
  spectra calculated for the Sun and Arcturus were used to assess
  the blending properties of the lines. We also performed a detailed
  investigation of available data for line broadening due to collisions
  with neutral hydrogen atoms, which are included in the data table as
  "Van der Waals broadening". <P />The atomic data are stored in a single
  table with one record for each transition. Hyperfine structure (HFS)
  components and different isotopes are included as separate transitions,
  where applicable. HFS components belonging to the same fine structure
  transition can be identified by having the exact same label and J
  value for both the lower and the upper levels. Both the preselected
  lines and the background line list are included. Preselected lines can
  be identified by having both non-empty (not '-') gf_flag and synflag
  entries. The set of molecular data is stored in a separate table. <P
  />We strongly encourage users of the Gaia-ESO line list to cite,
  in addition to the overview article, the individual sources for the
  atomic and molecular data used in a particular work. It is important
  that providers of atomic data receive credit for their work by citing
  the original publications. This is also a prerequisite for the continued
  funding of this type of research. To facilitate citations of original
  sources we provide, together with the data table, a BibTeX file with
  the relevant entries. <P />(4 data files).

---------------------------------------------------------
Title: The GALAH survey: a new constraint on cosmological lithium
    and Galactic lithium evolution from warm dwarf stars
Authors: Gao, Xudong; Lind, Karin; Amarsi, Anish M.; Buder, Sven;
   Bland-Hawthorn, Joss; Campbell, Simon W.; Asplund, Martin; Casey,
   Andrew R.; de Silva, Gayandhi M.; Freeman, Ken C.; Hayden, Michael R.;
   Lewis, Geraint F.; Martell, Sarah L.; Simpson, Jeffrey D.; Sharma,
   Sanjib; Zucker, Daniel B.; Zwitter, Tomaž; Horner, Jonathan; Munari,
   Ulisse; Nordlander, Thomas; Stello, Dennis; Ting, Yuan-Sen; Traven,
   Gregor; Wittenmyer, Robert A.; GALAH Collaboration
2020MNRAS.497L..30G    Altcode: 2020MNRAS.tmpL.103G; 2020arXiv200605173G
  Lithium depletion and enrichment in the cosmos is not yet well
  understood. To help tighten constraints on stellar and Galactic
  evolution models, we present the largest high-resolution analysis of
  Li abundances A(Li) to date, with results for over $100\, 000$ GALAH
  (Galactic Archeology with HERMES) field stars spanning effective
  temperatures $5900\, \mathrm{K} \lesssim T_{\mathrm{eff}}\lesssim
  7000\, \mathrm{K}$ and metallicities -3 ≲ [Fe/H] ≲ +0.5. We
  separated these stars into two groups, on the warm and cool sides of
  the so-called Li dip, a localized region of the Kiel diagram wherein
  lithium is severely depleted. We discovered that stars in these two
  groups show similar trends in the A(Li)-[Fe/H] plane, but with a
  roughly constant offset in A(Li) of $0.4\, \mathrm{dex}$ , the warm
  group having higher Li abundances. At $\rm [Fe/H]\gtrsim -0.5$ , a
  significant increase in Li abundance with increasing metallicity is
  evident in both groups, signalling the onset of significant Galactic
  production. At lower metallicity, stars in the cool group sit on the
  Spite plateau, showing a reduced lithium of around $0.4\, \mathrm{dex}$
  relative to the primordial value predicted from big bang nucleosynthesis
  (BBN). However, stars in the warm group between [Fe/H] = -1.0 and
  -0.5 form an elevated plateau that is largely consistent with the BBN
  prediction. This may indicate that these stars in fact preserve the
  primordial Li produced in the early Universe.

---------------------------------------------------------
Title: K2-HERMES II. Planet-candidate properties from K2 Campaigns
    1-13
Authors: Wittenmyer, Robert A.; Clark, Jake T.; Sharma, Sanjib; Stello,
   Dennis; Horner, Jonathan; Kane, Stephen R.; Stevens, Catherine P.;
   Wright, Duncan J.; Spina, Lorenzo; Čotar, Klemen; Asplund, Martin;
   Bland-Hawthorn, Joss; Buder, Sven; Casey, Andrew R.; De Silva, Gayandhi
   M.; D'Orazi, Valentina; Freeman, Ken; Kos, Janez; Lewis, Geraint; Lin,
   Jane; Lind, Karin; Martell, Sarah L.; Simpson, Jeffrey D.; Zucker,
   Daniel B.; Zwitter, Tomaz
2020MNRAS.496..851W    Altcode: 2020MNRAS.tmp.1681W; 2020arXiv200510959W
  Accurate and precise radius estimates of transiting exoplanets
  are critical for understanding their compositions and formation
  mechanisms. To know the planet, we must know the host star in
  as much detail as possible. We present complete results for
  planet-candidate hosts from the K2-HERMES survey, which uses the
  HERMES multi-object spectrograph on the Anglo-Australian Telescope
  to obtain $R\sim 28\, 000$ spectra for more than 30 000 K2 stars. We
  present complete host-star parameters and planet-candidate radii
  for 224 K2 candidate planets from C1-C13. Our results cast severe
  doubt on 30 K2 candidates, as we derive unphysically large radii,
  larger than 2R<SUB>Jup</SUB>. This work highlights the importance of
  obtaining accurate, precise, and self-consistent stellar parameters
  for ongoing large planet search programs - something that will only
  become more important in the coming years, as TESS begins to deliver
  its own harvest of exoplanets.

---------------------------------------------------------
Title: Convective excitation and damping of solar-like oscillations
Authors: Zhou, Yixiao; Asplund, Martin; Collet, Remo; Joyce, Meridith
2020MNRAS.495.4904Z    Altcode: 2020arXiv200510519Z; 2020MNRAS.tmp.1563Z
  The last decade has seen a rapid development in asteroseismology thanks
  to the CoRoT and Kepler missions. With more detailed asteroseismic
  observations available, it is becoming possible to infer exactly how
  oscillations are driven and dissipated in solar-type stars. We have
  carried out three-dimensional (3D) stellar atmosphere simulations
  together with one-dimensional (1D) stellar structural models of key
  benchmark turn-off and subgiant stars to study this problem from a
  theoretical perspective. Mode excitation and damping rates are extracted
  from 3D and 1D stellar models based on analytical expressions. Mode
  velocity amplitudes are determined by the balance between stochastic
  excitation and linear damping, which then allows the estimation of the
  frequency of maximum oscillation power, ν<SUB>max</SUB>, for the first
  time based on ab initio and parameter-free modelling. We have made
  detailed comparisons between our numerical results and observational
  data and achieved very encouraging agreement for all of our target
  stars. This opens the exciting prospect of using such realistic 3D
  hydrodynamical stellar models to predict solar-like oscillations across
  the Hertzsprung-Russell diagram, thereby enabling accurate estimates
  of stellar properties such as mass, radius, and age.

---------------------------------------------------------
Title: Detailed chemical compositions of planet-hosting stars -
    I. Exploration of possible planet signatures
Authors: Liu, F.; Yong, D.; Asplund, M.; Wang, H. S.; Spina, L.;
   Acuña, L.; Meléndez, J.; Ramírez, I.
2020MNRAS.495.3961L    Altcode: 2020arXiv200509846L; 2020MNRAS.tmp.1553L
  We present a line-by-line differential analysis of a sample of 16
  planet-hosting stars and 68 comparison stars using high-resolution, high
  signal-to-noise ratio spectra gathered using Keck. We obtained accurate
  stellar parameters and high-precision relative chemical abundances
  with average uncertainties in T<SUB>eff</SUB>, log g, [Fe/H], and
  [X/H] of 15 K, 0.034 cm s<SUP>-2</SUP> , 0.012 dex, and 0.025 dex,
  respectively. For each planet host, we identify a set of comparison
  stars and examine the abundance differences (corrected for Galactic
  chemical evolution effect) as a function of the dust condensation
  temperature, T<SUB>cond</SUB>, of the individual elements. While we
  confirm that the Sun exhibits a negative trend between abundance and
  T<SUB>cond</SUB>, we also confirm that the remaining planet hosts
  exhibit a variety of abundance-T<SUB>cond</SUB> trends with no clear
  dependence upon age, metallicity, or T<SUB>eff</SUB>. The diversity in
  the chemical compositions of planet-hosting stars relative to their
  comparison stars could reflect the range of possible planet-induced
  effects present in these planet hosts, from the sequestration of
  rocky material (refractory poor) to the possible ingestion of planets
  (refractory rich). Other possible explanations include differences
  in the time-scale, efficiency and degree of planet formation,
  or inhomogeneous chemical evolution. Although we do not find an
  unambiguous chemical signature of planet formation among our sample,
  the high-precision chemical abundances of the host stars are essential
  for constraining the composition and structure of their exoplanets.

---------------------------------------------------------
Title: The GALAH survey: multiple stars and our Galaxy. I. A
    comprehensive method for deriving properties of FGK binary stars
Authors: Traven, G.; Feltzing, S.; Merle, T.; Van der Swaelmen, M.;
   Čotar, K.; Church, R.; Zwitter, T.; Ting, Y. -S.; Sahlholdt, C.;
   Asplund, M.; Bland-Hawthorn, J.; De Silva, G.; Freeman, K.; Martell,
   S.; Sharma, S.; Zucker, D.; Buder, S.; Casey, A.; D'Orazi, V.; Kos,
   J.; Lewis, G.; Lin, J.; Lind, K.; Simpson, J.; Stello, D.; Munari,
   U.; Wittenmyer, R. A.
2020A&A...638A.145T    Altcode: 2020arXiv200500014T
  Context. Binary stellar systems form a large fraction of the Galaxy's
  stars. They are useful as laboratories for studying the physical
  processes taking place within stars, and must be correctly taken into
  account when observations of stars are used to study the structure
  and evolution of the Galaxy. The advent of large-scale spectroscopic
  and photometric surveys allows us to obtain large samples of binaries
  that permit characterising their populations. <BR /> Aims: We aim to
  obtain a large sample of double-lined spectroscopic binaries (SB2s)
  by analysis of spectra from the GALAH survey in combination with
  photometric and astrometric data. A combined analysis will provide
  stellar parameters of thousands of binary stars that can be combined
  to form statistical observables of a given population. We aim to
  produce a catalogue of well-characterised systems, which can in turn
  be compared to models of populations of binary stars, or to follow-up
  individual systems of interest. <BR /> Methods: We obtained a list
  of candidate SB2 systems from a t-distributed stochastic neighbour
  embedding (t-SNE) classification and a cross-correlation analysis of
  GALAH spectra. To compute parameters of the primary and secondary star,
  we used a Bayesian approach that includes a parallax prior from Gaia
  DR2, spectra from GALAH, and apparent magnitudes from APASS, Gaia DR2,
  2MASS, and WISE. We used a Markov chain Monte Carlo approach to sample
  the posterior distributions of the following model parameters for
  the two stars: T<SUB>eff[1,2]</SUB>, logg<SUB>[1,2]</SUB>, [Fe/H],
  V<SUB>r[1,2]</SUB>, v<SUB>mic[1,2]</SUB>, v<SUB>broad[1,2]</SUB>,
  R<SUB>[1,2]</SUB>, and E(B-V). <BR /> Results: We present results for
  12 760 binary stars detected as SB2s. We construct the statistical
  observables T<SUB>1</SUB>/T<SUB>2</SUB>, ΔV<SUB>r</SUB>, and
  R<SUB>1</SUB>/R<SUB>2</SUB>, which demonstrate that our sample mostly
  consists of dwarfs, with a significant fraction of evolved stars and
  several dozen members of the giant branch. The majority of these binary
  stars is concentrated at the lower boundary of the ΔV<SUB>r</SUB>
  distribution, and the R<SUB>1</SUB>/R<SUB>2</SUB> ratio is mostly close
  to unity. The derived metallicity of our binary stars is statistically
  lower than that of single dwarf stars from the same magnitude-limited
  sample. <BR /> Conclusions: Our sample of binary stars represents
  a large population of well-characterised double-lined spectroscopic
  binaries that are appropriate for statistical studies of the binary
  populations. The derived stellar properties and their distributions show
  trends that are expected for a population of close binary stars (a &lt;
  10 AU) detected through double lines in their spectra. Our detection
  technique allows us to probe binary systems with mass ratios 0.5 ≤q
  ≤ 1. <P />Catalogue is only available at the CDS via anonymous ftp to
  <A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/638/A145">http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/638/A145</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: GALAH survey. FGK binary stars
    (Traven+, 2020)
Authors: Traven, G.; Feltzing, S.; Merle, T.; van der Swaelmen, M.;
   Cotar, K.; Church, R.; Zwitter, T.; Ting, Y. -S.; Sahlholdt, C.;
   Asplund, M.; Bland-Hawthorn, J.; de Silva, G.; Freeman, K.; Martell,
   S.; Sharma, S.; Zucker, D.; Buder, S.; Casey, A.; D'Orazi, V.; Kos,
   J.; Lewis, G.; Lin, J.; Lind, K.; Simpson, J.; Stello, D.; Munari,
   U.; Wittenmyer, R. A.
2020yCat..36380145T    Altcode:
  We here analyse a specific data-set: the extended GALAH dataset. This
  consists of stellar spectra from the GALAH survey (reduced as explained
  in Kos et al., 2017MNRAS.464.1259K), apparent magnitudes from a
  variety of photometric catalogues (AAVSO Photometric All Sky Survey -
  APASS; Henden et al. 2016, Cat. II/336, Gaia DR2; Gaia Collaboration
  et al. 2018, Cat. I/345. Two Micron All Sky Survey - 2MASS; Skrutskie
  et al. 2006, Cat. VII/233, Wide-field Infrared Survey Explorer - WISE;
  Wright et al. 2010, Cat. II/311), and the parallax measurements from
  Gaia DR2. <P />The data provided in this catalogue are described in
  Table A.1 of the paper. <P />(1 data file).

---------------------------------------------------------
Title: VizieR Online Data Catalog: COMBS survey. Galactic Bulge
    metal-poor stars (Lucey+, 2019)
Authors: Lucey, M.; Hawkins, K.; Ness, M.; Asplund, M.; Bensby, T.;
   Casagrande, L.; Feltzing, S.; Freeman, K. C.; Kobayashi, C.; Marino,
   A. F.
2020yCat..74882283L    Altcode:
  Based on observations collected at the European Southern Observatory
  under ESO programme: 089.B-069 <P />(3 data files).

---------------------------------------------------------
Title: The 3D non-LTE solar nitrogen abundance from atomic lines
Authors: Amarsi, A. M.; Grevesse, N.; Grumer, J.; Asplund, M.; Barklem,
   P. S.; Collet, R.
2020A&A...636A.120A    Altcode: 2020arXiv200312561A
  Nitrogen is an important element in various fields of stellar and
  Galactic astronomy, and the solar nitrogen abundance is crucial as a
  yardstick for comparing different objects in the cosmos. In order to
  obtain a precise and accurate value for this abundance, we carried out
  N I line formation calculations in a 3D radiative-hydrodynamic STAGGER
  model solar atmosphere in full 3D non-local thermodynamic equilibrium
  (non-LTE). We used a model atom that includes physically motivated
  descriptions for the inelastic collisions of N I with free electrons and
  with neutral hydrogen. We selected five N I lines of high excitation
  energy to study in detail, based on their strengths and on their
  being relatively free of blends. We found that these lines are slightly
  strengthened from non-LTE photon losses and from 3D granulation effects,
  resulting in negative abundance corrections of around - 0.01 dex and -
  0.04 dex, respectively. Our advocated solar nitrogen abundance is log
  ɛ<SUB>N</SUB> = 7.77, with the systematic 1σ uncertainty estimated
  to be 0.05 dex. This result is consistent with earlier studies after
  correcting for differences in line selections and equivalent widths.

---------------------------------------------------------
Title: The GALAH survey: chemodynamics of the solar neighbourhood
Authors: Hayden, Michael R.; Bland-Hawthorn, Joss; Sharma, Sanjib;
   Freeman, Ken; Kos, Janez; Buder, Sven; Anguiano, Borja; Asplund,
   Martin; Chen, Boquan; De Silva, Gayandhi M.; Khanna, Shourya; Lin,
   Jane; Horner, Jonathan; Martell, Sarah; Ting, Yuan-Sen; Wyse, Rosemary;
   Zucker, Daniel; Zwitter, Tomaz
2020MNRAS.493.2952H    Altcode: 2020MNRAS.tmp..333H; 2019arXiv190107565H
  We present the chemodynamic structure of the solar neighbourhood
  using 55 652 stars within a 500 pc volume around the Sun observed by
  GALAH and with astrometric parameters from Gaia DR2. We measure the
  velocity dispersion for all three components (vertical, radial, and
  tangential) and find that it varies smoothly with [Fe/H] and [α/Fe]
  for each component. The vertical component is especially clean, with
  σ _{v_z} increasing from a low of 10 km s<SUP>-1</SUP> at solar
  [α/Fe] and [Fe/H] to a high of more than 50 km s<SUP>-1</SUP> for
  more metal-poor and [α/Fe] enhanced populations. We find no evidence
  of a large decrease in the velocity dispersion of the highest [α/Fe]
  populations as claimed in surveys prior to Gaia DR2. The eccentricity
  distribution for local stars varies most strongly as a function of
  [α/Fe], where stars with [α/Fe] &lt; 0.1 dex having generally circular
  orbits (e &lt; 0.15), while the median eccentricity increases rapidly
  for more [α/Fe] enhanced stellar populations up to e ∼ 0.35. These
  [α/Fe] enhanced populations have guiding radii consistent with origins
  in the inner Galaxy. Of the stars with metallicities much higher than
  the local interstellar medium ([Fe/H] &gt; 0.1 dex), we find that
  the majority have e &lt; 0.2 and are likely observed in the solar
  neighbourhood through churning/migration rather than blurring effects,
  as the epicyclic motion for these stars is not large enough to reach
  the radii at which they were likely born based on their metallicity.

---------------------------------------------------------
Title: The Stagger-grid: Synthetic stellar spectra and broad-band
    photometry
Authors: Chiavassa, Andrea; Casagrande, L.; Collet, R.; Magic, Z.;
   Bigot, L.; Thévenin, F.; Asplund, M.
2020IAUGA..30..463C    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Chemical evolution of the Galactic bulge as traced by
    microlensed dwarf and subgiant stars. VII. Lithium
Authors: Bensby, T.; Feltzing, S.; Yee, J. C.; Johnson, J. A.; Gould,
   A.; Asplund, M.; Meléndez, J.; Lucatello, S.
2020A&A...634A.130B    Altcode: 2020arXiv200106222B
  Lithium abundances are presented for 91 dwarf and subgiant stars in
  the Galactic bulge. The analysis is based on line synthesis of the
  <SUP>7</SUP>Li line at 6707 Å in high-resolution spectra obtained
  during gravitational microlensing events, when the brightnesses of the
  targets were highly magnified. Our main finding is that bulge stars
  at sub-solar metallicities that are older than about eight billion
  years do not show any sign of Li production; that is, the Li trend with
  metallicity is flat or even slightly declining. This indicates that no
  lithium was produced during the first few billion years in the history
  of the bulge. This finding is essentially identical to what is seen for
  the (old) thick disk stars in the solar neighbourhood, and adds another
  piece of evidence for a tight connection between the metal-poor bulge
  and the Galactic thick disk. For the bulge stars younger than about
  eight billion years, the sample contains a group of stars at very
  high metallicities at [Fe/H] ≈ +0.4 that have lithium abundances in
  the range A(Li) = 2.6 - 2.8. In the solar neighbourhood the lithium
  abundances have been found to peak at A(Li) ≈ 3.3 at [Fe/H] ≈ +0.1
  and then decrease by 0.4-0.5 dex when reaching [Fe/H] ≈ +0.4. The
  few bulge stars that we have at these metallicities seem to support
  this declining A(Li) trend. This could indeed support the recent claim
  that the low A(Li) abundances at the highest metallicities seen in
  the solar neighbourhood could be due to stars from the inner disk, or
  the bulge region, that have migrated to the solar neighbourhood. <P
  />Table 1 is only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr/">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/634/A130">http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/634/A130</A>
  <P />Based on data obtained with the European Southern Observatory
  telescopes (Proposal ID:s 87.B-0600, 88.B-0349, 89.B-0047, 90.B-0204,
  91.B-0289, 92.B-0626, 93.B-0700), and the Magellan Clay telescope at
  the Las Campanas observatory.

---------------------------------------------------------
Title: The GALAH survey: temporal chemical enrichment of the
    galactic disc
Authors: Lin, Jane; Asplund, Martin; Ting, Yuan-Sen; Casagrande,
   Luca; Buder, Sven; Bland-Hawthorn, Joss; Casey, Andrew R.; De Silva,
   Gayandhi M.; D'Orazi, Valentina; Freeman, Ken C.; Kos, Janez; Lind,
   K.; Martell, Sarah L.; Sharma, Sanjib; Simpson, Jeffrey D.; Zwitter,
   Tomaž; Zucker, Daniel B.; Minchev, Ivan; Čotar, Klemen; Hayden,
   Michael; Horner, Jonti; Lewis, Geraint F.; Nordlander, Thomas; Wyse,
   Rosemary F. G.; Žerjal, Maruša
2020MNRAS.491.2043L    Altcode: 2019arXiv191105221L; 2019MNRAS.tmp.2724L
  We present isochrone ages and initial bulk metallicities ([Fe/H]_{bulk},
  by accounting for diffusion) of 163 722 stars from the GALAH Data
  Release 2, mainly composed of main-sequence turn-off stars and
  subgiants (7000 K&gt; T_{ eff}&gt; 4000 K and log g&gt;3 dex). The local
  age-metallicity relationship (AMR) is nearly flat but with significant
  scatter at all ages; the scatter is even higher when considering the
  observed surface abundances. After correcting for selection effects,
  the AMR appears to have intrinsic structures indicative of two star
  formation events, which we speculate are connected to the thin and
  thick discs in the solar neighbourhood. We also present abundance
  ratio trends for 16 elements as a function of age, across different
  [Fe/H]_{bulk} bins. In general, we find the trends in terms of [X/Fe]
  versus age from our far larger sample to be compatible with studies
  based on small (∼100 stars) samples of solar twins, but we now extend
  them to both sub- and supersolar metallicities. The α-elements show
  differing behaviour: the hydrostatic α-elements O and Mg show a steady
  decline with time for all metallicities, while the explosive α-elements
  Si, Ca, and Ti are nearly constant during the thin-disc epoch (ages
  ≲ 12 Gyr). The s-process elements Y and Ba show increasing [X/Fe]
  with time while the r-process element Eu has the opposite trend,
  thus favouring a primary production from sources with a short time
  delay such as core-collapse supernovae over long-delay events such as
  neutron star mergers.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Lithium abundances in microlensed
    bulge dwarfs (Bensby+, 2020)
Authors: Bensby, T.; Feltzing, S.; Yee, J.; Johnson, J. A.; Gould,
   A.; Asplund, M.; Melendez, J.; Lucatello, S.
2020yCat..36340130B    Altcode:
  We perform a detailed analysis of Li in 91 microlensed dwarf stars in
  the Galactic bulge. Li abundances were determined through spectral line
  synthesis of the Li feature at 670.8 nm. The stellar sample traces
  the evolution of the Galactic bulge, and is the same as previously
  analysed by Bensby et al. (2017A&amp;A...605A..89B, Cat. J/A+A/605/A89)
  where stellar parameters and ages were taken from. <P />For each star we
  give the NLTE corrected Li abundance, the applied NLTE correction, and
  uncertainties in the form of NLTE corrected Li abundances based on the
  same analysis but increasing and decreasing the effective temperatures
  with their uncertainties. 22 stars have "good" Li abundances (flag=0
  in Flag column), and 69 stars have upper Li upper limits (flag=1 in
  Flag column). The uncertainties are not given for the stars with Li
  upper limit abundances <P />(1 data file).

---------------------------------------------------------
Title: The GALAH Survey: Chemically tagging the Fimbulthul stream
    to the globular cluster ω Centauri
Authors: Simpson, Jeffrey D.; Martell, Sarah L.; Da Costa, Gary;
   Horner, Jonathan; Wyse, Rosemary F. G.; Ting, Yuan-Sen; Asplund,
   Martin; Bland-Hawthorn, Joss; Buder, Sven; De Silva, Gayandhi M.;
   Freeman, Ken C.; Kos, Janez; Lewis, Geraint F.; Lind, Karin; Sharma,
   Sanjib; Zucker, Daniel B.; Zwitter, Tomaž; Čotar, Klemen; Cottrell,
   Peter L.; Nordlander, Thomas
2020MNRAS.491.3374S    Altcode: 2019arXiv191101548S; 2019MNRAS.tmp.2703S
  Using kinematics from Gaia and the large elemental abundance space
  of the second data release of the GALAH survey, we identify two new
  members of the Fimbulthul stellar stream, and chemically tag them to
  massive, multimetallic globular cluster ω Centauri. Recent analysis
  of the second data release of Gaia had revealed the Fimbulthul stellar
  stream in the halo of the Milky Way. It had been proposed that the
  stream is associated with the ω Cen, but this proposition relied
  exclusively upon the kinematics and metallicities of the stars to
  make the association. In this work, we find our two new members of the
  stream to be metal-poor stars that are enhanced in sodium and aluminium,
  typical of second population globular cluster stars, but not otherwise
  seen in field stars. Furthermore, the stars share the s-process
  abundance pattern seen in ω Cen, which is rare in field stars. Apart
  from one star within 1.5 deg of ω Cen, we find no other stars observed
  by GALAH spatially near ω Cen or the Fimbulthul stream that could be
  kinematically and chemically linked to the cluster. Chemically tagging
  stars in the Fimbulthul stream to ω Cen confirms the earlier work,
  and further links this tidal feature in the Milky Way halo to ω Cen.

---------------------------------------------------------
Title: The K2-HERMES Survey: age and metallicity of the thick disc
Authors: Sharma, Sanjib; Stello, Dennis; Bland-Hawthorn, Joss;
   Hayden, Michael R.; Zinn, Joel C.; Kallinger, Thomas; Hon, Marc;
   Asplund, Martin; Buder, Sven; De Silva, Gayandhi M.; D'Orazi,
   Valentina; Freeman, Ken; Kos, Janez; Lewis, Geraint F.; Lin, Jane;
   Lind, Karin; Martell, Sarah; Simpson, Jeffrey D.; Wittenmyer, Rob A.;
   Zucker, Daniel B.; Zwitter, Tomaz; Bedding, Timothy R.; Chen, Boquan;
   Cotar, Klemen; Esdaile, James; Horner, Jonathan; Huber, Daniel; Kafle,
   Prajwal R.; Khanna, Shourya; Li, Tanda; Ting, Yuan-Sen; Nataf, David
   M.; Nordlander, Thomas; Saadon, Mohd Hafiz Mohd; Traven, Gregor;
   Wright, Duncan; Wyse, Rosemary F. G.
2019MNRAS.490.5335S    Altcode: 2019MNRAS.tmp.2471S; 2019arXiv190412444S
  Asteroseismology is a promising tool to study Galactic structure and
  evolution because it can probe the ages of stars. Earlier attempts
  comparing seismic data from the Kepler satellite with predictions from
  Galaxy models found that the models predicted more low-mass stars
  compared to the observed distribution of masses. It was unclear if
  the mismatch was due to inaccuracies in the Galactic models, or the
  unknown aspects of the selection function of the stars. Using new data
  from the K2 mission, which has a well-defined selection function, we
  find that an old metal-poor thick disc, as used in previous Galactic
  models, is incompatible with the asteroseismic information. We use an
  importance-sampling framework, which takes the selection function into
  account, to fit for the metallicities of a population synthesis model
  using spectroscopic data. We show that spectroscopic measurements of
  [Fe/H] and [α/Fe] elemental abundances from the GALAH survey indicate
  a mean metallicity of log (Z/Z<SUB>⊙</SUB>) = -0.16 for the thick
  disc. Here Z is the effective solar-scaled metallicity, which is a
  function of [Fe/H] and [α/Fe]. With the revised disc metallicities,
  for the first time, the theoretically predicted distribution of seismic
  masses show excellent agreement with the observed distribution of
  masses. This indirectly verifies that the asteroseismic mass scaling
  relation is good to within five per cent. Assuming the asteroseismic
  scaling relations are correct, we estimate the mean age of the thick
  disc to be about 10 Gyr, in agreement with the traditional idea of an
  old α-enhanced thick disc.

---------------------------------------------------------
Title: The GALAH survey and Gaia DR2: Linking ridges, arches, and
    vertical waves in the kinematics of the Milky Way
Authors: Khanna, Shourya; Sharma, Sanjib; Tepper-Garcia, Thor;
   Bland-Hawthorn, Joss; Hayden, Michael; Asplund, Martin; Buder, Sven;
   Chen, Boquan; De Silva, Gayandhi M.; Freeman, Ken C.; Kos, Janez;
   Lewis, Geraint F.; Lin, Jane; Martell, Sarah L.; Simpson, Jeffrey D.;
   Nordlander, Thomas; Stello, Dennis; Ting, Yuan-Sen; Zucker, Daniel B.;
   Zwitter, Tomaž
2019MNRAS.489.4962K    Altcode: 2019MNRAS.tmp.2122K; 2019arXiv190210113K
  Gaia DR2 has revealed new small-scale and large-scale patterns in
  the phase-space distribution of stars in the Milky Way. In cylindrical
  Galactic coordinates (R,φ ,z), ridge-like structures can be seen in the
  (R,V_φ) plane and asymmetric arch-like structures in the (V_R,V_φ)
  plane. We show that the ridges are also clearly present when the third
  dimension of the (R,V_φ) plane is represented by &lt; z &gt;, &lt;
  V_z &gt;, &lt; V_R &gt;, &lt;[Fe/H]&gt;, and &lt; [α /Fe]&gt;. The
  maps suggest that stars along the ridges lie preferentially close to
  the Galactic mid-plane (|z|&lt; 0.2 kpc), and have metallicity and α
  elemental abundance similar to that of the Sun. We show that phase
  mixing of disrupting spiral arms can generate both the ridges and
  the arches. It also generates discrete groupings in orbital energy
  - the ridges and arches are simply surfaces of constant energy. We
  identify eight distinct ridges in the Gaia DR2 data: six of them have
  constant energy while two have constant angular momentum. Given that
  the signature is strongest for stars close to the plane, the presence
  of ridges in &lt; z &gt; and &lt; V_z &gt; suggests a coupling between
  planar and vertical directions. We demonstrate, using N-body simulations
  that such coupling can be generated both in isolated discs and in discs
  perturbed by an orbiting satellite like the Sagittarius dwarf galaxy.

---------------------------------------------------------
Title: Discovery of a 21 Myr old stellar population in the Orion
    complex⋆
Authors: Kos, Janez; Bland-Hawthorn, Joss; Asplund, Martin; Buder,
   Sven; Lewis, Geraint F.; Lin, Jane; Martell, Sarah L.; Ness, Melissa
   K.; Sharma, Sanjib; De Silva, Gayandhi M.; Simpson, Jeffrey D.;
   Zucker, Daniel B.; Zwitter, Tomaž; Čotar, Klemen; Spina, Lorenzo
2019A&A...631A.166K    Altcode: 2018arXiv181111762K
  Context. The Orion complex is arguably the most studied star-forming
  region in the Galaxy. While stars are still being born in the
  Orion nebula, the oldest part was believed to be no more than
  13 Myr old. <BR /> Aims: In order to study the full hierarchy of
  star formation across the Orion complex, we perform a clustering
  analysis of the Ori OB1a region using new stellar surveys and derive
  robust ages for each identified stellar aggregate. <BR /> Methods:
  We use Gaia DR2 parameters supplemented with radial velocities from
  the GALAH and APOGEE surveys to perform clustering of the Ori OB1a
  association. Five overdensities are resolved in a six-dimensional
  parameter space (positions, distance, proper motions, and radial
  velocity). Most correspond to previously known structures (ASCC 16,
  25 Orionis, ASCC 20, ASCC 21). We use Gaia DR2, Pan-STARRS1 and 2MASS
  photometry to fit isochrones to the colour-magnitude diagrams of the
  identified clusters. The ages of the clusters can thus be measured
  with ∼10% precision. <BR /> Results: While four of the clusters
  have ages between 11 and 13 Myr, the ASCC 20 cluster stands out at an
  age of 21 ± 3 Myr. This is significantly greater than the age of any
  previously known component of the Orion complex. To some degree, all
  clusters overlap in at least one of the six phase-space dimensions. <BR
  /> Conclusions: We argue that the formation history of the Orion
  complex, and its relation to the Gould belt, must be reconsidered. A
  significant challenge in reconstructing the history of the Ori OB1a
  association is to understand the impact of the newly discovered 21
  Myr old population on the younger parts of the complex, including
  their formation. <P />Movie associated to Fig. 3 is available at <A
  href="https://www.aanda.org/10.1051/0004-6361/201834710/olm">https://www.aanda.org</A>
  <P />Tables B.1-B.5 are only available at the CDS via anonymous ftp to
  <A href="http://cdsarc.u-strasbg.fr/">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/631/A166">http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/631/A166</A>

---------------------------------------------------------
Title: The SkyMapper DR1.1 search for extremely metal-poor stars
Authors: Da Costa, G. S.; Bessell, M. S.; Mackey, A. D.; Nordlander,
   T.; Asplund, M.; Casey, A. R.; Frebel, A.; Lind, K.; Marino, A. F.;
   Murphy, S. J.; Norris, J. E.; Schmidt, B. P.; Yong, D.
2019MNRAS.489.5900D    Altcode: 2019arXiv190906227D; 2019MNRAS.tmp.2195D
  We present and discuss the results of a search for extremely metal-poor
  stars based on photometry from data release DR1.1 of the SkyMapper
  imaging survey of the southern sky. In particular, we outline our
  photometric selection procedures and describe the low-resolution (R ≈
  3000) spectroscopic follow-up observations that are used to provide
  estimates of effective temperature, surface gravity, and metallicity
  ([Fe/H]) for the candidates. The selection process is very efficient:
  of the 2618 candidates with low-resolution spectra that have photometric
  metallicity estimates less than or equal to -2.0, 41 per cent have
  [Fe/H] ≤ -2.75 and only approximately seven per cent have [Fe/H] &gt;
  -2.0 dex. The most metal-poor candidate in the sample has [Fe/H] &lt;
  -4.75 and is notably carbon rich. Except at the lowest metallicities
  ([Fe/H] &lt; -4), the stars observed spectroscopically are dominated
  by a `carbon-normal' population with [C/Fe]<SUB>1D, LTE</SUB> ≤ +1
  dex. Consideration of the A(C)<SUB>1D, LTE</SUB> versus [Fe/H]<SUB>1D,
  LTE</SUB> diagram suggests that the current selection process is
  strongly biased against stars with A(C)<SUB>1D, LTE</SUB> &gt; 7.3
  (predominantly CEMP-s) while any bias against stars with A(C)<SUB>1D,
  LTE</SUB> &lt; 7.3 and [C/Fe]<SUB>1D</SUB>,<SUB>LTE</SUB> &gt;
  +1 (predominantly CEMP-no) is not readily quantifiable given the
  uncertainty in the SkyMapper v-band DR1.1 photometry. We find that
  the metallicity distribution function of the observed sample has a
  power-law slope of Δ(Log N)/Δ[Fe/H] = 1.5 ± 0.1 dex per dex for
  -4.0 ≤ [Fe/H] ≤ -2.75, but appears to drop abruptly at [Fe/H]
  ≈ -4.2, in line with previous studies.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Members of 5 cluster in Ori OB1a
    association (Kos+, 2019)
Authors: Kos, J.; Bland-Hawthorn, J.; Asplund, M.; Buder, S.; Lewis,
   G. F.; Lin, J.; Martell, S. L.; Ness, M. K.; Sharma, S.; de Silva,
   G. M.; Simpson, J. D.; Zucker, D. B.; Zwitter, T.; Cotar, K.; Spina, L.
2019yCat..36310166K    Altcode:
  The Gaia DR2 parameters supplemented with radial velocities from the
  GALAH and APOGEE surveys are used to perform clustering of the Ori
  OB1a association. <P />Table 1 contains the properties of 5 identified
  clusters clusters, including ages (derived using Gaia DR2, Pan-STARRS1
  and 2MASS photometry to fit isochrones to their colour-magnitude
  diagrams). Tableb 1 - tableb 5 contain the identified members of the
  different clusters. <P />(6 data files).

---------------------------------------------------------
Title: The lowest detected stellar Fe abundance: the halo star SMSS
    J160540.18-144323.1
Authors: Nordlander, T.; Bessell, M. S.; Da Costa, G. S.; Mackey,
   A. D.; Asplund, M.; Casey, A. R.; Chiti, A.; Ezzeddine, R.; Frebel,
   A.; Lind, K.; Marino, A. F.; Murphy, S. J.; Norris, J. E.; Schmidt,
   B. P.; Yong, D.
2019MNRAS.488L.109N    Altcode: 2019arXiv190407471N; 2019MNRAS.tmpL.112N
  We report the discovery of SMSS J160540.18-144323.1, a new ultra
  metal-poor halo star discovered with the SkyMapper telescope. We
  measure [{Fe}/{H}]= -6.2 ± 0.2 (1D LTE), the lowest ever detected
  abundance of iron in a star. The star is strongly carbon-enhanced,
  [{C}/{Fe}] = 3.9 ± 0.2, while other abundances are compatible with
  an α-enhanced solar-like pattern with [{Ca}/{Fe}] = 0.4 ± 0.2,
  [{Mg}/{Fe}] = 0.6 ± 0.2, [{Ti}/{Fe}] = 0.8 ± 0.2, and no significant
  s- or r-process enrichment, [{Sr}/{Fe}] &lt; 0.2 and [{Ba}/{Fe}] &lt;
  1.0 (3σ limits). Population III stars exploding as fallback supernovae
  may explain both the strong carbon enhancement and the apparent lack of
  enhancement of odd-Z and neutron-capture element abundances. Grids of
  supernova models computed for metal-free progenitor stars yield good
  matches for stars of about 10 M_⊙ imparting a low kinetic energy on
  the supernova ejecta, while models for stars more massive than roughly
  20 M_⊙ are incompatible with the observed abundance pattern.

---------------------------------------------------------
Title: The COMBS survey - I. Chemical origins of metal-poor stars
    in the Galactic bulge
Authors: Lucey, Madeline; Hawkins, Keith; Ness, Melissa; Asplund,
   Martin; Bensby, Thomas; Casagrande, Luca; Feltzing, Sofia; Freeman,
   Kenneth C.; Kobayashi, Chiaki; Marino, Anna F.
2019MNRAS.488.2283L    Altcode: 2019arXiv190311615L; 2019MNRAS.tmp.1795L
  Chemistry and kinematic studies can determine the origins of stellar
  population across the Milky Way. The metallicity distribution function
  of the bulge indicates that it comprises multiple populations, the
  more metal-poor end of which is particularly poorly understood. It
  is currently unknown if metal-poor bulge stars ([Fe/H] &lt;-1 dex)
  are part of the stellar halo in the inner most region, or a distinct
  bulge population or a combination of these. Cosmological simulations
  also indicate that the metal-poor bulge stars may be the oldest stars in
  the Galaxy. In this study, we successfully target metal-poor bulge stars
  selected using SkyMapper photometry. We determine the stellar parameters
  of 26 stars and their elemental abundances for 22 elements using R∼
  47 000 VLT/UVES spectra and contrast their elemental properties with
  that of other Galactic stellar populations. We find that the elemental
  abundances we derive for our metal-poor bulge stars have lower overall
  scatter than typically found in the halo. This indicates that these
  stars may be a distinct population confined to the bulge. If these stars
  are, alternatively, part of the innermost distribution of the halo, this
  indicates that the halo is more chemically homogeneous at small Galactic
  radii than at large radii. We also find two stars whose chemistry is
  consistent with second-generation globular cluster stars. This paper
  is the first part of the Chemical Origins of Metal-poor Bulge Stars
  (COMBS) survey that will chemodynamically characterize the metal-poor
  bulge population.

---------------------------------------------------------
Title: The GALAH survey: unresolved triple Sun-like stars discovered
    by the Gaia mission
Authors: Čotar, Klemen; Zwitter, Tomaž; Traven, Gregor; Kos, Janez;
   Asplund, Martin; Bland-Hawthorn, Joss; Buder, Sven; D'Orazi, Valentina;
   de Silva, Gayandhi M.; Lin, Jane; Martell, Sarah L.; Sharma, Sanjib;
   Simpson, Jeffrey D.; Zucker, Daniel B.; Horner, Jonathan; Lewis,
   Geraint F.; Nordlander, Thomas; Ting, Yuan-Sen; Wittenmyer, Rob A.;
   Galah Collaboration
2019MNRAS.487.2474C    Altcode: 2019MNRAS.tmp.1341C; 2019arXiv190404841C
  The latest Gaia data release enables us to accurately identify stars
  that are more luminous than would be expected on the basis of their
  spectral type and distance. During an investigation of the 329 best
  solar twin candidates uncovered among the spectra acquired by the
  GALAH survey, we identified 64 such overluminous stars. In order
  to investigate their exact composition, we developed a data-driven
  methodology that can generate a synthetic photometric signature
  and spectrum of a single star. By combining multiple such synthetic
  stars into an unresolved binary or triple system and comparing the
  results to the actual photometric and spectroscopic observations,
  we uncovered 6 definitive triple stellar system candidates and an
  additional 14 potential candidates whose combined spectrum mimics
  the solar spectrum. Considering the volume correction factor for a
  magnitude-limited survey, the fraction of probable unresolved triple
  stars with long orbital periods is ∼2 per cent. Possible orbital
  configurations of the candidates were investigated using the selection
  and observational limits. To validate the discovered multiplicity
  fraction, the same procedure was used to evaluate the multiplicity
  fraction of other stellar types.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Abundances for 79 Sun-like stars
    within 100pc (Bedell+, 2018)
Authors: Bedell, M.; Bean, J. L.; Melendez, J.; Spina, L.; Ramirez,
   I.; Asplund, M.; Alves-Brito, A.; Dos Santos, L.; Dreizler, S.; Yong,
   D.; Monroe, T.; Casagrande, L.
2019yCat..18650068B    Altcode:
  To achieve sufficient signal-to-noise for high-precision abundance
  work, we stacked &gt;=50 observations for each star. All spectra were
  taken with the High Accuracy Radial velocity Planet Searcher (HARPS)
  spectrograph on the 3.6m telescope of the European Southern Observatory
  (ESO), located at La Silla Observatory in Chile; with resolving power
  R=115000 and wavelength coverage between 378-691nm. A majority of
  the selected sample were observed by us in the course of a large ESO
  observing program on HARPS (Melendez+ 2015Msngr.161...28M). Other stars
  had a sufficient number of publicly available spectra in the online
  ESO Science Archive Facility. <P />The solar reference spectrum used
  in this work was created by combining multiple exposures of sunlight
  reflected from the asteroid Vesta. It was continuum-normalized in the
  same manner as the target spectra and has S/N~1300/pix at 600nm. <P
  />Spectra previously obtained with the MIKE spectrograph and analyzed
  in Ramirez+ (2014A&amp;A...572A..48R) were also used in some parts
  of this analysis. These spectra have S/N~400/pix at 600nm, resolution
  R=83000-65000 (on blue/red CCDs), and wavelength coverage between 320
  and 1000nm. <P />(2 data files).

---------------------------------------------------------
Title: HERBS II: Detailed chemical compositions of Galactic bulge
    stars
Authors: Duong, L.; Asplund, M.; Nataf, D. M.; Freeman, K. C.; Ness, M.
2019MNRAS.486.5349D    Altcode: 2019MNRAS.tmp.1135D; 2019arXiv190402261D
  This work explores the detailed chemistry of the Milky Way bulge using
  the HERMES spectrograph on the Anglo-Australian Telescope. Here,
  we present the abundance ratios of 13 elements for 832 red giant
  branch and clump stars along the minor bulge axis at latitudes b =
  -10<SUP>○</SUP>, - 7.5<SUP>○</SUP>, and -5<SUP>○</SUP>. Our
  results show that none of the abundance ratios vary significantly with
  latitude. We also observe disc-like [Na/Fe] abundance ratios, which
  indicate that the bulge does not contain helium-enhanced populations
  as observed in some globular clusters. Helium enhancement is therefore
  not the likely explanation for the double red-clump observed in the
  bulge. We confirm that bulge stars mostly follow abundance trends
  observed in the disc. However, this similarity is not confirmed
  across all elements and metallicity regimes. The more metal-poor
  bulge population at [Fe/H] ≲ - 0.8 is enhanced in the elements
  associated with core collapse supernovae (SNeII). In addition, the
  [La/Eu] abundance ratio suggests higher r-process contribution, and
  likely higher star formation in the bulge compared to the disc. This
  highlights the complex evolution in the bulge, which should be
  investigated further, both in terms of modelling; and with additional
  observations of the inner Galaxy.

---------------------------------------------------------
Title: Chemical (in)homogeneity and atomic diffusion in the open
    cluster M 67
Authors: Liu, F.; Asplund, M.; Yong, D.; Feltzing, S.; Dotter, A.;
   Meléndez, J.; Ramírez, I.
2019A&A...627A.117L    Altcode: 2019arXiv190211008L
  Context. The benchmark open cluster M 67 is known to have solar
  metallicity and an age similar to that of the Sun. It thus provides
  us with a great opportunity to study the properties of solar twins,
  as well as the evolution of Sun-like stars. <BR /> Aims: Previous
  spectroscopic studies of M 67 reported possible subtle changes in
  stellar surface abundances throughout the stellar evolutionary phase,
  namely the effect of atomic diffusion. In this study we attempt to
  confirm and quantify more precisely the effect of atomic diffusion,
  and to explore the level of chemical (in)homogeneity in M 67. <BR />
  Methods: We presented a strictly line-by-line differential chemical
  abundance analysis of two groups of stars in M 67: three turn-off
  stars and three subgiants. Stellar atmospheric parameters and elemental
  abundances were obtained with very high precision using the Keck/HIRES
  spectra. <BR /> Results: The subgiants in our sample show negligible
  abundance variations (≤0.02 dex), which implies that M 67 was born
  chemically homogeneous. We note that there is a significant abundance
  difference ( 0.1-0.2 dex) between subgiants and turn-off stars, which
  can be interpreted as the signature of atomic diffusion. Qualitatively
  stellar models with diffusion agree with the observed abundance
  results. Some turn-off stars do not follow the general pattern, which
  suggests that in some cases diffusion can be inhibited, or they might
  have undergone some sort of mixing event related to planets. <BR
  /> Conclusions: Our results pose additional challenges for chemical
  tagging when using turn-off stars. In particular, the effects of atomic
  diffusion, which could be as large as 0.1-0.2 dex, must be taken into
  account in order for chemical tagging to be successfully applied. <P
  />Table A.1 is only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/627/A117">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/627/A117</A>The
  data presented here were obtained at the W.M. Keck Observatory, which is
  operated as a scientific partnership among the California Institute of
  Technology, the University of California, and the National Aeronautics
  and Space Administration. The Observatory was made possible by the
  generous financial support of the W.M. Keck Foundation.

---------------------------------------------------------
Title: The Amplitude of Solar p-mode Oscillations from
    Three-dimensional Convection Simulations
Authors: Zhou, Yixiao; Asplund, Martin; Collet, Remo
2019ApJ...880...13Z    Altcode: 2019arXiv190513397Z
  The amplitude of solar p-mode oscillations is governed by stochastic
  excitation and mode damping, both of which take place in the surface
  convection zone. However, the time-dependent, turbulent nature of
  convection makes it difficult to self-consistently study excitation
  and damping processes through the use of traditional one-dimensional
  (1D) hydrostatic models. To this end, we carried out ab initio
  three-dimensional (3D), hydrodynamical numerical simulations of the
  solar atmosphere to investigate how p-modes are driven and dissipated
  in the Sun. The description of surface convection in the simulations
  is free from the tunable parameters typically adopted in traditional
  1D models. Mode excitation and damping rates are computed based on
  analytical expressions whose ingredients are evaluated directly from the
  3D model. With excitation and damping rates both available, we estimate
  the theoretical oscillation amplitude and frequency of maximum power,
  {ν }<SUB>\max </SUB>, for the Sun. We compare our numerical results
  with helioseismic observations, finding encouraging agreement between
  the two. The numerical method presented here provides a novel way to
  investigate the physical processes responsible for mode driving and
  damping, and should be valid for all solar-type oscillating stars.

---------------------------------------------------------
Title: HERBS I: Metallicity and alpha enhancement along the Galactic
    bulge minor axis
Authors: Duong, L.; Asplund, M.; Nataf, D. M.; Freeman, K. C.; Ness,
   M.; Howes, L. M.
2019MNRAS.486.3586D    Altcode: 2019arXiv190309706D; 2019MNRAS.tmp.1069D
  To better understand the origin and evolution of the Milky Way bulge,
  we have conducted a survey of bulge red giant branch and clump stars
  using the High Efficiency and Resolution Multi-Element Spectrograph
  on the Anglo-Australian Telescope. We targeted ARGOS survey stars
  with predetermined bulge memberships, covering the full metallicity
  distribution function. The spectra have signal-to-noise ratios
  comparable to, and were analysed using the same methods as the GALAH
  survey. In this work, we present the survey design, stellar parameters,
  distribution of metallicity, and alpha-element abundances along the
  minor bulge axis at latitudes b = -10°, - 7.5°, and -5°. Our analysis
  of ARGOS stars indicates that the centroids of ARGOS metallicity
  components should be located ≈0.09 dex closer together. The vertical
  distribution of α-element abundances is consistent with the varying
  contributions of the different metallicity components. Closer to the
  plane, alpha abundance ratios are lower as the metal-rich population
  dominates. At higher latitudes, the alpha abundance ratios increase as
  the number of metal-poor stars increases. However, we find that the
  trend of alpha-enrichment with respect to metallicity is independent
  of latitude. Comparison of our results with those of GALAH DR2 revealed
  that for [Fe/H] ≈ -0.8, the bulge shares the same abundance trend as
  the high-α disc population. However, the metal-poor bulge population
  ([Fe/H] ≲ -0.8) show enhanced alpha abundance ratios compared to the
  disc/halo. These observations point to fairly rapid chemical evolution
  in the bulge, and that the metal-poor bulge population does not share
  the same similarity with the disc as the more metal-rich populations.

---------------------------------------------------------
Title: VizieR Online Data Catalog: GALAH unresolved triple Sun-like
    star (Cotar+, 2019)
Authors: Cotar, K.; Zwitter, T.; Traven, G.; Kos, J.; Asplund, M.;
   Bland-Hawthorn, J.; Buder, S.; Dorazi, V.; de Silva, G. M.; Lin, J.;
   Martell, S. L.; Sharma, S.; Simpson, J. D.; Zucker, D. B.; Horner,
   J.; Lewis, G. F.; Nordlander, T.; Ting, Y. -S.; Wittenmyer, R. A.;
   GALAH Collaboration
2019yCat..74872474C    Altcode:
  We provide a list of 329 Sun-like stars that were analysed for their
  possible multiplicity based on their absolute magnitude and distance
  derived from Gaia DR2 data. The GALAH proprietary spectra are used to
  confirm their similarity with solar spectrum and to determine [Fe/H]
  of the determined systems. We uncovered 20 candidates for unresolved
  triple stellar systems that have to analysed with other approaches to
  confirm their multiple nature. <P />(1 data file).

---------------------------------------------------------
Title: VizieR Online Data Catalog: Equivalent widths for six M67 stars
    (Liu+, 2019)
Authors: Liu, F.; Asplund, M.; Yong, D.; Feltzing, S.; Dotter, A.;
   Melendez, J.; Ramirez, I.
2019yCat..36270117L    Altcode:
  Atomic line data, as well as the measured equivalent widths, adopted
  for our analysis. <P />(2 data files).

---------------------------------------------------------
Title: Keck HIRES spectroscopy of SkyMapper commissioning survey
    candidate extremely metal-poor stars
Authors: Marino, A. F.; Da Costa, G. S.; Casey, A. R.; Asplund, M.;
   Bessell, M. S.; Frebel, A.; Keller, S. C.; Lind, K.; Mackey, A. D.;
   Murphy, S. J.; Nordlander, T.; Norris, J. E.; Schmidt, B. P.; Yong, D.
2019MNRAS.485.5153M    Altcode: 2019arXiv190210611M; 2019MNRAS.tmp..627M
  We present results from the analysis of high-resolution spectra obtained
  with the Keck HIRES spectrograph for a sample of 17 candidate extremely
  metal-poor (EMP) stars originally selected from commissioning data
  obtained with the SkyMapper telescope. Fourteen of the stars have
  not been observed previously at high dispersion. Three have [Fe/H]
  ≤ -3.0, while the remainder, with two more metal-rich exceptions,
  have -3.0 ≤ [Fe/H] ≤ -2.0 dex. Apart from Fe, we also derive
  abundances for the elements C, N, Na, Mg, Al, Si, Ca, Sc, Ti, Cr, Mn,
  Co, Ni, and Zn, and for n-capture elements Sr, Ba, and Eu. None of
  the current sample of stars is found to be carbon-rich. In general,
  our chemical abundances follow previous trends found in the literature,
  although we note that two of the most metal-poor stars show very low
  [Ba/Fe] (∼-1.7) coupled with low [Sr/Ba] (∼-0.3). Such stars are
  relatively rare in the Galactic halo. One further star, and possibly
  two others, meet the criteria for classification as a r-I star. This
  study, together with that of Jacobson et al. (2015), completes the
  outcomes of the SkyMapper commissioning data survey for EMP stars.

---------------------------------------------------------
Title: The GALAH survey and Gaia DR2: dissecting the stellar disc's
    phase space by age, action, chemistry, and location
Authors: Bland-Hawthorn, Joss; Sharma, Sanjib; Tepper-Garcia, Thor;
   Binney, James; Freeman, Ken C.; Hayden, Michael R.; Kos, Janez; De
   Silva, Gayandhi M.; Ellis, Simon; Lewis, Geraint F.; Asplund, Martin;
   Buder, Sven; Casey, Andrew R.; D'Orazi, Valentina; Duong, Ly; Khanna,
   Shourya; Lin, Jane; Lind, Karin; Martell, Sarah L.; Ness, Melissa
   K.; Simpson, Jeffrey D.; Zucker, Daniel B.; Zwitter, Tomaž; Kafle,
   Prajwal R.; Quillen, Alice C.; Ting, Yuan-Sen; Wyse, Rosemary F. G.
2019MNRAS.486.1167B    Altcode: 2018arXiv180902658B; 2019MNRAS.tmp..222B
  We use the second data releases of the European Space AgencyGaia
  astrometric survey and the high-resolution Galactic Archaeology with
  HERMES (GALAH) spectroscopic survey to analyse the structure of
  our Galaxy's disc components. With GALAH, we separate the α-rich
  and α-poor discs (with respect to Fe), which are superposed in
  both position and velocity space, and examine their distributions
  in action space. We study the distribution of stars in the zV<SUB>
  z</SUB> phase plane, for both V<SUB>ϕ</SUB> and V<SUB>R</SUB>, and
  recover the remarkable `phase spiral' discovered by Gaia. We identify
  the anticipated quadrupole signature in zV<SUB> z</SUB> of a tilted
  velocity ellipsoid for stars above and below the Galactic plane. By
  connecting our work with earlier studies, we show that the phase
  spiral is likely to extend well beyond the narrow solar neighbourhood
  cylinder in which it was found. The phase spiral is a signature of
  corrugated waves that propagate through the disc, and the associated
  non-equilibrium phase mixing. The radially asymmetric distribution
  of stars involved in the phase spiral reveals that the corrugation,
  which is mostly confined to the α-poor disc, grows in z-amplitude with
  increasing radius. We present new simulations of tidal disturbance
  of the Galactic disc by the Sagittarius (Sgr) dwarf. The effect on
  the zV<SUB> z</SUB> phase plane lasts {≳ } 2 Gyr, but a subsequent
  disc crossing wipes out the coherent structure. We find that the phase
  spiral was excited {≲ } 0.5 Gyr ago by an object like Sgr with total
  mass ∼3 × 10<SUP>10</SUP> M<SUB>⊙</SUB> (stripped down from ∼5
  × 10<SUP>10</SUP> M<SUB>⊙</SUB> when it first entered the halo)
  passing through the plane.

---------------------------------------------------------
Title: Constraining the evolution of stellar rotation using solar
    twins
Authors: Lorenzo-Oliveira, Diego; Meléndez, Jorge; Yana Galarza,
   Jhon; Ponte, Geisa; dos Santos, Leonardo A.; Spina, Lorenzo; Bedell,
   Megan; Ramírez, Iván; Bean, Jacob L.; Asplund, Martin
2019MNRAS.485L..68L    Altcode: 2019arXiv190302630L; 2019MNRAS.tmpL..40L
  The stellar rotation versus age relation is commonly considered a
  useful tool to derive reliable ages for Sun-like stars. However,
  in the light of Kepler data, the presence of apparently old and fast
  rotators that do not obey the usual gyrochronology relations led to
  the hypothesis of weakened magnetic breaking in some stars. In this
  letter, we constrain the solar rotation evolutionary track using solar
  twins. Predicted rotational periods as a function of mass, age, [Fe/H],
  and given critical Rossby number (Ro<SUB>crit</SUB>) were estimated for
  the entire rotational sample. Our analysis favours the smooth rotational
  evolution scenario and suggests that if the magnetic weakened breaking
  scenario takes place at all, it should arise after Ro<SUB>crit</SUB>
  ≳ 2.29 or ages ≳5.3 Gyr (at 95 per cent confidence level).

---------------------------------------------------------
Title: The Li-age correlation: the Sun is unusually Li deficient
    for its age
Authors: Carlos, M.; Meléndez, J.; Spina, L.; dos Santos, L. A.;
   Bedell, M.; Ramirez, I.; Asplund, M.; Bean, J. L.; Yong, D.; Yana
   Galarza, J.; Alves-Brito, A.
2019MNRAS.485.4052C    Altcode: 2019arXiv190302735C; 2019MNRAS.tmp..667C
  This work aims to examine in detail the depletion of lithium in solar
  twins to better constrain stellar evolution models and investigate its
  possible connection with exoplanets. We employ spectral synthesis in the
  region of the asymmetric 6707.75 Å Li I line for a sample of 77 stars
  plus the Sun. As in previous works based on a smaller sample of solar
  twins, we find a strong correlation between Li depletion and stellar
  age. In addition, for the first time we show that the Sun has the lowest
  Li abundance in comparison with solar twins at similar age (4.6 ± 0.5
  Gyr). We compare the lithium content with the condensation temperature
  slope for a subsample of the best solar twins and determine that the
  most lithium-depleted stars also have fewer refractory elements. We
  speculate whether the low lithium content in the Sun might be related
  to the particular configuration of our Solar system.

---------------------------------------------------------
Title: The Detailed Science Case for the Maunakea Spectroscopic
    Explorer, 2019 edition
Authors: The MSE Science Team; Babusiaux, Carine; Bergemann, Maria;
   Burgasser, Adam; Ellison, Sara; Haggard, Daryl; Huber, Daniel;
   Kaplinghat, Manoj; Li, Ting; Marshall, Jennifer; Martell, Sarah;
   McConnachie, Alan; Percival, Will; Robotham, Aaron; Shen, Yue;
   Thirupathi, Sivarani; Tran, Kim-Vy; Yeche, Christophe; Yong, David;
   Adibekyan, Vardan; Silva Aguirre, Victor; Angelou, George; Asplund,
   Martin; Balogh, Michael; Banerjee, Projjwal; Bannister, Michele;
   Barría, Daniela; Battaglia, Giuseppina; Bayo, Amelia; Bechtol,
   Keith; Beck, Paul G.; Beers, Timothy C.; Bellinger, Earl P.; Berg,
   Trystyn; Bestenlehner, Joachim M.; Bilicki, Maciej; Bitsch, Bertram;
   Bland-Hawthorn, Joss; Bolton, Adam S.; Boselli, Alessandro; Bovy,
   Jo; Bragaglia, Angela; Buzasi, Derek; Caffau, Elisabetta; Cami, Jan;
   Carleton, Timothy; Casagrande, Luca; Cassisi, Santi; Catelan, Márcio;
   Chang, Chihway; Cortese, Luca; Damjanov, Ivana; Davies, Luke J. M.;
   de Grijs, Richard; de Rosa, Gisella; Deason, Alis; di Matteo, Paola;
   Drlica-Wagner, Alex; Erkal, Denis; Escorza, Ana; Ferrarese, Laura;
   Fleming, Scott W.; Font-Ribera, Andreu; Freeman, Ken; Gänsicke,
   Boris T.; Gabdeev, Maksim; Gallagher, Sarah; Gandolfi, Davide; García,
   Rafael A.; Gaulme, Patrick; Geha, Marla; Gennaro, Mario; Gieles, Mark;
   Gilbert, Karoline; Gordon, Yjan; Goswami, Aruna; Greco, Johnny P.;
   Grillmair, Carl; Guiglion, Guillaume; Hénault-Brunet, Vincent;
   Hall, Patrick; Handler, Gerald; Hansen, Terese; Hathi, Nimish;
   Hatzidimitriou, Despina; Haywood, Misha; Hernández Santisteban,
   Juan V.; Hillenbrand, Lynne; Hopkins, Andrew M.; Howlett, Cullan;
   Hudson, Michael J.; Ibata, Rodrigo; Ilić, Dragana; Jablonka,
   Pascale; Ji, Alexander; Jiang, Linhua; Juneau, Stephanie; Karakas,
   Amanda; Karinkuzhi, Drisya; Kim, Stacy Y.; Kong, Xu; Konstantopoulos,
   Iraklis; Krogager, Jens-Kristian; Lagos, Claudia; Lallement, Rosine;
   Laporte, Chervin; Lebreton, Yveline; Lee, Khee-Gan; Lewis, Geraint F.;
   Lianou, Sophia; Liu, Xin; Lodieu, Nicolas; Loveday, Jon; Mészáros,
   Szabolcs; Makler, Martin; Mao, Yao-Yuan; Marchesini, Danilo; Martin,
   Nicolas; Mateo, Mario; Melis, Carl; Merle, Thibault; Miglio, Andrea;
   Gohar Mohammad, Faizan; Molaverdikhani, Karan; Monier, Richard;
   Morel, Thierry; Mosser, Benoit; Nataf, David; Necib, Lina; Neilson,
   Hilding R.; Newman, Jeffrey A.; Nierenberg, A. M.; Nord, Brian;
   Noterdaeme, Pasquier; O'Dea, Chris; Oshagh, Mahmoudreza; Pace, Andrew
   B.; Palanque-Delabrouille, Nathalie; Pandey, Gajendra; Parker, Laura
   C.; Pawlowski, Marcel S.; Peter, Annika H. G.; Petitjean, Patrick;
   Petric, Andreea; Placco, Vinicius; Popović, Luka Č.; Price-Whelan,
   Adrian M.; Prsa, Andrej; Ravindranath, Swara; Rich, R. Michael; Ruan,
   John; Rybizki, Jan; Sakari, Charli; Sanderson, Robyn E.; Schiavon,
   Ricardo; Schimd, Carlo; Serenelli, Aldo; Siebert, Arnaud; Siudek,
   Malgorzata; Smiljanic, Rodolfo; Smith, Daniel; Sobeck, Jennifer;
   Starkenburg, Else; Stello, Dennis; Szabó, Gyula M.; Szabo, Robert;
   Taylor, Matthew A.; Thanjavur, Karun; Thomas, Guillaume; Tollerud,
   Erik; Toonen, Silvia; Tremblay, Pier-Emmanuel; Tresse, Laurence;
   Tsantaki, Maria; Valentini, Marica; Van Eck, Sophie; Variu, Andrei;
   Venn, Kim; Villaver, Eva; Walker, Matthew G.; Wang, Yiping; Wang,
   Yuting; Wilson, Michael J.; Wright, Nicolas; Xu, Siyi; Yildiz,
   Mutlu; Zhang, Huawei; Zwintz, Konstanze; Anguiano, Borja; Bedell,
   Megan; Chaplin, William; Collet, Remo; Cuillandre, Jean-Charles;
   Duc, Pierre-Alain; Flagey, Nicolas; Hermes, JJ; Hill, Alexis;
   Kamath, Devika; Laychak, Mary Beth; Małek, Katarzyna; Marley, Mark;
   Sheinis, Andy; Simons, Doug; Sousa, Sérgio G.; Szeto, Kei; Ting,
   Yuan-Sen; Vegetti, Simona; Wells, Lisa; Babas, Ferdinand; Bauman,
   Steve; Bosselli, Alessandro; Côté, Pat; Colless, Matthew; Comparat,
   Johan; Courtois, Helene; Crampton, David; Croom, Scott; Davies, Luke;
   de Grijs, Richard; Denny, Kelly; Devost, Daniel; di Matteo, Paola;
   Driver, Simon; Fernandez-Lorenzo, Mirian; Guhathakurta, Raja; Han,
   Zhanwen; Higgs, Clare; Hill, Vanessa; Ho, Kevin; Hopkins, Andrew;
   Hudson, Mike; Ibata, Rodrigo; Isani, Sidik; Jarvis, Matt; Johnson,
   Andrew; Jullo, Eric; Kaiser, Nick; Kneib, Jean-Paul; Koda, Jun;
   Koshy, George; Mignot, Shan; Murowinski, Rick; Newman, Jeff; Nusser,
   Adi; Pancoast, Anna; Peng, Eric; Peroux, Celine; Pichon, Christophe;
   Poggianti, Bianca; Richard, Johan; Salmon, Derrick; Seibert, Arnaud;
   Shastri, Prajval; Smith, Dan; Sutaria, Firoza; Tao, Charling; Taylor,
   Edwar; Tully, Brent; van Waerbeke, Ludovic; Vermeulen, Tom; Walker,
   Matthew; Willis, Jon; Willot, Chris; Withington, Kanoa
2019arXiv190404907T    Altcode:
  (Abridged) The Maunakea Spectroscopic Explorer (MSE) is an end-to-end
  science platform for the design, execution and scientific exploitation
  of spectroscopic surveys. It will unveil the composition and dynamics
  of the faint Universe and impact nearly every field of astrophysics
  across all spatial scales, from individual stars to the largest scale
  structures in the Universe. Major pillars in the science program for MSE
  include (i) the ultimate Gaia follow-up facility for understanding the
  chemistry and dynamics of the distant Milky Way, including the outer
  disk and faint stellar halo at high spectral resolution (ii) galaxy
  formation and evolution at cosmic noon, via the type of revolutionary
  surveys that have occurred in the nearby Universe, but now conducted at
  the peak of the star formation history of the Universe (iii) derivation
  of the mass of the neutrino and insights into inflationary physics
  through a cosmological redshift survey that probes a large volume of
  the Universe with a high galaxy density. MSE is positioned to become
  a critical hub in the emerging international network of front-line
  astronomical facilities, with scientific capabilities that naturally
  complement and extend the scientific power of Gaia, the Large Synoptic
  Survey Telescope, the Square Kilometer Array, Euclid, WFIRST, the 30m
  telescopes and many more.

---------------------------------------------------------
Title: 3D non-LTE line formation of neutral carbon in the Sun
Authors: Amarsi, A. M.; Barklem, P. S.; Collet, R.; Grevesse, N.;
   Asplund, M.
2019A&A...624A.111A    Altcode: 2019arXiv190308838A
  Carbon abundances in late-type stars are important in a variety of
  astrophysical contexts. However C I lines, one of the main abundance
  diagnostics, are sensitive to departures from local thermodynamic
  equilibrium (LTE). We present a model atom for non-LTE analyses of C
  I lines, that uses a new, physically-motivated recipe for the rates
  of neutral hydrogen impact excitation. We analyse C I lines in the
  solar spectrum, employing a three-dimensional (3D) hydrodynamic
  model solar atmosphere and 3D non-LTE radiative transfer. We find
  negative non-LTE abundance corrections for C I lines in the solar
  photosphere, in accordance with previous studies, reaching up to
  around 0.1 dex in the disk-integrated flux. We also present the first
  fully consistent 3D non-LTE solar carbon abundance determination:
  we infer log ɛ<SUB>C</SUB> = 8.44 ± 0.02, in good agreement with
  the current standard value. Our models reproduce the observed solar
  centre-to-limb variations of various C I lines, without any adjustments
  to the rates of neutral hydrogen impact excitation, suggesting that
  the proposed recipe may be a solution to the long-standing problem of
  how to reliably model inelastic collisions with neutral hydrogen in
  late-type stellar atmospheres.

---------------------------------------------------------
Title: The GALAH survey: An abundance, age, and kinematic inventory
    of the solar neighbourhood made with TGAS
Authors: Buder, S.; Lind, K.; Ness, M. K.; Asplund, M.; Duong, L.;
   Lin, J.; Kos, J.; Casagrande, L.; Casey, A. R.; Bland-Hawthorn,
   J.; de Silva, G. M.; D'Orazi, V.; Freeman, K. C.; Martell, S. L.;
   Schlesinger, K. J.; Sharma, S.; Simpson, J. D.; Zucker, D. B.;
   Zwitter, T.; Čotar, K.; Dotter, A.; Hayden, M. R.; Hyde, E. A.;
   Kafle, P. R.; Lewis, G. F.; Nataf, D. M.; Nordlander, T.; Reid, W.;
   Rix, H. -W.; Skúladóttir, Á.; Stello, D.; Ting, Y. -S.; Traven,
   G.; Wyse, R. F. G.; GALAH Collaboration
2019A&A...624A..19B    Altcode: 2018arXiv180405869B
  The overlap between the spectroscopic Galactic Archaeology with HERMES
  (GALAH) survey and Gaia provides a high-dimensional chemodynamical space
  of unprecedented size. We present a first analysis of a subset of this
  overlap, of 7066 dwarf, turn-off, and sub-giant stars. These stars have
  spectra from the GALAH survey and high parallax precision from the Gaia
  DR1 Tycho-Gaia Astrometric Solution. We investigate correlations between
  chemical compositions, ages, and kinematics for this sample. Stellar
  parameters and elemental abundances are derived from the GALAH spectra
  with the spectral synthesis code SPECTROSCOPY MADE EASY. We determine
  kinematics and dynamics, including action angles, from the Gaia
  astrometry and GALAH radial velocities. Stellar masses and ages are
  determined with Bayesian isochrone matching, using our derived stellar
  parameters and absolute magnitudes. We report measurements of Li, C, O,
  Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Y, as well
  as Ba and we note that we have employed non-LTE calculations for Li,
  O, Al, and Fe. We show that the use of astrometric and photometric
  data improves the accuracy of the derived spectroscopic parameters,
  especially log g. Focusing our investigation on the correlations between
  stellar age, iron abundance [Fe/H], and mean alpha-enhancement [α/Fe]
  of the magnitude-selected sample, we recover the result that stars
  of the high-α sequence are typically older than stars in the low-α
  sequence, the latter spanning iron abundances of -0.7 &lt; [Fe/H] &lt;
  +0.5. While these two sequences become indistinguishable in [α/Fe]
  vs. [Fe/H] at the metal-rich regime, we find that age can be used to
  separate stars from the extended high-α and the low-α sequence even
  in this regime. When dissecting the sample by stellar age, we find that
  the old stars (&gt;8 Gyr) have lower angular momenta L<SUB>z</SUB>
  than the Sun, which implies that they are on eccentric orbits and
  originate from the inner disc. Contrary to some previous smaller scale
  studies we find a continuous evolution in the high-α-sequence up
  to super-solar [Fe/H] rather than a gap, which has been interpreted
  as a separate "high-α metal-rich" population. Stars in our sample
  that are younger than 10 Gyr, are mainly found on the low α-sequence
  and show a gradient in L<SUB>z</SUB> from low [Fe/H] (L<SUB>z</SUB>
  &gt; L<SUB>z, ⊙</SUB>) towards higher [Fe/H] (L<SUB>z</SUB> &lt;
  L<SUB>z, ⊙</SUB>), which implies that the stars at the ends of this
  sequence are likely not originating from the close solar vicinity. <P
  />The catalogue is only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr/">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/624/A19">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/624/A19</A>

---------------------------------------------------------
Title: 4MOST: Project overview and information for the First Call
    for Proposals
Authors: de Jong, R. S.; Agertz, O.; Berbel, A. A.; Aird, J.;
   Alexander, D. A.; Amarsi, A.; Anders, F.; Andrae, R.; Ansarinejad,
   B.; Ansorge, W.; Antilogus, P.; Anwand-Heerwart, H.; Arentsen, A.;
   Arnadottir, A.; Asplund, M.; Auger, M.; Azais, N.; Baade, D.; Baker,
   G.; Baker, S.; Balbinot, E.; Baldry, I. K.; Banerji, M.; Barden,
   S.; Barklem, P.; Barthélémy-Mazot, E.; Battistini, C.; Bauer, S.;
   Bell, C. P. M.; Bellido-Tirado, O.; Bellstedt, S.; Belokurov, V.;
   Bensby, T.; Bergemann, M.; Bestenlehner, J. M.; Bielby, R.; Bilicki,
   M.; Blake, C.; Bland-Hawthorn, J.; Boeche, C.; Boland, W.; Boller,
   T.; Bongard, S.; Bongiorno, A.; Bonifacio, P.; Boudon, D.; Brooks,
   D.; Brown, M. J. I.; Brown, R.; Brüggen, M.; Brynnel, J.; Brzeski,
   J.; Buchert, T.; Buschkamp, P.; Caffau, E.; Caillier, P.; Carrick,
   J.; Casagrande, L.; Case, S.; Casey, A.; Cesarini, I.; Cescutti, G.;
   Chapuis, D.; Chiappini, C.; Childress, M.; Christlieb, N.; Church, R.;
   Cioni, M. -R. L.; Cluver, M.; Colless, M.; Collett, T.; Comparat, J.;
   Cooper, A.; Couch, W.; Courbin, F.; Croom, S.; Croton, D.; Daguisé,
   E.; Dalton, G.; Davies, L. J. M.; Davis, T.; de Laverny, P.; Deason,
   A.; Dionies, F.; Disseau, K.; Doel, P.; Döscher, D.; Driver, S. P.;
   Dwelly, T.; Eckert, D.; Edge, A.; Edvardsson, B.; Youssoufi, D. E.;
   Elhaddad, A.; Enke, H.; Erfanianfar, G.; Farrell, T.; Fechner, T.;
   Feiz, C.; Feltzing, S.; Ferreras, I.; Feuerstein, D.; Feuillet, D.;
   Finoguenov, A.; Ford, D.; Fotopoulou, S.; Fouesneau, M.; Frenk, C.;
   Frey, S.; Gaessler, W.; Geier, S.; Gentile Fusillo, N.; Gerhard,
   O.; Giannantonio, T.; Giannone, D.; Gibson, B.; Gillingham, P.;
   González-Fernández, C.; Gonzalez-Solares, E.; Gottloeber, S.; Gould,
   A.; Grebel, E. K.; Gueguen, A.; Guiglion, G.; Haehnelt, M.; Hahn, T.;
   Hansen, C. J.; Hartman, H.; Hauptner, K.; Hawkins, K.; Haynes, D.;
   Haynes, R.; Heiter, U.; Helmi, A.; Aguayo, C. H.; Hewett, P.; Hinton,
   S.; Hobbs, D.; Hoenig, S.; Hofman, D.; Hook, I.; Hopgood, J.; Hopkins,
   A.; Hourihane, A.; Howes, L.; Howlett, C.; Huet, T.; Irwin, M.; Iwert,
   O.; Jablonka, P.; Jahn, T.; Jahnke, K.; Jarno, A.; Jin, S.; Jofre,
   P.; Johl, D.; Jones, D.; Jönsson, H.; Jordan, C.; Karovicova, I.;
   Khalatyan, A.; Kelz, A.; Kennicutt, R.; King, D.; Kitaura, F.; Klar,
   J.; Klauser, U.; Kneib, J. -P.; Koch, A.; Koposov, S.; Kordopatis, G.;
   Korn, A.; Kosmalski, J.; Kotak, R.; Kovalev, M.; Kreckel, K.; Kripak,
   Y.; Krumpe, M.; Kuijken, K.; Kunder, A.; Kushniruk, I.; Lam, M. I.;
   Lamer, G.; Laurent, F.; Lawrence, J.; Lehmitz, M.; Lemasle, B.; Lewis,
   J.; Li, B.; Lidman, C.; Lind, K.; Liske, J.; Lizon, J. -L.; Loveday,
   J.; Ludwig, H. -G.; McDermid, R. M.; Maguire, K.; Mainieri, V.; Mali,
   S.; Mandel, H.; Mandel, K.; Mannering, L.; Martell, S.; Martinez
   Delgado, D.; Matijevic, G.; McGregor, H.; McMahon, R.; McMillan,
   P.; Mena, O.; Merloni, A.; Meyer, M. J.; Michel, C.; Micheva, G.;
   Migniau, J. -E.; Minchev, I.; Monari, G.; Muller, R.; Murphy, D.;
   Muthukrishna, D.; Nandra, K.; Navarro, R.; Ness, M.; Nichani, V.;
   Nichol, R.; Nicklas, H.; Niederhofer, F.; Norberg, P.; Obreschkow, D.;
   Oliver, S.; Owers, M.; Pai, N.; Pankratow, S.; Parkinson, D.; Paschke,
   J.; Paterson, R.; Pecontal, A.; Parry, I.; Phillips, D.; Pillepich,
   A.; Pinard, L.; Pirard, J.; Piskunov, N.; Plank, V.; Plüschke, D.;
   Pons, E.; Popesso, P.; Power, C.; Pragt, J.; Pramskiy, A.; Pryer,
   D.; Quattri, M.; Queiroz, A. B. d. A.; Quirrenbach, A.; Rahurkar,
   S.; Raichoor, A.; Ramstedt, S.; Rau, A.; Recio-Blanco, A.; Reiss, R.;
   Renaud, F.; Revaz, Y.; Rhode, P.; Richard, J.; Richter, A. D.; Rix,
   H. -W.; Robotham, A. S. G.; Roelfsema, R.; Romaniello, M.; Rosario, D.;
   Rothmaier, F.; Roukema, B.; Ruchti, G.; Rupprecht, G.; Rybizki, J.;
   Ryde, N.; Saar, A.; Sadler, E.; Sahlén, M.; Salvato, M.; Sassolas,
   B.; Saunders, W.; Saviauk, A.; Sbordone, L.; Schmidt, T.; Schnurr,
   O.; Scholz, R. -D.; Schwope, A.; Seifert, W.; Shanks, T.; Sheinis,
   A.; Sivov, T.; Skúladóttir, Á.; Smartt, S.; Smedley, S.; Smith,
   G.; Smith, R.; Sorce, J.; Spitler, L.; Starkenburg, E.; Steinmetz,
   M.; Stilz, I.; Storm, J.; Sullivan, M.; Sutherland, W.; Swann, E.;
   Tamone, A.; Taylor, E. N.; Teillon, J.; Tempel, E.; ter Horst, R.;
   Thi, W. -F.; Tolstoy, E.; Trager, S.; Traven, G.; Tremblay, P. -E.;
   Tresse, L.; Valentini, M.; van de Weygaert, R.; van den Ancker, M.;
   Veljanoski, J.; Venkatesan, S.; Wagner, L.; Wagner, K.; Walcher,
   C. J.; Waller, L.; Walton, N.; Wang, L.; Winkler, R.; Wisotzki, L.;
   Worley, C. C.; Worseck, G.; Xiang, M.; Xu, W.; Yong, D.; Zhao, C.;
   Zheng, J.; Zscheyge, F.; Zucker, D.
2019Msngr.175....3D    Altcode: 2019arXiv190302464D
  We introduce the 4-metre Multi-Object Spectroscopic Telescope (4MOST),
  a new high-multiplex, wide-field spectroscopic survey facility under
  development for the four-metre-class Visible and Infrared Survey
  Telescope for Astronomy (VISTA) at Paranal. Its key specifications
  are: a large field of view (FoV) of 4.2 square degrees and a high
  multiplex capability, with 1624 fibres feeding two low-resolution
  spectrographs (R = λ/Δλ 6500), and 812 fibres transferring light
  to the high-resolution spectrograph (R 20 000). After a description of
  the instrument and its expected performance, a short overview is given
  of its operational scheme and planned 4MOST Consortium science; these
  aspects are covered in more detail in other articles in this edition
  of The Messenger. Finally, the processes, schedules, and policies
  concerning the selection of ESO Community Surveys are presented,
  commencing with a singular opportunity to submit Letters of Intent
  for Public Surveys during the first five years of 4MOST operations.

---------------------------------------------------------
Title: The GALAH survey: a catalogue of carbon-enhanced stars and
    CEMP candidates
Authors: Čotar, Klemen; Zwitter, Tomaž; Kos, Janez; Munari, Ulisse;
   Martell, Sarah L.; Asplund, Martin; Bland-Hawthorn, Joss; Buder, Sven;
   de Silva, Gayandhi M.; Freeman, Kenneth C.; Sharma, Sanjib; Anguiano,
   Borja; Carollo, Daniela; Horner, Jonathan; Lewis, Geraint F.; Nataf,
   David M.; Nordlander, Thomas; Stello, Denis; Ting, Yuan-Sen; Tinney,
   Chris; Traven, Gregor; Wittenmyer, Rob A.; Galah Collaboration
2019MNRAS.483.3196C    Altcode: 2018MNRAS.tmp.2999C; 2018arXiv180707977C; 2019MNRAS.483.3196A
  Swan bands - characteristic molecular absorption features of
  the C<SUB>2</SUB> molecule - are a spectroscopic signature of
  carbon-enhanced stars. They can also be used to identify carbon-enhanced
  metal-poor (CEMP) stars. The GALAH (GALactic Archaeology with Hermes)
  is a magnitude-limited survey of stars producing high-resolution,
  high-signal-to-noise spectra. We used 627 708 GALAH spectra to
  search for carbon-enhanced stars with a supervised and unsupervised
  classification algorithm, relying on the imprint of the Swan bands. We
  identified 918 carbon-enhanced stars, including 12 already described
  in the literature. An unbiased selection function of the GALAH survey
  allows us to perform a population study of carbon-enhanced stars. Most
  of them are giants, out of which we find 28 CEMP candidates. A large
  fraction of our carbon-enhanced stars with repeated observations show
  variation in radial velocity, hinting that there is a large fraction
  of variables among them. 32 of the detected stars also show strong
  Lithium enhancement in their spectra.

---------------------------------------------------------
Title: 4MOST Consortium Survey 3: Milky Way Disc and Bulge
    Low-Resolution Survey (4MIDABLE-LR)
Authors: Chiappini, C.; Minchev, I.; Starkenburg, E.; Anders, F.;
   Gentile Fusillo, N.; Gerhard, O.; Guiglion, G.; Khalatyan, A.;
   Kordopatis, G.; Lemasle, B.; Matijevic, G.; Queiroz, A. B. D. A.;
   Schwope, A.; Steinmetz, M.; Storm, J.; Traven, G.; Tremblay, P. -E.;
   Valentini, M.; Andrae, R.; Arentsen, A.; Asplund, M.; Bensby, T.;
   Bergemann, M.; Casagrande, L.; Church, R.; Cescutti, G.; Feltzing,
   S.; Fouesneau, M.; Grebel, E. K.; Kovalev, M.; McMillan, P.; Monari,
   G.; Rybizki, J.; Ryde, N.; Rix, H. -W.; Walton, N.; Xiang, M.; Zucker,
   D.; 4MIDABLE-Lr Team
2019Msngr.175...30C    Altcode: 2019arXiv190302469C
  The mechanisms of the formation and evolution of the Milky Way are
  encoded in the orbits, chemistry and ages of its stars. With the
  4MOST MIlky way Disk And BuLgE Low-Resolution Survey (4MIDABLE-LR)
  we aim to study kinematic and chemical substructures in the Milky Way
  disc and bulge region with samples of unprecedented size out to larger
  distances and greater precision than conceivable with Gaia alone or any
  other ongoing or planned survey. Gaia gives us the unique opportunity
  for target selection based almost entirely on parallax and magnitude
  range, hence increasing the efficiency in sampling larger Milky Way
  volumes with well-defined and effective selection functions.

---------------------------------------------------------
Title: 4MOST Consortium Survey 2: The Milky Way Halo High-Resolution
    Survey
Authors: Christlieb, N.; Battistini, C.; Bonifacio, P.; Caffau, E.;
   Ludwig, H. -G.; Asplund, M.; Barklem, P.; Bergemann, M.; Church, R.;
   Feltzing, S.; Ford, D.; Grebel, E. K.; Hansen, C. J.; Helmi, A.;
   Kordopatis, G.; Kovalev, M.; Korn, A.; Lind, K.; Quirrenbach, A.;
   Rybizki, J.; Skúladóttir, Á.; Starkenburg, E.
2019Msngr.175...26C    Altcode: 2019arXiv190302468C
  We will study the formation history of the Milky Way, and the earliest
  phases of its chemical enrichment, with a sample of more than 1.5
  million stars at high galactic latitude. Elemental abundances of up to
  20 elements with a precision of better than 0.2 dex will be derived
  for these stars. The sample will include members of kinematically
  coherent substructures, which we will associate with their possible
  birthplaces by means of their abundance signatures and kinematics,
  allowing us to test models of galaxy formation. Our target catalogue
  is also expected to contain 30 000 stars at a metallicity of less than
  one hundredth that of the Sun. This sample will therefore be almost
  a factor of 100 larger than currently existing samples of metal-poor
  stars for which precise elemental abundances are available (determined
  from high-resolution spectroscopy), enabling us to study the early
  chemical evolution of the Milky Way in unprecedented detail.

---------------------------------------------------------
Title: 4MOST Consortium Survey 4: Milky Way Disc and Bulge
    High-Resolution Survey (4MIDABLE-HR)
Authors: Bensby, T.; Bergemann, M.; Rybizki, J.; Lemasle, B.; Howes,
   L.; Kovalev, M.; Agertz, O.; Asplund, M.; Barklem, P.; Battistini,
   C.; Casagrande, L.; Chiappini, C.; Church, R.; Feltzing, S.; Ford,
   D.; Gerhard, O.; Kushniruk, I.; Kordopatis, G.; Lind, K.; Minchev,
   I.; McMillan, P.; Rix, H. -W.; Ryde, N.; Traven, G.
2019Msngr.175...35B    Altcode: 2019arXiv190302470B
  The signatures of the formation and evolution of a galaxy are
  imprinted in its stars. Their velocities, ages, and chemical
  compositions present major constraints on models of galaxy formation,
  and on various processes such as the gas inflows and outflows,
  the accretion of cold gas, radial migration, and the variability of
  star formation activity. Understanding the evolution of the Milky
  Way requires large observational datasets of stars via which these
  quantities can be determined accurately. This is the science driver
  of the 4MOST MIlky way Disc And BuLgE High-Resolution (4MIDABLE-HR)
  survey: to obtain high-resolution spectra at &lt; i&gt;R 20 000 and
  to provide detailed elemental abundances for large samples of stars
  in the Galactic disc and bulge. High data quality will allow us to
  provide accurate spectroscopic diagnostics of two million stellar
  spectra: precise radial velocities; rotation; abundances of many
  elements, including those that are currently only accessible in the
  optical, such as Li, s-, and r-process; and multi-epoch spectra for a
  sub-sample of stars. Synergies with complementary missions like Gaia
  and TESS will provide masses, stellar ages and multiplicity, forming a
  multi-dimensional dataset that will allow us to explore and constrain
  the origin and structure of the Milky Way.

---------------------------------------------------------
Title: The GALAH survey: co-orbiting stars and chemical tagging
Authors: Simpson, Jeffrey D.; Martell, Sarah L.; Da Costa, Gary; Casey,
   Andrew R.; Freeman, Ken C.; Horner, Jonathan; Ting, Yuan-Sen; Nataf,
   David M.; Lewis, Geraint F.; Ness, Melissa K.; Zucker, Daniel B.;
   Cottrell, Peter L.; Čotar, Klemen; Asplund, Martin; Bland-Hawthorn,
   Joss; Buder, Sven; D'Orazi, Valentina; De Silva, Gayandhi M.; Duong,
   Ly; Kos, Janez; Lin, Jane; Lind, Karin; Schlesinger, Katharine J.;
   Sharma, Sanjib; Zwitter, Tomaž; Kafle, Prajwal R.; Nordlander, Thomas
2019MNRAS.482.5302S    Altcode: 2018MNRAS.tmp.2902S; 2018arXiv180405894S
  We present a study using the second data release of the GALAH survey
  of stellar parameters and elemental abundances of 15 pairs of stars
  identified by Oh et al. They identified these pairs as potentially
  co-moving pairs using proper motions and parallaxes from Gaia DR1. We
  find that 11 very wide (&gt;1 pc) pairs of stars do in fact have similar
  Galactic orbits, while a further four claimed co-moving pairs are not
  truly co-orbiting. Eight of the 11 co-orbiting pairs have reliable
  stellar parameters and abundances, and we find that three of those are
  quite similar in their abundance patterns, while five have significant
  [Fe/H] differences. For the latter, this indicates that they could be
  co-orbiting because of the general dynamical coldness of the thin disc,
  or perhaps resonances induced by the Galaxy, rather than a shared
  formation site. Stars such as these, wide binaries, debris of past
  star formation episodes, and coincidental co-orbiters, are crucial
  for exploring the limits of chemical tagging in the Milky Way.

---------------------------------------------------------
Title: Carbon and oxygen in metal-poor halo stars
Authors: Amarsi, A. M.; Nissen, P. E.; Asplund, M.; Lind, K.; Barklem,
   P. S.
2019A&A...622L...4A    Altcode: 2019arXiv190103592A
  Carbon and oxygen are key tracers of the Galactic chemical evolution;
  in particular, a reported upturn in [C/O] towards decreasing [O/H]
  in metal-poor halo stars could be a signature of nucleosynthesis by
  massive Population III stars. We reanalyse carbon, oxygen, and iron
  abundances in 39 metal-poor turn-off stars. For the first time, we
  take into account 3D hydrodynamic effects together with departures
  from local thermodynamic equilibrium (LTE) when determining both the
  stellar parameters and the elemental abundances, by deriving effective
  temperatures from 3D non-LTE Hβ profiles, surface gravities from Gaia
  parallaxes, iron abundances from 3D LTE Fe II equivalent widths, and
  carbon and oxygen abundances from 3D non-LTE C I and O I equivalent
  widths. We find that [C/Fe] stays flat with [Fe/H], whereas [O/Fe]
  increases linearly up to 0.75 dex with decreasing [Fe/H] down to -3.0
  dex. Therefore [C/O] monotonically decreases towards decreasing [C/H],
  in contrast to previous findings, mainly because the non-LTE effects
  for O I at low [Fe/H] are weaker with our improved calculations. <P
  />Tables 1-4 are only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr/">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/622/L4">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/622/L4</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: GALAH survey, chemodynamical
    analyse with TGAS (Buder+, 2019)
Authors: Buder, S.; Lind, K.; Ness, M. K.; Asplund, M.; Duong, L.;
   Lin, J.; Kos, J.; Casagrande, L.; Casey, A. R.; Bland-Hawthorn,
   J.; de Silva, G. M.; D'Orazi, V.; Freeman, K. C.; Martell, S. L.;
   Schlesinger, K. J.; Sharma, S.; Simpson, J. D.; Zucker, D. B.; Zwitter,
   T.; Cotar, K.; Dotter, A.; Hayden, M. R.; Hyde, E. A.; Kafle, P. R.;
   Lewis, G. F.; Nataf, D. M.; Nordlander, T.; Reid, W.; Rix, H. -W.;
   Skuladottir, A.; Stello, D.; Ting, Y. -S.; Traven, G.; Wyse, R. F. G.;
   Galah Collaboration
2019yCat..36240019B    Altcode:
  In the following tables we give stellar parameters, stellar ages,
  stellar masses, photometric parameters, astrometric parameters,
  kinematical parameters, orbital parameters, and detailed elemental
  abundances for Li, C, O, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe,
  Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Mo, Ru, Ba, La, Ce, Nd, Sm, and Eu for
  7066 main sequence and turn-off, and sub-giant stars observed by the
  GALAH survey and overlapping with Gaia DR1 TGAS. <P />(1 data file).

---------------------------------------------------------
Title: VizieR Online Data Catalog: GALAH carbon-enhanced stars &amp;
    CEMP candidates (Cotar+, 2019)
Authors: Cotar, K.; Zwitter, T.; Kos, J.; Munari, U.; Martell, S. L.;
   Asplund, M.; Bland-Hawthorn, J.; Buder, S.; de Silva, G. M.; Freeman,
   K. C.; Sharma, S.; Anguiano, B.; Carollo, D.; Horner, J.; Lewis, G. F.;
   Nataf, D. M.; Nordlander, T.; Stello, D.; Ting, Y. -S.; Tinney, C.;
   Traven, G.; Wittenmyer, R. A.; Galah Collaboration
2019yCat..74833196C    Altcode:
  The analysed set of stellar spectra was acquired by the High Efficiency
  and Resolution Multi-Element Spectrograph (HERMES), a fibre-fed
  multi-object spectrograph on the 3.9m Anglo-Australian Telescope (AAT)
  of the Australian Astronomical Observatory. <P />Spectra used in this
  study have been taken from multiple different observing programmes
  using this spectrograph: the GALactic Archaeology with HERMES (GALAH)
  pilot survey (Duong et al., 2018MNRAS.476.5216D), the main GALAH survey
  (De Silva et al., 2015MNRAS.449.2604D), the K2-HERMES survey (Wittenmyer
  et al. 2016 , AAS Meeting Abstracts #227), and the TESS-HERMES survey
  (Sharma et al., 2018MNRAS.473.2004S). <P />Our data set consists of
  627708 successfully reduced spectra of 576229 stars observed between
  2013 November and 2018 February. <P />(1 data file).

---------------------------------------------------------
Title: The GALAH survey: velocity fluctuations in the Milky Way
    using Red Clump giants
Authors: Khanna, Shourya; Sharma, Sanjib; Bland-Hawthorn, Joss; Hayden,
   Michael; Nataf, David M.; Ting, Yuan-Sen; Kos, Janez; Martell, Sarah;
   Zwitter, Tomaž; De Silva, Gayandhi; Asplund, Martin; Buder, Sven;
   Duong, Ly; Lin, Jane; Simpson, Jeffrey D.; Anguiano, Borja; Horner,
   Jonathan; Kafle, Prajwal R.; Lewis, Geraint F.; Nordlander, Thomas;
   Wyse, Rosemary F. G.; Wittenmyer, Robert A.; Zucker, Daniel B.
2019MNRAS.482.4215K    Altcode: 2018arXiv180407217K; 2018MNRAS.tmp.2790K
  If the Galaxy is axisymmetric and in dynamical equilibrium, we expect
  negligible fluctuations in the residual line-of-sight velocity
  field. Recent results using the APOGEE survey find significant
  fluctuations in velocity for stars in the mid-plane (|z| &lt;0.25
  kpc) out to 5 kpc, suggesting that the dynamical influence of
  non-axisymmetric features, i.e. the Milky Way's bar, spiral arms, and
  merger events extends out to the Solar neighbourhood. Their measured
  power spectrum has a characteristic amplitude of 11 km s<SUP>-1</SUP> on
  a scale of 2.5 kpc. The existence of such large-scale streaming motions
  has important implications for determining the Sun's motion about the
  Galactic Centre. Using Red Clump stars from GALAH and APOGEE, we map
  the line-of-sight velocities around the Sun (d &lt; 5 kpc), and |z|
  &lt;1.25 kpc from the mid-plane. By subtracting a smooth axisymmetric
  model for the velocity field, we study the residual fluctuations
  and compare our findings with mock survey generated by GALAXIA. We
  find negligible large-scale fluctuations away from the plane. In the
  mid-plane, we reproduce the earlier APOGEE power spectrum but with 20
  per cent smaller amplitude (9.3 km s<SUP>-1</SUP>) after taking into
  account a few systematics (e.g. volume completeness). Using a flexible
  axisymmetric model the power amplitude is further reduced to 6.3 km
  s<SUP>-1</SUP>. Additionally, our simulations show that, in the plane,
  distances are underestimated for high-mass Red Clump stars which can
  lead to spurious power amplitude of about 5.2 km s<SUP>-1</SUP>. Taking
  this into account, we estimate the amplitude of real fluctuations to
  be &lt;4.6 km s<SUP>-1</SUP>, about a factor of three less than the
  APOGEE result.

---------------------------------------------------------
Title: Thorium in solar twins: implications for habitability in
    rocky planets
Authors: Botelho, R. B.; Milone, A. de C.; Meléndez, J.; Bedell,
   M.; Spina, L.; Asplund, M.; dos Santos, L.; Bean, J. L.; Ramírez,
   I.; Yong, D.; Dreizler, S.; Alves-Brito, A.; Yana Galarza, J.
2019MNRAS.482.1690B    Altcode: 2018MNRAS.tmp.2659B; 2018arXiv181010413B
  We have investigated the thorium (Th) abundance in a sample of 53 thin
  disc solar twins covering a wide range of ages. These data provide
  constrains on the mantle energy budget of terrestrial planets that
  can be formed over the evolution of the Galaxy's thin disc. We have
  estimated Th abundances with an average precision of 0.025 dex (in both
  [Th/H] and [Th/Fe]) through comprehensive spectral synthesis of a Th II
  line present at 4019.1290 Å, using very high resolution (R = 115 000)
  high quality HARPS spectra obtained at the ESO La Silla Observatory. We
  have confirmed that there is a large energy budget from Th decay for
  maintaining mantle convection inside potential rocky planets around
  solar twins, from the Galactic thin disc formation until now, because
  the pristine [Th/H]<SUB>ZAMS</SUB> is super-solar on average under
  a uniform dispersion of 0.056 dex (varying from +0.037 up to +0.138
  dex based on linear fits against isochrone stellar age). Comparing to
  neodymium (Nd) and europium (Eu), two others neutron-capture elements,
  the stellar pristine abundance of Th follows Eu along the Galactic thin
  disc evolution, but it does not follow Nd, probably because neodymium
  has a significant contribution from the s-process (about 60 per cent).

---------------------------------------------------------
Title: VizieR Online Data Catalog: GALAH Survey DR2 (Buder+, 2018)
Authors: Buder, S.; Asplund, M.; Duong, L.; Kos, J.; Lind, K.; Ness,
   M. K.; Sharma, S.; Bland-Hawthorn, J.; Casey, A. R.; de Silva, G. M.;
   D'Orazi, V.; Freeman, K. C.; Lewis, G. F.; Lin, J.; Martell, S. L.;
   Schlesinger, K. J.; Simpson, J. D.; Zucker, D. B.; Zwitter, T.; Amarsi,
   A. M.; Anguiano, B.; Carollo, D.; Casagrande, L.; Cotar, K.; Cottrell,
   P. L.; da Costa, G.; Gao, X. D.; Hayden, M. R.; Horner, J.; Ireland,
   M. J.; Kafle, P. R.; Munari, U.; Nataf, D. M.; Nordlander, T.; Stello,
   D.; Ting, Y. -S.; Traven, G.; Watson, F.; Wittenmyer, R. A.; Wyse,
   R. F. G.; Yong, D.; Zinn, J. C.; Zerjal, M.; GALAH Collaboration
2019yCat..74784513B    Altcode:
  This is the second data release of the GALAH survey. Data for the
  GALAH survey are taken with the HERMES spectrograph on the 3.9-metre
  Anglo-Australian Telescope (AAT) at Siding Spring Observatory. HERMES
  is a fibre-fed high-resolution (R=28000) spectrograph optimized to do
  Galactic archaeology from a 4m class telescope, with four discrete
  optical wavelength channels covering 4713-4903Å, 5648-5873Å,
  6478-6737Å, and 7585-7887Å. <P />(1 data file).

---------------------------------------------------------
Title: Galactic archaeology with the GALAH survey
Authors: Asplund, M.
2019gage.confE...1A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: VizieR Online Data Catalog: Carbon and oxygen in metal-poor
    halo stars (Amarsi+, 2019)
Authors: Amarsi, A. M.; Nissen, P. E.; Asplund, M.; Lind, K.; Barklem,
   P. S.
2019yCat..36229004A    Altcode:
  table1.dat contains stellar parameters and abundances. table2.dat
  contains line-by-line equivalent widths and abundances for The FeII
  lines used in this work. table3.dat contains line-by-line equivalent
  widths and abundances for the CI lines used in this work. table4.dat
  contains line-by-line equivalent widths and abundances for the OI
  lines used in this work. <P />(4 data files).

---------------------------------------------------------
Title: The GALAH survey: verifying abundance trends in the open
    cluster M67 using non-LTE modelling
Authors: Gao, Xudong; Lind, Karin; Amarsi, Anish M.; Buder, Sven;
   Dotter, Aaron; Nordlander, Thomas; Asplund, Martin; Bland-Hawthorn,
   Joss; de Silva, Gayandhi M.; D'Orazi, Valentina; Freeman, Ken C.; Kos,
   Janez; Lewis, Geraint F.; Lin, Jane; Martell, Sarah L.; Schlesinger,
   Katharine J.; Sharma, Sanjib; Simpson, Jeffrey D.; Zucker, Daniel B.;
   Zwitter, Tomaž; da Costa, Gary; Anguiano, Borja; Horner, Jonathan;
   Hyde, Elaina A.; Kafle, Prajwal R.; Nataf, David M.; Reid, Warren;
   Stello, Dennis; Ting, Yuan-Sen; Galah Collaboration
2018MNRAS.481.2666G    Altcode: 2018MNRAS.tmp.2299G; 2018arXiv180406394G
  Open cluster members are coeval and share the same initial bulk chemical
  composition. Consequently, differences in surface abundances between
  members of a cluster that are at different evolutionary stages can be
  used to study the effects of mixing and internal chemical processing. We
  carry out an abundance analysis of seven elements (Li, O, Na, Mg,
  Al, Si, and Fe) in 66 stars belonging to the open cluster M67, based
  on high resolution GALAH spectra, 1D MARCS model atmospheres, and
  non-local thermodynamic equilibrium (non-LTE) radiative transfer. From
  the non-LTE analysis, we find a typical star-to-star scatter in the
  abundance ratios of around 0.05 dex. We find trends in the abundance
  ratios with effective temperature, indicating systematic differences in
  the surface abundances between turn-off and giant stars; these trends
  are more pronounced when LTE is assumed. However, trends with effective
  temperature remain significant for Al and Si also in non-LTE. Finally,
  we compare the derived abundances with prediction from stellar evolution
  models including effects of atomic diffusion. We find overall good
  agreement for the abundance patterns of dwarfs and sub-giant stars,
  but the abundances of cool giants are lower relative to less evolved
  stars than predicted by the diffusion models, in particular for Mg.

---------------------------------------------------------
Title: The GALAH survey: accurate radial velocities and library of
    observed stellar template spectra
Authors: Zwitter, Tomaž; Kos, Janez; Chiavassa, Andrea; Buder,
   Sven; Traven, Gregor; Čotar, Klemen; Lin, Jane; Asplund, Martin;
   Bland-Hawthorn, Joss; Casey, Andrew R.; De Silva, Gayandhi; Duong,
   Ly; Freeman, Kenneth C.; Lind, Karin; Martell, Sarah; D'Orazi,
   Valentina; Schlesinger, Katharine J.; Simpson, Jeffrey D.; Sharma,
   Sanjib; Zucker, Daniel B.; Anguiano, Borja; Casagrande, Luca; Collet,
   Remo; Horner, Jonathan; Ireland, Michael J.; Kafle, Prajwal R.; Lewis,
   Geraint; Munari, Ulisse; Nataf, David M.; Ness, Melissa; Nordlander,
   Thomas; Stello, Dennis; Ting, Yuan-Sen; Tinney, Chris G.; Watson,
   Fred; Wittenmyer, Rob A.; Žerjal, Maruša
2018MNRAS.481..645Z    Altcode: 2018MNRAS.tmp.2178Z; 2018arXiv180406344Z
  GALAH is a large-scale magnitude-limited southern stellar spectroscopic
  survey. Its second data release (GALAH DR2) provides values of stellar
  parameters and abundances of 23 elements for 342 682 stars (Buder
  et al.). Here we add a description of the public release of radial
  velocities with a typical accuracy of 0.1 km s<SUP>-1</SUP> for 336
  215 of these stars, achievable due to the large wavelength coverage,
  high resolving power, and good signal-to-noise ratio of the observed
  spectra, but also because convective motions in stellar atmosphere and
  gravitational redshift from the star to the observer are taken into
  account. In the process we derive medians of observed spectra that
  are nearly noiseless, as they are obtained from between 100 and 1116
  observed spectra belonging to the same bin with a width of 50 K in
  temperature, 0.2 dex in gravity, and 0.1 dex in metallicity. Publicly
  released 1181 median spectra have a resolving power of 28 000 and trace
  the well-populated stellar types with metallicities between -0.6 and
  +0.3. Note that radial velocities from GALAH are an excellent match
  to the accuracy of velocity components along the sky plane derived
  by Gaia for the same stars. The level of accuracy achieved here is
  adequate for studies of dynamics within stellar clusters, associations,
  and streams in the Galaxy. So it may be relevant for studies of the
  distribution of dark matter.

---------------------------------------------------------
Title: Holistic spectroscopy: complete reconstruction of a wide-field,
    multiobject spectroscopic image using a photonic comb
Authors: Kos, Janez; Bland-Hawthorn, Joss; Betters, Christopher H.;
   Leon-Saval, Sergio; Asplund, Martin; Buder, Sven; Casey, Andrew R.;
   D'Orazi, Valentina; de Silva, Gayandhi; Freeman, Ken; Lewis, Geraint;
   Lin, Jane; Martell, Sarah L.; Schlesinger, Katharine; Sharma, Sanjib;
   Simpson, Jeffrey D.; Zucker, Daniel; Zwitter, Tomaž; Hayden, Michael;
   Horner, Jonathan; Nataf, David M.; Ting, Yuan-Sen
2018MNRAS.480.5475K    Altcode: 2018MNRAS.tmp.2085K; 2018arXiv180405851K
  The primary goal of Galactic archaeology is to learn about the origin
  of the Milky Way from the detailed chemistry and kinematics of millions
  of stars. Wide-field multifibre spectrographs are increasingly used
  to obtain spectral information for huge samples of stars. Some
  surveys (e.g. GALAH) are attempting to measure up to 30 separate
  elements per star. Stellar abundance spectroscopy is a subtle art that
  requires a very high degree of spectral uniformity across each of the
  fibres. However, wide-field spectrographs are notoriously non-uniform
  due to the fast output optics necessary to image many fibre outputs on
  to the detector. We show that precise spectroscopy is possible with
  such instruments across all fibres by employing a photonic comb -
  a device that produces uniformly spaced spots of light on the CCD to
  precisely map complex aberrations. Aberrations are parametrized by a
  set of orthogonal moments with ∼100 independent parameters. We then
  reproduce the observed image by convolving high-resolution spectral
  templates with measured aberrations as opposed to extracting the
  spectra from the observed image. Such a forward modelling approach
  also trivializes some spectroscopic reduction problems like fibre
  cross-talk, and reliably extracts spectra with a resolution ∼2.3
  times above the nominal resolution of the instrument. Our rigorous
  treatment of optical aberrations also encourages a less conservative
  spectrograph design in the future.

---------------------------------------------------------
Title: The GALAH survey and Gaia DR2: (non-)existence of five sparse
    high-latitude open clusters
Authors: Kos, Janez; de Silva, Gayandhi; Buder, Sven; Bland-Hawthorn,
   Joss; Sharma, Sanjib; Asplund, Martin; D'Orazi, Valentina; Duong, Ly;
   Freeman, Ken; Lewis, Geraint F.; Lin, Jane; Lind, Karin; Martell, Sarah
   L.; Schlesinger, Katharine J.; Simpson, Jeffrey D.; Zucker, Daniel B.;
   Zwitter, Tomaž; Bedding, Timothy R.; Čotar, Klemen; Horner, Jonathan;
   Nordlander, Thomas; Stello, Denis; Ting, Yuan-Sen; Traven, Gregor
2018MNRAS.480.5242K    Altcode: 2018arXiv180700822K; 2018MNRAS.tmp.2084K
  Sparse open clusters can be found at high galactic latitudes where
  loosely populated clusters are more easily detected against the lower
  stellar background. Because most star formation takes place in the thin
  disc, the observed population of clusters far from the Galactic plane is
  hard to explain. We combined spectral parameters from the GALAH survey
  with the Gaia DR2 catalogue to study the dynamics and chemistry of five
  old sparse high-latitude clusters in more detail. We find that four of
  them (NGC 1252, NGC 6994, NGC 7772, NGC 7826) - originally classified
  in 1888 - are not clusters but are instead chance projections on the
  sky. Member stars quoted in the literature for these four clusters are
  unrelated in our multidimensional physical parameter space; the quoted
  cluster properties in the literature are therefore meaningless. We
  confirm the existence of visually similar NGC 1901 for which we provide
  a probabilistic membership analysis. An overdensity in three spatial
  dimensions proves to be enough to reliably detect sparse clusters,
  but the whole six-dimensional space must be used to identify members
  with high confidence, as demonstrated in the case of NGC 1901.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Solar Twins age-chromospheric
    activity (Lorenzo-Oliveira+, 2018))
Authors: Lorenzo-Oliveira, D.; Freitas, F.; Melendez, J.; Bedell,
   M.; Ramirez, I.; Bean, J.; Asplund, M.; Spina, L.; Dreizler, S.;
   Alves-Brito, A.; Casagrande, L.
2018yCat..36190073L    Altcode:
  Our sample was selected from the 88 solar twins presented in Ramirez et
  al. (2014A&amp;A...572A..48R). From this sample, we obtained data for
  70 stars with the HARPS instrument (Mayor et al., 2003Msngr.114...20M)
  at the 3.6 m telescope at the La Silla observatory, to search for
  planets around solar twins (program 188.C-0265, Bedell et al.,
  2015A&amp;A...581A..34B; Melendez et al., 2015Msngr.161...28M,
  2017A&amp;A...597A..34M). Additional data for 12 stars were found in
  the ESO archive. <P />(2 data files).

---------------------------------------------------------
Title: The Solar Twin Planet Search. The age-chromospheric activity
    relation
Authors: Lorenzo-Oliveira, Diego; Freitas, Fabrício C.; Meléndez,
   Jorge; Bedell, Megan; Ramírez, Iván; Bean, Jacob L.; Asplund, Martin;
   Spina, Lorenzo; Dreizler, Stefan; Alves-Brito, Alan; Casagrande, Luca
2018A&A...619A..73L    Altcode: 2018arXiv180608014L
  Context. It is well known that the magnetic activity of solar-type stars
  decreases with age, but it is widely debated in the literature whether
  there is a smooth decline or if there is an early sharp drop until
  1-2 Gyr that is followed by a relatively inactive constant phase. <BR
  /> Aims: We revisited the activity-age relation using time-series
  observations of a large sample of solar twins whose precise isochronal
  ages and other important physical parameters have been determined. <BR
  /> Methods: We measured the Ca II H and K activity indices using ≈9000
  HARPS spectra of 82 solar twins. In addition, the average solar activity
  was calculated through asteroids and Moon reflection spectra using
  the same instrumentation. Thus, we transformed our activity indices
  into the S Mount Wilson scale (S<SUB>MW</SUB>), recalibrated the
  Mount Wilson absolute flux and photospheric correction equations as a
  function of T<SUB>eff</SUB>, and then computed an improved bolometric
  flux normalized activity index log R'<SUB>HK</SUB> (T<SUB>eff</SUB>)
  for the entire sample. <BR /> Results: New relations between activity
  and the age of solar twins were derived by assessing the chromospheric
  age-dating limits using log R'<SUB>HK</SUB> (T<SUB>eff</SUB>). We
  measured an average solar activity of S<SUB>MW</SUB> = 0.1712 ± 0.0017
  during solar magnetic cycles 23-24 covered by HARPS observations,
  and we also inferred an average of S<SUB>MW</SUB> = 0.1694 ± 0.0025
  for cycles 10-24, anchored on a sunspot number correlation of S index
  versus. We also found a simple relation between the average and the
  dispersion of the activity levels of solar twins. This enabled us to
  predict the stellar variability effects on the age-activity diagram,
  and consequently, to estimate the chromospheric age uncertainties that
  are due to the same phenomena. The age-activity relation is still
  statistically significant up to ages around 6-7 Gyr, in agreement
  with previous works using open clusters and field stars with precise
  ages. <BR /> Conclusions: Our research confirms that Ca II H &amp;
  K lines remain a useful chromospheric evolution tracer until stars
  reach ages of at least 6-7 Gyr. We found evidence that for the most
  homogenous set of old stars, the chromospheric activity indices seem
  to continue to decrease after the solar age toward the end of the main
  sequence. Our results indicate that a significant part of the scatter
  observed in the age-activity relation of solar twins can be attributed
  to stellar cycle modulations effects. The Sun seems to have a normal
  activity level and variability for its age. <P />Based on observations
  collected at the European Organisation for Astronomical Research in
  the Southern Hemisphere under ESO programs 188.C-0265, 183.D-0729,
  292.C-5004, 097.C-0571, 092.C-0721, 093.C-0409, 072.C-0488, 183.C-0972,
  091.C-0936, 192.C-0852, 196.C-1006, 076.C-0155, 096.C-0499, 185.D-0056,
  192.C-0224, 075.C-0332, 090.C-0421, 091.C-0034, 077.C-0364, 089.C-0415,
  60.A-9036, 092.C-0832, 295.C-5035, 295.C-5031, 60.A-9700, 289.D-5015,
  096.C-0210, 086.C-0284, 088.C-0323, 0100.D-0444, and 099.C-0491.Tables
  1 and 2 are only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/619/A73">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/619/A73</A>

---------------------------------------------------------
Title: The Chemical Homogeneity of Sun-like Stars in the Solar
    Neighborhood
Authors: Bedell, Megan; Bean, Jacob L.; Meléndez, Jorge; Spina,
   Lorenzo; Ramírez, Ivan; Asplund, Martin; Alves-Brito, Alan; dos
   Santos, Leonardo; Dreizler, Stefan; Yong, David; Monroe, TalaWanda;
   Casagrande, Luca
2018ApJ...865...68B    Altcode: 2018arXiv180202576B
  The compositions of stars are a critical diagnostic tool for many
  topics in astronomy such as the evolution of our Galaxy, the formation
  of planets, and the uniqueness of the Sun. Previous spectroscopic
  measurements indicate a large intrinsic variation in the elemental
  abundance patterns of stars with similar overall metal content. However,
  systematic errors arising from inaccuracies in stellar models are known
  to be a limiting factor in such studies, and thus it is uncertain to
  what extent the observed diversity of stellar abundance patterns is
  real. Here we report the abundances of 30 elements with precisions of 2%
  for 79 Sun-like stars within 100 pc. Systematic errors are minimized in
  this study by focusing on solar twin stars and performing a line-by-line
  differential analysis using high-resolution, high-signal-to-noise
  spectra. We resolve [X/Fe] abundance trends in galactic chemical
  evolution at precisions of 10<SUP>-3</SUP> dex Gyr<SUP>-1</SUP>
  and reveal that stars with similar ages and metallicities have
  nearly identical abundance patterns. Contrary to previous results,
  we find that the ratios of carbon-to-oxygen and magnesium-to-silicon
  in solar-metallicity stars are homogeneous to within 10% throughout
  the solar neighborhood, implying that exoplanets may exhibit much less
  compositional diversity than previously thought. Finally, we demonstrate
  that the Sun has a subtle deficiency in refractory material relative
  to &gt;80% of solar twins (at 2σ confidence), suggesting a possible
  signpost for planetary systems like our own.

---------------------------------------------------------
Title: The age and abundance structure of the stellar populations
    in the central sub-kpc of the Milky Way
Authors: Bensby, T.; Feltzing, S.; Gould, A.; Yee, J. C.; Johnson,
   J. A.; Asplund, M.; Meléndez, J.; Lucatello, S.; Howes, L. M.
2018IAUS..334...86B    Altcode: 2017arXiv170705960B
  The four main findings about the age and abundance structure of the
  Milky Way bulge based on microlensed dwarf and subgiant stars are: (1)
  a wide metallicity distribution with distinct peaks at [Fe/H] = -1.09,
  -0.63, -0.20, +0.12, +0.41; (2) a high fraction of intermediate-age to
  young stars where at [Fe/H] &gt; 0 more than 35 % are younger than 8
  Gyr, (3) several episodes of significant star formation in the bulge 3,
  6, 8, and 11 Gyr ago; (4) the `knee' in the α-element abundance trends
  of the sub-solar metallicity bulge appears to be located at a slightly
  higher [Fe/H] (about 0.05 to 0.1 dex) than in the local thick disk.

---------------------------------------------------------
Title: Inelastic O+H collisions and the O I 777 nm solar
    centre-to-limb variation
Authors: Amarsi, A. M.; Barklem, P. S.; Asplund, M.; Collet, R.;
   Zatsarinny, O.
2018A&A...616A..89A    Altcode: 2018arXiv180310531A
  The O I 777 nm triplet is a key diagnostic of oxygen abundances
  in the atmospheres of FGK-type stars; however, it is sensitive to
  departures from local thermodynamic equilibrium (LTE). The accuracy
  of non-LTE line formation calculations has hitherto been limited by
  errors in the inelastic O+H collisional rate coefficients; several
  recent studies have used the Drawin recipe, albeit with a correction
  factor S<SUB>H</SUB> that is calibrated to the solar centre-to-limb
  variation of the triplet. We present a new model oxygen atom that
  incorporates inelastic O+H collisional rate coefficients using an
  asymptotic two-electron model based on linear combinations of atomic
  orbitals, combined with a free electron model based on the impulse
  approximation. Using a 3D hydrodynamic STAGGER model solar atmosphere
  and 3D non-LTE line formation calculations, we demonstrate that
  this physically motivated approach is able to reproduce the solar
  centre-to-limb variation of the triplet to 0.02 dex, without any
  calibration of the inelastic collisional rate coefficients or other
  free parameters. We infer log ɛ<SUB>O</SUB> = 8.69 ± 0.03 from the
  triplet alone, strengthening the case for a low solar oxygen abundance.

---------------------------------------------------------
Title: The GALAH Survey: second data release
Authors: Buder, Sven; Asplund, Martin; Duong, Ly; Kos, Janez; Lind,
   Karin; Ness, Melissa K.; Sharma, Sanjib; Bland-Hawthorn, Joss; Casey,
   Andrew R.; de Silva, Gayandhi M.; D'Orazi, Valentina; Freeman, Ken C.;
   Lewis, Geraint F.; Lin, Jane; Martell, Sarah L.; Schlesinger, Katharine
   J.; Simpson, Jeffrey D.; Zucker, Daniel B.; Zwitter, Tomaž; Amarsi,
   Anish M.; Anguiano, Borja; Carollo, Daniela; Casagrande, Luca; Čotar,
   Klemen; Cottrell, Peter L.; da Costa, Gary; Gao, Xudong D.; Hayden,
   Michael R.; Horner, Jonathan; Ireland, Michael J.; Kafle, Prajwal R.;
   Munari, Ulisse; Nataf, David M.; Nordlander, Thomas; Stello, Dennis;
   Ting, Yuan-Sen; Traven, Gregor; Watson, Fred; Wittenmyer, Robert A.;
   Wyse, Rosemary F. G.; Yong, David; Zinn, Joel C.; Žerjal, Maruša;
   Galah Collaboration
2018MNRAS.478.4513B    Altcode: 2018MNRAS.tmp.1218B; 2018arXiv180406041B
  The Galactic Archaeology with HERMES (GALAH) survey is a large-scale
  stellar spectroscopic survey of the Milky Way, designed to deliver
  complementary chemical information to a large number of stars covered
  by the Gaia mission. We present the GALAH second public data release
  (GALAH DR2) containing 342 682 stars. For these stars, the GALAH
  collaboration provides stellar parameters and abundances for up to
  23 elements to the community. Here we present the target selection,
  observation, data reduction, and detailed explanation of how the spectra
  were analysed to estimate stellar parameters and element abundances. For
  the stellar analysis, we have used a multistep approach. We use the
  physics-driven spectrum synthesis of Spectroscopy Made Easy (SME)
  to derive stellar labels (T<SUB>eff</SUB>, log g, [Fe/H], [X/Fe],
  v<SUB>mic</SUB>, vsin i, A_{K_S}) for a representative training
  set of stars. This information is then propagated to the whole
  sample with the data-driven method of The Cannon. Special care has
  been exercised in the spectral synthesis to only consider spectral
  lines that have reliable atomic input data and are little affected by
  blending lines. Departures from local thermodynamic equilibrium (LTE)
  are considered for several key elements, including Li, O, Na, Mg, Al,
  Si, and Fe, using 1D MARCS stellar atmosphere models. Validation tests
  including repeat observations, Gaia benchmark stars, open and globular
  clusters, and K2 asteroseismic targets lend confidence to our methods
  and results. Combining the GALAH DR2 catalogue with the kinematic
  information from Gaia will enable a wide range of Galactic Archaeology
  studies, with unprecedented detail, dimensionality, and scope.

---------------------------------------------------------
Title: Stellar ages and masses in the solar neighbourhood: Bayesian
    analysis using spectroscopy and Gaia DR1 parallaxes
Authors: Lin, Jane; Dotter, Aaron; Ting, Yuan-Sen; Asplund, Martin
2018MNRAS.477.2966L    Altcode: 2018MNRAS.477.2606L; 2018MNRAS.tmp..697L; 2018arXiv180310875L
  We present a Bayesian implementation of isochrone fitting in
  deriving stellar ages and masses, incorporating absolute K magnitude
  (M_K) derived from 2MASS photometry and Gaia DR1 parallax and
  differentiation between initial bulk metallicity and present-day surface
  metallicity, with allowance for incorporating further constraints
  (e.g. asteroseismology) when available. As a test, we re-computed
  stellar ages and masses of ∼4000 stars in the solar neighbourhood
  from six well-studied literature samples using both Hipparcos and
  TGAS parallaxes. Our ages are found to be compatible with literature
  values but with reduced uncertainties in general. The inclusion of
  parallax-based M_K serves as an additional constraint on the derived
  quantities, especially when systematic errors in stellar parameters are
  underestimated. We reconstructed the age-metallicity relationship in
  the solar neighbourhood by re-analysing the Geneva-Copenhagen Survey
  with the inclusion of TGAS-parallaxes and initial bulk metallicity
  sampling. We found a flat trend for disc stars with ages &lt;11 Gyr
  but with smaller scatter at all ages compared to literature.

---------------------------------------------------------
Title: Detailed chemical compositions of the wide binary HD
80606/80607: revised stellar properties and constraints on planet
    formation
Authors: Liu, F.; Yong, D.; Asplund, M.; Feltzing, S.; Mustill, A. J.;
   Meléndez, J.; Ramírez, I.; Lin, J.
2018A&A...614A.138L    Altcode: 2018arXiv180209306L
  Differences in the elemental abundances of planet-hosting stars in
  binary systems can give important clues and constraints about planet
  formation and evolution. In this study we performed a high-precision,
  differential elemental abundance analysis of a wide binary system,
  <ASTROBJ>HD 80606</ASTROBJ>/<ASTROBJ>80607</ASTROBJ>, based on
  high-resolution spectra with high signal-to-noise ratio obtained with
  Keck/HIRES. <ASTROBJ>HD 80606</ASTROBJ> is known to host a giant planet
  with the mass of four Jupiters, but no planet has been detected around
  <ASTROBJ>HD 80607</ASTROBJ> so far. We determined stellar parameters as
  well as abundances for 23 elements for these two stars with extremely
  high precision. Our main results are that (i) we confirmed that the two
  components share very similar chemical compositions, but <ASTROBJ>HD
  80606</ASTROBJ> is marginally more metal-rich than <ASTROBJ>HD
  80607</ASTROBJ>, with an average difference of +0.013 ± 0.002 dex
  (σ = 0.009 dex); and (ii) there is no obvious trend between abundance
  differences and condensation temperature. Assuming that this binary
  formed from material with the same chemical composition, it is difficult
  to understand how giant planet formation could produce the present-day
  photospheric abundances of the elements we measure. We cannot
  exclude the possibility that <ASTROBJ>HD 80606</ASTROBJ> might have
  accreted about 2.5 to 5 M<SUB>Earth</SUB> material onto its surface,
  possibly from a planet destabilised by the known highly eccentric
  giant. <P />The data presented herein were obtained at the W.M. Keck
  Observatory, which is operated as a scientific partnership among the
  California Institute of Technology, the University of California and
  the National Aeronautics and Space Administration. The Observatory
  was made possible by the generous financial support of the W.M. Keck
  Foundation.Table A.1 is only available at the CDS via anonymous ftp to
  <A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/614/A138">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/614/A138</A>

---------------------------------------------------------
Title: The GALAH survey: stellar streams and how stellar velocity
    distributions vary with Galactic longitude, hemisphere, and
    metallicity
Authors: Quillen, Alice C.; De Silva, Gayandhi; Sharma, Sanjib;
   Hayden, Michael; Freeman, Ken; Bland-Hawthorn, Joss; Žerjal, Maruša;
   Asplund, Martin; Buder, Sven; D'Orazi, Valentina; Duong, Ly; Kos,
   Janez; Lin, Jane; Lind, Karin; Martell, Sarah; Schlesinger, Katharine;
   Simpson, Jeffrey D.; Zucker, Daniel B.; Zwitter, Tomaz; Anguiano,
   Borja; Carollo, Daniela; Casagrande, Luca; Cotar, Klemen; Cottrell,
   Peter L.; Ireland, Michael; Kafle, Prajwal R.; Horner, Jonathan;
   Lewis, Geraint F.; Nataf, David M.; Ting, Yuan-Sen; Watson, Fred;
   Wittenmyer, Rob; Wyse, Rosemary
2018MNRAS.478..228Q    Altcode: 2018MNRAS.tmp..840Q; 2018arXiv180202924Q
  Using GALAH (GALactic Archaeology with HERMES) survey data of
  nearby stars, we look at how structure in the planar (u, v) velocity
  distribution depends on metallicity and on viewing direction within the
  Galaxy. In nearby stars with distance d ≲ 1 kpc, the Hercules stream
  is most strongly seen in higher metallicity stars [Fe/H] &gt; 0.2. The
  Hercules stream peak v value depends on viewed galactic longitude,
  which we interpret as due to the gap between the stellar stream and
  more circular orbits being associated with a specific angular momentum
  value of about 1640 km s<SUP>-1</SUP> kpc. The association of the
  gap with a particular angular momentum value supports a bar resonant
  model for the Hercules stream. Moving groups previously identified in
  Hipparcos(HIgh Precision Parallax COllecting Satellite) observations are
  easiest to see in stars nearer than 250 pc, and their visibility and
  peak velocities in the velocity distributions depends on both viewing
  direction (galactic longitude and hemisphere) and metallicity. We
  infer that there is fine structure in local velocity distributions
  that varies over distances of a few hundred pc in the Galaxy.

---------------------------------------------------------
Title: Effective temperature determinations of late-type stars based
    on 3D non-LTE Balmer line formation
Authors: Amarsi, A. M.; Nordlander, T.; Barklem, P. S.; Asplund, M.;
   Collet, R.; Lind, K.
2018A&A...615A.139A    Altcode: 2018arXiv180402305A
  Hydrogen Balmer lines are commonly used as spectroscopic effective
  temperature diagnostics of late-type stars. However, reliable
  inferences require accurate model spectra, and the absolute accuracy of
  classical methods that are based on one-dimensional (1D) hydrostatic
  model atmospheres and local thermodynamic equilibrium (LTE) is still
  unclear. To investigate this, we carry out 3D non-LTE calculations for
  the Balmer lines, performed, for the first time, over an extensive grid
  of 3D hydrodynamic STAGGER model atmospheres. For Hα, Hβ, and Hγ we
  find significant 1D non-LTE versus 3D non-LTE differences (3D effects):
  the outer wings tend to be stronger in 3D models, particularly for
  Hγ, while the inner wings can be weaker in 3D models, particularly
  for Hα. For Hα, we also find significant 3D LTE versus 3D non-LTE
  differences (non-LTE effects): in warmer stars (T<SUB>eff</SUB>
  ≈ 6500 K) the inner wings tend to be weaker in non-LTE models,
  while at lower effective temperatures (T<SUB>eff</SUB> ≈ 4500 K)
  the inner wings can be stronger in non-LTE models; the non-LTE effects
  are more severe at lower metallicities. We test our 3D non-LTE models
  against observations of well-studied benchmark stars. For the Sun,
  we infer concordant effective temperatures from Hα, Hβ, and Hγ;
  however the value is too low by around 50 K which could signal residual
  modelling shortcomings. For other benchmark stars, our 3D non-LTE
  models generally reproduce the effective temperatures to within 1σ
  uncertainties. For Hα, the absolute 3D effects and non-LTE effects
  can separately reach around 100 K, in terms of inferred effective
  temperatures. For metal-poor turn-off stars, 1D LTE models of Hα can
  underestimate effective temperatures by around 150 K. Our 3D non-LTE
  model spectra are publicly available, and can be used for more reliable
  spectroscopic effective temperature determinations. <P />The 3D non-LTE
  model spectra is also available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/615/A139">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/615/A139</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: 3D non-LTE Balmer line formation
    (Amarsi+, 2018)
Authors: Amarsi, A. M.; Nordlander, T.; Barklem, P. S.; Asplund, M.;
   Collet, R.; Lind, K.
2018yCat..36150139A    Altcode:
  File lineprof.txt: contains emergent total (I) and continuum (Ic)
  intensities at specific wavelengths (wl, or wl_air) and viewing angles
  (mu), the latter with weights (wmu), for the model atmospheres
  with different effective temperatures (Teff), surface gravities
  (lgg), and iron abundance ratios ([Fe/H]). If rotational broadening
  and instrumental broadening are to be neglected, the normalised
  flux can be obtained via Sum(I * mu * wmu) / Sum(Ic * mu * wmu),
  at a given wavelength and for a given model atmosphere. <P />File
  flux_3d.fits: contains a regular grid of normalised fluxes constructed
  by interpolation/extrapolation of the data in lineprof.txt. The fluxes
  are given for different effective temperatures (Teff), surface gravities
  (lgg), iron abundance ratios ([Fe/H]), projected rotational velocity
  (vsini), Gaussian instrumental profile velocity widths (vbroad),
  vacuum wavelengths (wl), and lines. <P />(2 data files).

---------------------------------------------------------
Title: Measuring Oxygen Abundances from Stellar Spectra without
    Oxygen Lines
Authors: Ting, Yuan-Sen; Conroy, Charlie; Rix, Hans-Walter; Asplund,
   Martin
2018ApJ...860..159T    Altcode: 2018arXiv180107370T
  Oxygen is the most abundant “metal” element in stars and in
  the cosmos. But determining oxygen abundances in stars has proven
  challenging, because of the shortage of detectable atomic oxygen lines
  in their optical spectra as well as observational and theoretical
  complications with these lines (e.g., blends, three-dimensional,
  non-LTE). Nonetheless, Ting et al. were recently able to demonstrate
  that oxygen abundances can be determined from low-resolution (R ≃
  2000) optical spectra. Here, we investigate the physical processes
  that enable such a measurement for cool stars, such as K-giants. We
  show that the strongest spectral diagnostics of oxygen come from the
  CNO atomic-molecular network but are manifested in spectral features
  that do not involve oxygen. In the outer atmosphere layers, most of
  the carbon is locked up in CO, and changes to the oxygen abundance
  directly affect the abundances of all other carbon-bearing molecules,
  thereby changing the strength of CH, CN, and C<SUB>2</SUB> features
  across the optical spectrum. In deeper atmosphere layers, most of the
  carbon is in atomic form, and any change in the oxygen abundance has
  little effect on the other carbon-bearing molecules. The key physical
  effect enabling such oxygen abundance measurements is that spectral
  features in the optical arise from both the CO-dominant and the atomic
  carbon-dominant regions, providing non-degenerate constraints on both
  C and O. Beyond the case at hand, the results show that physically
  sound abundances measurements need not be limited to those elements
  that have observable lines themselves.

---------------------------------------------------------
Title: The GALAH survey: properties of the Galactic disc(s) in the
    solar neighbourhood
Authors: Duong, L.; Freeman, K. C.; Asplund, M.; Casagrande, L.; Buder,
   S.; Lind, K.; Ness, M.; Bland-Hawthorn, J.; De Silva, G. M.; D'Orazi,
   V.; Kos, J.; Lewis, G. F.; Lin, J.; Martell, S. L.; Schlesinger, K.;
   Sharma, S.; Simpson, J. D.; Zucker, D. B.; Zwitter, T.; Anguiano, B.;
   Da Costa, G. S.; Hyde, E.; Horner, J.; Kafle, P. R.; Nataf, D. M.;
   Reid, W.; Stello, D.; Ting, Y. -S.; Wyse, R. F. G.
2018MNRAS.476.5216D    Altcode: 2018arXiv180101514D; 2018MNRAS.tmp..504D
  Using data from the GALAH pilot survey, we determine properties of the
  Galactic thin and thick discs near the solar neighbourhood. The data
  cover a small range of Galactocentric radius (7.9 ≲ R_GC ≲ 9.5 kpc),
  but extend up to 4 kpc in height from the Galactic plane, and several
  kpc in the direction of Galactic anti-rotation (at longitude 260°
  ≤ ℓ ≤ 280°). This allows us to reliably measure the vertical
  density and abundance profiles of the chemically and kinematically
  defined `thick' and `thin' discs of the Galaxy. The thin disc (low-α
  population) exhibits a steep negative vertical metallicity gradient,
  at d[M/H]/dz = -0.18 ± 0.01 dex kpc<SUP>-1</SUP>, which is broadly
  consistent with previous studies. In contrast, its vertical α-abundance
  profile is almost flat, with a gradient of d[α/M]/dz = 0.008 ± 0.002
  dex kpc<SUP>-1</SUP>. The steep vertical metallicity gradient of the
  low-α population is in agreement with models where radial migration has
  a major role in the evolution of the thin disc. The thick disc (high-α
  population) has a weaker vertical metallicity gradient d[M/H]/dz =
  -0.058 ± 0.003 dex kpc<SUP>-1</SUP>. The α-abundance of the thick
  disc is nearly constant with height, d[α/M]/dz = 0.007 ± 0.002 dex
  kpc<SUP>-1</SUP>. The negative gradient in metallicity and the small
  gradient in [α/M] indicate that the high-α population experienced
  a settling phase, but also formed prior to the onset of major Type
  Ia supernova enrichment. We explore the implications of the distinct
  α-enrichments and narrow [α/M] range of the sub-populations in the
  context of thick disc formation.

---------------------------------------------------------
Title: Metallicity Variations in the Type II Globular Cluster NGC 6934
Authors: Marino, A. F.; Yong, D.; Milone, A. P.; Piotto, G.; Lundquist,
   M.; Bedin, L. R.; Chené, A. -N.; Da Costa, G.; Asplund, M.; Jerjen, H.
2018ApJ...859...81M    Altcode: 2018arXiv180404158M
  The Hubble Space Telescope photometric survey of Galactic globular
  clusters (GCs) has revealed a peculiar “chromosome map” for NGC
  6934. In addition to a typical sequence, similar to that observed
  in Type I GCs, NGC 6934 displays additional stars on the red side,
  analogous to the anomalous Type II GCs, as defined in our previous
  work. We present a chemical abundance analysis of four red giants in
  this GC. Two stars are located on the chromosome map sequence common
  to all GCs, and another two lie on the additional sequence. We find (i)
  star-to-star Fe variations, with the two anomalous stars being enriched
  by ∼0.2 dex. Because of our small-size sample, this difference is
  at the ∼2.5σ level. (ii) There is no evidence for variations in
  the slow neutron-capture abundances over Fe, at odds with what is
  often observed in anomalous Type II GCs, e.g., M 22 and ω Centauri
  (iii) no large variations in light elements C, O, and Na, compatible
  with locations of the targets on the lower part of the chromosome
  map where such variations are not expected. Since the analyzed stars
  are homogeneous in light elements, the only way to reproduce the
  photometric splits on the sub-giant (SGB) and the red giant (RGB)
  branches is to assume that red RGB/faint SGB stars are enhanced in
  [Fe/H] by ∼0.2. This fact corroborates the spectroscopic evidence
  of a metallicity variation in NGC 6934. The observed chemical pattern
  resembles only partially the other Type II GCs, suggesting that NGC
  6934 might belong either to a third class of GCs, or be a link between
  normal Type I and anomalous Type II GCs. <P />Based on observations
  with the NASA/ESA Hubble Space Telescope, obtained at the Space
  Telescope Science Institute, which is operated by AURA, Inc., under
  NASA contract NAS 5-26555. This paper includes data gathered with the
  6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile,
  and Gemini Telescope at Canada-France-Hawaii Telescope.

---------------------------------------------------------
Title: VizieR Online Data Catalog: M67 solar twins chemical
    compositions (Liu+, 2016)
Authors: Liu, F.; Asplund, M.; Yong, D.; Melendez, J.; Ramirez, I.;
   Karakas, A. I.; Carlos, M.; Marino, A. F.
2018yCat..74630696L    Altcode:
  We observed two solar-type members in M67: M67-1194 and
  M67-1315. One of which (M67-1194) has been studied previously by
  Oenehag et al. (2011A&amp;A...528A..85O). We obtained high resolution
  (R=λ/Δλ=50000), high signal-to-noise ratio (SNR) spectra with the
  0.86" slit of the High Resolution Echelle Spectrometer (HIRES) on the
  10 m Keck I telescope during January 24-25, 2015. <P />(1 data file).

---------------------------------------------------------
Title: The benchmark halo giant HD 122563: CNO abundances revisited
    with three-dimensional hydrodynamic model stellar atmospheres
Authors: Collet, R.; Nordlund, Å.; Asplund, M.; Hayek, W.;
   Trampedach, R.
2018MNRAS.475.3369C    Altcode: 2017arXiv171208099C
  We present an abundance analysis of the low-metallicity benchmark
  red giant star HD 122563 based on realistic, state-of-the-art,
  high-resolution, three-dimensional (3D) model stellar atmospheres
  including non-grey radiative transfer through opacity binning with
  4, 12, and 48 bins. The 48-bin 3D simulation reaches temperatures
  lower by ∼300-500 K than the corresponding 1D model in the upper
  atmosphere. Small variations in the opacity binning, adopted line
  opacities, or chemical mixture can cool the photospheric layers by
  a further ∼100-300 K and alter the effective temperature by ∼100
  K. A 3D local thermodynamic equilibrium (LTE) spectroscopic analysis
  of Fe I and Fe II lines gives discrepant results in terms of derived
  Fe abundance, which we ascribe to non-LTE effects and systematic errors
  on the stellar parameters. We also determine C, N, and O abundances by
  simultaneously fitting CH, OH, NH, and CN molecular bands and lines
  in the ultraviolet, visible, and infrared. We find a small positive
  3D-1D abundance correction for carbon (+0.03 dex) and negative ones for
  nitrogen (-0.07 dex) and oxygen (-0.34 dex). From the analysis of the [O
  I] line at 6300.3 Å, we derive a significantly higher oxygen abundance
  than from molecular lines (+0.46 dex in 3D and +0.15 dex in 1D). We rule
  out important OH photodissociation effects as possible explanation for
  the discrepancy and note that lowering the surface gravity would reduce
  the oxygen abundance difference between molecular and atomic indicators.

---------------------------------------------------------
Title: The GALAH and TESS-HERMES surveys: high-resolution spectroscopy
    of luminous supergiants in the Magellanic Clouds and Bridge
Authors: Simpson, Jeffrey D.; Stello, Dennis; Sharma, Sanjib; Ting,
   Yuan-Sen; Nataf, David M.; Da Costa, Gary; Wittenmyer, Robert A.;
   Horner, Jonathan; Martell, Sarah L.; Lewis, Geraint F.; De Silva,
   Gayandhi M.; Cottrell, Peter L.; Asplund, Martin; Bland-Hawthorn, Joss;
   Buder, Sven; D'Orazi, Valentina; Duong, Ly; Freeman, Ken C.; Kos,
   Janez; Lin, Jane; Lind, Karin; Schlesinger, Katharine. J.; Zucker,
   Daniel B.; Zwitter, Tomaž; Kafle, Prajwal R.; Khanna, Shourya;
   Nordlander, Thomas
2018arXiv180405900S    Altcode:
  We report the serendipitous observations of 571 luminous supergiants
  in the Magellanic Clouds by the spectroscopic GALAH and TESS-HERMES
  surveys: 434 stars in the Large Magellanic Cloud and 137 in the Small
  Magellanic Cloud. We also find one star that appears associated with
  structured star formation in the Magellanic Bridge. Both of these
  surveys are aimed at the local volume of the Galaxy but have simple,
  magnitude-limited selection functions that mean they include some
  observations of luminous extra-Galactic stars. The surveys determine
  stellar parameter and abundances using The Cannon, a data-driven
  generative modelling approach. In this work, we explore the results
  from The Cannon when it is fed the spectra of these intrinsically
  luminous supergiants in the Magellanic Clouds, which are well
  outside the normal bounds of The Cannon's training set. We find that,
  although the parameters are astrophysically incorrect, the $v\sin i$
  and the abundances of lithium, barium, and magnesium are excellent
  discriminants of these stars. It shows that in the future, with an
  expanded training set, it should be possible to determine accurate
  values for these types of stars.

---------------------------------------------------------
Title: Accurate effective temperatures of the metal-poor benchmark
    stars HD 140283, HD 122563, and HD 103095 from CHARA interferometry
Authors: Karovicova, I.; White, T. R.; Nordlander, T.; Lind, K.;
   Casagrande, L.; Ireland, M. J.; Huber, D.; Creevey, O.; Mourard, D.;
   Schaefer, G. H.; Gilmore, G.; Chiavassa, A.; Wittkowski, M.; Jofré,
   P.; Heiter, U.; Thévenin, F.; Asplund, M.
2018MNRAS.475L..81K    Altcode: 2018arXiv180103274K; 2018MNRAS.tmpL..10K
  Large stellar surveys of the Milky Way require validation with reference
  to a set of `benchmark' stars whose fundamental properties are well
  determined. For metal-poor benchmark stars, disagreement between
  spectroscopic and interferometric effective temperatures has called
  the reliability of the temperature scale into question. We present
  new interferometric measurements of three metal-poor benchmark stars,
  HD 140283, HD 122563, and HD 103095, from which we determine their
  effective temperatures. The angular sizes of all the stars were
  determined from observations with the PAVO beam combiner at visible
  wavelengths at the CHARA array, with additional observations of HD
  103095 made with the VEGA instrument, also at the CHARA array. Together
  with photometrically derived bolometric fluxes, the angular diameters
  give a direct measurement of the effective temperature. For HD 140283,
  we find θ<SUB>LD</SUB> = 0.324 ± 0.005 mas, T<SUB>eff</SUB> =
  5787 ± 48 K; for HD 122563, θ<SUB>LD</SUB> = 0.926 ± 0.011 mas,
  T<SUB>eff</SUB> = 4636 ± 37 K; and for HD 103095, θ<SUB>LD</SUB> =
  0.595 ± 0.007 mas, T<SUB>eff</SUB> = 5140 ± 49 K. Our temperatures for
  HD 140283 and HD 103095 are hotter than the previous interferometric
  measurements by 253 and 322 K, respectively. We find good agreement
  between our temperatures and recent spectroscopic and photometric
  estimates. We conclude some previous interferometric measurements
  have been affected by systematic uncertainties larger than their
  quoted errors.

---------------------------------------------------------
Title: The STAGGER-grid: A grid of 3D stellar atmosphere
    models. V. Synthetic stellar spectra and broad-band photometry
Authors: Chiavassa, A.; Casagrande, L.; Collet, R.; Magic, Z.; Bigot,
   L.; Thévenin, F.; Asplund, M.
2018A&A...611A..11C    Altcode: 2018arXiv180101895C
  Context. The surface structures and dynamics of cool stars are
  characterised by the presence of convective motions and turbulent flows
  which shape the emergent spectrum. <BR /> Aims: We used realistic
  three-dimensional (3D) radiative hydrodynamical simulations from
  the STAGGER-grid to calculate synthetic spectra with the radiative
  transfer code OPTIM3D for stars with different stellar parameters to
  predict photometric colours and convective velocity shifts. <BR />
  Methods: We calculated spectra from 1000 to 200 000 Å with a constant
  resolving power of λ/Δλ = 20 000 and from 8470 and 8710 Å (Gaia
  Radial Velocity Spectrometer - RVS - spectral range) with a constant
  resolving power of λ/Δλ = 300 000. <BR /> Results: We used synthetic
  spectra to compute theoretical colours in the Johnson-Cousins UBV
  (RI)<SUB>C</SUB>, SDSS, 2MASS, Gaia, SkyMapper, Strömgren systems,
  and HST-WFC3. Our synthetic magnitudes are compared with those obtained
  using 1D hydrostatic models. We showed that 1D versus 3D differences
  are limited to a small percent except for the narrow filters that
  span the optical and UV region of the spectrum. In addition, we
  derived the effect of the convective velocity fields on selected Fe
  I lines. We found the overall convective shift for 3D simulations
  with respect to the reference 1D hydrostatic models, revealing line
  shifts of between -0.235 and +0.361 km s<SUP>-1</SUP>. We showed a net
  correlation of the convective shifts with the effective temperature:
  lower effective temperatures denote redshifts and higher effective
  temperatures denote blueshifts. We conclude that the extraction
  of accurate radial velocities from RVS spectra need an appropriate
  wavelength correction from convection shifts. <BR /> Conclusions: The
  use of realistic 3D hydrodynamical stellar atmosphere simulations has
  a small but significant impact on the predicted photometry compared
  with classical 1D hydrostatic models for late-type stars. We make
  all the spectra publicly available for the community through the
  POLLUX database. <P />Tables 5-8 are only available at the CDS and
  Table B.1 is also available at the CDS and via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A> (<A
  href="http://cdsarc.u-strasbg.fr">http://130.79.128.5</A>) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/611/A11">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/611/A11</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: HD 80606/80607 equivalent widths
    (Lui+, 2018)
Authors: Liu, F.; Yong, D.; Asplund, M.; Feltzing, S.; Mustill, A. J.;
   Melendez, J.; Ramirez, I.; Lin, J.
2018yCat..36140138L    Altcode:
  We obtained high-resolution (R=86000) spectra of HD 80606/80607
  using the 0.4" slit and 'kv408' filter of the High Resolution Echelle
  Spectrometer (HIRES) on the 10m Keck I telescope on 1 November 2015. The
  spectral wavelength coverage is almost complete from 420 to 860nm. <P
  />Atomic line data, as well as the equivalent width measurements,
  adopted for our analysis. <P />(1 data file).

---------------------------------------------------------
Title: VizieR Online Data Catalog: Temporal evolution of
    neutron-capture elements (Spina+, 2018)
Authors: Spina, L.; Melendez, J.; Karakas, A. I.; Dos Santos, L.;
   Bedell, M.; Asplund, M.; Ramirez, I.; Yong, D.; Alves-Brito, A.;
   Bean, J. L.; Dreizler, S.
2018yCat..74742580S    Altcode:
  Spectroscopic parameters and abundances for the 79 solar twin stars
  analysed in this paper. <P />(4 data files).

---------------------------------------------------------
Title: The K2-HERMES Survey. I. Planet-candidate Properties from K2
    Campaigns 1-3
Authors: Wittenmyer, Robert A.; Sharma, Sanjib; Stello, Dennis; Buder,
   Sven; Kos, Janez; Asplund, Martin; Duong, Ly; Lin, Jane; Lind, Karin;
   Ness, Melissa; Zwitter, Tomaz; Horner, Jonathan; Clark, Jake; Kane,
   Stephen R.; Huber, Daniel; Bland-Hawthorn, Joss; Casey, Andrew R.; De
   Silva, Gayandhi M.; D'Orazi, Valentina; Freeman, Ken; Martell, Sarah;
   Simpson, Jeffrey D.; Zucker, Daniel B.; Anguiano, Borja; Casagrande,
   Luca; Esdaile, James; Hon, Marc; Ireland, Michael; Kafle, Prajwal R.;
   Khanna, Shourya; Marshall, J. P.; Saddon, Mohd Hafiz Mohd; Traven,
   Gregor; Wright, Duncan
2018AJ....155...84W    Altcode: 2017arXiv171206774W
  Accurate and precise radius estimates of transiting exoplanets
  are critical for understanding their compositions and formation
  mechanisms. To know the planet, we must know the host star in as
  much detail as possible. We present first results from the K2-HERMES
  project, which uses the HERMES multi-object spectrograph on the
  Anglo-Australian Telescope to obtain R ∼ 28000 spectra of up
  to 360 stars in one exposure. This ongoing project aims to derive
  self-consistent spectroscopic parameters for about half of K2 target
  stars. We present complete stellar parameters and isochrone-derived
  masses and radii for 46 stars hosting 57 K2 candidate planets in
  Campaigns 1-3. Our revised host-star radii cast severe doubt on three
  candidate planets: EPIC 201407812.01, EPIC 203070421.01, and EPIC
  202843107.01, all of which now have inferred radii well in excess of
  the largest known inflated Jovian planets.

---------------------------------------------------------
Title: The temporal evolution of neutron-capture elements in the
    Galactic discs
Authors: Spina, Lorenzo; Meléndez, Jorge; Karakas, Amanda I.; dos
   Santos, Leonardo; Bedell, Megan; Asplund, Martin; Ramírez, Ivan;
   Yong, David; Alves-Brito, Alan; Bean, Jacob L.; Dreizler, Stefan
2018MNRAS.474.2580S    Altcode: 2017arXiv171103643S
  Important insights into the formation and evolution of the Galactic
  disc(s) are contained in the chemical compositions of stars. We
  analysed high-resolution and high signal-to-noise HARPS spectra of 79
  solar twin stars in order to obtain precise determinations of their
  atmospheric parameters, ages (σ ∼0.4 Gyr) and chemical abundances
  (σ &lt;0.01 dex) of 12 neutron-capture elements (Sr, Y, Zr, Ba, La,
  Ce, Pr, Nd, Sm, Eu, Gd and Dy). This valuable data set allows us to
  study the [X/Fe]-age relations over a time interval of ∼10 Gyr and
  among stars belonging to the thin and thick discs. These relations show
  that (i) the s-process has been the main channel of nucleosynthesis
  of n-capture elements during the evolution of the thin disc; (ii)
  the thick disc is rich in r-process elements which suggests that its
  formation has been rapid and intensive. In addition, the heavy (Ba,
  La, Ce) and light (Sr, Y, Zr) s-process elements revealed details on
  the dependence between the yields of AGB stars and the stellar mass
  or metallicity. Finally, we confirmed that both [Y/Mg] and [Y/Al]
  ratios can be employed as stellar clocks, allowing ages of solar twin
  stars to be estimated with an average precision of ∼0.5 Gyr.

---------------------------------------------------------
Title: The GALAH survey: chemical tagging of star clusters and new
    members in the Pleiades
Authors: Kos, Janez; Bland-Hawthorn, Joss; Freeman, Ken; Buder, Sven;
   Traven, Gregor; De Silva, Gayandhi M.; Sharma, Sanjib; Asplund, Martin;
   Duong, Ly; Lin, Jane; Lind, Karin; Martell, Sarah; Simpson, Jeffrey D.;
   Stello, Dennis; Zucker, Daniel B.; Zwitter, Tomaž; Anguiano, Borja;
   Da Costa, Gary; D'Orazi, Valentina; Horner, Jonathan; Kafle, Prajwal
   R.; Lewis, Geraint; Munari, Ulisse; Nataf, David M.; Ness, Melissa;
   Reid, Warren; Schlesinger, Katie; Ting, Yuan-Sen; Wyse, Rosemary
2018MNRAS.473.4612K    Altcode: 2017arXiv170900794K
  The technique of chemical tagging uses the elemental abundances
  of stellar atmospheres to 'reconstruct' chemically homogeneous star
  clusters that have long since dispersed. The GALAH spectroscopic survey
  - which aims to observe one million stars using the Anglo-Australian
  Telescope - allows us to measure up to 30 elements or dimensions in the
  stellar chemical abundance space, many of which are not independent. How
  to find clustering reliably in a noisy high-dimensional space is
  a difficult problem that remains largely unsolved. Here, we explore
  t-distributed stochastic neighbour embedding (t-SNE) - which identifies
  an optimal mapping of a high-dimensional space into fewer dimensions
  - whilst conserving the original clustering information. Typically,
  the projection is made to a 2D space to aid recognition of clusters by
  eye. We show that this method is a reliable tool for chemical tagging
  because it can: (i) resolve clustering in chemical space alone, (ii)
  recover known open and globular clusters with high efficiency and low
  contamination, and (iii) relate field stars to known clusters. t-SNE
  also provides a useful visualization of a high-dimensional space. We
  demonstrate the method on a data set of 13 abundances measured in
  the spectra of 187 000 stars by the GALAH survey. We recover seven
  of the nine observed clusters (six globular and three open clusters)
  in chemical space with minimal contamination from field stars and
  low numbers of outliers. With chemical tagging, we also identify two
  Pleiades supercluster members (which we confirm kinematically), one
  as far as 6° - one tidal radius away from the cluster centre.

---------------------------------------------------------
Title: VizieR Online Data Catalog: STAGGER-grid of 3D stellar
    models. V. (Chiavassa+, 2018)
Authors: Chiavassa, A.; Casagrande, L.; Collet, R.; Magic, Z.; Bigot,
   L.; Thevenin, F.; Asplund, M.
2018yCat..36110011C    Altcode:
  Table B0: RHD simulations' stellar parameters, bolometric magnitude,
  and bolometric correction for Johnson-Cousins, 2MASS, SDSS (columns
  13 to 17), and Gaia systems <P />Table 4: RHD simulations' stellar
  parameters, bolometric magnitude, and bolometric correction for
  SkyMapper photometric system, and Stroemgren index b-y, m1=(v-b)-(b-y),
  and c1=(u-v)-(v-b) <P />Table 5: RHD simulations' stellar parameters,
  bolometric magnitude, and bolometric correction for the HST-WFC3
  in VEGA system <P />Table 6: RHD simulations' stellar parameters,
  bolometric magnitude, and bolometric correction for the HST-WFC3 in ST
  system <P />Table 7: RHD simulations' stellar parameters, bolometric
  magnitude, and bolometric correction for the HST-WFC3 in AB system <P
  />(5 data files).

---------------------------------------------------------
Title: The GALAH survey: the ancient Galactic thin and thick disks
Authors: Asplund, M.
2018cdeg.confE..20A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The TESS-HERMES survey data release 1: high-resolution
    spectroscopy of the TESS southern continuous viewing zone
Authors: Sharma, Sanjib; Stello, Dennis; Buder, Sven; Kos, Janez;
   Bland-Hawthorn, Joss; Asplund, Martin; Duong, Ly; Lin, Jane; Lind,
   Karin; Ness, Melissa; Huber, Daniel; Zwitter, Tomaz; Traven, Gregor;
   Hon, Marc; Kafle, Prajwal R.; Khanna, Shourya; Saddon, Hafiz; Anguiano,
   Borja; Casey, Andrew R.; Freeman, Ken; Martell, Sarah; De Silva,
   Gayandhi M.; Simpson, Jeffrey D.; Wittenmyer, Rob A.; Zucker, Daniel B.
2018MNRAS.473.2004S    Altcode: 2017arXiv170705753S
  The Transiting Exoplanet Survey Satellite (TESS) will provide
  high-precision time series photometry for millions of stars with
  at least a half-hour cadence. Of particular interest are the
  circular regions of 12° radius centred around the ecliptic poles
  that will be observed continuously for a full year. Spectroscopic
  stellar parameters are desirable to characterize and select suitable
  targets for TESS, whether they are focused on exploring exoplanets,
  stellar astrophysics or Galactic archaeology. Here, we present
  spectroscopic stellar parameters (T<SUB>eff</SUB>, log g, [Fe/H],
  v sin i, v<SUB>micro</SUB>) for about 16 000 dwarf and subgiant
  stars in TESS' southern continuous viewing zone. For almost all
  the stars, we also present Bayesian estimates of stellar properties
  including distance, extinction, mass, radius and age using theoretical
  isochrones. Stellar surface gravity and radius are made available
  for an additional set of roughly 8500 red giants. All our target
  stars are in the range 10 &lt; V &lt; 13.1. Among them, we identify
  and list 227 stars belonging to the Large Magellanic Cloud. The data
  were taken using the High Efficiency and Resolution Multi-Element
  Spectrograph (HERMES; R ∼ 28 000) at the Anglo-Australian Telescope
  as part of the TESS-HERMES survey. Comparing our results with the
  TESS Input Catalogue (TIC) shows that the TIC is generally efficient
  in separating dwarfs and giants, but it has flagged more than 100
  cool dwarfs (T<SUB>eff</SUB> &lt; 4800 K) as giants, which ought to
  be high-priority targets for the exoplanet search. The catalogue can
  be accessed via http://www.physics.usyd.edu.au/tess-hermes/, or at
  Mikulski Archive for Space Telescopes (MAST).

---------------------------------------------------------
Title: Spectroscopic binaries in the Solar Twin Planet Search program:
    from substellar-mass to M dwarf companions
Authors: dos Santos, Leonardo A.; Meléndez, Jorge; Bedell, Megan;
   Bean, Jacob L.; Spina, Lorenzo; Alves-Brito, Alan; Dreizler, Stefan;
   Ramírez, Iván; Asplund, Martin
2017MNRAS.472.3425D    Altcode: 2017arXiv170807465D
  Previous studies on the rotation of Sun-like stars revealed that
  the rotational rates of young stars converge towards a well-defined
  evolution that follows a power-law decay. It seems, however, that some
  binary stars do not obey this relation, often by displaying enhanced
  rotational rates and activity. In the Solar Twin Planet Search program,
  we observed several solar twin binaries, and found a multiplicity
  fraction of 42 per cent ± 6 per cent in the whole sample; moreover,
  at least three of these binaries (HIP 19911, HIP 67620 and HIP 103983)
  clearly exhibit the aforementioned anomalies. We investigated the
  configuration of the binaries in the program, and discovered new
  companions for HIP 6407, HIP 54582, HIP 62039 and HIP 30037, of which
  the latter is orbited by a 0.06 M<SUB>⊙</SUB> brown dwarf in a 1
  m long orbit. We report the orbital parameters of the systems with
  well-sampled orbits and, in addition, the lower limits of parameters
  for the companions that only display a curvature in their radial
  velocities. For the linear trend binaries, we report an estimate
  of the masses of their companions when their observed separation
  is available, and a minimum mass otherwise. We conclude that solar
  twin binaries with low-mass stellar companions at moderate orbital
  periods do not display signs of a distinct rotational evolution when
  compared to single stars. We confirm that the three peculiar stars are
  double-lined binaries, and that their companions are polluting their
  spectra, which explains the observed anomalies.

---------------------------------------------------------
Title: Red supergiant stars in NGC 4449, NGC 5055, and NGC 5457
Authors: Chun, Sang-Hyun; Sohn, Yong-Jong; Asplund, Martin; Casagrande,
   Luca
2017IAUS..329..392C    Altcode:
  Nearby galaxies are ideal objects for the study of the mechanisms of
  galaxy formation and evolution, and massive stars in nearby galaxies
  are useful sources to investigate the structures and formation of the
  galaxies. It is important to gather the contents of massive stars for
  a number of galaxies spanning various metallicities. We focus on the
  red supergiants (RSGs) in nearby galaxies NGC 4449, NGC 5055, and
  NGC 5457, and the photometric properties of RSGs of three galaxies
  were investigated using near-infrared (JHK) imaging data obtained
  from WFCAM UKIRT. The (J - K, K)<SUB>0</SUB> CMDs are investigated
  and compared with theoretical isochrones (Figure 1). The majority
  of RSGs in three galaxies have common age ranges from log(t <SUB>
  yr </SUB>) = 6.9 to log(t <SUB> yr </SUB>) = 7.3, and this indicates
  that these galaxies have experienced recent star formation within 20
  Myr. Spatial correlation of RSGs with H II regions and their colour
  distribution were also investigated. For NGC 4449 and NGC 5457, the
  RSGs are spatially correlated with the H II regions, which however is
  not the case for NGC 5055. We found a similar colour distribution and
  a constant peak magnitude of M <SUB> K </SUB> = -11.9 for the RSGs in
  the three galaxies.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Abundances of solar twins from
    Keck/HIRES (Bedell+, 2017)
Authors: Bedell, M.; Bean, J. L.; Melendez, J.; Mills, S. M.; Fabrycky,
   D. C.; Freitas, F. C.; Ramirez, I.; Asplund, M.; Liu, F.; Yong, D.
2017yCat..18390094B    Altcode:
  Over the course of two consecutive nights (2015 July 26-27), we made 22
  exposures of Kepler-11 of 1200s each for a coadded result of S/N~260
  per pixel in the continuum near 600nm. For these observations, HIRES
  was used with a resolution R~67000 and wavelength coverage between
  390 and 830nm. We also observed the solar spectrum (via reflection
  from Ceres) and nine bright potential Kepler-11 twins with the same
  instrumental setup and similar S/N. <P />(2 data files).

---------------------------------------------------------
Title: VizieR Online Data Catalog: EMBLA survey. Galactic bulge
    metal-poor stars (Howes+, 2016)
Authors: Howes, L. M.; Asplund, M.; Keller, S. C.; Casey, A. R.; Yong,
   D.; Lind, K.; Frebel, A.; Hays, A.; Alves-Brito, A.; Bessell, M. S.;
   Casagrande, L.; Marino, A. F.; Nataf, D. M.; Owen, C. I.; da Costa,
   G. S.; Schmidt, B. P.; Tisserand, P.
2017yCat..74600884H    Altcode:
  Ten stars were observed using the MIKE high-resolution spectrograph
  on Magellan's 6.5m Clay telescope. The observations took place between
  April and June of 2012, and all make use of the full wavelength coverage
  offered by MIKE, with the spectra covering (as a minimum) 370-890nm. All
  except one star (SMSS J182637.10-342924.2) were configured with a
  1.0 arcsec slit, resulting in resolving powers of 22000 in the blue
  and 28000 in the red, and were binned by two in both the spatial and
  spectral directions. SMSS J182637.10-342924.2 was instead observed in
  April as part of a different set of observations, where a slit with
  width of 0.35-arcsec and no spatial or spectral binning, was used. This
  provided resolving powers of 83000 and 65000, in the blue and red,
  respectively. <P />(5 data files).

---------------------------------------------------------
Title: Chemical evolution of the Galactic bulge as traced by
    microlensed dwarf and subgiant stars. VI. Age and abundance structure
    of the stellar populations in the central sub-kpc of the Milky Way
Authors: Bensby, T.; Feltzing, S.; Gould, A.; Yee, J. C.; Johnson,
   J. A.; Asplund, M.; Meléndez, J.; Lucatello, S.; Howes, L. M.;
   McWilliam, A.; Udalski, A.; Szymański, M. K.; Soszyński, I.; Poleski,
   R.; Wyrzykowski, Ł.; Ulaczyk, K.; Kozłowski, S.; Pietrukowicz, P.;
   Skowron, J.; Mróz, P.; Pawlak, M.; Abe, F.; Asakura, Y.; Bhattacharya,
   A.; Bond, I. A.; Bennett, D. P.; Hirao, Y.; Nagakane, M.; Koshimoto,
   N.; Sumi, T.; Suzuki, D.; Tristram, P. J.
2017A&A...605A..89B    Altcode: 2017arXiv170202971B
  We present a detailed elemental abundance study of 90 F and G
  dwarf, turn-off, and subgiant stars in the Galactic bulge. Based on
  high-resolution spectra acquired during gravitational microlensing
  events, stellar ages and abundances for 11 elements (Na, Mg, Al,
  Si, Ca, Ti, Cr, Fe, Zn, Y and Ba) have been determined. Four main
  findings are presented: (1) a wide metallicity distribution with
  distinct peaks at [Fe/H] = -1.09, -0.63, -0.20, + 0.12, + 0.41; (2)
  ahigh fraction of intermediate-age to young stars where at [Fe/H] &gt;
  0 more than 35% are younger than 8 Gyr, and for [Fe/H] ≲ -0.5 most
  stars are 10 Gyr or older; (3) several episodes of significant star
  formation in the bulge has been identified: 3, 6, 8, and 11 Gyr ago;
  (4) tentatively the "knee" in the α-element abundance trends of the
  sub-solar metallicity bulge is located at a slightly higher [Fe/H] than
  in the local thick disk. These findings show that the Galactic bulge
  has complex age and abundance properties that appear to be tightly
  connected to the main Galactic stellar populations. In particular,
  the peaks in the metallicity distribution, the star formation episodes,
  and the abundance trends, show similarities with the properties of the
  Galactic thin and thick disks. At the same time, the star formation
  rate appears to have been slightly faster in the bulge than in the
  local thick disk, which most likely is an indication of the denser
  stellar environment closer to the Galactic centre. There are also
  additional components not seen outside the bulge region, and that most
  likely can be associated with the Galactic bar. Our results strengthen
  the observational evidence that support the idea of a secular origin
  for the Galactic bulge, formed out of the other main Galactic stellar
  populations present in the central regions of our Galaxy. Additionally,
  our analysis of this enlarged sample suggests that the (V-I)<SUB>0</SUB>
  colour of the bulge red clump should be revised to 1.09. <P />Based
  on data obtained with the European Southern Observatory telescopes
  (Proposal ID:s 87.B-0600, 88.B-0349, 89.B-0047, 90.B-0204, 91.B-0289,
  92.B-0626, 93.B-0700, 94.B-0282), the Magellan Clay telescope at the
  Las Campanas observatory, and the Keck I telescope at the W.M. Keck
  Observatory, which is operated as a scientific partnership among the
  California Institute of Technology, the University of California
  and the National Aeronautics and Space Administration.Full Tables
  A.1 and A.2 are only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (<A href="http://130.79.128.5">http://130.79.128.5</A>) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/605/A89">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/605/A89</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: Spectra of the post-AGB star
    J005252.87-722842.9 (Kamath+, 2017)
Authors: Kamath, D.; van Winckel, H.; Wood, P. R.; Asplund, M.;
   Karakas, A. I.; Lattanzio, J. C.
2017yCat..18360015K    Altcode:
  We obtained high-resolution optical spectra using the UVES echelle
  spectrograph, mounted on the 8m UT2 Kueyen Telescope of the VLT array
  at the Paranal Observatory of ESO in Chile. <P />(2 data files).

---------------------------------------------------------
Title: Non-LTE line formation of Fe in late-type stars - IV. Modelling
    of the solar centre-to-limb variation in 3D
Authors: Lind, K.; Amarsi, A. M.; Asplund, M.; Barklem, P. S.;
   Bautista, M.; Bergemann, M.; Collet, R.; Kiselman, D.; Leenaarts,
   J.; Pereira, T. M. D.
2017MNRAS.468.4311L    Altcode: 2017arXiv170304027L
  Our ability to model the shapes and strengths of iron lines in the solar
  spectrum is a critical test of the accuracy of the solar iron abundance,
  which sets the absolute zero-point of all stellar metallicities. We use
  an extensive 463-level Fe atom with new photoionization cross-sections
  for Fe I and quantum mechanical calculations of collisional excitation
  and charge transfer with neutral hydrogen; the latter effectively remove
  a free parameter that has hampered all previous line formation studies
  of Fe in non-local thermodynamic equilibrium (NLTE). For the first
  time, we use realistic 3D NLTE calculations of Fe for a quantitative
  comparison to solar observations. We confront our theoretical line
  profiles with observations taken at different viewing angles across
  the solar disc with the Swedish 1-m Solar Telescope. We find that
  3D modelling well reproduces the observed centre-to-limb behaviour
  of spectral lines overall, but highlight aspects that may require
  further work, especially cross-sections for inelastic collisions with
  electrons. Our inferred solar iron abundance is log (ɛ<SUB>Fe</SUB>)
  = 7.48 ± 0.04 dex.

---------------------------------------------------------
Title: Spectroscopy and Photometry of Multiple Populations along
    the Asymptotic Giant Branch of NGC 2808 and NGC 6121 (M4)
Authors: Marino, A. F.; Milone, A. P.; Yong, D.; Da Costa, G.;
   Asplund, M.; Bedin, L. R.; Jerjen, H.; Nardiello, D.; Piotto, G.;
   Renzini, A.; Shetrone, M.
2017ApJ...843...66M    Altcode: 2017arXiv170602278M
  We present a photometric and spectroscopic study of multiple populations
  along the asymptotic giant branch (AGB) of the intermediate-metallicity
  globular clusters (GCs) NGC 2808 and NGC 6121 (M4). Chemical abundances
  of O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe, Co, Ni, Zn, Y, and Ce in
  AGB stars from high-resolution FLAMES+UVES@VLT spectra are reported
  for both clusters. Our spectroscopic results have been combined with
  multiwavelength photometry from the Hubble Space Telescope UV survey
  of Galactic GCs and ground-based photometry, as well as proper motions
  derived by combining stellar positions from ground-based images and
  Gaia DR1. Our analysis reveals that the AGBs of both clusters host
  multiple populations with different chemical compositions. In M4,
  we have identified two main populations of stars with different Na/O
  content lying on distinct AGBs in the {m}<SUB>{{F</SUB>}438{{W}}}
  versus {C}<SUB>{{F</SUB>}275{{W}},{{F}}336{{W}},{{F}}438{{W}}} and
  the V versus {C}<SUB>{{U</SUB>},{{B}},{{I}}} pseudo-color-magnitude
  diagrams. In the more massive and complex GC NGC 2808, three groups
  of stars with different chemical abundances occupy different locations
  on the so-called “chromosome map” photometric diagram constructed
  for AGB stars. The spectroscopic + photometric comparison of stellar
  populations along the AGB and the red giants of this GC suggests that
  the AGB hosts stellar populations with a range in helium abundances
  from primordial to high contents of Y∼ 0.32. By contrast, from
  our data set, there is no evidence for stars with extreme helium
  abundance (Y∼ 0.38) on the AGB, suggesting that the most He-rich
  stars of NGC 2808 do not reach this phase. <P />Based on observations
  collected at the European Organisation for Astronomical Research in
  the Southern Hemisphere under ESO programs 093.D-0789 and 094.D-0455
  and on observations with the NASA/ESA Hubble Space Telescope, obtained
  at the Space Telescope Science Institute, which is operated by AURA,
  Inc., under NASA contract NAS 5-26555.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Abundances of microlensed Bulge
    dwarf stars. VI. (Bensby+, 2017)
Authors: Bensby, T.; Feltzing, S.; Gould, A.; Yee; J. C.; Johnson,
   J. A.; Asplund, M.; Melendez, J.; Lucatello, S.; Howes, L. M.;
   McWilliam, A.; Udalski, A.; Szymanski, M. K.; Soszynski, I.; Poleski,
   R.; Wyrzykowski, L.; Ulaczyk, K.; Kozlowski, S.; Pietrukowicz, P.;
   Skowron, J.; Mroz, P.; Pawlak; M.; Abe, F.; Asakura, Y.; Bhattacharya,
   A.; Bond, I. A.; Bennett, D. P.; Hirao, Y.; Nagakane, M.; Koshimoto,
   N.; Sumi, T.; Suzuki, D.; Tristram, P. J.
2017yCat..36050089B    Altcode:
  For each spectral line we give the lower excitation potential,
  measured equivalent widths, and derived absolute abundances. We
  also give median abundances for each star, normalised to the Sun,
  and errors in the median abundances. These tables contain data for
  all so far 91 microlensed dwarf stars, and superseeds the tables
  in Bensby et al. (2009, Cat. J/A+A/499/737), Bensby et al. (2010,
  Cat. J/A+A/512/A41), Bensby et al. (2011, Cat. J/A+A/533/A134), and
  Bensby et al. (2013, Cat. J/A+A/549/A147). <P />(2 data files).

---------------------------------------------------------
Title: Red supergiant stars in NGC 4449, NGC 5055 (M63) and NGC 5457
    (M101)
Authors: Chun, Sang-Hyun; Sohn, Young-Jong; Asplund, Martin;
   Casagrande, Luca
2017MNRAS.467..102C    Altcode:
  The photometric properties of red supergiants (RSGs) in three nearby
  galaxies NGC 4449, NGC 5055 and NGC 5457 were investigated using
  near-infrared (JHK) imaging data obtained from WFCAM UKIRT. The
  resulting near-infrared photometric catalogue was combined with
  optical archive data to remove foreground Galactic stars. We found
  that the foreground stars can be separated from the supergiants in
  a (I - K, r - I) colour-colour diagram. The (J - K, K)<SUB>0</SUB>
  colour-magnitude diagrams of the three galaxies are investigated and
  compared with theoretical isochrones. The majority of RSGs in the three
  galaxies have common age ranges from log (t<SUB>yr</SUB>) = 6.9 to log
  (t<SUB>yr</SUB>) = 7.3, and this indicates that these galaxies have
  experienced recent star formation within 20 Myr. For NGC 4449 and NGC
  5457, the RSGs are spatially correlated with the H II regions, which,
  however, is not the case for NGC 5055. We were not able to identify
  a clear metallicity dependence on the colours and the peak absolute
  magnitudes of the RSGs in the three galaxies. The inaccuracy of our
  photometric data contributes to the unclear metallicity effect on the
  colours of RSGs. Instead, we found a similar colour distribution and
  a constant peak magnitude of M<SUB>K</SUB> = -11.9 for the RSGs in
  the three galaxies. Therefore, we note that additional spectroscopy
  data for our RSG candidates, including photometry, are necessary to
  examine whether the RSG population changes with metallicity.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Line list for stellar chemical
    abundances (Bedell+, 2014)
Authors: Bedell, M.; Melendez, J.; Bean, J. L.; Ramirez, I.; Leite,
   P.; Asplund, M.
2017yCat..17950023B    Altcode:
  The five solar spectra used in this analysis were obtained with very
  high resolution and signal-to-noise ratios (S/Ns) characteristic of
  data used in past stellar abundance analyses. Two spectra were taken
  with the Echelle SpectroPolarimetric Device for the Observation of
  Stars (ESPaDOnS) instrument (Donati 2003, Solar Polarization (ASP
  Conf. Ser. 307), ed. J. Trujillo-Bueno &amp; J. Sanchez Almeida
  (San Francisco, CA: ASP), 41) at the 3.6 m Canada-France-Hawaii
  Telescope on the night of 2013 March 4. The asteroids Ceres and
  Vesta were each observed in "star only" mode at a spectral resolving
  power R=81000. The remaining three solar spectra were taken with the
  Magellan Inamori Kyocera Echelle (MIKE) spectrograph (Bernstein et
  al. 2003SPIE.4841.1694B) at the 6.5 m Magellan Clay telescope. The
  asteroid Vesta was observed twice and Iris was observed once during
  three separate observing runs spanning January to September of 2011. All
  observations were carried out in MIKE's standard setup with the 0.35
  arcsec width slit, giving a spectral resolving power of R=83000 on
  the blue CCD and 65000 on the red CCD. <P />(1 data file).

---------------------------------------------------------
Title: Sun-like stars unlike the Sun: Clues for chemical anomaliesof
    cool stars
Authors: Adibekyan, V.; Delgado-Mena, E.; Feltzing, S.; González
   Hernández, J. I.; Hinkel, N. R.; Korn, A. J.; Asplund, M.; Beck,
   P. G.; Deal, M.; Gustafsson, B.; Honda, S.; Lind, K.; Nissen, P. E.;
   Spina, L.
2017AN....338..442A    Altcode: 2017arXiv170105737A
  We present a summary of the splinter session "Sun-like stars unlike
  the Sun" that was held on June 9, 2016, as part of the Cool Stars
  19 conference (Uppsala, Sweden), in which the main limitations
  (in the theory and observations) in the derivation of very precise
  stellar parameters and chemical abundances of Sun-like stars were
  discussed. The most important and most debated processes that can
  produce chemical peculiarities in solar-type stars were outlined and
  discussed. Finally, in an open discussion between all the participants,
  we tried to identify new pathways and prospects toward future solutions
  of the currently open questions.

---------------------------------------------------------
Title: The Influence of Atomic Diffusion on Stellar Ages and Chemical
    Tagging
Authors: Dotter, Aaron; Conroy, Charlie; Cargile, Phillip; Asplund,
   Martin
2017ApJ...840...99D    Altcode: 2017arXiv170403465D
  In the era of large stellar spectroscopic surveys, there is an emphasis
  on deriving not only stellar abundances but also the ages for millions
  of stars. In the context of Galactic archeology, stellar ages provide a
  direct probe of the formation history of the Galaxy. We use the stellar
  evolution code MESA to compute models with atomic diffusion—with
  and without radiative acceleration—and extra mixing in the surface
  layers. The extra mixing consists of both density-dependent turbulent
  mixing and envelope overshoot mixing. Based on these models we argue
  that it is important to distinguish between initial, bulk abundances
  (parameters) and current, surface abundances (variables) in the
  analysis of individual stellar ages. In stars that maintain radiative
  regions on evolutionary timescales, atomic diffusion modifies the
  surface abundances. We show that when initial, bulk metallicity is
  equated with current, surface metallicity in isochrone age analysis,
  the resulting stellar ages can be systematically overestimated by up
  to 20%. The change of surface abundances with evolutionary phase also
  complicates chemical tagging, which is the concept that dispersed star
  clusters can be identified through unique, high-dimensional chemical
  signatures. Stars from the same cluster, but in different evolutionary
  phases, will show different surface abundances. We speculate that
  calibration of stellar models may allow us to estimate not only stellar
  ages but also initial abundances for individual stars. In the meantime,
  analyzing the chemical properties of stars in similar evolutionary
  phases is essential to minimize the effects of atomic diffusion in
  the context of chemical tagging.

---------------------------------------------------------
Title: Kepler-11 is a Solar Twin: Revising the Masses and Radii of
    Benchmark Planets via Precise Stellar Characterization
Authors: Bedell, Megan; Bean, Jacob L.; Meléndez, Jorge; Mills,
   Sean M.; Fabrycky, Daniel C.; Freitas, Fabrício C.; Ramírez, Ivan;
   Asplund, Martin; Liu, Fan; Yong, David
2017ApJ...839...94B    Altcode: 2016arXiv161106239B
  The six planets of the Kepler-11 system are the archetypal example of
  a population of surprisingly low-density transiting planets revealed
  by the Kepler mission. We have determined the fundamental parameters
  and chemical composition of the Kepler-11 host star to unprecedented
  precision using an extremely high-quality spectrum from Keck-HIRES (R
  ≃ 67,000, S/N per pixel ≃ 260 at 600 nm). Contrary to previously
  published results, our spectroscopic constraints indicate that Kepler-11
  is a young main-sequence solar twin. The revised stellar parameters and
  new analysis raise the densities of the Kepler-11 planets by between
  20% and 95% per planet, making them more typical of the emerging
  class of “puffy” close-in exoplanets. We obtain photospheric
  abundances of 22 elements and find that Kepler-11 has an abundance
  pattern similar to that of the Sun with a slightly higher overall
  metallicity. We additionally analyze the Kepler light curves using
  a photodynamical model and discuss the tension between spectroscopic
  and transit/TTV-based estimates of stellar density.

---------------------------------------------------------
Title: Asymmetries on red giant branch surfaces from CHARA/MIRC
    optical interferometry
Authors: Chiavassa, A.; Norris, R.; Montargès, M.; Ligi, R.; Fossati,
   L.; Bigot, L.; Baron, F.; Kervella, P.; Monnier, J. D.; Mourard, D.;
   Nardetto, N.; Perrin, G.; Schaefer, G. H.; ten Brummelaar, T. A.;
   Magic, Z.; Collet, R.; Asplund, M.
2017A&A...600L...2C    Altcode: 2017arXiv170302406C
  Context. Red giant branch (RGB) stars are very bright objects in
  galaxies and are often used as standard candles. Interferometry
  is the ideal tool to characterize the dynamics and morphology of
  their atmospheres. <BR /> Aims: We aim at precisely characterising
  the surface dynamics of a sample of RGB stars. <BR /> Methods: We
  obtained interferometric observations for three RGB stars with the
  MIRC instrument mounted at the CHARA interferometer. We looked for
  asymmetries on the stellar surfaces using limb-darkening models. <BR
  /> Results: We measured the apparent diameters of HD 197989 (ɛ Cyg)
  = 4.61 ± 0.02 mas, HD 189276 (HR 7633) = 2.95 ± 0.01 mas, and HD
  161096 (β Oph) = 4.43 ± 0.01 mas. We detected departures from the
  centrosymmetric case for all three stars with the tendency of a greater
  effect for lower logg of the sample. We explored the causes of this
  signal and conclude that a possible explanation to the interferometric
  signal is the convection-related and/or the magnetic-related surface
  activity. However, it is necessary to monitor these stars with new
  observations, possibly coupled with spectroscopy, in order to firmly
  establish the cause.

---------------------------------------------------------
Title: VizieR Online Data Catalog: GALAH semi-automated classification
    scheme (Traven+, 2017)
Authors: Traven, G.; Matijevic, G.; Zwitter, T.; Zerjal, M.; Kos, J.;
   Asplund, M.; Bland-Hawthorn, J.; Casey, A. R.; de Silva, G.; Freeman,
   K.; Lin, J.; Martell, S. L.; Schlesinger, K. J.; Sharma, S.; Simpson,
   J. D.; Zucker, D. B.; Anguiano, B.; da Costa, G.; Duong, L.; Horner,
   J.; Hyde, E. A.; Kafle, P. R.; Munari, U.; Nataf, D.; Navin, C. A.;
   Reid, W.; Ting, Y. -S.
2017yCat..22280024T    Altcode:
  The GALactic Archaeology with HERMES (GALAH) survey was the main
  driver for the construction of Hermes (High Efficiency and Resolution
  Multi-Element Spectrograph), a fiber-fed multi-object spectrograph
  on the 3.9m Anglo-Australian Telescope. Its spectral resolving power
  (R) is about 28000, and there is also an R=45000 mode using a slit
  mask. Hermes has four simultaneous non-contiguous spectral arms
  centered at 4800, 5761, 6610, and 7740Å, covering about 1000Å in
  total, including Hα and Hβ lines. About 300000 spectra have been
  taken to date, including various calibration exposures. However, we
  concentrate on ~210000 spectra recorded before 2016 January 30. <P
  />We devise a custom classification procedure which is based on two
  independently developed methods, the novel dimensionality reduction
  technique t-SNE (t-distributed stochastic neighbor embedding; van der
  Maaten &amp; Hinton 2008, Journal of Machine Learning Research 9, 2579)
  and the renowned clustering algorithm DBSCAN (Ester+ 1996, Proc. 2nd
  Int. Conf. on KDD, 226 ed. E. Simoudis, J. Han, and U. Fayyad). <P
  />(4 data files).

---------------------------------------------------------
Title: 18 Sco: a solar twin rich in refractory and neutron-capture
    elements. Implications for chemical tagging.
Authors: Melendez, J.; Ramirez, I.; Karakas, A. I.; Yong, D.; Monroe,
   T. R.; Bedell, M.; Bergemann, M.; Asplund, M.; Tucci, Maia M.; Bean,
   J.; Do Nascimento, J. -D., Jr; Bazot, M.; Alves-Brito, A.; Freitas,
   F. C.; Castro, M.
2017yCat..17910014M    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The GALAH survey: observational overview and Gaia DR1 companion
Authors: Martell, S. L.; Sharma, S.; Buder, S.; Duong, L.; Schlesinger,
   K. J.; Simpson, J.; Lind, K.; Ness, M.; Marshall, J. P.; Asplund, M.;
   Bland-Hawthorn, J.; Casey, A. R.; De Silva, G.; Freeman, K. C.; Kos,
   J.; Lin, J.; Zucker, D. B.; Zwitter, T.; Anguiano, B.; Bacigalupo,
   C.; Carollo, D.; Casagrande, L.; Da Costa, G. S.; Horner, J.; Huber,
   D.; Hyde, E. A.; Kafle, P. R.; Lewis, G. F.; Nataf, D.; Navin, C. A.;
   Stello, D.; Tinney, C. G.; Watson, F. G.; Wittenmyer, R.
2017MNRAS.465.3203M    Altcode: 2016arXiv160902822M
  The Galactic Archaeology with HERMES (GALAH) survey is a massive
  observational project to trace the Milky Way's history of star
  formation, chemical enrichment, stellar migration and minor
  mergers. Using high-resolution (R ≃ 28 000) spectra, taken with the
  High Efficiency and Resolution Multi-Element Spectrograph (HERMES)
  instrument at the Anglo-Australian Telescope, GALAH will determine
  stellar parameters and abundances of up to 29 elements for up to one
  million stars. Selecting targets from a colour-unbiased catalogue
  built from 2MASS, APASS and UCAC4 data, we expect to observe dwarfs
  at 0.3-3 kpc and giants at 1-10 kpc. This enables a thorough local
  chemical inventory of the Galactic thin and thick discs, and also
  captures smaller samples of the bulge and halo. In this paper, we
  present the plan, process and progress as of early 2016 for GALAH
  survey observations. In our first two years of survey observing we
  have accumulated the largest high-quality spectroscopic data set at
  this resolution, over 200 000 stars. We also present the first public
  GALAH data catalogue: stellar parameters (T<SUB>eff</SUB>, log(g),
  [Fe/H], [α/Fe]), radial velocity, distance modulus and reddening for
  10 680 observations of 9860 Tycho-2 stars, 7894 of which are included
  in the first Gaia data release.

---------------------------------------------------------
Title: Using the multi-object adaptive optics demonstrator RAVEN to
    observe metal-poor stars in and towards the Galactic Centre
Authors: Lamb, M.; Venn, K.; Andersen, D.; Oya, S.; Shetrone, M.;
   Fattahi, A.; Howes, L.; Asplund, M.; Lardière, O.; Akiyama, M.;
   Ono, Y.; Terada, H.; Hayano, Y.; Suzuki, G.; Blain, C.; Jackson, K.;
   Correia, C.; Youakim, K.; Bradley, C.
2017MNRAS.465.3536L    Altcode: 2016arXiv161102712L
  The chemical abundances for five metal-poor stars in and towards
  the Galactic bulge have been determined from the H-band infrared
  spectroscopy taken with the RAVEN multi-object adaptive optics science
  demonstrator and the Infrared Camera and Spectrograph at the Subaru
  8.2-m telescope. Three of these stars are in the Galactic bulge and
  have metallicities between -2.1 &lt; [Fe/H] &lt; -1.5, and high [α/Fe]
  ∼ +0.3, typical of Galactic disc and bulge stars in this metallicity
  range; [Al/Fe] and [N/Fe] are also high, whereas [C/Fe] &lt; +0.3. An
  examination of their orbits suggests that two of these stars may be
  confined to the Galactic bulge and one is a halo trespasser, though
  proper motion values used to calculate orbits are quite uncertain. An
  additional two stars in the globular cluster M22 show [Fe/H] values
  consistent to within 1σ, although one of these two stars has [Fe/H]
  = -2.01 ± 0.09, which is on the low end for this cluster. The [α/Fe]
  and [Ni/Fe] values differ by 2σ, with the most metal-poor star showing
  significantly higher values for these elements. M22 is known to show
  element abundance variations, consistent with a multipopulation scenario
  though our results cannot discriminate this clearly given our abundance
  uncertainties. This is the first science demonstration of multi-object
  adaptive optics with high-resolution infrared spectroscopy, and we also
  discuss the feasibility of this technique for use in the upcoming era
  of 30-m class telescope facilities.

---------------------------------------------------------
Title: The asteroseismic surface effect from a grid of 3D convection
    simulations - I. Frequency shifts from convective expansion of
    stellar atmospheres
Authors: Trampedach, Regner; Aarslev, Magnus J.; Houdek, Günter;
   Collet, Remo; Christensen-Dalsgaard, Jørgen; Stein, Robert F.;
   Asplund, Martin
2017MNRAS.466L..43T    Altcode: 2016arXiv161102638T
  We analyse the effect on adiabatic stellar oscillation frequencies
  of replacing the near-surface layers in 1D stellar structure models
  with averaged 3D stellar surface convection simulations. The main
  difference is an expansion of the atmosphere by 3D convection,
  expected to explain a major part of the asteroseismic surface effect,
  a systematic overestimation of p-mode frequencies due to inadequate
  surface physics. We employ pairs of 1D stellar envelope models and 3D
  simulations from a previous calibration of the mixing-length parameter,
  α. That calibration constitutes the hitherto most consistent matching
  of 1D models to 3D simulations, ensuring that their differences are not
  spurious, but entirely due to the 3D nature of convection. The resulting
  frequency shift is identified as the structural part of the surface
  effect. The important, typically non-adiabatic, modal components of
  the surface effect are not included in this analysis, but relegated to
  future papers. Evaluating the structural surface effect at the frequency
  of maximum mode amplitude, ν<SUB>max </SUB>, we find shifts from δν =
  -0.8 μHz for giants at log g = 2.2 to - 35 μHz for a (T<SUB>eff</SUB>
  = 6901 K, log g = 4.29) dwarf. The fractional effect δν(ν<SUB>max
  </SUB>)/ν<SUB>max </SUB>, ranges from -0.1 per cent for a cool dwarf
  (4185 K, 4.74) to -6 per cent for a warm giant (4962 K, 2.20).

---------------------------------------------------------
Title: Discovery of a Metal-poor, Luminous Post-AGB Star that Failed
    the Third Dredge-up.
Authors: Kamath, D.; Van Winckel, H.; Wood, P. R.; Asplund, M.;
   Karakas, A. I.; Lattanzio, J. C.
2017ApJ...836...15K    Altcode: 2017arXiv171004368K
  Post-asymptotic giant branch (post-AGB) stars are known to be chemically
  diverse. In this paper we present the first observational evidence of
  a star that has failed the third dredge-up (TDU). J005252.87-722842.9
  is an A-type (T <SUB>eff</SUB> = 8250 ± 250 K) luminous (8200 ±
  700 L <SUB>⊙</SUB>) metal-poor ([Fe/H] = -1.18 ± 0.10) low-mass
  (M <SUB>initial</SUB> ≈ 1.5-2.0 M <SUB>⊙</SUB>) post-AGB star
  in the Small Magellanic Cloud. Through a systematic abundance study,
  using high-resolution optical spectra from UVES, we found that this
  likely post-AGB object shows an intriguing photospheric composition
  with no confirmed carbon-enhancement (upper limit of [C/Fe] &lt; 0.50)
  nor enrichment of s-process elements. We derived an oxygen abundance of
  [O/Fe] = 0.29 ± 0.1. For Fe and O, we took the effects of nonlocal
  thermodynamic equilibrium into account. We could not derive an upper
  limit for the nitrogen abundance as there are no useful nitrogen lines
  within our spectral coverage. The chemical pattern displayed by this
  object has not been observed in single or binary post-AGBs. Based on its
  derived stellar parameters and inferred evolutionary state, single-star
  nucleosynthesis models predict that this star should have undergone TDU
  episodes while on the AGB, and it should be carbon enriched. However,
  our observations are in contrast with these predictions. We identify
  two possible Galactic analogs that are likely to be post-AGB stars, but
  the lack of accurate distances (hence luminosities) to these objects
  does not allow us to confirm their post-AGB status. If they have low
  luminosities, then they are likely to be dusty post-RGB stars. The
  discovery of J005252.87-722842.9 reveals a new stellar evolutionary
  channel whereby a star evolves without any TDU episodes.

---------------------------------------------------------
Title: Are open clusters chemically homogeneous?
Authors: Asplund, Martin
2017koa..prop....1A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Gaia-ESO Survey: Calibration strategy
Authors: Pancino, E.; Lardo, C.; Altavilla, G.; Marinoni, S.; Ragaini,
   S.; Cocozza, G.; Bellazzini, M.; Sabbi, E.; Zoccali, M.; Donati, P.;
   Heiter, U.; Koposov, S. E.; Blomme, R.; Morel, T.; Símon-Díaz, S.;
   Lobel, A.; Soubiran, C.; Montalban, J.; Valentini, M.; Casey, A. R.;
   Blanco-Cuaresma, S.; Jofré, P.; Worley, C. C.; Magrini, L.; Hourihane,
   A.; François, P.; Feltzing, S.; Gilmore, G.; Randich, S.; Asplund, M.;
   Bonifacio, P.; Drew, J. E.; Jeffries, R. D.; Micela, G.; Vallenari,
   A.; Alfaro, E. J.; Allende Prieto, C.; Babusiaux, C.; Bensby, T.;
   Bragaglia, A.; Flaccomio, E.; Hambly, N.; Korn, A. J.; Lanzafame,
   A. C.; Smiljanic, R.; Van Eck, S.; Walton, N. A.; Bayo, A.; Carraro,
   G.; Costado, M. T.; Damiani, F.; Edvardsson, B.; Franciosini, E.;
   Frasca, A.; Lewis, J.; Monaco, L.; Morbidelli, L.; Prisinzano, L.;
   Sacco, G. G.; Sbordone, L.; Sousa, S. G.; Zaggia, S.; Koch, A.
2017A&A...598A...5P    Altcode: 2016arXiv161006480P
  The Gaia-ESO survey (GES) is now in its fifth and last year of
  observations and has produced tens of thousands of high-quality spectra
  of stars in all Milky Way components. This paper presents the strategy
  behind the selection of astrophysical calibration targets, ensuring
  that all GES results on radial velocities, atmospheric parameters,
  and chemical abundance ratios will be both internally consistent and
  easily comparable with other literature results, especially from
  other large spectroscopic surveys and from Gaia. The calibration
  of GES is particularly delicate because of (I) the large space of
  parameters covered by its targets, ranging from dwarfs to giants,
  from O to M stars; these targets have a large wide of metallicities
  and also include fast rotators, emission line objects, and stars
  affected by veiling; (II) the variety of observing setups, with
  different wavelength ranges and resolution; and (III) the choice of
  analyzing the data with many different state-of-the-art methods, each
  stronger in a different region of the parameter space, which ensures
  a better understanding of systematic uncertainties. An overview
  of the GES calibration and homogenization strategy is also given,
  along with some examples of the usage and results of calibrators in
  GES iDR4, which is the fourth internal GES data release and will form
  the basis of the next GES public data release. The agreement between
  GES iDR4 recommended values and reference values for the calibrating
  objects are very satisfactory. The average offsets and spreads are
  generally compatible with the GES measurement errors, which in iDR4 data
  already meet the requirements set by the main GES scientific goals. <P
  />Based on data products from observations made with ESO Telescopes
  at the La Silla Paranal Observatory under programme IDs 188.B-3002 and
  193.B-0936.Full Table 2 is only available at the CDS via anonymous ftp
  to <A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (<A href="http://130.79.128.5">http://130.79.128.5</A>) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/598/A5">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/598/A5</A>

---------------------------------------------------------
Title: The Galah Survey: Classification and Diagnostics with t-SNE
    Reduction of Spectral Information
Authors: Traven, G.; Matijevič, G.; Zwitter, T.; Žerjal, M.; Kos, J.;
   Asplund, M.; Bland-Hawthorn, J.; Casey, A. R.; De Silva, G.; Freeman,
   K.; Lin, J.; Martell, S. L.; Schlesinger, K. J.; Sharma, S.; Simpson,
   J. D.; Zucker, D. B.; Anguiano, B.; Da Costa, G.; Duong, L.; Horner,
   J.; Hyde, E. A.; Kafle, P. R.; Munari, U.; Nataf, D.; Navin, C. A.;
   Reid, W.; Ting, Y. -S.
2017ApJS..228...24T    Altcode: 2016arXiv161202242T
  Galah is an ongoing high-resolution spectroscopic survey with the goal
  of disentangling the formation history of the Milky Way using the fossil
  remnants of disrupted star formation sites that are now dispersed around
  the Galaxy. It is targeting a randomly selected magnitude-limited
  (V ≤ 14) sample of stars, with the goal of observing one million
  objects. To date, 300,000 spectra have been obtained. Not all of them
  are correctly processed by parameter estimation pipelines, and we need
  to know about them. We present a semi-automated classification scheme
  that identifies different types of peculiar spectral morphologies in an
  effort to discover and flag potentially problematic spectra and thus
  help to preserve the integrity of the survey results. To this end,
  we employ the recently developed dimensionality reduction technique
  t-SNE (t-distributed stochastic neighbor embedding), which enables
  us to represent the complex spectral morphology in a two-dimensional
  projection map while still preserving the properties of the local
  neighborhoods of spectra. We find that the majority (178,483) of
  the 209,533 Galah spectra considered in this study represents normal
  single stars, whereas 31,050 peculiar and problematic spectra with very
  diverse spectral features pertaining to 28,579 stars are distributed
  into 10 classification categories: hot stars, cool metal-poor giants,
  molecular absorption bands, binary stars, Hα/Hβ emission, Hα/Hβ
  emission superimposed on absorption, Hα/Hβ P-Cygni, Hα/Hβ inverted
  P-Cygni, lithium absorption, and problematic. Classified spectra with
  supplementary information are presented in the catalog, indicating
  candidates for follow-up observations and population studies of the
  short-lived phases of stellar evolution.

---------------------------------------------------------
Title: The GALAH survey: the data reduction pipeline
Authors: Kos, Janez; Lin, Jane; Zwitter, Tomaž; Žerjal, Maruška;
   Sharma, Sanjib; Bland-Hawthorn, Joss; Asplund, Martin; Casey, Andrew
   R.; De Silva, Gayandhi M.; Freeman, Ken C.; Martell, Sarah L.; Simpson,
   Jeffrey D.; Schlesinger, Katharine J.; Zucker, Daniel; Anguiano,
   Borja; Bacigalupo, Carlos; Bedding, Timothy R.; Betters, Christopher;
   Da Costa, Gary; Duong, Ly; Hyde, Elaina; Ireland, Michael; Kafle,
   Prajwal R.; Leon-Saval, Sergio; Lewis, Geraint F.; Munari, Ulisse;
   Nataf, David; Stello, Dennis; Tinney, C. G.; Traven, Gregor; Watson,
   Fred; Wittenmyer, Robert A.
2017MNRAS.464.1259K    Altcode: 2016arXiv160804391K; 2016MNRAS.tmp.1183K
  We present the data reduction procedures being used by the GALactic
  Archeology with Hermes (GALAH) survey, carried out with the HERMES
  fibre-fed, multi-object spectrograph on the 3.9-m Anglo-Australian
  Telescope. GALAH is a unique survey, targeting 1 million stars brighter
  than magnitude V = 14 at a resolution of 28 000 with a goal to measure
  the abundances of 29 elements. Such a large number of high-resolution
  spectra necessitate the development of a reduction pipeline optimized
  for speed, accuracy, and consistency. We outline the design and
  structure of the IRAF-based reduction pipeline that we developed,
  specifically for GALAH, to produce fully calibrated spectra aimed
  for subsequent stellar atmospheric parameter estimation. The pipeline
  takes advantage of existing IRAF routines and other readily available
  software so as to be simple to maintain, testable, and reliable. A
  radial velocity and stellar atmospheric parameter estimator code is also
  presented, which is used for further data analysis and yields a useful
  verification of the reduction quality. We have used this estimator
  to quantify the data quality of GALAH for fibre cross-talk level
  (≲0.5 per cent) and scattered light (∼5 counts in a typical 20
  min exposure), resolution across the field, sky spectrum properties,
  wavelength solution reliability (better than 1 km s<SUP>-1</SUP>
  accuracy), and radial velocity precision.

---------------------------------------------------------
Title: The solar silicon abundance based on 3D non-LTE calculations
Authors: Amarsi, A. M.; Asplund, M.
2017MNRAS.464..264A    Altcode: 2016arXiv160907283A
  We present 3D non-local thermodynamic equilibrium (non-LTE) radiative
  transfer calculations for silicon in the solar photosphere, using an
  extensive model atom that includes recent, realistic neutral hydrogen
  collisional cross-sections. We find that photon losses in the Si I
  lines give rise to slightly negative non-LTE abundance corrections
  of the order of -0.01 dex. We infer a 3D non-LTE-based solar silicon
  abundance of lg ɛ_{Si{⊙}}=7.51 dex. With silicon commonly chosen
  to be the anchor between the photospheric and meteoritic abundances,
  we find that the meteoritic abundance scale remains unchanged compared
  with the Asplund et al. and Lodders et al. results.

---------------------------------------------------------
Title: The Solar Twin Planet Search. V. Close-in, low-mass planet
    candidates and evidence of planet accretion in the solar twin
    HIP 68468
Authors: Meléndez, Jorge; Bedell, Megan; Bean, Jacob L.; Ramírez,
   Iván; Asplund, Martin; Dreizler, Stefan; Yan, Hong-Liang; Shi,
   Jian-Rong; Lind, Karin; Ferraz-Mello, Sylvio; Galarza, Jhon Yana; dos
   Santos, Leonardo; Spina, Lorenzo; Maia, Marcelo Tucci; Alves-Brito,
   Alan; Monroe, TalaWanda; Casagrande, Luca
2017A&A...597A..34M    Altcode: 2016arXiv161009067M; 2016A&A...597A..34M
  Context. More than two thousand exoplanets have been discovered to
  date. Of these, only a small fraction have been detected around solar
  twins, which are key stars because we can obtain accurate elemental
  abundances especially for them, which is crucial for studying the
  planet-star chemical connection with the highest precision. <BR />
  Aims: We aim to use solar twins to characterise the relationship between
  planet architecture and stellar chemical composition. <BR /> Methods:
  We obtained high-precision (1 m s<SUP>-1</SUP>) radial velocities
  with the HARPS spectrograph on the ESO 3.6 m telescope at La Silla
  Observatory and determined precise stellar elemental abundances ( 0.01
  dex) using spectra obtained with the MIKE spectrograph on the Magellan
  6.5 m telescope. <BR /> Results: Our data indicate the presence of a
  planet with a minimum mass of 26 ± 4 Earth masses around the solar
  twin HIP 68468. The planet is more massive than Neptune (17 Earth
  masses), but unlike the distant Neptune in our solar system (30 AU),
  HIP 68468c is close-in, with a semi-major axis of 0.66 AU, similar to
  that of Venus. The data also suggest the presence of a super-Earth with
  a minimum mass of 2.9 ± 0.8 Earth masses at 0.03 AU; if the planet is
  confirmed, it will be the fifth least massive radial velocity planet
  candidate discovery to date and the first super-Earth around a solar
  twin. Both isochrones (5.9 ± 0.4 Gyr) and the abundance ratio [Y/Mg]
  (6.4 ± 0.8 Gyr) indicate an age of about 6 billion years. The star
  is enhanced in refractory elements when compared to the Sun, and the
  refractory enrichment is even stronger after corrections for Galactic
  chemical evolution. We determined a nonlocal thermodynamic equilibrium
  Li abundance of 1.52 ± 0.03 dex, which is four times higher than
  what would be expected for the age of HIP 68468. The older age is
  also supported by the low log () (-5.05) and low jitter (&lt;1 m
  s<SUP>-1</SUP>). Engulfment of a rocky planet of 6 Earth masses can
  explain the enhancement in both lithium and the refractory elements. <BR
  /> Conclusions: The super-Neptune planet candidate is too massive for in
  situ formation, and therefore its current location is most likely the
  result of planet migration that could also have driven other planets
  towards its host star, enhancing thus the abundance of lithium and
  refractory elements in HIP 68468. The intriguing evidence of planet
  accretion warrants further observations to verify the existence of
  the planets that are indicated by our data and to better constrain
  the nature of the planetary system around this unique star.

---------------------------------------------------------
Title: 3D NLTE analysis of the most iron-deficient star, SMSS0313-6708
Authors: Nordlander, T.; Amarsi, A. M.; Lind, K.; Asplund, M.; Barklem,
   P. S.; Casey, A. R.; Collet, R.; Leenaarts, J.
2017A&A...597A...6N    Altcode: 2016arXiv160907416N; 2016A&A...597A...6N
  Context. Models of star formation in the early universe require
  a detailed understanding of accretion, fragmentation and radiative
  feedback in metal-free molecular clouds. Different simulations predict
  different initial mass functions of the first stars, ranging from
  predominantly low-mass (0.1-10 M<SUB>⊙</SUB>), to massive (10-100
  M<SUB>⊙</SUB>), or even supermassive (100-1000 M<SUB>⊙</SUB>). The
  mass distribution of the first stars should lead to unique chemical
  imprints on the low-mass second and later generation metal-poor
  stars still in existence. The chemical composition of SMSS0313-6708,
  which has the lowest abundances of Ca and Fe of any star known,
  indicates it was enriched by a single massive supernova. <BR /> Aims:
  The photospheres of metal-poor stars are relatively transparent in
  the UV, which may lead to large three-dimensional (3D) effects as
  well as departures from local thermodynamical equilibrium (LTE),
  even for weak spectral lines. If 3D effects and departures from LTE
  (NLTE) are ignored or treated incorrectly, errors in the inferred
  abundances may significantly bias the inferred properties of the
  polluting supernovae. We redetermine the chemical composition of
  SMSS0313-6708by means of the most realistic methods available, and
  compare the results to predicted supernova yields. <BR /> Methods:
  A 3D hydrodynamical Staggermodel atmosphere and 3D NLTE radiative
  transfer were applied to obtain accurate abundances for Li, Na, Mg, Al,
  Ca and Fe. The model atoms employ realistic collisional rates, with
  no calibrated free parameters. <BR /> Results: We find significantly
  higher abundances in 3D NLTE than 1D LTE by 0.8 dex for Fe, and 0.5
  dex for Mg, Al and Ca, while Li and Na are unaffected to within 0.03
  dex. In particular, our upper limit for [Fe/H] is now a factor ten
  larger, at [Fe/H] &lt; -6.53 (3σ), than previous estimates based on
  ⟨ 3D ⟩NLTE (I.e., using averaged 3D models). This higher estimate
  is due to a conservative upper limit estimation, updated NLTE data,
  and 3D-⟨ 3D ⟩NLTE differences, all of which lead to a higher
  abundance determination. <BR /> Conclusions: We find that supernova
  yields for models in a wide range of progenitor masses reproduce the
  revised chemical composition. In addition to massive progenitors of
  20-60 M<SUB>⊙</SUB> exploding with low energies (1-2 B, where 1
  B = 10<SUP>51</SUP> erg), we also find good fits for progenitors of
  10 M<SUB>⊙</SUB>, with very low explosion energies (&lt;1 B). We
  cannot reconcile the new abundances with supernovae or hypernovae with
  explosion energies above 2.5 B, nor with pair-instability supernovae.

---------------------------------------------------------
Title: Measuring stellar granulation during planet transits
Authors: Chiavassa, A.; Caldas, A.; Selsis, F.; Leconte, J.; Von Paris,
   P.; Bordé, P.; Magic, Z.; Collet, R.; Asplund, M.
2017A&A...597A..94C    Altcode: 2016arXiv160908966C
  Context. Stellar activity and convection-related surface structures
  might cause bias in planet detection and characterization that use
  these transits. Surface convection simulations help to quantify the
  granulation signal. <BR /> Aims: We used realistic three-dimensional
  (3D) radiative hydrodynamical (RHD) simulations from the STAGGER grid
  and synthetic images computed with the radiative transfer code OPTIM3D
  to model the transits of three prototype planets: a hot Jupiter,
  a hot Neptune, and a terrestrial planet. <BR /> Methods: We computed
  intensity maps from RHD simulations of the Sun and a K-dwarf star at
  different wavelength bands from optical to far-infrared that cover
  the range of several ground- and space-based telescopes which observe
  exoplanet transits. We modeled the transit using synthetic stellar-disk
  images obtained with a spherical-tile imaging method and emulated the
  temporal variation of the granulation intensity generating random
  images covering a granulation time-series of 13.3 h. We measured
  the contribution of the stellar granulation on the light curves
  during the planet transit. <BR /> Results: We identified two types of
  granulation noise that act simultaneously during the planet transit:
  (i) the intrinsic change in the granulation pattern with timescale
  (e.g., 10 min for solar-type stars assumed in this work) is smaller
  than the usual planet transit (~hours as in our prototype cases); and
  (ii) the fact that the transiting planet occults isolated regions of
  the photosphere that differ in local surface brightness as a result
  of convective-related surface structures. First, we showed that
  our modeling approach returns granulation timescale fluctuations
  that are comparable with what has been observed for the Sun. Then,
  our statistical approach shows that the granulation pattern of solar
  and K-dwarf-type stars have a non-negligible effect of the light curve
  depth during the transit, and, consequentially on the determination of
  the planet transit parameters such as the planet radius (up to 0.90%
  and ~0.47% for terrestrial and gaseous planets, respectively). We also
  showed that larger (or smaller) orbital inclination angles with respect
  to values corresponding to transit at the stellar center display a
  shallower transit depth and longer ingress and egress times, but also
  granulation fluctuations that are correlated to the center-to-limb
  variation: they increase (or decrease) the value of the inclination,
  which amplifies the fluctuations. The granulation noise appears to be
  correlated among the different wavelength ranges either in the visible
  or in the infrared regions. <BR /> Conclusions: The prospects for planet
  detection and characterization with transiting methods are excellent
  with access to large amounts of data for stars. The granulation has
  to be considered as an intrinsic uncertainty (as a result of stellar
  variability) on the precise measurements of exoplanet transits of
  planets. The full characterization of the granulation is essential for
  determining the degree of uncertainty on the planet parameters. In this
  context, the use of 3D RHD simulations is important to measure the
  convection-related fluctuations. This can be achieved by performing
  precise and continuous observations of stellar photometry and radial
  velocity, as we explained with RHD simulations, before, after, and
  during the transit periods.

---------------------------------------------------------
Title: Non-LTE line formation of Fe in late-type stars - III. 3D
    non-LTE analysis of metal-poor stars
Authors: Amarsi, A. M.; Lind, K.; Asplund, M.; Barklem, P. S.;
   Collet, R.
2016MNRAS.463.1518A    Altcode: 2016arXiv160806390A; 2016MNRAS.tmp.1203A
  As one of the most important elements in astronomy, iron abundance
  determinations need to be as accurate as possible. We investigate the
  accuracy of spectroscopic iron abundance analyses using archetypal
  metal-poor stars. We perform detailed 3D non-LTE radiative transfer
  calculations based on 3D hydrodynamic STAGGER model atmospheres, and
  employ a new model atom that includes new quantum-mechanical neutral
  hydrogen collisional rate coefficients. With the exception of the
  red giant HD122563, we find that the 3D non-LTE models achieve Fe
  I/Fe II excitation and ionization balance as well as not having any
  trends with equivalent width to within modelling uncertainties of
  0.05 dex, all without having to invoke any microturbulent broadening;
  for HD122563 we predict that the current best parallax-based surface
  gravity is overestimated by 0.5 dex. Using a 3D non-LTE analysis, we
  infer iron abundances from the 3D model atmospheres that are roughly
  0.1 dex higher than corresponding abundances from 1D MARCS model
  atmospheres; these differences go in the same direction as the non-LTE
  effects themselves. We make available grids of departure coefficients,
  equivalent widths and abundance corrections, calculated on 1D MARCS
  model atmospheres and horizontally and temporally averaged 3D STAGGER
  model atmospheres.

---------------------------------------------------------
Title: The chemical compositions of solar twins in the open cluster
    M67
Authors: Liu, F.; Asplund, M.; Yong, D.; Meléndez, J.; Ramírez,
   I.; Karakas, A. I.; Carlos, M.; Marino, A. F.
2016MNRAS.463..696L    Altcode: 2016MNRAS.tmp.1165L; 2016arXiv160803788L
  Stars in open clusters are expected to share an identical abundance
  pattern. Establishing the level of chemical homogeneity in a given
  open cluster deserves further study as it is the basis of the concept
  of chemical tagging to unravel the history of the Milky Way. M67 is
  particularly interesting given its solar metallicity and age as well as
  being a dense cluster environment. We conducted a strictly line-by-line
  differential chemical abundance analysis of two solar twins in M67:
  M67-1194 and M67-1315. Stellar atmospheric parameters and elemental
  abundances were obtained with high precision using Keck/High Resolution
  Echelle Spectrometer spectra. M67-1194 is essentially identical to the
  Sun in terms of its stellar parameters. M67-1315 is warmer than M67-1194
  by ≈150 K as well as slightly more metal-poor than M67-1194 by ≈0.05
  dex. M67-1194 is also found to have identical chemical composition to
  the Sun, confirming its solar-twin nature. The abundance ratios [X/Fe]
  of M67-1315 are similar to the solar abundances for elements with atomic
  number Z ≤ 30, while most neutron-capture elements are enriched by
  ≈0.05 dex, which might be attributed to enrichment from a mixture of
  asymptotic giant branch ejecta and r-process material. The distinct
  chemical abundances for the neutron-capture elements in M67-1315 and
  the lower metallicity of this star compared to M67-1194, indicate that
  the stars in M67 are likely not chemically homogeneous. This poses
  a challenge for the concept of chemical tagging since it is based on
  the assumption of stars forming in the same star-forming aggregate.

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Title: Implications of solar wind measurements for solar models
    and composition
Authors: Serenelli, Aldo; Scott, Pat; Villante, Francesco L.;
   Vincent, Aaron C.; Asplund, Martin; Basu, Sarbani; Grevesse, Nicolas;
   Peña-Garay, Carlos
2016MNRAS.463....2S    Altcode: 2016arXiv160405318S; 2016MNRAS.tmp.1051S
  We critically examine recent claims of a high solar metallicity by von
  Steiger &amp; Zurbuchen (2016, vSZ16) based on in situ measurements
  of the solar wind, rather than the standard spectroscopically inferred
  abundances (Asplund et al. 2009, hereafter AGSS09). We test the claim
  by Vagnozzi et al. (2016) that a composition based on the solar wind
  enables one to construct a standard solar model in agreement with
  helioseismological observations and thus solve the decades-old solar
  modelling problem. We show that, although some helioseismological
  observables are improved compared to models computed with spectroscopic
  abundances, most are in fact worse. The high abundance of refractory
  elements leads to an overproduction of neutrinos, with a predicted
  <SUP>8</SUP>B flux that is nearly twice its observed value, and
  <SUP>7</SUP>Be and CNO fluxes that are experimentally ruled out at high
  confidence. A combined likelihood analysis shows that models using the
  vSZ16 abundances are worse than AGSS09 despite a higher metallicity. We
  also present astrophysical and spectroscopic arguments showing the vSZ16
  composition to be an implausible representation of the solar interior,
  identifying the first ionization potential effect in the outer solar
  atmosphere and wind as the likely culprit.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Gaia-ESO Survey iDR4 calibrators
    (Pancino+, 2017)
Authors: Pancino, E.; Lardo, C.; Altavilla, G.; Marinoni, S.; Ragaini,
   S.; Cocozza, G.; Bellazzini, M.; Sabbi, E.; Zoccali, M.; Donati,
   P.; Heiter, U.; Koposov, S. E.; Blomme, R.; Morel, T.; Simon-Diaz,
   S.; Lobel, A.; Soubiran, C.; Montalban, J.; Valentini, M.; Casey,
   A. R.; Blanco-Cuaresma, S.; Jofre, P.; Worley, C. C.; Magrini, L.;
   Hourihane, A.; Francois, P.; Feltzing, S.; Gilmore, G.; Randich, S.;
   Asplund, M.; Bonifacio, P.; Drew, J. E.; Jeffries, R. D.; Micela,
   G.; Vallenari, A.; Alfaro, E. J.; Allende Prieto, C.; Babusiaux,
   C.; Bensby, T.; Bragaglia, A.; Flaccomio, E.; Hambly, N.; Korn,
   A. J.; Lanzafame, A. C.; Smiljanic, R.; van Eck, S.; Walton, N. A.;
   Bayo, A.; Carraro, G.; Costado, M. T.; Damiani, F.; Edvardsson, B.;
   Franciosini, E.; Frasca, A.; Lewis, J.; Monaco, L.; Morbidelli, L.;
   Prisinzano, L.; Sacco, G. G.; Sbordone, L.; Sousa, S. G.; Zaggia,
   S.; Koch, A.; Gaia-ESO Collaboration
2016yCat..35980005P    Altcode:
  List of GES iDR4 calibrators. It can be used to select the iDR4
  calibrators from the upcoming ESO Phase 3 public release. The columns
  contain: the GES unique identifier of each star (the CName), based on
  the object sexagesimal coordinates; the calibration type, which can
  be GC or OC for clusters, RV for radial velocity standards, BM for
  benchmark stars, or CR for CoRoT targets; the field name; and the
  2MASS J and K magnitudes, when available. <P />(1 data file).

---------------------------------------------------------
Title: Nucleosynthetic history of elements in the Galactic
    disk. [X/Fe]-age relations from high-precision spectroscopy
Authors: Spina, L.; Meléndez, J.; Karakas, A. I.; Ramírez, I.;
   Monroe, T. R.; Asplund, M.; Yong, D.
2016A&A...593A.125S    Altcode: 2016arXiv160604842S
  Context. The chemical composition of stars is intimately linked to the
  formation and evolution of the Galaxy. <BR /> Aims: We aim to trace
  the chemical evolution of the Galactic disk through the inspection of
  the [X/Fe]-age relations of 24 species from C to Eu. <BR /> Methods:
  Using high-resolution and high signal-to-noise UVES spectra of
  nine solar twins, we obtained precise estimates of stellar ages and
  chemical abundances. These determinations have been integrated with
  additional accurate age and abundance determinations from recent
  spectroscopic studies of solar twins existing in the literature,
  comprising superb abundances with 0.01 dex precision. Based on this
  data set, we outlined the [X/Fe]-age relations over a time interval of
  10 Gyr. <BR /> Results: We present the [X/Fe] - age relations for 24
  elements (C, O, Na, Mg, Al, Si, S, K, Ca, Sc, Ti, V, Cr, Mn, Co, Ni,
  Cu, Zn, Y, Ba, La, Ce, Nd, and Eu). Each different class of elements
  showed a distinct evolution with time that relies on the different
  characteristics, rates, and timescales of the nucleosynthesis sites from
  which they are produced. The α-elements are characterized by a [X/Fe]
  decrease with time. Strikingly, the opposite behavior is observed for
  Ca. The iron-peak elements show an early [X/Fe] increase followed by
  a decrease towards the youngest stars. The [X/Fe] for the n-capture
  elements decrease with age. We also found that both [Mg/Y] and [Al/Y]
  are precise stellar clocks, with [Al/Y] showing the steepest dependence
  on age. <BR /> Conclusions: Knowledge of the [X/Fe]-age relations
  is a gold mine from which we can achieve a great understanding of
  the processes that governed the formation and evolution of the Milky
  Way. Through the reverse engineering of these relations we will be
  able to put strong constraints on the nature of the stellar formation
  history, the SNe rates, the stellar yields, and the variety of the
  SNe progenitors. <P />Based on observations obtained at the ESO VLT
  at Paranal Observatory (Observing program 083.D-0871).

---------------------------------------------------------
Title: The Gaia-ESO Survey: Hydrogen lines in red giants directly
    trace stellar mass
Authors: Bergemann, Maria; Serenelli, Aldo; Schönrich, Ralph; Ruchti,
   Greg; Korn, Andreas; Hekker, Saskia; Kovalev, Mikhail; Mashonkina,
   Lyudmila; Gilmore, Gerry; Randich, Sofia; Asplund, Martin; Rix,
   Hans-Walter; Casey, Andrew R.; Jofre, Paula; Pancino, Elena;
   Recio-Blanco, Alejandra; de Laverny, Patrick; Smiljanic, Rodolfo;
   Tautvaisiene, Grazina; Bayo, Amelia; Lewis, Jim; Koposov, Sergey;
   Hourihane, Anna; Worley, Clare; Morbidelli, Lorenzo; Franciosini,
   Elena; Sacco, Germano; Magrini, Laura; Damiani, Francesco;
   Bestenlehner, Joachim M.
2016A&A...594A.120B    Altcode: 2016arXiv160605661B
  Red giant stars are perhaps the most important type of stars for
  Galactic and extra-galactic archaeology: they are luminous, occur in
  all stellar populations, and their surface temperatures allow precise
  abundance determinations for many different chemical elements. Yet,
  the full star formation and enrichment history of a galaxy can be
  traced directly only if two key observables can be determined for large
  stellar samples: age and chemical composition. While spectroscopy is a
  powerful method to analyse the detailed abundances of stars, stellar
  ages are the missing link in the chain, since they are not a direct
  observable. However, spectroscopy should be able to estimate stellar
  masses, which for red giants directly infer ages provided their chemical
  composition is known. Here we establish a new empirical relation between
  the shape of the hydrogen line in the observed spectra of red giants
  and stellar mass determined from asteroseismology. The relation allows
  determining stellar masses and ages with an accuracy of 10-15%. The
  method can be used with confidence for stars in the following range
  of stellar parameters: 4000 &lt; T<SUB>eff</SUB> &lt; 5000 K, 0.5
  &lt; log g&lt; 3.5, -2.0 &lt; [Fe/H] &lt; 0.3, and luminosities log
  L/L<SUB>Sun</SUB> &lt; 2.5. Our analysis provides observational evidence
  that the H<SUB>α</SUB> spectral characteristics of red giant stars
  are tightly correlated with their mass and therefore their age. We
  also show that the method samples well all stellar populations with
  ages above 1 Gyr. Targeting bright giants, the method allows obtaining
  simultaneous age and chemical abundance information far deeper than
  would be possible with asteroseismology, extending the possible survey
  volume to remote regions of the Milky Way and even to neighbouring
  galaxies such as Andromeda or the Magellanic Clouds even with current
  instrumentation, such as the VLT and Keck facilities.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Kepler-10 chemical composition
    (Liu+, 2016)
Authors: Liu, F.; Yong, D.; Asplund, M.; Ramirez, I.; Melendez,
   J.; Gustafsson, B.; Howes, L. M.; Roederer, I. U.; Lambert, D. L.;
   Bensby, T.
2016yCat..74562636L    Altcode:
  We obtained high resolution and high SNR spectra with the
  Canada-France-Hawaii Telescope (CFHT), the Hobby-Eberly Telescope (HET)
  and the Magellan Clay Telescope. <P />We observed Kepler-10 with the
  Echelle SpectroPolarimetric Device for the Observation of Stars at
  the CFHT during 2013 June. The spectral revolving power is 68000 and
  the spectral range is 3800-8900Å. <P />We also observed Kepler-10
  with the High Resolution Spectrograph (HRS) on the HET at McDonald
  Observatory during 2011 May. A total integration time of 6.8h was
  needed to achieve SNR&gt;350 per pixel. The spectrum has a spectral
  resolving power of 60000 and covers 4100-7800Å, with a gap of about
  100Å around 6000Å. <P />(4 data files).

---------------------------------------------------------
Title: VizieR Online Data Catalog: GALAH observational overview
    (Martell+, 2017)
Authors: Martell, S. L.; Sharma, S.; Buder, S.; Duong, L.; Schlesinger,
   K. J.; Simpson, J.; Lind, K.; Ness, M.; Marshall, J. P.; Asplund, M.;
   Bland-Hawthorn, J.; Casey, A. R.; de Silva, G.; Freeman, K. C.; Kos,
   J.; Lin, J.; Zucker, D. B.; Zwitter, T.; Anguiano, B.; Bacigalupo,
   C.; Carollo, D.; Casagrande, L.; da Costa, G. S.; Horner, J.; Huber,
   D.; Hyde, E. A.; Kafle, P. R.; Lewis, G. F.; Nataf, D.; Navin, C. A.;
   Stello, D.; Tinney, C. G.; Watson, F. G.; Wittenmyer, R.
2016yCat..74653203M    Altcode:
  Identifiers, positions, derived stellar parameters, radial velocities,
  distance moduli and reddenings for stars from the Tycho-2 catalogue
  observed by the GALAH Survey. <P />(1 data file).

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Title: Nominal Values for Selected Solar and Planetary Quantities:
    IAU 2015 Resolution B3
Authors: Prša, Andrej; Harmanec, Petr; Torres, Guillermo; Mamajek,
   Eric; Asplund, Martin; Capitaine, Nicole; Christensen-Dalsgaard,
   Jørgen; Depagne, Éric; Haberreiter, Margit; Hekker, Saskia; Hilton,
   James; Kopp, Greg; Kostov, Veselin; Kurtz, Donald W.; Laskar, Jacques;
   Mason, Brian D.; Milone, Eugene F.; Montgomery, Michele; Richards,
   Mercedes; Schmutz, Werner; Schou, Jesper; Stewart, Susan G.
2016AJ....152...41P    Altcode: 2016arXiv160509788P
  In this brief communication we provide the rationale for and the
  outcome of the International Astronomical Union (IAU) resolution
  vote at the XXIXth General Assembly in Honolulu, Hawaii, in 2015,
  on recommended nominal conversion constants for selected solar and
  planetary properties. The problem addressed by the resolution is a lack
  of established conversion constants between solar and planetary values
  and SI units: a missing standard has caused a proliferation of solar
  values (e.g., solar radius, solar irradiance, solar luminosity, solar
  effective temperature, and solar mass parameter) in the literature,
  with cited solar values typically based on best estimates at the time
  of paper writing. As precision of observations increases, a set of
  consistent values becomes increasingly important. To address this, an
  IAU Working Group on Nominal Units for Stellar and Planetary Astronomy
  formed in 2011, uniting experts from the solar, stellar, planetary,
  exoplanetary, and fundamental astronomy, as well as from general
  standards fields to converge on optimal values for nominal conversion
  constants. The effort resulted in the IAU 2015 Resolution B3, passed at
  the IAU General Assembly by a large majority. The resolution recommends
  the use of nominal solar and planetary values, which are by definition
  exact and are expressed in SI units. These nominal values should be
  understood as conversion factors only, not as the true solar/planetary
  properties or current best estimates. Authors and journal editors are
  urged to join in using the standard values set forth by this resolution
  in future work and publications to help minimize further confusion.

---------------------------------------------------------
Title: The Solar Twin Planet Search. IV. The Sun as a typical rotator
    and evidence for a new rotational braking law for Sun-like stars
Authors: dos Santos, Leonardo A.; Meléndez, Jorge; do Nascimento,
   José-Dias; Bedell, Megan; Ramírez, Iván; Bean, Jacob L.; Asplund,
   Martin; Spina, Lorenzo; Dreizler, Stefan; Alves-Brito, Alan;
   Casagrande, Luca
2016A&A...592A.156D    Altcode: 2016arXiv160606214D
  Context. It is still unclear how common the Sun is when compared to
  other similar stars in regards to some of its physical properties,
  such as rotation. Considering that gyrochronology relations are
  widely used today to estimate ages of stars in the main sequence,
  and that the Sun is used to calibrate it, it is crucial to assess
  whether these procedures are acceptable. <BR /> Aims: We analyze the
  rotational velocities, limited by the unknown rotation axis inclination
  angle, of an unprecedented large sample of solar twins to study the
  rotational evolution of Sun-like stars, and assess whether the Sun is a
  typical rotator. <BR /> Methods: We used high-resolution (R = 115 000)
  spectra obtained with the HARPS spectrograph and the 3.6 m telescope
  at La Silla Observatory. The projected rotational velocities for 81
  solar twins were estimated by line profile fitting with synthetic
  spectra. Macroturbulence velocities were inferred from a prescription
  that accurately reflects their dependence with effective temperature
  and luminosity of the stars. <BR /> Results: Our sample of solar twins
  include some spectroscopic binaries with enhanced rotational velocities,
  and we do not find any nonspectroscopic binaries with unusually high
  rotation velocities. We verified that the Sun does not have a peculiar
  rotation, but the solar twins exhibit rotational velocities that depart
  from the Skumanich relation. <BR /> Conclusions: The Sun is a regular
  rotator when compared to solar twins with a similar age. Additionally,
  we obtain a rotational braking law that better describes the stars in
  our sample (v ∝ t<SUP>-0.6</SUP>) in contrast to previous, often-used
  scalings. <P />Based on observations collected at the European
  Organisation for Astronomical Research in the Southern Hemisphere under
  ESO programs 188.C-0265, 183.D-0729, 292.C-5004, 077.C-0364, 072.C-0488,
  092.C-0721, 093.C-0409, 183.C-0972, 192.C-0852, 091.C-0936, 089.C-0732,
  091.C-0034, 076.C-0155, 185.D-0056, 074.C-0364, 075.C-0332, 089.C-0415,
  60.A-9036, 075.C-0202, 192.C-0224, 090.C-0421 and 088.C-0323.Full
  Table 3 is only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (<A href="http://130.79.128.5">http://130.79.128.5</A>) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A156">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A156</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: The Solar Twin Planet
    Search. IV. (dos Santos+, 2016)
Authors: Dos Santos, L. A.; Melendez, J.; Do Nascimento, J. -D. Jr;
   Bedell, M.; Ramirez, I.; Bean, J. L.; Asplund, M.; Spina, L.; Dreizler,
   S.; Alves-Brito, A.; Casagrande, L.
2016yCat..35920156D    Altcode:
  Ages, the measured projected rotational velocities (vsini) and stellar
  parameters of the 81 solar twins and the Sun. The ages of all solar
  twins and stellar parameters for HIP68468 were obtained by Tucci Maia et
  al. (2016A&amp;A...590A..32T). Stellar parameters for the other solar
  twins were obtained by Ramirez et al. (2014A&amp;A...572A..48R). The
  vsini were measured by line profile fitting using red spectra from
  HARPS (R=115000). Macroturbulence velocities were inferred from the
  scaling Eq. 2 in our study. <P />(1 data file).

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Title: The EMBLA survey - metal-poor stars in the Galactic bulge
Authors: Howes, Louise M.; Asplund, Martin; Keller, Stefan C.; Casey,
   Andrew R.; Yong, David; Lind, Karin; Frebel, Anna; Hays, Austin;
   Alves-Brito, Alan; Bessell, Michael S.; Casagrande, Luca; Marino,
   Anna F.; Nataf, David M.; Owen, Christopher I.; Da Costa, Gary S.;
   Schmidt, Brian P.; Tisserand, Patrick
2016MNRAS.460..884H    Altcode: 2016arXiv160407834H; 2016MNRAS.tmp..776H
  Cosmological models predict the oldest stars in the Galaxy should be
  found closest to the centre of the potential well, in the bulge. The
  Extremely Metal-poor BuLge stars with AAOmega survey (EMBLA)
  successfully searched for these old, metal-poor stars by making
  use of the distinctive SkyMapper photometric filters to discover
  candidate metal-poor stars in the bulge. Their metal-poor nature was
  then confirmed using the AAOmega spectrograph on the Anglo-Australian
  Telescope. Here we present an abundance analysis of 10 bulge stars with
  -2.8 &lt; [Fe/H] &lt; -1.7 from MIKE/Magellan observations, in total
  determining the abundances of 22 elements. Combining these results with
  our previous high-resolution data taken as part of the Gaia-ESO Survey,
  we have started to put together a picture of the chemical and kinematic
  nature of the most metal-poor stars in the bulge. The currently
  available kinematic data are consistent with the stars belonging to the
  bulge, although more accurate measurements are needed to constrain the
  stars' orbits. The chemistry of these bulge stars deviates from that
  found in halo stars of the same metallicity. Two notable differences
  are the absence of carbon-enhanced metal-poor bulge stars, and the
  α element abundances exhibit a large intrinsic scatter and include
  stars which are underabundant in these typically enhanced elements.

---------------------------------------------------------
Title: GRACES observations of young [α/Fe]-rich stars
Authors: Yong, David; Casagrande, Luca; Venn, Kim A.; Chené,
   André-Nicolas; Keown, Jared; Malo, Lison; Martioli, Eder; Alves-Brito,
   Alan; Asplund, Martin; Dotter, Aaron; Martell, Sarah L.; Meléndez,
   Jorge; Schlesinger, Katharine J.
2016MNRAS.459..487Y    Altcode: 2016MNRAS.tmp..463Y; 2016arXiv160307034Y
  We measure chemical abundance ratios and radial velocities in four
  massive (I.e. young) [α/Fe]-rich red giant stars using high-resolution
  high-S/N spectra from ESPaDOnS fed by Gemini-GRACES. Our differential
  analysis ensures that our chemical abundances are on the same scale
  as the Alves-Brito et al. (2010) study of bulge, thin, and thick disc
  red giants. We confirm that the program stars have enhanced [α/Fe]
  ratios and are slightly metal poor. Aside from lithium enrichment in
  one object, the program stars exhibit no chemical abundance anomalies
  when compared to giant stars of similar metallicity throughout the
  Galaxy. This includes the elements Li, O, Si, Ca, Ti, Cr, Ni, Cu,
  Ba, La, and Eu. Therefore, there are no obvious chemical signatures
  that can help to reveal the origin of these unusual stars. While our
  new observations show that only one star (not the Li-rich object)
  exhibits a radial velocity variation, simulations indicate that we
  cannot exclude the possibility that all four could be binaries. In
  addition, we find that two (possibly three) stars show evidence for
  an infrared excess, indicative of a debris disc. This is consistent
  with these young [α/Fe]-rich stars being evolved blue stragglers,
  suggesting their apparent young age is a consequence of a merger or
  mass transfer. We would expect a binary fraction of ∼50 per cent or
  greater for the entire sample of these stars, but the signs of the
  circumbinary disc may have been lost since these features can have
  short time-scales. Radial velocity monitoring is needed to confirm
  the blue straggler origin.

---------------------------------------------------------
Title: The Detailed Science Case for the Maunakea Spectroscopic
Explorer: the Composition and Dynamics of the Faint Universe
Authors: McConnachie, Alan; Babusiaux, Carine; Balogh, Michael; Driver,
   Simon; Côté, Pat; Courtois, Helene; Davies, Luke; Ferrarese, Laura;
   Gallagher, Sarah; Ibata, Rodrigo; Martin, Nicolas; Robotham, Aaron;
   Venn, Kim; Villaver, Eva; Bovy, Jo; Boselli, Alessandro; Colless,
   Matthew; Comparat, Johan; Denny, Kelly; Duc, Pierre-Alain; Ellison,
   Sara; de Grijs, Richard; Fernandez-Lorenzo, Mirian; Freeman, Ken;
   Guhathakurta, Raja; Hall, Patrick; Hopkins, Andrew; Hudson, Mike;
   Johnson, Andrew; Kaiser, Nick; Koda, Jun; Konstantopoulos, Iraklis;
   Koshy, George; Lee, Khee-Gan; Nusser, Adi; Pancoast, Anna; Peng, Eric;
   Peroux, Celine; Petitjean, Patrick; Pichon, Christophe; Poggianti,
   Bianca; Schmid, Carlo; Shastri, Prajval; Shen, Yue; Willot, Chris;
   Croom, Scott; Lallement, Rosine; Schimd, Carlo; Smith, Dan; Walker,
   Matthew; Willis, Jon; Colless, Alessandro Bosselli Matthew; Goswami,
   Aruna; Jarvis, Matt; Jullo, Eric; Kneib, Jean-Paul; Konstantopoloulous,
   Iraklis; Newman, Jeff; Richard, Johan; Sutaria, Firoza; Taylor,
   Edwar; van Waerbeke, Ludovic; Battaglia, Giuseppina; Hall, Pat;
   Haywood, Misha; Sakari, Charli; Schmid, Carlo; Seibert, Arnaud;
   Thirupathi, Sivarani; Wang, Yuting; Wang, Yiping; Babas, Ferdinand;
   Bauman, Steve; Caffau, Elisabetta; Laychak, Mary Beth; Crampton,
   David; Devost, Daniel; Flagey, Nicolas; Han, Zhanwen; Higgs, Clare;
   Hill, Vanessa; Ho, Kevin; Isani, Sidik; Mignot, Shan; Murowinski,
   Rick; Pandey, Gajendra; Salmon, Derrick; Siebert, Arnaud; Simons,
   Doug; Starkenburg, Else; Szeto, Kei; Tully, Brent; Vermeulen, Tom;
   Withington, Kanoa; Arimoto, Nobuo; Asplund, Martin; Aussel, Herve;
   Bannister, Michele; Bhatt, Harish; Bhargavi, SS; Blakeslee, John;
   Bland-Hawthorn, Joss; Bullock, James; Burgarella, Denis; Chang,
   Tzu-Ching; Cole, Andrew; Cooke, Jeff; Cooper, Andrew; Di Matteo, Paola;
   Favole, Ginevra; Flores, Hector; Gaensler, Bryan; Garnavich, Peter;
   Gilbert, Karoline; Gonzalez-Delgado, Rosa; Guhathakurta, Puragra;
   Hasinger, Guenther; Herwig, Falk; Hwang, Narae; Jablonka, Pascale;
   Jarvis, Matthew; Kamath, Umanath; Kewley, Lisa; Le Borgne, Damien;
   Lewis, Geraint; Lupton, Robert; Martell, Sarah; Mateo, Mario; Mena,
   Olga; Nataf, David; Newman, Jeffrey; Pérez, Enrique; Prada, Francisco;
   Puech, Mathieu; Recio-Blanco, Alejandra; Robin, Annie; Saunders, Will;
   Smith, Daniel; Stalin, C. S.; Tao, Charling; Thanjuvur, Karun; Tresse,
   Laurence; van Waerbeke, Ludo; Wang, Jian-Min; Yong, David; Zhao,
   Gongbo; Boisse, Patrick; Bolton, James; Bonifacio, Piercarlo; Bouchy,
   Francois; Cowie, Len; Cunha, Katia; Deleuil, Magali; de Mooij, Ernst;
   Dufour, Patrick; Foucaud, Sebastien; Glazebrook, Karl; Hutchings,
   John; Kobayashi, Chiaki; Kudritzki, Rolf-Peter; Li, Yang-Shyang;
   Lin, Lihwai; Lin, Yen-Ting; Makler, Martin; Narita, Norio; Park,
   Changbom; Ransom, Ryan; Ravindranath, Swara; Eswar Reddy, Bacham;
   Sawicki, Marcin; Simard, Luc; Srianand, Raghunathan; Storchi-Bergmann,
   Thaisa; Umetsu, Keiichi; Wang, Ting-Gui; Woo, Jong-Hak; Wu, Xue-Bing
2016arXiv160600043M    Altcode:
  MSE is an 11.25m aperture observatory with a 1.5 square degree field of
  view that will be fully dedicated to multi-object spectroscopy. More
  than 3200 fibres will feed spectrographs operating at low (R ~ 2000 -
  3500) and moderate (R ~ 6000) spectral resolution, and approximately
  1000 fibers will feed spectrographs operating at high (R ~ 40000)
  resolution. MSE is designed to enable transformational science in areas
  as diverse as tomographic mapping of the interstellar and intergalactic
  media; the in-situ chemical tagging of thick disk and halo stars;
  connecting galaxies to their large scale structure; measuring the mass
  functions of cold dark matter sub-halos in galaxy and cluster-scale
  hosts; reverberation mapping of supermassive black holes in quasars;
  next generation cosmological surveys using redshift space distortions
  and peculiar velocities. MSE is an essential follow-up facility to
  current and next generations of multi-wavelength imaging surveys,
  including LSST, Gaia, Euclid, WFIRST, PLATO, and the SKA, and is
  designed to complement and go beyond the science goals of other planned
  and current spectroscopic capabilities like VISTA/4MOST, WHT/WEAVE,
  AAT/HERMES and Subaru/PFS. It is an ideal feeder facility for E-ELT, TMT
  and GMT, and provides the missing link between wide field imaging and
  small field precision astronomy. MSE is optimized for high throughput,
  high signal-to-noise observations of the faintest sources in the
  Universe with high quality calibration and stability being ensured
  through the dedicated operational mode of the observatory. (abridged)

---------------------------------------------------------
Title: The Solar Twin Planet Search. III. The [Y/Mg] clock: estimating
    stellar ages of solar-type stars
Authors: Tucci Maia, M.; Ramírez, I.; Meléndez, J.; Bedell, M.;
   Bean, J. L.; Asplund, M.
2016A&A...590A..32T    Altcode: 2016arXiv160405733T
  Context. Solar twins are stars with similar stellar (surface)
  parameters to the Sun that can have a wide range of ages. This provides
  an opportunity to analyze the variation of their chemical abundances
  with age. Nissen (2015, A&amp;A, 579, A52) recently suggested that the
  abundances of the s-process element Y and the α-element Mg could be
  used to estimate stellar ages. <BR /> Aims: This paper aims to determine
  with high precision the Y, Mg, and Fe abundances for a sample of 88
  solar twins that span a broad age range (0.3-10.0 Gyr) and investigate
  their use for estimating ages. <BR /> Methods: We obtained high-quality
  Magellan Inamori Kyocera Echelle (MIKE) spectra and determined Y and
  Mg abundances using equivalent widths and a line-by-line differential
  method within a 1D LTE framework. Stellar parameters and iron abundances
  were measured in Paper I of this series for all stars, but a few (three)
  required a small revision. <BR /> Results: The [Y/Mg] ratio shows a
  strong correlation with age. It has a slope of -0.041 ± 0.001 dex/Gyr
  and a significance of 41σ. This is in excellent agreement with the
  relation first proposed by Nissen (2015). We found some outliers that
  turned out to be binaries where mass transfer may have enhanced the
  yttrium abundance. Given a precise measurement of [Y/Mg] with typical
  error of 0.02 dex in solar twins, our formula can be used to determine
  a stellar age with ~0.8 Gyr precision in the 0 to 10 Gyr range. <P
  />Based on observations obtained at the Clay Magellan Telescopes at
  Las Campanas Observatory, Chile and at the 3.6 m Telescope at the La
  Silla ESO Observatory, Chile (program ID 188.C-0265).

---------------------------------------------------------
Title: High-precision analysis of the solar twin HIP 100963
Authors: Yana Galarza, Jhon; Meléndez, Jorge; Ramírez, Ivan; Yong,
   David; Karakas, Amanda I.; Asplund, Martin; Liu, Fan
2016A&A...589A..17Y    Altcode: 2016A&A...589A..17G; 2016arXiv160208008Y
  Context. HIP 100963 was one of the first solar twins
  identified. Although some high-precision analyses are available, a
  comprehensive high-precision study of chemical elements from different
  nucleosynthetic sources is still lacking from which to obtain potential
  new insights on planets, stellar evolution, and Galactic chemical
  evolution (GCE). <BR /> Aims: We analyze and investigate the origin
  of the abundance pattern of HIP 100963 in detail, in particular the
  pattern of the light element Li, the volatile and refractory elements,
  and heavy elements from the s- and r-processes. <BR /> Methods:
  We used the HIRES spectrograph on the Keck I telescope to acquire
  high-resolution (R ≈ 70 000) spectra with a high signal-to-noise ratio
  (S/N ≈ 400-650 per pixel) of HIP 100963 and the Sun for a differential
  abundance analysis. We measured the equivalent widths (EWs) of iron
  lines to determine the stellar parameters by employing the differential
  spectroscopic equilibrium. We determined the composition of volatile,
  refractory, and neutron-capture elements through a differential
  abundance analysis with respect to the Sun. <BR /> Results: The
  stellar parameters we found are T<SUB>eff</SUB> = 5818 ± 4 K, log g =
  4.49 ± 0.01 dex, v<SUB>t</SUB> = 1.03 ± 0.01km s<SUP>-1</SUP>, and
  [Fe/H] = -0.003 ± 0.004 dex. These low errors allow us to compute a
  precise mass (1.03<SUP>+0.02</SUP><SUB>-0.01</SUB> M<SUB>⊙</SUB>)
  and age (2.0 ± 0.4 Gyr), obtained using Yonsei-Yale isochrones. Using
  our [Y/Mg] ratio, we have determined an age of 2.1 ± 0.4 Gyr, in
  agreement with the age computed using isochrones. Our isochronal age
  also agrees with the age determined from stellar activity (2.4 ± 0.3
  Gyr). We study the abundance pattern with condensation temperature
  (T<SUB>cond</SUB>) taking corrections by the GCE into account. We
  show that the enhancements of neutron-capture elements are explained
  by contributions from both the s- and r-process. The lithium abundance
  follows the tight Li-age correlation seen in other solar twins. <BR />
  Conclusions: We confirm that HIP 100963 is a solar twin and demonstrate
  that its abundance pattern is about solar after corrections for
  GCE. The star also shows enrichment in s- and r-process elements,
  as well as depletion in lithium that is caused by stellar evolution.

---------------------------------------------------------
Title: Atomic diffusion and mixing in old stars. VI. The lithium
    content of M30
Authors: Gruyters, Pieter; Lind, Karin; Richard, Olivier; Grundahl,
   Frank; Asplund, Martin; Casagrande, Luca; Charbonnel, Corinne; Milone,
   Antonino; Primas, Francesca; Korn, Andreas J.
2016A&A...589A..61G    Altcode: 2016arXiv160301565G
  Context. The prediction of the Planck-constrained primordial lithium
  abundance in the Universe is in discordance with the observed Li
  abundances in warm Population II dwarf and subgiant stars. Among
  the physically best motivated ideas, it has been suggested that this
  discrepancy can be alleviated if the stars observed today had undergone
  photospheric depletion of lithium. <BR /> Aims: The cause of this
  depletion is investigated by accurately tracing the behaviour of the
  lithium abundances as a function of effective temperature. Globular
  clusters are ideal laboratories for such an abundance analysis as
  the relative stellar parameters of their stars can be precisely
  determined. <BR /> Methods: We performed a homogeneous chemical
  abundance analysis of 144 stars in the metal-poor globular cluster
  M30, ranging from the cluster turnoff point to the tip of the red
  giant branch. Non-local thermal equilibrium (NLTE) abundances for Li,
  Ca, and Fe were derived where possible by fitting spectra obtained
  with VLT/FLAMES-GIRAFFE using the quantitative-spectroscopy package
  SME. Stellar parameters were derived by matching isochrones to the
  observed V vs. V-I colour-magnitude diagram. Independent effective
  temperatures were obtained from automated profile fitting of the
  Balmer lines and by applying colour-T<SUB>eff</SUB> calibrations
  to the broadband photometry. <BR /> Results: Li abundances of the
  turnoff and early subgiant stars form a thin plateau that is broken
  off abruptly in the middle of the SGB as a result of the onset of Li
  dilution caused by the first dredge-up. Abundance trends with effective
  temperature for Fe and Ca are observed and compared to predictions
  from stellar structure models including atomic diffusion and ad hoc
  additional mixing below the surface convection zone. The comparison
  shows that the stars in M30 are affected by atomic diffusion and
  additional mixing, but we were unable to determine the efficiency of
  the additional mixing precisely. This is the fourth globular cluster
  (after NGC 6397, NGC 6752, and M4) in which atomic diffusion signatures
  are detected. After applying a conservative correction (T6.0 model)
  for atomic diffusion, we find an initial Li abundance of A(Li) = 2.48
  ± 0.10 for the globular cluster M30. We also detected a Li-rich SGB
  star with a Li abundance of A(Li) = 2.39. The finding makes Li-rich mass
  transfer a likely scenario for this star and rules out models in which
  its Li enhancement is created during the RGB bump phase. <P />Based
  on data collected at the ESO telescopes under program 085.D-0375.Full
  Tables 1 and 5 are only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/589/A61">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/589/A61</A>

---------------------------------------------------------
Title: Highlights of IAU Commission 29: Recent Advances and
    Perspectives on Stellar Spectroscopy
Authors: Cunha, Katia; Soderblom, David R.; Piskunov, Nikolai; Aoki,
   Wako; Asplund, Martin; Carpenter, Kenneth G.; Crowther, Paul; Melendez,
   Jorge; Venn, Kimberly; Hill, Vanessa; Yong, David
2016IAUTA..29..428C    Altcode:
  IAU Commission 29 - Stellar Spectra has been one of the IAU commissions
  from the onset, until its dissolution at the most recent IAU General
  Assembly in Honolulu in 2015. This commission belonged to IAU Division
  G (“Stars and Stellar Physics”), the latter committed with fostering
  research in stellar astrophysics. Within the general field of stellar
  astrophysics, stellar spectroscopy plays a key role, as stellar
  spectra are a powerful tool providing a view into the detailed physical
  properties of stars and the physical processes occuring within them.

---------------------------------------------------------
Title: Division G Commission 36: Theory of Stellar Atmospheres
Authors: Puls, Joachim; Hubeny, Ivan; Asplund, Martin; Allard, France;
   Allende Prieto, Carlos; Ayres, Thomas R.; Carlsson, Mats; Gustafsson,
   Bengt; Kudritzki, Rolf-Peter; Ryabchikova, Tatiana A.
2016IAUTA..29..453P    Altcode:
  Different from previous triennial reports, this report covers the
  activities of IAU Commission 36 `Theory of Stellar Atmospheres'
  over the past six years†, and will be the last report from the
  `old' Commission 36. After the General Assembly in Honolulu (August
  2015), a new Commission `Stellar and Planetary Atmospheres' (C.G5,
  under Division G, `Stars and Stellar Physics') has come into life,
  and will continue our work devoted to the outer envelopes of stars,
  as well as extend it to the atmospheres of planets (see Sect. 4).

---------------------------------------------------------
Title: The Hyades open cluster is chemically inhomogeneous
Authors: Liu, F.; Yong, D.; Asplund, M.; Ramírez, I.; Meléndez, J.
2016MNRAS.457.3934L    Altcode: 2016arXiv160107354L; 2016MNRAS.tmp...38L
  We present a high-precision differential abundance analysis of 16
  solar-type stars in the Hyades open cluster based on high-resolution,
  high signal-to-noise ratio (S/N ≈ 350-400) spectra obtained from the
  McDonald 2.7-m telescope. We derived stellar parameters and differential
  chemical abundances for 19 elements (C, O, Na, Mg, Al, Si, S, Ca, Sc,
  Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Ba) with uncertainties as low
  as ∼0.01-0.02 dex. Our main results include: (1) there is no clear
  chemical signature of planet formation detected among the sample stars,
  I.e. no correlations in abundances versus condensation temperature;
  (2) the observed abundance dispersions are a factor of ≈1.5-2 larger
  than the average measurement errors for most elements; (3) there are
  positive correlations, of high statistical significance, between the
  abundances of at least 90 per cent of pairs of elements. We demonstrate
  that none of these findings can be explained by errors due to the
  stellar parameters. Our results reveal that the Hyades is chemically
  inhomogeneous at the 0.02 dex level. Possible explanations for the
  abundance variations include (1) inhomogeneous chemical evolution in the
  proto-cluster environment, (2) supernova ejection in the proto-cluster
  cloud and (3) pollution of metal-poor gas before complete mixing of the
  proto-cluster cloud. Our results provide significant new constraints
  on the chemical composition of open clusters and a challenge to the
  current view of Galactic archaeology.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Abundance analysis of solar twin
    HIP 100963 (Yana Galarza+, 2016)
Authors: Yana Galarza, J.; Melendez, J.; Ramirez, I.; Yong, D.;
   Karakas, A. I.; Asplund, M.; Liu, F.
2016yCat..35890017Y    Altcode:
  Stellar abundances [X/H] of HIP 100963 relative to the Sun and
  corresponding errors. <P />(1 data file).

---------------------------------------------------------
Title: The detailed chemical composition of the terrestrial planet
    host Kepler-10
Authors: Liu, F.; Yong, D.; Asplund, M.; Ramírez, I.; Meléndez,
   J.; Gustafsson, B.; Howes, L. M.; Roederer, I. U.; Lambert, D. L.;
   Bensby, T.
2016MNRAS.456.2636L    Altcode: 2015arXiv151109287L
  Chemical abundance studies of the Sun and solar twins have demonstrated
  that the solar composition of refractory elements is depleted when
  compared to volatile elements, which could be due to the formation
  of terrestrial planets. In order to further examine this scenario, we
  conducted a line-by-line differential chemical abundance analysis of the
  terrestrial planet host Kepler-10 and 14 of its stellar twins. Stellar
  parameters and elemental abundances of Kepler-10 and its stellar twins
  were obtained with very high precision using a strictly differential
  analysis of high quality Canada-France-Hawaii Telescope, Hobby-Eberly
  Telescope and Magellan spectra. When compared to the majority of
  thick disc twins, Kepler-10 shows a depletion in the refractory
  elements relative to the volatile elements, which could be due to
  the formation of terrestrial planets in the Kepler-10 system. The
  average abundance pattern corresponds to ∼13 Earth masses, while
  the two known planets in Kepler-10 system have a combined ∼20 Earth
  masses. For two of the eight thick disc twins, however, no depletion
  patterns are found. Although our results demonstrate that several
  factors [e.g. planet signature, stellar age, stellar birth location and
  Galactic chemical evolution (GCE)] could lead to or affect abundance
  trends with condensation temperature, we find that the trends give
  further support for the planetary signature hypothesis.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Stellar parameters and abundances
    for M30 (Gruyters+, 2016)
Authors: Gruyters, P.; Lind, K.; Richard, F.; Grundahl, O.; Asplund,
   M.; Casagrande, L.; Charbonnel, C.; Milone, A.; Primas, F.; Korn, A. J.
2016yCat..35890061G    Altcode:
  Coordinates, photometry and derived effective temperatures for the 144
  observed stars in M30. Effective temperatures where derived using three
  different temperature scales: a scale based on a Victoria isochrone
  (Vandenberg et al., 2014ApJ...794...72V), a scale based on the Alonso
  relations (Alonso, 1996A&amp;A...313..873A, 1999A&amp;AS..140..261A)
  and a scale based on the Ramirez (2005ApJ...626..465R) and Casagrande
  (2010A&amp;A...512A..54C, Cat. J/A+A/512/A54) relations. Additionally,
  the derived Hα temperatures are given. <P />(2 data files).

---------------------------------------------------------
Title: Non-LTE oxygen line formation in 3D hydrodynamic model
    stellar atmospheres
Authors: Amarsi, A. M.; Asplund, M.; Collet, R.; Leenaarts, J.
2016MNRAS.455.3735A    Altcode: 2015arXiv151101155A
  The O I 777 nm lines are among the most commonly used diagnostics for
  the oxygen abundances in the atmospheres of FGK-type stars. However,
  they form in conditions that are far from local thermodynamic
  equilibrium (LTE). We explore the departures from LTE of atomic
  oxygen, and their impact on O I lines, across the STAGGER-grid of
  three-dimensional hydrodynamic model atmospheres. For the O I 777 nm
  triplet, we find significant departures from LTE. These departures are
  larger in stars with larger effective temperatures, smaller surface
  gravities, and larger oxygen abundances. We present grids of predicted
  3D non-LTE based equivalent widths for the O I 616 nm, [O I] 630 nm,
  [O I] 636 nm, and O I 777 nm lines, as well as abundance corrections
  to 1D LTE based results.

---------------------------------------------------------
Title: First high-precision differential abundance analysis of
    extremely metal-poor stars
Authors: Reggiani, Henrique; Meléndez, Jorge; Yong, David; Ramírez,
   Ivan; Asplund, Martin
2016A&A...586A..67R    Altcode: 2015arXiv151203349R
  Context. Studies of extremely metal-poor stars indicate that chemical
  abundance ratios [X/Fe] have a root mean square scatter as low as
  0.05 dex (12%). It remains unclear whether this reflects observational
  uncertainties or intrinsic astrophysical scatter arising from physical
  conditions in the interstellar medium at early times. <BR /> Aims: We
  measure differential chemical abundance ratios in extremely metal-poor
  stars to investigate the limits of precision and to understand
  whether cosmic scatter or observational errors are dominant. <BR />
  Methods: We used high-resolution (R ~ 95 000) and high signal-to-noise
  (S/N = 700 at 5000 Å) HIRES/Keck spectra to determine high-precision
  differential abundances between two extremely metal-poor stars through
  a line-by-line differential approach. We determined stellar parameters
  for the star G64-37 with respect to the standard star G64-12. We
  performed EW measurements for the two stars for the lines recognized
  in both stars and performed spectral synthesis to study the carbon
  abundances. <BR /> Results: The differential approach allowed us to
  obtain errors of σ(T<SUB>eff</SUB>) = 27 K, σ(log g) = 0.06 dex, σ(
  [Fe/H] ) = 0.02 dex and σ(v<SUB>t</SUB>) = 0.06 km s<SUP>-1</SUP>. We
  estimated relative chemical abundances with a precision as low as
  σ([X/Fe]) ≈ 0.01 dex. The small uncertainties demonstrate that
  there are genuine abundance differences larger than the measurement
  errors. The observed Li difference cannot be explained by the
  difference in mass because the less massive star has more Li. <BR />
  Conclusions: It is possible to achieve an abundance precision around
  ≈ 0.01-0.05 dex for extremely metal-poor stars, which opens new
  windows on the study of the early chemical evolution of the Galaxy. <P
  />Table A.1 is also available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/586/A67">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/586/A67</A>

---------------------------------------------------------
Title: The most metal-rich stars: probing exoplanets, stars, the
    Milky Way and galaxies
Authors: Asplund, Martin
2016koa..prop..428A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Measuring the vertical age structure of the Galactic disc
    using asteroseismology and SAGA
Authors: Casagrande, L.; Silva Aguirre, V.; Schlesinger, K. J.;
   Stello, D.; Huber, D.; Serenelli, A. M.; Schönrich, R.; Cassisi, S.;
   Pietrinferni, A.; Hodgkin, S.; Milone, A. P.; Feltzing, S.; Asplund, M.
2016MNRAS.455..987C    Altcode: 2015arXiv151001376C
  The existence of a vertical age gradient in the Milky Way disc
  has been indirectly known for long. Here, we measure it directly
  for the first time with seismic ages, using red giants observed by
  Kepler. We use Strömgren photometry to gauge the selection function
  of asteroseismic targets, and derive colour and magnitude limits
  where giants with measured oscillations are representative of the
  underlying population in the field. Limits in the 2MASS system are
  also derived. We lay out a method to assess and correct for target
  selection effects independent of Galaxy models. We find that low-mass,
  I.e. old red giants dominate at increasing Galactic heights, whereas
  closer to the Galactic plane they exhibit a wide range of ages and
  metallicities. Parametrizing this as a vertical gradient returns
  approximately 4 Gyr kpc<SUP>-1</SUP> for the disc we probe, although
  with a large dispersion of ages at all heights. The ages of stars show
  a smooth distribution over the last ≃10 Gyr, consistent with a mostly
  quiescent evolution for the Milky Way disc since a redshift of about
  2. We also find a flat age-metallicity relation for disc stars. Finally,
  we show how to use secondary clump stars to estimate the present-day
  intrinsic metallicity spread, and suggest using their number count as
  a new proxy for tracing the ageing of the disc. This work highlights
  the power of asteroseismology for Galactic studies; however, we also
  emphasize the need for better constraints on stellar mass-loss, which
  is a major source of systematic age uncertainties in red giant stars.

---------------------------------------------------------
Title: IAU Commission 36 (Theory of Stellar Atmospheres): Hexennial
    Report 2009-2015
Authors: Puls, Joachim; Asplund, Martin
2015arXiv151206972P    Altcode:
  This hexennial report covers the activities of IAU Commission 36 --
  'Theory of Stellar Atmospheres' -- during the years 2009 to 2015,
  and will be the last report from this Commission, being replaced by
  Commission C.G5. After outlining the composition of the Organization
  Committee(s), we list the scientific meetings held between 2009 and 2015
  that were of relevance for our Commission members, and comment on the
  establishment and objectives of the new Commission C.G5 ('Stellar and
  Planetary Atmospheres') within the re-structuring process of the IAU. In
  the main part of the report, we briefly review specific contributions
  and achievements within our research field during the last six years,
  concentrating on the theoretical aspect, and dividing between late-type
  and massive star atmospheres. We also provide a more general overview
  of primary research areas, and finish our report with a collection of
  useful web links.

---------------------------------------------------------
Title: HIP 10725: The first solar twin/analogue field blue straggler
Authors: Schirbel, Lucas; Meléndez, Jorge; Karakas, Amanda I.;
   Ramírez, Iván; Castro, Matthieu; Faria, Marcos A.; Lugaro, Maria;
   Asplund, Martin; Tucci Maia, Marcelo; Yong, David; Howes, Louise;
   do Nascimento, José D.
2015A&A...584A.116S    Altcode: 2015arXiv151001793S
  Context. Blue stragglers are easy to identify in globular clusters,
  but are much harder to identify in the field. Here we present the
  serendipitous discovery of one field blue straggler, HIP 10725,
  that closely matches the Sun in mass and age, but with a metallicity
  slightly lower than solar. <BR /> Aims: We characterise the solar
  twin/analogue HIP 10725 to assess whether this star is a blue
  straggler. <BR /> Methods: We employed spectra with high resolution
  (R ~ 10<SUP>5</SUP>) and high signal-to-noise ratio (330) obtained
  with UVES at the VLT to perform a differential abundance analysis of
  the solar analogue HIP 10725. Radial velocities obtained by other
  instruments were also used to check for binarity. We also studied
  its chromospheric activity, age, and rotational velocity. <BR />
  Results: HIP 10725 is severely depleted in beryllium ([ Be/H ]
  ≤ -1.2 dex) for its stellar parameters and age. The abundances
  relative to solar of the elements with Z ≤ 30 show a correlation
  with condensation temperature, and the neutron capture elements
  produced by the s-process are greatly enhanced, while the r-process
  elements seem normal. We found its projected rotational velocity
  (vsini = 3.3 ± 0.1 km s<SUP>-1</SUP>) to be significantly higher
  than solar and incompatible with its isochrone-derived age. Radial
  velocity monitoring shows that the star has a binary companion. <BR />
  Conclusions: Based on the high s-process element enhancements and low
  beryllium abundance, we suggest that HIP 10725 has been polluted by mass
  transfer from an AGB star that probably had an initial mass of about 2
  M<SUB>⊙</SUB>. The radial velocity variations suggest the presence
  of an unseen binary companion, probably the remnant of a former AGB
  star. Isochrones predict a solar-age star, but this disagrees with the
  high projected rotational velocity and high chromospheric activity. We
  conclude that HIP 10725 is a field blue straggler, rejuvenated by
  the mass-transfer process of its former AGB companion. <P />Based
  on observations obtained at the European Southern Observatory (ESO)
  Very Large Telescope (VLT) at Paranal Observatory, Chile (observing
  programs 083.D-0871, 082.C-0446, 093.D-0807), and complemented with
  observations taken at the Observatório Pico dos Dias (OPD), Brazil
  (program OP2014A-011).Appendix A is available in electronic form at <A
  href="http://www.aanda.org/10.1051/0004-6361/201527303/olm">http://www.aanda.org</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: G64-12 and G64-37 linelist and EWs
    (Reggiani+, 2016)
Authors: Reggiani, H.; Melendez, J.; Yong, D.; Ramirez, I.; Asplund, M.
2015yCat..35860067R    Altcode:
  The linelist employed in the differential analysis. Includes wavelength,
  species, excitation potential, log(gf), and equivalent widths for both
  stars analyzed. <P />(1 data file).

---------------------------------------------------------
Title: PICK2: Planets in Clusters with K2
Authors: Cochran, William D.; Endl, Michael; Johnson, Marshall C.;
   Lee, Byeong-Cheol; Park, Chan; Han, Inwoo; Rauer, Heike; Cabrera,
   Juan; Csizmadia, Szilard; Paetzold, Martin; Yong, David; Asplund,
   Martin; Hatzes, Artie P.
2015DPS....4741702C    Altcode:
  Open clusters are remarkable laboratories for a wide variety of
  astrophysical investigations. They comprise the most homogeneous
  samples of stars that we can ever hope to find. They are stars that
  share the same age, initial chemical composition, distance and dynamical
  environment. The fundamental property that distinguishes one star from
  another in a cluster is simply the stellar mass. This gives us the
  very rare opportunity to conduct well controlled astrophysical studies
  of stars, and as a result there is a vast astronomical literature
  focused on understanding and characterizing the members of stellar
  clusters.We are searching for transiting planets in five open clusters
  in the NASA K2 mission Fields 4, 5 and 7. These clusters range in
  age from 125My (Pleiades) through the 625My ages of the Hyades and
  Praesepe, up to the much older Ruprecht 147 (2.5 Gyr) and M67 (3-5
  Gyr) clusters. Examination of the distribution of planetary orbital
  parameters as well as the planetary multiplicity, radius and mass
  distributions as a function of stellar age (and in comparison with
  field stars from both K2 and Kepler) will provide a powerful test of
  theories of planetary system formation and dynamical evolution. The
  radii of hot Jupiters and Saturns as a function of cluster age will
  provide a sensitive test of theories to explain the population of
  inflated hot Jupiters.Our team will process the K2 pixel files into
  light curves for each target star, and will then search these light
  curves for possible planet transit events. We will apply standard
  vetting procedures to remove likely false-positives and we will then
  model the transit profiles. We will then conduct an extensive set of
  ground-based follow-up observations using a wide range of observational
  facilities at our disposal. These will include imaging, high resolution
  visible and near-IR spectroscopy, precise radial velocity measurement,
  and ground-based observations of further transits, as appropriate.

---------------------------------------------------------
Title: The Galactic chemical evolution of oxygen inferred from 3D
    non-LTE spectral-line-formation calculations.
Authors: Amarsi, A. M.; Asplund, M.; Collet, R.; Leenaarts, J.
2015MNRAS.454L..11A    Altcode: 2015arXiv150804857A
  We revisit the Galactic chemical evolution of oxygen, addressing the
  systematic errors inherent in classical determinations of the oxygen
  abundance that arise from the use of one-dimensional (1D) hydrostatic
  model atmospheres and from the assumption of local thermodynamic
  equilibrium (LTE). We perform detailed 3D non-LTE radiative-transfer
  calculations for atomic oxygen lines across a grid of 3D hydrodynamic
  STAGGER model atmospheres for dwarfs and subgiants. We apply our grid
  of predicted line strengths of the [O I] 630 nm and O I 777 nm lines
  using accurate stellar parameters from the literature. We infer a steep
  decay in [O/Fe] for [Fe/H] ≳ -1.0, a plateau [O/Fe] ≈ 0.5 down to
  [Fe/H] ≈ -2.5, and an increasing trend for [Fe/H] ≲ -2.5. Our 3D
  non-LTE calculations yield overall concordant results from the two
  oxygen abundance diagnostics.

---------------------------------------------------------
Title: Extremely metal-poor stars from the cosmic dawn in the bulge
    of the Milky Way
Authors: Howes, L. M.; Casey, A. R.; Asplund, M.; Keller, S. C.; Yong,
   D.; Nataf, D. M.; Poleski, R.; Lind, K.; Kobayashi, C.; Owen, C. I.;
   Ness, M.; Bessell, M. S.; da Costa, G. S.; Schmidt, B. P.; Tisserand,
   P.; Udalski, A.; Szymański, M. K.; Soszyński, I.; Pietrzyński,
   G.; Ulaczyk, K.; Wyrzykowski, Ł.; Pietrukowicz, P.; Skowron, J.;
   Kozłowski, S.; Mróz, P.
2015Natur.527..484H    Altcode: 2015arXiv151103930H
  The first stars are predicted to have formed within 200 million
  years after the Big Bang, initiating the cosmic dawn. A true first
  star has not yet been discovered, although stars with tiny amounts
  of elements heavier than helium (‘metals’) have been found in
  the outer regions (‘halo’) of the Milky Way. The first stars and
  their immediate successors should, however, preferentially be found
  today in the central regions (‘bulges’) of galaxies, because they
  formed in the largest over-densities that grew gravitationally with
  time. The Milky Way bulge underwent a rapid chemical enrichment during
  the first 1-2 billion years, leading to a dearth of early, metal-poor
  stars. Here we report observations of extremely metal-poor stars in
  the Milky Way bulge, including one star with an iron abundance about
  10,000 times lower than the solar value without noticeable carbon
  enhancement. We confirm that most of the metal-poor bulge stars are on
  tight orbits around the Galactic Centre, rather than being halo stars
  passing through the bulge, as expected for stars formed at redshifts
  greater than 15. Their chemical compositions are in general similar
  to typical halo stars of the same metallicity although intriguing
  differences exist, including lower abundances of carbon.

---------------------------------------------------------
Title: IAU 2015 Resolution B2 on Recommended Zero Points for the
    Absolute and Apparent Bolometric Magnitude Scales
Authors: Mamajek, E. E.; Torres, G.; Prsa, A.; Harmanec, P.;
   Asplund, M.; Bennett, P. D.; Capitaine, N.; Christensen-Dalsgaard,
   J.; Depagne, E.; Folkner, W. M.; Haberreiter, M.; Hekker, S.; Hilton,
   J. L.; Kostov, V.; Kurtz, D. W.; Laskar, J.; Mason, B. D.; Milone,
   E. F.; Montgomery, M. M.; Richards, M. T.; Schou, J.; Stewart, S. G.
2015arXiv151006262M    Altcode:
  The XXIXth IAU General Assembly in Honolulu adopted IAU 2015 Resolution
  B2 on recommended zero points for the absolute and apparent bolometric
  magnitude scales. The resolution was proposed by the IAU Inter-Division
  A-G Working Group on Nominal Units for Stellar and Planetary
  Astronomy after consulting with a broad spectrum of researchers from
  the astronomical community. Resolution B2 resolves the long-standing
  absence of an internationally-adopted zero point for the absolute and
  apparent bolometric magnitude scales. Resolution B2 defines the zero
  point of the absolute bolometric magnitude scale such that a radiation
  source with $M_{\rm Bol}$ = 0 has luminosity L$_{\circ}$ = 3.0128e28
  W. The zero point of the apparent bolometric magnitude scale ($m_{\rm
  Bol}$ = 0) corresponds to irradiance $f_{\circ}$ = 2.518021002e-8
  W/m$^2$. The zero points were chosen so that the nominal solar
  luminosity (3.828e26 W) adopted by IAU 2015 Resolution B3 corresponds
  approximately to $M_{\rm Bol}$(Sun) = 4.74, the value most commonly
  adopted in recent literature. The nominal total solar irradiance (1361
  W/m$^2$) adopted in IAU 2015 Resolution B3 corresponds approximately to
  apparent bolometric magnitude $m_{\rm bol}$(Sun) = -26.832. Implicit
  in the IAU 2015 Resolution B2 definition of the apparent bolometric
  magnitude scale is an exact definition for the parsec (648000/$\pi$ au)
  based on the IAU 2012 Resolution B2 definition of the astronomical unit.

---------------------------------------------------------
Title: IAU 2015 Resolution B3 on Recommended Nominal Conversion
    Constants for Selected Solar and Planetary Properties
Authors: Mamajek, E. E.; Prsa, A.; Torres, G.; Harmanec, P.;
   Asplund, M.; Bennett, P. D.; Capitaine, N.; Christensen-Dalsgaard,
   J.; Depagne, E.; Folkner, W. M.; Haberreiter, M.; Hekker, S.; Hilton,
   J. L.; Kostov, V.; Kurtz, D. W.; Laskar, J.; Mason, B. D.; Milone,
   E. F.; Montgomery, M. M.; Richards, M. T.; Schou, J.; Stewart, S. G.
2015arXiv151007674M    Altcode:
  Astronomers commonly quote the properties of celestial objects in
  units of parameters for the Sun, Jupiter, or the Earth. The resolution
  presented here was proposed by the IAU Inter-Division Working Group
  on Nominal Units for Stellar and Planetary Astronomy and passed by the
  XXIXth IAU General Assembly in Honolulu. IAU 2015 Resolution B3 adopts
  a set of nominal solar, terrestrial, and jovian conversion constants
  for stellar and (exo)planetary astronomy which are defined to be
  exact SI values. While the nominal constants are based on current best
  estimates (CBEs; which have uncertainties, are not secularly constant,
  and are updated regularly using new observations), they should be
  interpreted as standard values and not as CBEs. IAU 2015 Resolution
  B3 adopts five solar conversion constants (nominal solar radius,
  nominal total solar irradiance, nominal solar luminosity, nominal
  solar effective temperature, and nominal solar mass parameter) and six
  planetary conversion constants (nominal terrestrial equatorial radius,
  nominal terrestrial polar radius, nominal jovian equatorial radius,
  nominal jovian polar radius, nominal terrestrial mass parameter,
  and nominal jovian mass parameter).

---------------------------------------------------------
Title: Using Solar Twins to Explore the Planet-Star Connection with
    Unparallelled Precision
Authors: Meléndez, J.; Bean, J. L.; Bedell, M.; Ramírez, I.; Asplund,
   M.; Dreizler, S.; Alves-Brito, A.; Spina, L.; Casagrande, L.; Monroe,
   T.; Maia, M. T.; Freitas, F.
2015Msngr.161...28M    Altcode:
  This year marks the 20th anniversary of the first definitive
  detection of an exoplanet orbiting a Sun-like star by Mayor and
  Queloz (1995). Almost 2000 exoplanets have been discovered since this
  breakthrough, but many fundamental questions remain open despite the
  enormous progress: How common are analogues of the Solar System? How
  do planets form and evolve? What is the relationship between stars and
  planets? We are observing stars that are near-perfect matches to the
  Sun to provide new insights into the above questions, thus exploring
  the planet-star connection with unprecedented precision.

---------------------------------------------------------
Title: The Solar Twin Planet Search. II. A Jupiter twin around a
    solar twin
Authors: Bedell, M.; Meléndez, J.; Bean, J. L.; Ramírez, I.; Asplund,
   M.; Alves-Brito, A.; Casagrande, L.; Dreizler, S.; Monroe, T.; Spina,
   L.; Tucci Maia, M.
2015A&A...581A..34B    Altcode: 2015arXiv150703998B
  Context. With high-precision radial velocity surveys reaching a
  sufficiently long time baseline, the domain of long-period planet
  detections has recently opened up. The search for Jupiter-like planets
  is especially important if we wish to investigate the prevalence
  of solar system analogs, but their detection is complicated by the
  existence of stellar activity cycles on similar timescales. Radial
  velocity data with sufficiently long-term instrumental precision and
  robust methods of diagnosing activity are crucial to the detection of
  extrasolar Jupiters. <BR /> Aims: Through our HARPS survey for planets
  around solar twin stars, we have identified a promising Jupiter twin
  candidate around the star HIP11915. We characterize this Keplerian
  signal and investigate its potential origins in stellar activity. <BR
  /> Methods: We carry out a Markov chain Monte Carlo (MCMC) analysis of
  the radial velocity data. To examine the signal's origin, we employ
  a variety of statistical tests using activity diagnostics such as
  the Ca II H and K lines and line asymmetry tracers. <BR /> Results:
  Our analysis indicates that HIP11915 hosts a Jupiter-mass planet with
  a 3800-day orbital period and low eccentricity. Although we cannot
  definitively rule out an activity cycle interpretation, we find that a
  planet interpretation is more likely based on a joint analysis of radial
  velocity and activity index data. <BR /> Conclusions: The challenges of
  long-period radial velocity signals addressed in this paper are critical
  for the ongoing discovery of Jupiter-like exoplanets. If planetary in
  nature, the signal investigated here represents a very close analog to
  the solar system in terms of both Sun-like host star and Jupiter-like
  planet. <P />Table 3 and Fig. 5 are available in electronic form at <A
  href="http://www.aanda.org/10.1051/0004-6361/201525748/olm">http://www.aanda.org</A>

---------------------------------------------------------
Title: The Surface of Stellar Models - Now with more 3D simulations!
Authors: Trampedach, Regner; Christensen-Dalsgaard, Jørgen; Asplund,
   Martin; Stein, Robert F.; Nordlund, Åke
2015EPJWC.10106064T    Altcode:
  We have constructed a grid of 3D hydrodynamic simulations of deep
  convective and line-blanketed atmospheres. We have developed a
  new consistent method for computing and employing T(τ) relations
  from these simulations, as surface boundary conditions for 1D
  stellar structure models. These 1D models have, in turn, had their
  mixing-length, α, calibrated against the averaged structure of
  each of the simulations. Both α and T(τ) vary significantly with
  T<SUB>eff</SUB> and log g.

---------------------------------------------------------
Title: The most metal-rich stars: probing exoplanets, stellar
    nucleosynthesis, Galactic archaeology and galaxy evolution
Authors: Asplund, Martin
2015koa..prop..210A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Asteroseismology for Galactic archaeology: bridging two fields
Authors: Casagrande, Luca; Silva Aguirre, Victor; Stello, Dennis;
   Huber, Daniel; Serenelli, Aldo; Schlesinger, Katharine J.; Milone,
   Antonino; Asplund, Martin
2015IAUGA..2256260C    Altcode:
  Asteroseismology has the capability of precisely determining stellar
  properties that would otherwise be inaccessible, such as radii, masses,
  and thus ages of field stars. When coupling this information with
  classical determinations of stellar parameters, such as metallicities,
  effective temperatures, and angular diameters, powerful new diagnostics
  for Galactic studies can be obtained. An overview of the ongoing
  Strömgren survey for Asteroseismology and Galactic Archaeology (SAGA)
  is presented, along with recent results using asteroseismology to
  investigate the age structure of the Milky Way disc.

---------------------------------------------------------
Title: Division II: Commission 12: Solar Radiation and Structure
Authors: Kosovichev, Alexander; Cauzzi, Gianna; Martinez Pillet,
   Valentin; Asplund, Martin; Brandenburg, Axel; Chou, Dean-Yi;
   Christensen-Dalsgaard, Jorgen; Gan, Weiqun; Kuznetsov, Vladimir D.;
   Rovira, Marta G.; Shchukina, Nataliya; Venkatakrishnan, P.
2015IAUTB..28..109K    Altcode:
  The President of C12, Alexander Kosovichev, presented the status of
  the Commission and its working Group(s). Primary activities included
  organization of international meetings (IAU Symposia, Special Sessions
  and Joint Discussion); review and support of proposals for IAU sponsored
  meetings; organization of working groups on the Commission topics
  to promote the international cooperation; preparation of triennial
  report on the organizational and science activities of Commission
  members. Commission 12 broadly encompasses topics of solar research
  which include studies of the Sun's internal structure, composition,
  dynamics and magnetism (through helioseismology and other techniques),
  studies of the quiet photosphere, chromosphere and corona, and also
  research of the mechanisms of solar radiation, and its variability on
  various time scales. Some overlap with topics covered by Commission
  10 Solar Activity is unavoidable, and many activities are sponsored
  jointly by these two commissions. The Commission website can be found
  at http://sun.stanford.edu/IAU-Com12/, with information about related
  IAU Symposiums and activities, and links to appropriate web sites.

---------------------------------------------------------
Title: The Gaia-ESO Survey: Empirical determination of the precision
    of stellar radial velocities and projected rotation velocities
Authors: Jackson, R. J.; Jeffries, R. D.; Lewis, J.; Koposov, S. E.;
   Sacco, G. G.; Randich, S.; Gilmore, G.; Asplund, M.; Binney, J.;
   Bonifacio, P.; Drew, J. E.; Feltzing, S.; Ferguson, A. M. N.;
   Micela, G.; Neguerela, I.; Prusti, T.; Rix, H. -W.; Vallenari,
   A.; Alfaro, E. J.; Allende Prieto, C.; Babusiaux, C.; Bensby, T.;
   Blomme, R.; Bragaglia, A.; Flaccomio, E.; Francois, P.; Hambly, N.;
   Irwin, M.; Korn, A. J.; Lanzafame, A. C.; Pancino, E.; Recio-Blanco,
   A.; Smiljanic, R.; Van Eck, S.; Walton, N.; Bayo, A.; Bergemann, M.;
   Carraro, G.; Costado, M. T.; Damiani, F.; Edvardsson, B.; Franciosini,
   E.; Frasca, A.; Heiter, U.; Hill, V.; Hourihane, A.; Jofré, P.; Lardo,
   C.; de Laverny, P.; Lind, K.; Magrini, L.; Marconi, G.; Martayan, C.;
   Masseron, T.; Monaco, L.; Morbidelli, L.; Prisinzano, L.; Sbordone,
   L.; Sousa, S. G.; Worley, C. C.; Zaggia, S.
2015A&A...580A..75J    Altcode: 2015arXiv150507019J
  Context. The Gaia-ESO Survey (GES) is a large public spectroscopic
  survey at the European Southern Observatory Very Large Telescope. <BR
  /> Aims: A key aim is to provide precise radial velocities (RVs) and
  projected equatorial velocities (vsini) for representative samples
  of Galactic stars, which will complement information obtained by the
  Gaia astrometry satellite. <BR /> Methods: We present an analysis
  to empirically quantify the size and distribution of uncertainties
  in RV and vsini using spectra from repeated exposures of the same
  stars. <BR /> Results: We show that the uncertainties vary as simple
  scaling functions of signal-to-noise ratio (S/N) and vsini, that the
  uncertainties become larger with increasing photospheric temperature,
  but that the dependence on stellar gravity, metallicity and age is
  weak. The underlying uncertainty distributions have extended tails
  that are better represented by Student's t-distributions than by
  normal distributions. <BR /> Conclusions: Parametrised results are
  provided, which enable estimates of the RV precision for almost all GES
  measurements, and estimates of the vsini precision for stars in young
  clusters, as a function of S/N, vsini and stellar temperature. The
  precision of individual high S/N GES RV measurements is 0.22-0.26 km
  s<SUP>-1</SUP>, dependent on instrumental configuration. <P />Based on
  observations collected with the FLAMES spectrograph at VLT/UT2 telescope
  (Paranal Observatory, ESO, Chile), for the Gaia- ESO Large Public Survey
  (188.B-3002).Full Table 2 is only available at the CDS via anonymous ftp
  to <A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/580/A75">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/580/A75</A>

---------------------------------------------------------
Title: Exploring the vertical age structure of the Galactic disc
Authors: Casagrande, Luca; Silva Aguirre, Victor; Schlesinger,
   Katharine J.; Stello, Dennis; Huber, Daniel; Serenelli, Aldo;
   Schoenrich, Ralph; Asplund, Martin; Feltzing, Sofia
2015IAUGA..2256224C    Altcode:
  While in external or high-redshift galaxies we can only measure
  integrated stellar properties at best, the Milky Way offers us the
  unique opportunity to study its individual baryonic components,
  including stars. We use oscillations measured in giant stars by the
  Kepler satellite to derive stellar ages and explore the vertical age
  structure across few kpc of the Milky Way disc. We find that old stars
  dominate at increasing Galactic heights, whereas closer to the plane
  a rich zoology of ages exists. The age distribution of stars shows
  a smooth decline over the last 10 Gyr, which together with a flat
  age-metallicity relation is consistent with a quiescent evolution for
  the Milky Way disc since a redshift of about two.

---------------------------------------------------------
Title: The Gaia-ESO Survey: a quiescent Milky Way with no significant
    dark/stellar accreted disc
Authors: Ruchti, G. R.; Read, J. I.; Feltzing, S.; Serenelli, A. M.;
   McMillan, P.; Lind, K.; Bensby, T.; Bergemann, M.; Asplund, M.;
   Vallenari, A.; Flaccomio, E.; Pancino, E.; Korn, A. J.; Recio-Blanco,
   A.; Bayo, A.; Carraro, G.; Costado, M. T.; Damiani, F.; Heiter, U.;
   Hourihane, A.; Jofré, P.; Kordopatis, G.; Lardo, C.; de Laverny,
   P.; Monaco, L.; Morbidelli, L.; Sbordone, L.; Worley, C. C.; Zaggia, S.
2015MNRAS.450.2874R    Altcode: 2015arXiv150402481R
  According to our current cosmological model, galaxies like the Milky Way
  are expected to experience many mergers over their lifetimes. The most
  massive of the merging galaxies will be dragged towards the disc plane,
  depositing stars and dark matter into an accreted disc structure. In
  this work, we utilize the chemodynamical template developed in Ruchti
  et al. to hunt for accreted stars. We apply the template to a sample
  of 4675 stars in the third internal data release from the Gaia-ESO
  Spectroscopic Survey. We find a significant component of accreted halo
  stars, but find no evidence of an accreted disc component. This suggests
  that the Milky Way has had a rather quiescent merger history since
  its disc formed some 8-10 billion years ago and therefore possesses
  no significant dark matter disc.

---------------------------------------------------------
Title: An Elemental Assay of Very, Extremely, and Ultra-metal-poor
    Stars
Authors: Hansen, T.; Hansen, C. J.; Christlieb, N.; Beers, T. C.;
   Yong, D.; Bessell, M. S.; Frebel, A.; García Pérez, A. E.; Placco,
   V. M.; Norris, J. E.; Asplund, M.
2015ApJ...807..173H    Altcode: 2015arXiv150600579H
  We present a high-resolution elemental-abundance analysis for a
  sample of 23 very metal-poor ([Fe/H] &lt; -2.0) stars, 12 of which
  are extremely metal-poor ([Fe/H] &lt; -3.0), and 4 of which are
  ultra-metal-poor ([Fe/H] &lt; -4.0). These stars were targeted to
  explore differences in the abundance ratios for elements that constrain
  the possible astrophysical sites of element production, including
  Li, C, N, O, the α-elements, the iron-peak elements, and a number
  of neutron-capture elements. This sample substantially increases the
  number of known carbon-enhanced metal-poor (CEMP) and nitrogen-enhanced
  metal-poor (NEMP) stars—our program stars include eight that are
  considered “normal” metal-poor stars, six CEMP-no stars, five
  CEMP-s stars, two CEMP-r stars, and two CEMP-r/s stars. One of the
  CEMP-r stars and one of the CEMP-r/s stars are possible NEMP stars. We
  detect lithium for three of the six CEMP-no stars, all of which are
  Li depleted with respect to the Spite plateau. The majority of the
  CEMP stars have [C/N] &gt; 0. The stars with [C/N] &lt; 0 suggest
  a larger degree of mixing; the few CEMP-no stars that exhibit this
  signature are only found at [Fe/H] &lt; -3.4, a metallicity below
  which we also find the CEMP-no stars with large enhancements in Na,
  Mg, and Al. We confirm the existence of two plateaus in the absolute
  carbon abundances of CEMP stars, as suggested by Spite et al. We also
  present evidence for a “floor” in the absolute Ba abundances of
  CEMP-no stars at A(Ba) ∼ -2.0. <P />Based on observations made with
  the European Southern Observatory telescopes.

---------------------------------------------------------
Title: The Dissimilar Chemical Composition of the Planet-hosting
    Stars of the XO-2 Binary System
Authors: Ramírez, I.; Khanal, S.; Aleo, P.; Sobotka, A.; Liu, F.;
   Casagrande, L.; Meléndez, J.; Yong, D.; Lambert, D. L.; Asplund, M.
2015ApJ...808...13R    Altcode: 2015arXiv150601025R
  Using high-quality spectra of the twin stars in the XO-2 binary system,
  we have detected significant differences in the chemical composition
  of their photospheres. The differences correlate strongly with the
  elements’ dust condensation temperature. In XO-2N, volatiles are
  enhanced by about 0.015 dex and refractories are overabundant by
  up to 0.090 dex. On average, our error bar in relative abundance is
  0.012 dex. We present an early metal-depletion scenario in which the
  formation of the gas giant planets known to exist around these stars are
  responsible for a 0.015 dex offset in the abundances of all elements
  while 20 M<SUB>⨁</SUB> of non-detected rocky objects that formed
  around XO-2S explain the additional refractory-element difference. An
  alternative explanation involves the late accretion of at least 20
  M<SUB>⨁</SUB> of planet-like material by XO-2N, allegedly as a result
  of the migration of the hot Jupiter detected around that star. Dust
  cleansing by a nearby hot star as well as age or Galactic birthplace
  effects can be ruled out as valid explanations for this phenomenon.

---------------------------------------------------------
Title: High-Resolution Spectroscopic Study of Extremely Metal-Poor
    Star Candidates from the SkyMapper Survey
Authors: Jacobson, Heather R.; Keller, Stefan; Frebel, Anna; Casey,
   Andrew R.; Asplund, Martin; Bessell, Michael S.; Da Costa, Gary S.;
   Lind, Karin; Marino, Anna F.; Norris, John E.; Peña, José M.;
   Schmidt, Brian P.; Tisserand, Patrick; Walsh, Jennifer M.; Yong,
   David; Yu, Qinsi
2015ApJ...807..171J    Altcode: 2015arXiv150403344J
  The SkyMapper Southern Sky Survey is carrying out a search for
  the most metal-poor stars in the Galaxy. It identifies candidates
  by way of its unique filter set which allows for estimation of
  stellar atmospheric parameters. The set includes a narrow filter
  centered on the Ca ii K 3933 Å line, enabling a robust estimate
  of stellar metallicity. Promising candidates are then confirmed
  with spectroscopy. We present the analysis of Magellan Inamori
  Kyocera Echelle high-resolution spectroscopy of 122 metal-poor
  stars found by SkyMapper in the first two years of commissioning
  observations. Forty-one stars have [{Fe}/{{H}}]≤slant -3.0. Nine
  have [{Fe}/{{H}}]≤slant -3.5, with three at [{Fe}/{{H}}]∼ -4. A
  1D LTE abundance analysis of the elements Li, C, Na, Mg, Al, Si,
  Ca, Sc, Ti, Cr, Mn, Co, Ni, Zn, Sr, Ba, and Eu shows these stars
  have [X/Fe] ratios typical of other halo stars. One star with low
  [X/Fe] values appears to be “Fe-enhanced,” while another star
  has an extremely large [Sr/Ba] ratio: \gt 2. Only one other star is
  known to have a comparable value. Seven stars are “CEMP-no” stars
  ([{{C}}/{Fe}]\gt 0.7, [{Ba}/{Fe}]\lt 0). 21 stars exhibit mild r-process
  element enhancements (0.3≤slant [{Eu}/{Fe}]\lt 1.0), while four stars
  have [{Eu}/{Fe}]≥slant 1.0. These results demonstrate the ability
  to identify extremely metal-poor stars from SkyMapper photometry,
  pointing to increased sample sizes and a better characterization of
  the metal-poor tail of the halo metallicity distribution function
  in the future. <P />This paper includes data gathered with the 6.5 m
  Magellan Telescopes located at Las Campanas Observatory, Chile.

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Title: First light results from the High Efficiency and Resolution
    Multi-Element Spectrograph at the Anglo-Australian Telescope
Authors: Sheinis, Andrew; Anguiano, Borja; Asplund, Martin; Bacigalupo,
   Carlos; Barden, Sam; Birchall, Michael; Bland-Hawthorn, Joss; Brzeski,
   Jurek; Cannon, Russell; Carollo, Daniela; Case, Scott; Casey, Andrew;
   Churilov, Vladimir; Warrick, Couch; Dean, Robert; De Silva, Gayandhi;
   D'Orazi, Valentina; Duong, Ly; Farrell, Tony; Fiegert, Kristin;
   Freeman, Kenneth; Gabriella, Frost; Gers, Luke; Goodwin, Michael; Gray,
   Doug; Green, Andrew; Heald, Ron; Heijmans, Jeroen; Ireland, Michael;
   Jones, Damien; Kafle, Prajwal; Keller, Stefan; Klauser, Urs; Kondrat,
   Yuriy; Kos, Janez; Lawrence, Jon; Lee, Steve; Mali, Slavko; Martell,
   Sarah; Mathews, Darren; Mayfield, Don; Miziarski, Stan; Muller, Rolf;
   Pai, Naveen; Patterson, Robert; Penny, Ed; Orr, David; Schlesinger,
   Katharine; Sharma, Sanjib; Shortridge, Keith; Simpson, Jeffrey;
   Smedley, Scott; Smith, Greg; Stafford, Darren; Staszak, Nicholas;
   Vuong, Minh; Waller, Lewis; de Boer, Elizabeth Wylie; Xavier, Pascal;
   Zheng, Jessica; Zhelem, Ross; Zucker, Daniel; Zwitter, Tomaz
2015JATIS...1c5002S    Altcode:
  The High Efficiency and Resolution Multi Element Spectrograph, HERMES,
  is a facility-class optical spectrograph for the Anglo-Australian
  Telescope (AAT). It is designed primarily for Galactic Archaeology,
  the first major attempt to create a detailed understanding of galaxy
  formation and evolution by studying the history of our own galaxy,
  the Milky Way. The goal of the GALAH survey is to reconstruct the
  mass assembly history of the Milky Way through a detailed chemical
  abundance study of one million stars. The spectrograph is based at
  the AAT and is fed by the existing 2dF robotic fiber positioning
  system. The spectrograph uses volume phase holographic gratings to
  achieve a spectral resolving power of 28,000 in standard mode and also
  provides a high-resolution mode ranging between 40,000 and 50,000 using
  a slit mask. The GALAH survey requires an SNR greater than 100 for a
  star brightness of V=14 in an exposure time of one hour. The total
  spectral coverage of the four channels is about 100 nm between 370
  and 1000 nm for up to 392 simultaneous targets within the 2-degree
  field of view. HERMES has been commissioned over three runs, during
  bright time in October, November, and December 2013, in parallel with
  the beginning of the GALAH pilot survey, which started in November
  2013. We present the first-light results from the commissioning run
  and the beginning of the GALAH survey, including performance results
  such as throughput and resolution, as well as instrument reliability.

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Title: VizieR Online Data Catalog: Velocity precision in the Gaia-ESO
    Survey (Jackson+, 2015)
Authors: Jackson, R. J.; Jeffries, R. D.; Lewis, J.; Koposov, S. E.;
   Sacco, G. G.; Randich, S.; Gilmore, G.; Asplund, M.; Binney, J.;
   Bonifacio, P.; Drew, J. E.; Feltzing, S.; Ferguson, A. M. N.;
   Micela, G.; Neguerela, I.; Prusti, T.; Rix, H. -W.; Vallenari,
   A.; Alfaro, E. J.; Allende Prieto, C.; Babusiaux, C.; Bensby, T.;
   Blomme, R.; Bragaglia, A.; Flaccomio, E.; Francois, P.; Hambly, N.;
   Irwin, M.; Korn, A. J.; Lanzafame, A. C.; Pancino, E.; Recio-Blanco,
   A.; Smiljanic, R.; Van Eck, S.; Walton, N.; Bayo, A.; Bergemann, M.;
   Carraro, G.; Costado, M. T.; Damiani, F.; Edvardsson, B.; Franciosini,
   E.; Frasca, A.; Heiter, U.; Hill, V.; Hourihane, A.; Jof, P.; Lardo,
   C.; de Laverny, P.; Lind, K.; Magrini, L.; Marconi, G.; Martayan, C.;
   Masseron, T.; Monaco, L.; Morbidelli, L.; Prisinzano, L.; Sbordone,
   L.; Sousa, S. G.; Worley, C. C.; Zaggia, S.
2015yCat..35800075J    Altcode:
  The Gaia-ESO Survey (GES) is a large public spectroscopic survey at
  the European Southern Observatory Very LargeTelescope. A key aim is
  to provide precise radial velocities (RVs) and projected equatorial
  velocities (vsini) for representative samples of Galactic stars,
  which will complement information obtained by the Gaia astrometry
  satellite. We present an analysis to empirically quantify the size
  and distribution of uncertainties in RV and vsini using spectra from
  repeated exposures of the same stars. We show that the uncertainties
  vary as simple scaling functions of signal-to-noise ratio (S/N) and
  vsini, that the uncertainties become larger with increasing photospheric
  temperature, but that the dependence on stellar gravity, metallicity
  and age is weak. The underlying uncertainty distributions have extended
  tails that are better represented by Students t-distributions than
  by normal distributions. Parametrised results are provided, which
  enable estimates of the RV precision for almost all GES measurements,
  and estimates of the vsini precision for stars in young clusters,
  as a function of S/N, vsini and stellar temperature. The precision of
  individual high S/N GES RV measurements is 0.22-0.26km/s, dependent
  on instrumental configuration. <P />(1 data file).

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Title: Nucleosynthesis in a Primordial Supernova: Carbon and Oxygen
    Abundances in SMSS J031300.36-670839.3
Authors: Bessell, Michael S.; Collet, Remo; Keller, Stefan C.; Frebel,
   Anna; Heger, Alexander; Casey, Andrew R.; Masseron, Thomas; Asplund,
   Martin; Jacobson, Heather R.; Lind, Karin; Marino, Anna F.; Norris,
   John E.; Yong, David; Da Costa, Gary; Chan, Conrad; Magic, Zazralt;
   Schmidt, Brian; Tisserand, Patrick
2015ApJ...806L..16B    Altcode: 2015arXiv150503756B
  SMSS J031300.36-670839.3 (hereafter SM0313-6708) is a sub-giant halo
  star, with no detectable Fe lines and large overabundances of C and
  Mg relative to Ca. We obtained Very Large Telescope-Ultraviolet
  and Visual Echelle Spectrograph (UVES) spectra extending to 3060
  Å showing strong OH A-X band lines enabling an oxygen abundance to
  be derived. The OH A-X band lines in SM0313-6708 are much stronger
  than the CH C-X band lines. Spectrum synthesis fits indicate an [O/C]
  ratio of 0.02 ± 0.175. Our high signal-to-noise ratio UVES data also
  enabled us to lower the Fe abundance limit to {{[Fe/H]}<SUB>&lt; 3D&gt;
  ,NLTE</SUB>}\lt -7.52 (3σ). These data support our previous suggestion
  that the star formed from the iron-poor ejecta of a single massive
  star Population III supernova. <P />Based on observations obtained with
  European Southern Observatory (ESO) telescopes (proposal 092.D-0742).

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Title: Iron and s-elements abundance variations in NGC 5286:
    comparison with `anomalous' globular clusters and Milky Way satellites
Authors: Marino, A. F.; Milone, A. P.; Karakas, A. I.; Casagrande,
   L.; Yong, D.; Shingles, L.; Da Costa, G.; Norris, J. E.; Stetson,
   P. B.; Lind, K.; Asplund, M.; Collet, R.; Jerjen, H.; Sbordone, L.;
   Aparicio, A.; Cassisi, S.
2015MNRAS.450..815M    Altcode: 2015arXiv150207438M
  We present a high-resolution spectroscopic analysis of 62 red giants
  in the Milky Way globular cluster (GC) NGC 5286. We have determined
  abundances of representative light proton-capture, α, Fe-peak and
  neutron-capture element groups, and combined them with photometry of
  multiple sequences observed along the colour-magnitude diagram. Our
  principal results are: (i) a broad, bimodal distribution in s-process
  element abundance ratios, with two main groups, the s-poor and
  s-rich groups; (ii) substantial star-to-star Fe variations, with the
  s-rich stars having higher Fe, e.g. &lt; [Fe/H]&gt; _{s-rich}} - &lt;
  [Fe/H]&gt; _{s-poor}} ∼ 0.2 dex; and (iii) the presence of O-Na-Al
  (anti)correlations in both stellar groups. We have defined a new
  photometric index, c<SUB>BVI</SUB> = (B - V) - (V - I), to maximize
  the separation in the colour-magnitude diagram between the two stellar
  groups with different Fe and s-element content, and this index is not
  significantly affected by variations in light elements (such as the O-Na
  anticorrelation). The variations in the overall metallicity present in
  NGC 5286 add this object to the class of anomalous GCs. Furthermore,
  the chemical abundance pattern of NGC 5286 resembles that observed
  in some of the anomalous GCs, e.g. M 22, NGC 1851, M 2, and the more
  extreme ω Centauri, that also show internal variations in s-elements,
  and in light elements within stars with different Fe and s-elements
  content. In view of the common variations in s-elements, we propose
  the term s-Fe-anomalous GCs to describe this sub-class of objects. The
  similarities in chemical abundance ratios between these objects strongly
  suggest similar formation and evolution histories, possibly associated
  with an origin in tidally disrupted dwarf satellites.

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Title: Testing the chemical tagging technique with open clusters
Authors: Blanco-Cuaresma, S.; Soubiran, C.; Heiter, U.; Asplund,
   M.; Carraro, G.; Costado, M. T.; Feltzing, S.; González-Hernández,
   J. I.; Jiménez-Esteban, F.; Korn, A. J.; Marino, A. F.; Montes, D.;
   San Roman, I.; Tabernero, H. M.; Tautvaišienė, G.
2015A&A...577A..47B    Altcode: 2015arXiv150302082B
  Context. Stars are born together from giant molecular clouds and, if
  we assume that the priors were chemically homogeneous and well-mixed,
  we expect them to share the same chemical composition. Most of
  the stellar aggregates are disrupted while orbiting the Galaxy and
  most of the dynamic information is lost, thus the only possibility
  of reconstructing the stellar formation history is to analyze the
  chemical abundances that we observe today. <BR /> Aims: The chemical
  tagging technique aims to recover disrupted stellar clusters based
  merely on their chemical composition. We evaluate the viability of this
  technique to recover co-natal stars that are no longer gravitationally
  bound. <BR /> Methods: Open clusters are co-natal aggregates that have
  managed to survive together. We compiled stellar spectra from 31 old
  and intermediate-age open clusters, homogeneously derived atmospheric
  parameters, and 17 abundance species, and applied machine learning
  algorithms to group the stars based on their chemical composition. This
  approach allows us to evaluate the viability and efficiency of the
  chemical tagging technique. <BR /> Results: We found that stars at
  different evolutionary stages have distinct chemical patterns that may
  be due to NLTE effects, atomic diffusion, mixing, and biases. When
  separating stars into dwarfs and giants, we observed that a few
  open clusters show distinct chemical signatures while the majority
  show a high degree of overlap. This limits the recovery of co-natal
  aggregates by applying the chemical tagging technique. Nevertheless,
  there is room for improvement if more elements are included and models
  are improved. <P />Based on observations obtained at the Telescope
  Bernard Lyot (USR5026) operated by the Observatoire Midi-Pyrénées,
  Université de Toulouse (Paul Sabatier), Centre National de la
  Recherche Scientifique of France, and on public data obtained from
  the ESO Science Archive Facility under requests number 81252 and 81618.

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Title: Atomic and molecular data for optical stellar spectroscopy
Authors: Heiter, U.; Lind, K.; Asplund, M.; Barklem, P. S.; Bergemann,
   M.; Magrini, L.; Masseron, T.; Mikolaitis, Š.; Pickering, J. C.;
   Ruffoni, M. P.
2015PhyS...90e4010H    Altcode: 2015arXiv150606697H
  High-precision spectroscopy of large stellar samples plays a crucial
  role for several topical issues in astrophysics. Examples include
  studying the chemical structure and evolution of the Milky Way
  Galaxy, tracing the origin of chemical elements, and characterizing
  planetary host stars. Data are accumulating from instruments that
  obtain high-quality spectra of stars in the ultraviolet, optical and
  infrared wavelength regions on a routine basis. These instruments
  are located at ground-based 2-10 m class telescopes around the world,
  in addition to the spectrographs with unique capabilities available at
  the Hubble Space Telescope. The interpretation of these spectra requires
  high-quality transition data for numerous species, in particular neutral
  and singly ionized atoms, and di- or triatomic molecules. We rely
  heavily on the continuous efforts of laboratory astrophysics groups
  that produce and improve the relevant experimental and theoretical
  atomic and molecular data. The compilation of the best available data
  is facilitated by databases and electronic infrastructures such as
  the NIST Atomic Spectra Database, the VALD database, or the Virtual
  Atomic and Molecular Data Centre. We illustrate the current status
  of atomic data for optical stellar spectra with the example of the
  Gaia-ESO Public Spectroscopic Survey. Data sources for 35 chemical
  elements were reviewed in an effort to construct a line list for a
  homogeneous abundance analysis of up to 10<SUP>5</SUP> stars.

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Title: The GALAH survey: scientific motivation
Authors: De Silva, G. M.; Freeman, K. C.; Bland-Hawthorn, J.; Martell,
   S.; de Boer, E. Wylie; Asplund, M.; Keller, S.; Sharma, S.; Zucker,
   D. B.; Zwitter, T.; Anguiano, B.; Bacigalupo, C.; Bayliss, D.;
   Beavis, M. A.; Bergemann, M.; Campbell, S.; Cannon, R.; Carollo, D.;
   Casagrande, L.; Casey, A. R.; Da Costa, G.; D'Orazi, V.; Dotter, A.;
   Duong, L.; Heger, A.; Ireland, M. J.; Kafle, P. R.; Kos, J.; Lattanzio,
   J.; Lewis, G. F.; Lin, J.; Lind, K.; Munari, U.; Nataf, D. M.; O'Toole,
   S.; Parker, Q.; Reid, W.; Schlesinger, K. J.; Sheinis, A.; Simpson,
   J. D.; Stello, D.; Ting, Y. -S.; Traven, G.; Watson, F.; Wittenmyer,
   R.; Yong, D.; Žerjal, M.
2015MNRAS.449.2604D    Altcode: 2015arXiv150204767D
  The Galactic Archaeology with HERMES (GALAH) survey is a large
  high-resolution spectroscopic survey using the newly commissioned
  High Efficiency and Resolution Multi-Element Spectrograph (HERMES)
  on the Anglo-Australian Telescope. The HERMES spectrograph provides
  high-resolution (R ∼ 28 000) spectra in four passbands for 392 stars
  simultaneously over a 2 deg field of view. The goal of the survey is
  to unravel the formation and evolutionary history of the Milky Way,
  using fossil remnants of ancient star formation events which have been
  disrupted and are now dispersed throughout the Galaxy. Chemical tagging
  seeks to identify such dispersed remnants solely from their common and
  unique chemical signatures; these groups are unidentifiable from their
  spatial, photometric or kinematic properties. To carry out chemical
  tagging, the GALAH survey will acquire spectra for a million stars down
  to V ∼ 14. The HERMES spectra of FGK stars contain absorption lines
  from 29 elements including light proton-capture elements, α-elements,
  odd-Z elements, iron-peak elements and n-capture elements from the
  light and heavy s-process and the r-process. This paper describes the
  motivation and planned execution of the GALAH survey, and presents
  some results on the first-light performance of HERMES.

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Title: New view on exoplanet transits. Transit of Venus described
    using three-dimensional solar atmosphere STAGGER-grid simulations
Authors: Chiavassa, A.; Pere, C.; Faurobert, M.; Ricort, G.; Tanga,
   P.; Magic, Z.; Collet, R.; Asplund, M.
2015A&A...576A..13C    Altcode: 2015arXiv150106207C
  Context. An important benchmark for current observational techniques and
  theoretical modeling of exoplanet atmospheres is the transit of Venus
  (ToV). Stellar activity and, in particular, convection-related surface
  structures, potentially cause fluctuations that can affect the transit
  light curves. Surface convection simulations can help interpreting the
  ToV as well as other transits outside our solar system. <BR /> Aims:
  We used the realistic three-dimensional (3D) radiative hydrodynamical
  (RHD) simulation of the Sun from the Stagger-grid and synthetic images
  computed with the radiative transfer code Optim3D to predict the transit
  of Venus (ToV) in 2004 that was observed by the satellite ACRIMSAT. <BR
  /> Methods: We computed intensity maps from the RHD simulation of the
  Sun and produced a synthetic stellar disk image as an observer would
  see, accounting for the center-to-limb variations. The contribution of
  the solar granulation was considered during the ToV. We computed the
  light curve and compared it to the ACRIMSAT observations as well as
  to light curves obtained with solar surface representations carried
  out using radial profiles with different limb-darkening laws. We
  also applied the same spherical tile imaging method as used for RHD
  simulation to the observations of center-to-limb solar granulation with
  Hinode. <BR /> Results: We explain ACRIMSAT observations of 2004 ToV and
  show that the granulation pattern causes fluctuations in the transit
  light curve. We compared different limb-darkening models to the RHD
  simulation and evaluated the contribution of the granulation to the
  ToV. We showed that the granulation pattern can partially explain the
  observed discrepancies between models and data. Moreover, we found
  that the overall agreement between real and RHD solar granulation
  is good, either in terms of depth or ingress/egress slopes of the
  transit curve. This confirms that the limb-darkening and granulation
  pattern simulated in 3D RHD of the Sun represent well what is imaged
  by Hinode. In the end, we found that the contribution of the Venusean
  aureole during ToV is ~10<SUP>-6</SUP> times less intense than the
  solar photosphere, and thus, accurate measurements of this phenomena
  are extremely challenging. <BR /> Conclusions: The prospects for
  planet detection and characterization with transiting methods are
  excellent with access to large a amount of data for stars. Being able
  to consistently explain the data of 2004 ToV is a new step forward
  for 3D RHD simulations, which are becoming essential for detecting
  and characterizing exoplanets. They show that granulation has to
  be considered as an intrinsic uncertainty (as a result of stellar
  variability) on precise measurements of exoplanet transits of, most
  likely, planets with small diameters. In this context, it is mandatory
  to obtain a comprehensive knowledge of the host star, including a
  detailed study of the stellar surface convection.

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Title: Shallow extra mixing in solar twins inferred from Be abundances
Authors: Tucci Maia, M.; Meléndez, J.; Castro, M.; Asplund, M.;
   Ramírez, I.; Monroe, T. R.; do Nascimento, J. D., Jr.; Yong, D.
2015A&A...576L..10T    Altcode: 2015arXiv150307882T
  Context. Lithium and beryllium are destroyed at different temperatures
  in stellar interiors. As such, their relative abundances offer excellent
  probes of the nature and extent of mixing processes within and below the
  convection zone. <BR /> Aims: We determine Be abundances for a sample
  of eight solar twins for which Li abundances have previously been
  determined. The analyzed solar twins span a very wide range of age,
  0.5-8.2 Gyr, which enables us to study secular evolution of Li and Be
  depletion. <BR /> Methods: We gathered high-quality UVES/VLT spectra
  and obtained Be abundances by spectral synthesis of the Be ii 313 nm
  doublet. <BR /> Results: The derived beryllium abundances exhibit no
  significant variation with age. The more fragile Li, however, exhibits
  a monotonically decreasing abundance with increasing age. Therefore,
  relatively shallow extra mixing below the convection zone is necessary
  to simultaneously account for the observed Li and Be behavior in
  the Sun and solar twins. <P />Based on observations obtained at the
  European Southern Observatory (ESO) Very Large Telescope (VLT) at
  Paranal Observatory, Chile (observing program 083.D-0871).

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Title: Gaia-ESO Survey: Analysis of pre-main sequence stellar spectra
Authors: Lanzafame, A. C.; Frasca, A.; Damiani, F.; Franciosini, E.;
   Cottaar, M.; Sousa, S. G.; Tabernero, H. M.; Klutsch, A.; Spina, L.;
   Biazzo, K.; Prisinzano, L.; Sacco, G. G.; Randich, S.; Brugaletta, E.;
   Delgado Mena, E.; Adibekyan, V.; Montes, D.; Bonito, R.; Gameiro,
   J. F.; Alcalá, J. M.; González Hernández, J. I.; Jeffries,
   R.; Messina, S.; Meyer, M.; Gilmore, G.; Asplund, M.; Binney, J.;
   Bonifacio, P.; Drew, J. E.; Feltzing, S.; Ferguson, A. M. N.; Micela,
   G.; Negueruela, I.; Prusti, T.; Rix, H. -W.; Vallenari, A.; Alfaro,
   E. J.; Allende Prieto, C.; Babusiaux, C.; Bensby, T.; Blomme, R.;
   Bragaglia, A.; Flaccomio, E.; Francois, P.; Hambly, N.; Irwin, M.;
   Koposov, S. E.; Korn, A. J.; Smiljanic, R.; Van Eck, S.; Walton, N.;
   Bayo, A.; Bergemann, M.; Carraro, G.; Costado, M. T.; Edvardsson,
   B.; Heiter, U.; Hill, V.; Hourihane, A.; Jackson, R. J.; Jofré, P.;
   Lardo, C.; Lewis, J.; Lind, K.; Magrini, L.; Marconi, G.; Martayan,
   C.; Masseron, T.; Monaco, L.; Morbidelli, L.; Sbordone, L.; Worley,
   C. C.; Zaggia, S.
2015A&A...576A..80L    Altcode: 2015arXiv150104450L
  Context. The Gaia-ESO Public Spectroscopic Survey is obtaining
  high-quality spectroscopy of some 100 000 Milky Way stars using the
  FLAMES spectrograph at the VLT, down to V = 19 mag, systematically
  covering all the main components of the Milky Way and providing the
  first homogeneous overview of the distributions of kinematics and
  chemical element abundances in the Galaxy. Observations of young open
  clusters, in particular, are giving new insights into their initial
  structure, kinematics, and their subsequent evolution. <BR /> Aims:
  This paper describes the analysis of UVES and GIRAFFE spectra acquired
  in the fields of young clusters whose population includes pre-main
  sequence (PMS) stars. The analysis is applied to all stars in such
  fields, regardless of any prior information on membership, and provides
  fundamental stellar atmospheric parameters, elemental abundances, and
  PMS-specific parameters such as veiling, accretion, and chromospheric
  activity. <BR /> Methods: When feasible, different methods were used
  to derive raw parameters (e.g. line equivalent widths) fundamental
  atmospheric parameters and derived parameters (e.g. abundances). To
  derive some of these parameters, we used methods that have been
  extensively used in the past and new ones developed in the context
  of the Gaia-ESO survey enterprise. The internal precision of these
  quantities was estimated by inter-comparing the results obtained by
  these different methods, while the accuracy was estimated by comparison
  with independent external data, such as effective temperature and
  surface gravity derived from angular diameter measurements, on a
  sample of benchmarks stars. A validation procedure based on these
  comparisons was applied to discard spurious or doubtful results and
  produce recommended parameters. Specific strategies were implemented to
  resolve problems of fast rotation, accretion signatures, chromospheric
  activity, and veiling. <BR /> Results: The analysis carried out on
  spectra acquired in young cluster fields during the first 18 months
  of observations, up to June 2013, is presented in preparation of the
  first release of advanced data products. These include targets in
  the fields of the <ASTROBJ>ρ Oph</ASTROBJ>, <ASTROBJ>Cha I</ASTROBJ>,
  <ASTROBJ>NGC 2264</ASTROBJ>, <ASTROBJ>γ Vel</ASTROBJ>, and <ASTROBJ>NGC
  2547</ASTROBJ> clusters. Stellar parameters obtained with the higher
  resolution and larger wavelength coverage from UVES are reproduced with
  comparable accuracy and precision using the smaller wavelength range
  and lower resolution of the GIRAFFE setup adopted for young stars,
  which allows us to provide stellar parameters with confidence for the
  much larger GIRAFFE sample. Precisions are estimated to be ≈120 K
  rms in T<SUB>eff</SUB>, ≈0.3 dex rms in log g, and ≈0.15 dex rms in
  [Fe/H] for the UVES and GIRAFFE setups.

---------------------------------------------------------
Title: The Gaia-ESO Survey: A globular cluster escapee in the
    Galactic halo
Authors: Lind, K.; Koposov, S. E.; Battistini, C.; Marino, A. F.;
   Ruchti, G.; Serenelli, A.; Worley, C. C.; Alves-Brito, A.; Asplund,
   M.; Barklem, P. S.; Bensby, T.; Bergemann, M.; Blanco-Cuaresma, S.;
   Bragaglia, A.; Edvardsson, B.; Feltzing, S.; Gruyters, P.; Heiter,
   U.; Jofre, P.; Korn, A. J.; Nordlander, T.; Ryde, N.; Soubiran,
   C.; Gilmore, G.; Randich, S.; Ferguson, A. M. N.; Jeffries, R. D.;
   Vallenari, A.; Allende Prieto, C.; Pancino, E.; Recio-Blanco, A.;
   Romano, D.; Smiljanic, R.; Bellazzini, M.; Damiani, F.; Hill, V.;
   de Laverny, P.; Jackson, R. J.; Lardo, C.; Zaggia, S.
2015A&A...575L..12L    Altcode: 2015arXiv150203934L
  A small fraction of the halo field is made up of stars that share the
  light element (Z ≤ 13) anomalies characteristic of second generation
  globular cluster (GC) stars. The ejected stars shed light on the
  formation of the Galactic halo by tracing the dynamical history of
  the clusters, which are believed to have once been more massive. Some
  of these ejected stars are expected to show strong Al enhancement at
  the expense of shortage of Mg, but until now no such star has been
  found. We search for outliers in the Mg and Al abundances of the few
  hundreds of halo field stars observed in the first eighteen months of
  the Gaia-ESO public spectroscopic survey. One halo star at the base
  of the red giant branch, here referred to as 22593757-4648029 is found
  to have [ Mg/Fe ] = -0.36 ± 0.04 and [ Al/Fe ] = 0.99 ± 0.08, which
  is compatible with the most extreme ratios detected in GCs so far. We
  compare the orbit of 22593757-4648029 to GCs of similar metallicity
  andfind it unlikely that this star has been tidally stripped with low
  ejection velocity from any of the clusters. However, both chemical
  and kinematic arguments render it plausible that the star has been
  ejected at high velocity from the anomalous GC ω Centauri within
  the last few billion years. We cannot rule out other progenitor GCs,
  because some may have disrupted fully, and the abundance and orbital
  data are inadequate for many of those that are still intact. <P
  />Based on data acquired by the Gaia-ESO Survey, programme ID
  188.B-3002. Observations were made with ESO Telescopes at the La Silla
  Paranal Observatory.Appendix A is available in electronic form at <A
  href="http://www.aanda.org/10.1051/0004-6361/201425554/olm">http://www.aanda.org</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: Photometry and abundances of
    NGC1851 stars (Marino+, 2014)
Authors: Marino, A. F.; Milone, A. P.; Yong, D.; Dotter, A.; Da Costa,
   G.; Asplund, M.; Jerjen, H.; Mackey, D.; Norris, J.; Cassisi, S.;
   Sbordone, L.; Stetson, P. B.; Weiss, A.; Aparicio, A.; Bedin, L. R.;
   Lind, K.; Monelli, M.; Piotto, G.; Angeloni, R.; Buonanno, R.
2015yCat..74423044M    Altcode:
  In this paper, we used four distinct photometric data sets. First,
  we used Stetson (2000PASP..112..925S) ground-based B, V, R and I
  photometry. This photometric catalogue has been established from about
  550 images taken at different telescopes, i.e. the Max Planck 2.2m,
  the Cerro Tololo Inter-American Observatory (CTIO) 4, 1.5 and 0.9m
  telescopes, and the Dutch 0.9m telescope in La Silla. In the present
  work, we have complemented the Stetson catalogue with images collected
  with the Wide Field Imager (WFI) of the Max Planck 2.2m telescope at
  La Silla (WFI@2.2m) through the U filter under the SUrvey of Multiple
  pOpulations (SUMO) campaign. <P />Secondly, to study stars in the halo
  of NGC 1851, we collected BVI images with WFI@2.2m of a field between
  ~10 and 35 arcmin to the south of the cluster centre. Photometry
  and astrometry for this data set have been obtained by using the
  program img2xym_WFI and the procedure described by Anderson et
  al. (2006A&amp;A...454.1029A). <P />Third and finally, to investigate
  the most crowded central regions, we use Hubble Space Telescope (HST)
  F606W and F814W photometry obtained with the Wide Field Channel of the
  Advanced Camera for Survey (WFC/ACS) and F275W photometry collected
  with the Ultraviolet and Visual Channel of the Wide Field Camera 3
  (UVIS/WFC3). <P />(2 data files).

---------------------------------------------------------
Title: The oldest objects in the Universe: extremely metal-poor
    stars in the Galactic bulge (via telecon)
Authors: Asplund, Martin
2015mwss.confE..55A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Stagger-grid: A grid of 3D stellar atmosphere
    models. IV. Limb darkening coefficients
Authors: Magic, Z.; Chiavassa, A.; Collet, R.; Asplund, M.
2015A&A...573A..90M    Altcode: 2014arXiv1403.3487M
  <BR /> Aims: We compute the emergent stellar spectra from the UV to
  far infrared for different viewing angles using realistic 3D model
  atmospheres for a large range in stellar parameters to predict the
  stellar limb darkening. <BR /> Methods: We have computed full 3D
  LTE synthetic spectra based on 3D radiative hydrodynamic atmosphere
  models from the Stagger-grid in the ranges: T<SUB>eff</SUB> from 4000
  to 7000 K, log g from 1.5 to 5.0, and [Fe/H], from -4.0 to +0.5. From
  the resulting intensities, we derived coefficients for the standard
  limb darkening laws considering a number of often-used photometric
  filters. Furthermore, we calculated theoretical transit light curves,
  in order to quantify the differences between predictions by the
  widely used 1D model atmosphere and our 3D models. <BR /> Results:
  The 3D models are often found to predict steeper darkening towards
  the limb compared to the 1D models, mainly due to the temperature
  stratifications and temperature gradients being different in the
  3D models compared to those predicted with 1D models based on the
  mixing length theory description of convective energy transport. The
  resulting differences in the transit light curves are rather small;
  however, these can be significant for high-precision observations of
  extrasolar transits, and are able to lower the residuals from the fits
  with 1D limb darkening profiles. <BR /> Conclusions: We advocate the
  use of the new limb darkening coefficients provided for the standard
  four-parameter non-linear power law, which can fit the limb darkening
  more accurately than other choices. <P />Full Table A.1 and the grid
  of spectra are only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/573/A90">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/573/A90</A>,
  as well as at <A
  href="http://www.stagger-stars.net">http://www.stagger-stars.net</A>

---------------------------------------------------------
Title: The Stagger-grid: A grid of 3D stellar atmosphere
    models. III. The relation to mixing length convection theory
Authors: Magic, Z.; Weiss, A.; Asplund, M.
2015A&A...573A..89M    Altcode: 2014arXiv1403.1062M
  <BR /> Aims: We investigate the relation between 1D atmosphere models
  that rely on the mixing length theory and models based on full 3D
  radiative hydrodynamic (RHD) calculations to describe convection in
  the envelopes of late-type stars. <BR /> Methods: The adiabatic
  entropy value of the deep convection zone, s<SUB>bot</SUB>,
  and the entropy jump, Δs, determined from the 3D RHD models,
  were matched with the mixing length parameter, α<SUB>MLT</SUB>,
  from 1D hydrostatic atmosphere models with identical microphysics
  (opacities and equation-of-state). We also derived the mass mixing
  length parameter, α<SUB>m</SUB>, and the vertical correlation
  length of the vertical velocity, C[v<SUB>z</SUB>,v<SUB>z</SUB>],
  directly from the 3D hydrodynamical simulations of stellar subsurface
  convection. <BR /> Results: The calibrated mixing length parameter
  for the Sun is α<SUP>๏</SUP><SUB>MLT</SUB> (S<SUB>bot</SUB>)
  = 1.98. . For different stellar parameters, α<SUB>MLT</SUB>
  varies systematically in the range of 1.7 - 2.4. In particular,
  α<SUB>MLT</SUB> decreases towards higher effective temperature,
  lower surface gravity and higher metallicity. We find equivalent
  results for α<SUP>๏</SUP><SUB>MLT</SUB> (ΔS). In addition, we find
  a tight correlation between the mixing length parameter and the inverse
  entropy jump. We derive an analytical expression from the hydrodynamic
  mean-field equations that motivates the relation to the mass mixing
  length parameter, α<SUB>m</SUB>, and find that it qualitatively shows
  a similar variation with stellar parameter (between 1.6 and 2.4) with
  the solar value of α<SUP>๏</SUP><SUB>m</SUB> = 1.83.. The vertical
  correlation length scaled with the pressure scale height yields 1.71
  for the Sun, but only displays a small systematic variation with
  stellar parameters, the correlation length slightly increases with
  T<SUB>eff</SUB>. <BR /> Conclusions: We derive mixing length parameters
  for various stellar parameters that can be used to replace a constant
  value. Within any convective envelope, α<SUB>m</SUB> and related
  quantities vary strongly. Our results will help to replace a constant
  α<SUB>MLT</SUB>. <P />Appendices are available in electronic form at <A
  href="http://www.aanda.org/10.1051/0004-6361/201423760/olm">http://www.aanda.org</A>Full
  Table A.1 is only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/573/A89">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/573/A89</A>
  as well as at <A
  href="http://www.stagger-stars.net">http://www.stagger-stars.net</A>

---------------------------------------------------------
Title: The elemental composition of the Sun. III. The heavy elements
    Cu to Th
Authors: Grevesse, Nicolas; Scott, Pat; Asplund, Martin; Sauval,
   A. Jacques
2015A&A...573A..27G    Altcode: 2014arXiv1405.0288G
  We re-evaluate the abundances of the elements in the Sun from copper
  (Z = 29) to thorium (Z = 90). Our results are mostly based on
  neutral and singly-ionised lines in the solar spectrum. We use the
  latest 3D hydrodynamic solar model atmosphere, and in a few cases
  also correct for departures from local thermodynamic equilibrium
  (LTE) using non-LTE (NLTE) calculations performed in 1D. In order
  to minimise statistical and systematic uncertainties, we make
  stringent line selections, employ the highest-quality observational
  data and carefully assess oscillator strengths, hyperfine constants
  and isotopic separations available in the literature, for every line
  included in our analysis. Our results are typically in good agreement
  with the abundances in the most pristine meteorites, but there are
  some interesting exceptions. This analysis constitutes both a full
  exposition and a slight update of the relevant parts of the preliminary
  results we presented in Asplund et al. (2009, ARA&amp;A, 47, 481),
  including full line lists and details of all input data that we have
  employed. <P />Tables 1-3 are available in electronic form at <A
  href="http://www.aanda.org/10.1051/0004-6361/201424111/olm">http://www.aanda.org</A>

---------------------------------------------------------
Title: The elemental composition of the Sun. II. The iron group
    elements Sc to Ni
Authors: Scott, Pat; Asplund, Martin; Grevesse, Nicolas; Bergemann,
   Maria; Sauval, A. Jacques
2015A&A...573A..26S    Altcode: 2014arXiv1405.0287S
  We redetermine the abundances of all iron group nuclei in the Sun,
  based on neutral and singly-ionised lines of Sc, Ti, V, Mn, Fe, Co and
  Ni in the solar spectrum. We employ a realistic 3D hydrodynamic model
  solar atmosphere, corrections for departures from local thermodynamic
  equilibrium (NLTE), stringent line selection procedures and high
  quality observational data. We have scoured the literature for
  the best quality oscillator strengths, hyperfine constants and
  isotopic separations available for our chosen lines. We find log
  ɛ<SUB>Sc</SUB> = 3.16 ± 0.04, log ɛ<SUB>Ti</SUB> = 4.93 ± 0.04,
  log ɛ<SUB>V</SUB> = 3.89 ± 0.08, log ɛ<SUB>Cr</SUB> = 5.62 ± 0.04,
  log ɛ<SUB>Mn</SUB> = 5.42 ± 0.04, log ɛ<SUB>Fe</SUB> = 7.47 ± 0.04,
  log ɛ<SUB>Co</SUB> = 4.93 ± 0.05 and log ɛ<SUB>Ni</SUB> = 6.20 ±
  0.04. Our uncertainties factor in both statistical and systematic errors
  (the latter estimated for possible errors in the model atmospheres and
  NLTE line formation). The new abundances are generally in good agreement
  with the CI meteoritic abundances but with some notable exceptions. This
  analysis constitutes both a full exposition and a slight update of the
  preliminary results we presented in Asplund et al. (2009, ARA&amp;A,
  47, 481), including full line lists and details of all input data
  we employed. <P />Tables 1-3 are available in electronic form at <A
  href="http://www.aanda.org/10.1051/0004-6361/201424110/olm">http://www.aanda.org</A>

---------------------------------------------------------
Title: The elemental composition of the Sun. I. The intermediate
    mass elements Na to Ca
Authors: Scott, Pat; Grevesse, Nicolas; Asplund, Martin; Sauval,
   A. Jacques; Lind, Karin; Takeda, Yoichi; Collet, Remo; Trampedach,
   Regner; Hayek, Wolfgang
2015A&A...573A..25S    Altcode: 2014arXiv1405.0279S
  The chemical composition of the Sun is an essential piece of reference
  data for astronomy, cosmology, astroparticle, space and geo-physics:
  elemental abundances of essentially all astronomical objects are
  referenced to the solar composition, and basically every process
  involving the Sun depends on its composition. This article, dealing
  with the intermediate-mass elements Na to Ca, is the first in a
  series describing the comprehensive re-determination of the solar
  composition. In this series we severely scrutinise all ingredients
  of the analysis across all elements, to obtain the most accurate,
  homogeneous and reliable results possible. We employ a highly
  realistic 3D hydrodynamic model of the solar photosphere, which has
  successfully passed an arsenal of observational diagnostics. For
  comparison, and to quantify remaining systematic errors, we repeat
  the analysis using three different 1D hydrostatic model atmospheres
  (marcs, miss and Holweger &amp; Müller 1974, Sol. Phys., 39, 19) and
  a horizontally and temporally-averaged version of the 3D model (⟨ 3D
  ⟩). We account for departures from local thermodynamic equilibrium
  (LTE) wherever possible. We have scoured the literature for the best
  possible input data, carefully assessing transition probabilities,
  hyperfine splitting, partition functions and other data for inclusion
  in the analysis. We have put the lines we use through a very stringent
  quality check in terms of their observed profiles and atomic data, and
  discarded all that we suspect to be blended. Our final recommended
  3D+NLTE abundances are: log ɛ<SUB>Na</SUB> = 6.21 ± 0.04, log
  ɛ<SUB>Mg</SUB> = 7.59 ± 0.04, log ɛ<SUB>Al</SUB> = 6.43 ± 0.04,
  log ɛ<SUB>Si</SUB> = 7.51 ± 0.03, log ɛ<SUB>P</SUB> = 5.41 ± 0.03,
  log ɛ<SUB>S</SUB> = 7.13 ± 0.03, log ɛ<SUB>K</SUB> = 5.04 ± 0.05
  and log ɛ<SUB>Ca</SUB> = 6.32 ± 0.03. The uncertainties include both
  statistical and systematic errors. Our results are systematically
  smaller than most previous ones with the 1D semi-empirical
  Holweger &amp; Müller model, whereas the ⟨ 3D ⟩ model returns
  abundances very similar to the full 3D calculations. This analysis
  provides a complete description and a slight update of the results
  presented in Asplund et al. (2009, ARA&amp;A, 47, 481) for Na to
  Ca, and includes full details of all lines and input data used. <P
  />Tables 1-4 and Appendix A are available in electronic form at <A
  href="http://www.aanda.org/10.1051/0004-6361/201424109/olm">http://www.aanda.org</A>

---------------------------------------------------------
Title: Magnesium isotopes in giants in the Milky Way inner disk and
bulge: First results with 3D stellar atmospheres.
Authors: Thygesen, Anders; Sbordone, Luca; Christlieb, Norbert;
   Asplund, Martin
2015AAS...22513303T    Altcode:
  The Milky Way bulge is one of the most poorly understood components of
  our galaxy and its formation history is still a matter of debate (early
  collapse vs. disk instability). All knowledge of its chemical evolution
  history has been so far derived by measuring elemental abundances:
  no isotopic mixtures have been measured so far in the Bulge. While
  quite challenging, isotopic measurements can be accomplished with
  present instruments in bulge stars for a few elements, Magnesium being
  one of them.Of the three stable Mg isotopes, the most common one,
  <SUP>24</SUP>Mg, is mainly produced by α capture in SN II, while
  the other two, <SUP>25</SUP>Mg and <SUP>26</SUP>Mg, can be produced
  efficiently in massive AGB stars, through the <SUP>22</SUP>Ne(α,
  n)<SUP>25</SUP>Mg(n, γ)<SUP>26</SUP>Mg reactions as well as the
  Mg-Al chain. Moreover, SN II production of <SUP>25</SUP>Mg and
  <SUP>26</SUP>Mg increases with increasing progenitor metallicity,
  so in older stellar populations, where only the signature of
  metal-poor SNe is to be expected, one should not see a significant
  <SUP>25</SUP>Mg or <SUP>26</SUP>Mg fraction. However, if larger
  <SUP>25</SUP>Mg/<SUP>24</SUP>Mg and <SUP>26</SUP>Mg/<SUP>24</SUP>Mg
  ratios are observed, relative to what is produced in SNe, this is a
  clear sign of an AGB contribution. As such, Mg isotopic ratios are
  a very useful probe of AGB pollution onset and chemical enrichment
  timescale in a stellar population.Here, we present the first ever
  measurements of Mg isotopes in 7 red giant stars in the Milky Way
  bulge and inner disk, including two stars in the bulge globular
  cluster NGC6522. The isotopic abundances have been derived from high
  resolution, high signal-to-noise VLT-UVES spectra using both standard
  1D atmospheric models as well as state-of-the-art 3D hydrodynamical
  models and spectrosynthesis. The use of 3D atmospheric models impacts
  the derived ratios and this work represents the first derivation of
  Mg isotopes using full 3D spectrosynthesis. These results yield new
  constraints on the proposed formation scenarios of the Milky Way bulge.

---------------------------------------------------------
Title: The Solar Twin Planet Search. I. Fundamental parameters of
    the stellar sample
Authors: Ramírez, I.; Meléndez, J.; Bean, J.; Asplund, M.; Bedell,
   M.; Monroe, T.; Casagrande, L.; Schirbel, L.; Dreizler, S.; Teske,
   J.; Tucci Maia, M.; Alves-Brito, A.; Baumann, P.
2014A&A...572A..48R    Altcode: 2014arXiv1408.4130R
  Context. We are carrying out a search for planets around a sample
  of solar twin stars using the HARPS spectrograph. The goal of this
  project is to exploit the advantage offered by solar twins to obtain
  chemical abundances of unmatched precision. This survey will enable
  new studies of the stellar composition - planet connection. <BR />
  Aims: We determine the fundamental parameters of the 88 solar twin
  stars that have been chosen as targets for our experiment. <BR />
  Methods: We used the MIKE spectrograph on the Magellan Clay Telescope
  to acquire high resolution, high signal-to-noise ratio spectra of
  our sample stars. We measured the equivalent widths of iron lines
  and used strict differential excitation/ionization balance analysis
  to determine atmospheric parameters of unprecedented internal
  precision: σ(T<SUB>eff</SUB>) = 7 K, σ(log g) = 0.019, σ( [Fe/H]
  ) = 0.006 dex, σ(v<SUB>t</SUB>) = 0.016 km s<SUP>-1</SUP>. Reliable
  relative ages and highly precise masses were then estimated using
  theoretical isochrones. <BR /> Results: The spectroscopic parameters
  we derived are in good agreement with those measured using other
  independent techniques. There is even better agreement if the
  sample is restricted to those stars with the most internally precise
  determinations of stellar parameters in every technique involved. The
  root-mean-square scatter of the differences seen is fully compatible
  with the observational errors, demonstrating, as assumed thus far,
  that systematic uncertainties in the stellar parameters are negligible
  in the study of solar twins. We find a tight activity-age relation
  for our sample stars, which validates the internal precision of our
  dating method. Furthermore, we find that the solar cycle is perfectly
  consistent both with this trend and its star-to-star scatter. <BR />
  Conclusions: We present the largest sample of solar twins analyzed
  homogeneously using high quality spectra. The fundamental parameters
  derived from this work will be employed in subsequent work that aims to
  explore the connections between planet formation and stellar chemical
  composition. <P />Tables 2-4 are available in electronic form at <A
  href="http://www.aanda.org/10.1051/0004-6361/201424244/olm">http://www.aanda.org</A>

---------------------------------------------------------
Title: Improvements to stellar structure models, based on a grid of 3D
    convection simulations - II. Calibrating the mixing-length formulation
Authors: Trampedach, Regner; Stein, Robert F.; Christensen-Dalsgaard,
   Jørgen; Nordlund, Åke; Asplund, Martin
2014MNRAS.445.4366T    Altcode: 2014arXiv1410.1559T
  We perform a calibration of the mixing length of convection in stellar
  structure models against realistic 3D radiation-coupled hydrodynamics
  simulations of convection in stellar surface layers, determining
  the adiabat deep in convective stellar envelopes. The mixing-length
  parameter α is calibrated by matching averages of the 3D simulations
  to 1D stellar envelope models, ensuring identical atomic physics
  in the two cases. This is done for a previously published grid of
  solar-metallicity convection simulations, covering from 4200 to 6900 K
  on the main sequence, and from 4300 to 5000 K for giants with log g =
  2.2. Our calibration results in an α varying from 1.6 for the warmest
  dwarf, which is just cool enough to admit a convective envelope, and
  up to 2.05 for the coolest dwarfs in our grid. In between these is a
  triangular plateau of α ∼ 1.76. The Sun is located on this plateau
  and has seen little change during its evolution so far. When stars
  ascend the giant branch, they largely do so along tracks of constant
  α, with α decreasing with increasing mass.

---------------------------------------------------------
Title: The Gaia-ESO Survey: the most metal-poor stars in the
    Galactic bulge
Authors: Howes, L. M.; Asplund, M.; Casey, A. R.; Keller, S. C.; Yong,
   D.; Gilmore, G.; Lind, K.; Worley, C.; Bessell, M. S.; Casagrande, L.;
   Marino, A. F.; Nataf, D. M.; Owen, C. I.; Da Costa, G. S.; Schmidt,
   B. P.; Tisserand, P.; Randich, S.; Feltzing, S.; Vallenari, A.;
   Allende Prieto, C.; Bensby, T.; Flaccomio, E.; Korn, A. J.; Pancino,
   E.; Recio-Blanco, A.; Smiljanic, R.; Bergemann, M.; Costado, M. T.;
   Damiani, F.; Heiter, U.; Hill, V.; Hourihane, A.; Jofré, P.; Lardo,
   C.; de Laverny, P.; Magrini, L.; Maiorca, E.; Masseron, T.; Morbidelli,
   L.; Sacco, G. G.; Minniti, D.; Zoccali, M.
2014MNRAS.445.4241H    Altcode: 2014arXiv1409.7952H
  We present the first results of the EMBLA survey (Extremely
  Metal-poor BuLge stars with AAOmega), aimed at finding metal-poor
  stars in the Milky Way bulge, where the oldest stars should now
  preferentially reside. EMBLA utilizes SkyMapper photometry to
  pre-select metal-poor candidates, which are subsequently confirmed
  using AAOmega spectroscopy. We describe the discovery and analysis
  of four bulge giants with -2.72 ≤ [Fe/H] ≤ -2.48, the lowest
  metallicity bulge stars studied with high-resolution spectroscopy to
  date. Using FLAMES/UVES spectra through the Gaia-ESO Survey we have
  derived abundances of twelve elements. Given the uncertainties, we
  find a chemical similarity between these bulge stars and halo stars
  of the same metallicity, although the abundance scatter may be larger,
  with some of the stars showing unusual [α/Fe] ratios.

---------------------------------------------------------
Title: NGC 6522: a typical globular cluster in the Galactic bulge
    without signatures of rapidly rotating Population III stars
Authors: Ness, Melissa; Asplund, Martin; Casey, Andrew R.
2014MNRAS.445.2994N    Altcode: 2014arXiv1408.0290N
  We present an abundance analysis of eight potential member stars of
  the old Galactic bulge globular cluster NGC 6522. The same stars
  have previously been studied by Chiappini et al., who found very
  high abundances of the slow neutron capture elements compared with
  other clusters and field stars of similar metallicity, which they
  interpreted as reflecting nucleosynthesis in rapidly rotating,
  massive Population III stars. In contrast to their analysis, we do
  not find any unusual enhancements of the neutron capture elements Sr,
  Y, Ba and Eu and conclude that previous claims result mainly from not
  properly accounting for blending lines. Instead, we find NGC 6522 to
  be an unremarkable globular cluster with comparable abundance trends
  to other Galactic globular clusters at the same metallicity ([Fe/H] =
  -1.15 ± 0.16). The stars are also chemically similar to halo and bulge
  field stars at the same metallicity, spanning a small range in [Y/Ba]
  and with normal α-element abundances. We thus find no observational
  evidence for any chemical signatures of rapidly rotating Population
  III stars in NGC 6522.

---------------------------------------------------------
Title: The chemical composition of red giants in 47
    Tucanae. I. Fundamental parameters and chemical abundance patterns
Authors: Thygesen, A. O.; Sbordone, L.; Andrievsky, S.; Korotin,
   S.; Yong, D.; Zaggia, S.; Ludwig, H. -G.; Collet, R.; Asplund, M.;
   Ventura, P.; D'Antona, F.; Meléndez, J.; D'Ercole, A.
2014A&A...572A.108T    Altcode: 2014arXiv1409.4694T
  Context. The study of chemical abundance patterns in globular
  clusters is key importance to constraining the different candidates
  for intracluster pollution of light elements. <BR /> Aims: We aim
  at deriving accurate abundances for a wide range of elements in the
  globular cluster 47 Tucanae (NGC 104) to add new constraints to the
  pollution scenarios for this particular cluster, expanding the range of
  previously derived element abundances. <BR /> Methods: Using tailored
  1D local thermodynamic equilibrium (LTE) atmospheric models, together
  with a combination of equivalent width measurements, LTE, and NLTE
  synthesis, we derive stellar parameters and element abundances from
  high-resolution, high signal-to-noise spectra of 13 red giant stars
  near the tip of the RGB. <BR /> Results: We derive abundances of a
  total 27 elements (O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co,
  Ni, Cu, Zn, Y, Zr, Mo, Ru, Ba, La, Ce, Pr, Nd, Eu, Dy). Departures
  from LTE were taken into account for Na, Al, and Ba. We find a mean
  [Fe/H] = -0.78 ± 0.07 and [ α/ Fe ] = 0.34 ± 0.03 in good agreement
  with previous studies. The remaining elements show good agreement with
  the literature, but including NLTE for Al has a significant impact on
  the behavior of this key element. <BR /> Conclusions: We confirm the
  presence of an Na-O anti-correlation in 47 Tucanae found by several
  other works. Our NLTE analysis of Al shifts the [Al/Fe] to lower values,
  indicating that this may be overestimated in earlier works. No evidence
  of an intrinsic variation is found in any of the remaining elements. <P
  />Based on observations made with the ESO Very Large Telescope at
  Paranal Observatory, Chile (Programmes 084.B-0810 and 086.B-0237).Full
  Tables 2, 5, and 9 are only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/572/A108">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/572/A108</A>Appendix
  A is available in electronic form at <A
  href="http://www.aanda.org/10.1051/0004-6361/201424533/olm">http://www.aanda.org</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: NGC 2808 HB stars abundances
    (Marino+, 2014)
Authors: Marino, A. F.; Milone, A. P.; Przybilla, N.; Bergemann,
   M.; Lind, K.; Asplund, M.; Cassisi, S.; Catelan, M.; Casagrande, L.;
   Valcarce, A. A. R.; Bedin, L. R.; Cortes, C.; D'Antona, F.; Jerjen,
   H.; Piotto, G.; Schlesinger, K.; Zoccali, M.; Angeloni, R.
2014yCat..74371609M    Altcode:
  To identify our stellar sample, we use the photometric catalogue of
  Momany et al. (2004), which has been obtained from U, B and V images
  collected with the Wide-Field Imager (WFI) mounted at the 2.2m ESO-MPI
  (Max-Planck-Institut) telescope at La Silla observatory, Chile. <P
  />Our spectroscopic data consist of FLAMES/GIRAFFE and FLAMES/UVES data
  collected under the ESO programme 086.D-0141 (PI: Marino). The GIRAFFE
  fibres were used with the HR12 setup, covering the spectral range from
  ~5820 to ~6140Å with a resolution of ~18700. <P />(6 data files).

---------------------------------------------------------
Title: The PLATO 2.0 mission
Authors: Rauer, H.; Catala, C.; Aerts, C.; Appourchaux, T.; Benz,
   W.; Brandeker, A.; Christensen-Dalsgaard, J.; Deleuil, M.; Gizon,
   L.; Goupil, M. -J.; Güdel, M.; Janot-Pacheco, E.; Mas-Hesse,
   M.; Pagano, I.; Piotto, G.; Pollacco, D.; Santos, Ċ.; Smith, A.;
   Suárez, J. -C.; Szabó, R.; Udry, S.; Adibekyan, V.; Alibert, Y.;
   Almenara, J. -M.; Amaro-Seoane, P.; Eiff, M. Ammler-von; Asplund, M.;
   Antonello, E.; Barnes, S.; Baudin, F.; Belkacem, K.; Bergemann, M.;
   Bihain, G.; Birch, A. C.; Bonfils, X.; Boisse, I.; Bonomo, A. S.;
   Borsa, F.; Brandão, I. M.; Brocato, E.; Brun, S.; Burleigh, M.;
   Burston, R.; Cabrera, J.; Cassisi, S.; Chaplin, W.; Charpinet, S.;
   Chiappini, C.; Church, R. P.; Csizmadia, Sz.; Cunha, M.; Damasso, M.;
   Davies, M. B.; Deeg, H. J.; Díaz, R. F.; Dreizler, S.; Dreyer, C.;
   Eggenberger, P.; Ehrenreich, D.; Eigmüller, P.; Erikson, A.; Farmer,
   R.; Feltzing, S.; de Oliveira Fialho, F.; Figueira, P.; Forveille,
   T.; Fridlund, M.; García, R. A.; Giommi, P.; Giuffrida, G.; Godolt,
   M.; Gomes da Silva, J.; Granzer, T.; Grenfell, J. L.; Grotsch-Noels,
   A.; Günther, E.; Haswell, C. A.; Hatzes, A. P.; Hébrard, G.; Hekker,
   S.; Helled, R.; Heng, K.; Jenkins, J. M.; Johansen, A.; Khodachenko,
   M. L.; Kislyakova, K. G.; Kley, W.; Kolb, U.; Krivova, N.; Kupka, F.;
   Lammer, H.; Lanza, A. F.; Lebreton, Y.; Magrin, D.; Marcos-Arenal,
   P.; Marrese, P. M.; Marques, J. P.; Martins, J.; Mathis, S.; Mathur,
   S.; Messina, S.; Miglio, A.; Montalban, J.; Montalto, M.; Monteiro,
   M. J. P. F. G.; Moradi, H.; Moravveji, E.; Mordasini, C.; Morel, T.;
   Mortier, A.; Nascimbeni, V.; Nelson, R. P.; Nielsen, M. B.; Noack,
   L.; Norton, A. J.; Ofir, A.; Oshagh, M.; Ouazzani, R. -M.; Pápics,
   P.; Parro, V. C.; Petit, P.; Plez, B.; Poretti, E.; Quirrenbach, A.;
   Ragazzoni, R.; Raimondo, G.; Rainer, M.; Reese, D. R.; Redmer, R.;
   Reffert, S.; Rojas-Ayala, B.; Roxburgh, I. W.; Salmon, S.; Santerne,
   A.; Schneider, J.; Schou, J.; Schuh, S.; Schunker, H.; Silva-Valio,
   A.; Silvotti, R.; Skillen, I.; Snellen, I.; Sohl, F.; Sousa, S. G.;
   Sozzetti, A.; Stello, D.; Strassmeier, K. G.; Švanda, M.; Szabó,
   Gy. M.; Tkachenko, A.; Valencia, D.; Van Grootel, V.; Vauclair,
   S. D.; Ventura, P.; Wagner, F. W.; Walton, N. A.; Weingrill, J.;
   Werner, S. C.; Wheatley, P. J.; Zwintz, K.
2014ExA....38..249R    Altcode: 2014ExA...tmp...41R; 2013arXiv1310.0696R
  PLATO 2.0 has recently been selected for ESA's M3 launch opportunity
  (2022/24). Providing accurate key planet parameters (radius, mass,
  density and age) in statistical numbers, it addresses fundamental
  questions such as: How do planetary systems form and evolve? Are there
  other systems with planets like ours, including potentially habitable
  planets? The PLATO 2.0 instrument consists of 34 small aperture
  telescopes (32 with 25 s readout cadence and 2 with 2.5 s candence)
  providing a wide field-of-view (2232 deg <SUP>2</SUP>) and a large
  photometric magnitude range (4-16 mag). It focusses on bright (4-11
  mag) stars in wide fields to detect and characterize planets down to
  Earth-size by photometric transits, whose masses can then be determined
  by ground-based radial-velocity follow-up measurements. Asteroseismology
  will be performed for these bright stars to obtain highly accurate
  stellar parameters, including masses and ages. The combination of
  bright targets and asteroseismology results in high accuracy for
  the bulk planet parameters: 2 %, 4-10 % and 10 % for planet radii,
  masses and ages, respectively. The planned baseline observing strategy
  includes two long pointings (2-3 years) to detect and bulk characterize
  planets reaching into the habitable zone (HZ) of solar-like stars
  and an additional step-and-stare phase to cover in total about 50 %
  of the sky. PLATO 2.0 will observe up to 1,000,000 stars and detect
  and characterize hundreds of small planets, and thousands of planets
  in the Neptune to gas giant regime out to the HZ. It will therefore
  provide the first large-scale catalogue of bulk characterized planets
  with accurate radii, masses, mean densities and ages. This catalogue
  will include terrestrial planets at intermediate orbital distances,
  where surface temperatures are moderate. Coverage of this parameter
  range with statistical numbers of bulk characterized planets is unique
  to PLATO 2.0. The PLATO 2.0 catalogue allows us to e.g.: - complete
  our knowledge of planet diversity for low-mass objects, - correlate the
  planet mean density-orbital distance distribution with predictions from
  planet formation theories,- constrain the influence of planet migration
  and scattering on the architecture of multiple systems, and - specify
  how planet and system parameters change with host star characteristics,
  such as type, metallicity and age. The catalogue will allow us to study
  planets and planetary systems at different evolutionary phases. It
  will further provide a census for small, low-mass planets. This will
  serve to identify objects which retained their primordial hydrogen
  atmosphere and in general the typical characteristics of planets
  in such low-mass, low-density range. Planets detected by PLATO 2.0
  will orbit bright stars and many of them will be targets for future
  atmosphere spectroscopy exploring their atmosphere. Furthermore,
  the mission has the potential to detect exomoons, planetary rings,
  binary and Trojan planets. The planetary science possible with PLATO
  2.0 is complemented by its impact on stellar and galactic science via
  asteroseismology as well as light curves of all kinds of variable stars,
  together with observations of stellar clusters of different ages. This
  will allow us to improve stellar models and study stellar activity. A
  large number of well-known ages from red giant stars will probe the
  structure and evolution of our Galaxy. Asteroseismic ages of bright
  stars for different phases of stellar evolution allow calibrating
  stellar age-rotation relationships. Together with the results of ESA's
  Gaia mission, the results of PLATO 2.0 will provide a huge legacy to
  planetary, stellar and galactic science.

---------------------------------------------------------
Title: Stellar Chemical Abundances: In Pursuit of the Highest
    Achievable Precision
Authors: Bedell, Megan; Meléndez, Jorge; Bean, Jacob L.; Ramírez,
   Ivan; Leite, Paulo; Asplund, Martin
2014ApJ...795...23B    Altcode: 2014arXiv1409.1230B
  The achievable level of precision on photospheric abundances of stars
  is a major limiting factor on investigations of exoplanet host star
  characteristics, the chemical histories of star clusters, and the
  evolution of the Milky Way and other galaxies. While model-induced
  errors can be minimized through the differential analysis of spectrally
  similar stars, the maximum achievable precision of this technique
  has been debated. As a test, we derive differential abundances of 19
  elements from high-quality asteroid-reflected solar spectra taken using
  a variety of instruments and conditions. We treat the solar spectra as
  being from unknown stars and use the resulting differential abundances,
  which are expected to be zero, as a diagnostic of the error in our
  measurements. Our results indicate that the relative resolution of
  the target and reference spectra is a major consideration, with use
  of different instruments to obtain the two spectra leading to errors
  up to 0.04 dex. Use of the same instrument at different epochs for
  the two spectra has a much smaller effect (~0.007 dex). The asteroid
  used to obtain the solar standard also has a negligible effect (~0.006
  dex). Assuming that systematic errors from the stellar model atmospheres
  have been minimized, as in the case of solar twins, we confirm that
  differential chemical abundances can be obtained at sub-0.01 dex
  precision with due care in the observations, data reduction, and
  abundance analysis.

---------------------------------------------------------
Title: The make-up of stars
Authors: Asplund, Martin
2014AIPC.1632...58A    Altcode:
  The chemical composition of stars contain vital clues not only about
  the stars themselves but also about the conditions prevailing before
  their births. As such, stellar spectroscopy plays a key role in
  contemporary astrophysics and cosmology by probing cosmic, galactic,
  stellar and planetary evolution. In this review I will describe the
  theoretical foundations of quantitative stellar spectroscopy: stellar
  atmosphere models and spectral line formation. I will focus mainly
  on more recent advances in the field, in particular the advent of
  realistic time-dependent, 3D, (magneto-)hydrodynamical simulations
  of stellar surface convection and atmospheres and non-LTE radiative
  transfer relevant for stars like the Sun. I will also discuss some
  particular applications of this type of modelling which have resulted
  in some exciting break-throughs in our understanding and with wider
  implications: the solar chemical composition, the chemical signatures
  of planet formation imprinted in stellar abundances, the cosmological
  Li problem(s) and where the first stars may be residing today.

---------------------------------------------------------
Title: The Gaia-ESO Survey: The analysis of high-resolution UVES
    spectra of FGK-type stars
Authors: Smiljanic, R.; Korn, A. J.; Bergemann, M.; Frasca, A.;
   Magrini, L.; Masseron, T.; Pancino, E.; Ruchti, G.; San Roman,
   I.; Sbordone, L.; Sousa, S. G.; Tabernero, H.; Tautvaišienė,
   G.; Valentini, M.; Weber, M.; Worley, C. C.; Adibekyan, V. Zh.;
   Allende Prieto, C.; Barisevičius, G.; Biazzo, K.; Blanco-Cuaresma,
   S.; Bonifacio, P.; Bragaglia, A.; Caffau, E.; Cantat-Gaudin, T.;
   Chorniy, Y.; de Laverny, P.; Delgado-Mena, E.; Donati, P.; Duffau,
   S.; Franciosini, E.; Friel, E.; Geisler, D.; González Hernández,
   J. I.; Gruyters, P.; Guiglion, G.; Hansen, C. J.; Heiter, U.; Hill, V.;
   Jacobson, H. R.; Jofre, P.; Jönsson, H.; Lanzafame, A. C.; Lardo, C.;
   Ludwig, H. -G.; Maiorca, E.; Mikolaitis, Š.; Montes, D.; Morel, T.;
   Mucciarelli, A.; Muñoz, C.; Nordlander, T.; Pasquini, L.; Puzeras,
   E.; Recio-Blanco, A.; Ryde, N.; Sacco, G.; Santos, N. C.; Serenelli,
   A. M.; Sordo, R.; Soubiran, C.; Spina, L.; Steffen, M.; Vallenari,
   A.; Van Eck, S.; Villanova, S.; Gilmore, G.; Randich, S.; Asplund,
   M.; Binney, J.; Drew, J.; Feltzing, S.; Ferguson, A.; Jeffries, R.;
   Micela, G.; Negueruela, I.; Prusti, T.; Rix, H. -W.; Alfaro, E.;
   Babusiaux, C.; Bensby, T.; Blomme, R.; Flaccomio, E.; François, P.;
   Irwin, M.; Koposov, S.; Walton, N.; Bayo, A.; Carraro, G.; Costado,
   M. T.; Damiani, F.; Edvardsson, B.; Hourihane, A.; Jackson, R.; Lewis,
   J.; Lind, K.; Marconi, G.; Martayan, C.; Monaco, L.; Morbidelli, L.;
   Prisinzano, L.; Zaggia, S.
2014A&A...570A.122S    Altcode: 2014arXiv1409.0568S
  Context. The ongoing Gaia-ESO Public Spectroscopic Survey is using
  FLAMES at the VLT to obtain high-quality medium-resolution Giraffe
  spectra for about 10<SUP>5</SUP> stars and high-resolution UVES spectra
  for about 5000 stars. With UVES, the Survey has already observed
  1447 FGK-type stars. <BR /> Aims: These UVES spectra are analyzed
  in parallel by several state-of-the-art methodologies. Our aim is
  to present how these analyses were implemented, to discuss their
  results, and to describe how a final recommended parameter scale is
  defined. We also discuss the precision (method-to-method dispersion)
  and accuracy (biases with respect to the reference values) of the
  final parameters. These results are part of the Gaia-ESO second
  internal release and will be part of its first public release of
  advanced data products. <BR /> Methods: The final parameter scale is
  tied to the scale defined by the Gaia benchmark stars, a set of stars
  with fundamental atmospheric parameters. In addition, a set of open
  and globular clusters is used to evaluate the physical soundness
  of the results. Each of the implemented methodologies is judged
  against the benchmark stars to define weights in three different
  regions of the parameter space. The final recommended results are
  the weighted medians of those from the individual methods. <BR />
  Results: The recommended results successfully reproduce the atmospheric
  parameters of the benchmark stars and the expected T<SUB>eff</SUB>-log
  g relation of the calibrating clusters. Atmospheric parameters and
  abundances have been determined for 1301 FGK-type stars observed with
  UVES. The median of the method-to-method dispersion of the atmospheric
  parameters is 55 K for T<SUB>eff</SUB>, 0.13 dex for log g and 0.07
  dex for [Fe/H]. Systematic biases are estimated to be between 50-100
  K for T<SUB>eff</SUB>, 0.10-0.25 dex for log g and 0.05-0.10 dex for
  [Fe/H]. Abundances for 24 elements were derived: C, N, O, Na, Mg, Al,
  Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, Mo, Ba, Nd, and
  Eu. The typical method-to-method dispersion of the abundances varies
  between 0.10 and 0.20 dex. <BR /> Conclusions: The Gaia-ESO sample of
  high-resolution spectra of FGK-type stars will be among the largest of
  its kind analyzed in a homogeneous way. The extensive list of elemental
  abundances derived in these stars will enable significant advances in
  the areas of stellar evolution and Milky Way formation and evolution. <P
  />Based on observations made with the ESO/VLT, at Paranal Observatory,
  under program 188.B-3002 (The Gaia-ESO Public Spectroscopic Survey, PIs
  Gilmore and Randich). Appendices are available in electronic form at <A
  href="http://www.aanda.org/10.1051/0004-6361/201423937/olm">http://www.aanda.org</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: STAGGER-grid of 3D stellar
    models. IV. (Magic+, 2015)
Authors: Magic, Z.; Chiavassa, A.; Collet, R.; Asplund, M.
2014yCat..35730090M    Altcode: 2014yCat..35739090M
  We compute the emergent stellar spectra from the UV to far infrared
  for different viewing angles using realistic 3D model atmospheres
  for a large range in stellar parameters to predict the stellar limb
  darkening. <P />We have computed full 3D LTE synthetic spectra based
  on 3D radiative hydrodynamic atmosphere models from the Stagger-grid
  in the ranges: Teff from 4000 to 7000K, logg from 1.5 to 5.0, and
  [Fe/H], from -4.0 to +0.5. From the resulting intensities at different
  wavelength, we derived coefficients for the standard limb darkening laws
  considering a number of often-used photometric filters. Furthermore,
  we calculated theoretical transit light curves, in order to quantify the
  differences between predictions by the widely used 1D model atmosphere
  and our 3D models. <P />(1 data file).

---------------------------------------------------------
Title: VizieR Online Data Catalog: STAGGER-grid of 3D stellar
    models. III. (Magic+, 2015)
Authors: Magic, Z.; Weiss, A.; Asplund, M.
2014yCat..35730089M    Altcode: 2014yCat..35739089M
  We investigate the relation between 1D atmosphere models that rely
  on the mixing length theory and models based on full 3D radiative
  hydrodynamic (RHD) calculations to describe convection in the envelopes
  of late-type stars. <P />The adiabatic entropy value of the deep
  convection zone, s<SUB>bot</SUB>, and the entropy jump, Δs, determined
  from the 3D RHD models, are matched with the mixing length parameter,
  α<SUB>MLT</SUB>, from 1D hydrostatic atmosphere models with identical
  microphysics (opacities and equation-of-state). We also derive the mass
  mixing length, α<SUB>m</SUB>, and the vertical correlation length of
  the vertical velocity, C[V<SUB>z</SUB>,V<SUB>z</SUB>], directly from
  the 3D hydrodynamical simulations of stellar subsurface convection. <P
  />(1 data file).

---------------------------------------------------------
Title: VizieR Online Data Catalog: 47 Tuc red giants chemical
    composition (Thygesen+, 2014)
Authors: Thygesen, A. O.; Sbordone, L.; Andrievsky, S.; Korotin,
   S.; Yong, D.; Zaggia, S.; Ludwig, H. -G.; Collet, R.; Asplund, M.;
   Ventura, P.; D'Antona, F.; Melendez, J.; D'Ercole, A.
2014yCat..35720108T    Altcode: 2014yCat..35729108T
  Table 2 contains linelist of the non-HFS elements. These lines were used
  for equivalent width measurements. Sorted by element number. Table 5
  contains all the lines used for HFS synthesis. With the exception of
  Ba, all lines are split into individual HFS components, including
  isotopes. log(gf) values reflect this. Solar isotope mixture is
  assumed. Sorted by element number. Table 8 contains the fundamental
  stellar parameters. Table 9 contains [Fe/H] as well as abundance ratios
  [X/Fe] for all stars. All measurements have an associated uncertainty
  sig[X/Fe] and the number of lines used in each individual star. In
  cases where no measurement exist, the value "-9.99" is given. <P />(5
  data files).

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Title: 18 Sco: A Solar Twin Rich in Refractory and Neutron-capture
    Elements. Implications for Chemical Tagging
Authors: Meléndez, Jorge; Ramírez, Iván; Karakas, Amanda I.; Yong,
   David; Monroe, TalaWanda R.; Bedell, Megan; Bergemann, Maria; Asplund,
   Martin; Tucci Maia, Marcelo; Bean, Jacob; do Nascimento, José-Dias,
   Jr.; Bazot, Michael; Alves-Brito, Alan; Freitas, Fabrício C.;
   Castro, Matthieu
2014ApJ...791...14M    Altcode: 2014arXiv1406.5244M
  We study with unprecedented detail the chemical composition and stellar
  parameters of the solar twin 18 Sco in a strictly differential sense
  relative to the Sun. Our study is mainly based on high-resolution (R ~
  110,000), high signal-to-noise ratio (800-1,000) Very Large Telescope
  UVES spectra, which allow us to achieve a precision of about 0.005
  dex in differential abundances. The effective temperature and surface
  gravity of 18 Sco are T <SUB>eff</SUB> = 5823 ± 6 K and log g =
  4.45 ± 0.02 dex, i.e., 18 Sco is 46 ± 6 K hotter than the Sun and
  log g is 0.01 ± 0.02 dex higher. Its metallicity is [Fe/H] = 0.054
  ± 0.005 dex, and its microturbulence velocity is +0.02 ± 0.01 km
  s<SUP>-1</SUP> higher than solar. Our precise stellar parameters
  and differential isochrone analysis show that 18 Sco has a mass
  of 1.04 ± 0.02 M <SUB>⊙</SUB> and that it is ~1.6 Gyr younger
  than the Sun. We use precise High Accuracy Radial velocity Planet
  Searcher (HARPS) radial velocities to search for planets, but none
  are detected. The chemical abundance pattern of 18 Sco displays
  a clear trend with condensation temperature, thus showing higher
  abundances of refractories in 18 Sco than in the Sun. Intriguingly,
  there are enhancements in the neutron-capture elements relative to the
  Sun. Despite the small element-to-element abundance differences among
  nearby n-capture elements (~0.02 dex), we successfully reproduce the
  r-process pattern in the Solar System. This is independent evidence
  for the universality of the r process. Our results have important
  implications for chemical tagging in our Galaxy and nucleosynthesis in
  general. <P />Based on observations obtained at the European Southern
  Observatory (ESO) Very Large Telescope (VLT) at Paranal Observatory;
  the 3.6 m telescope at La Silla Observatory, Chile (observing programs
  083.D-0871 and 188.C-0265); and at the W.M. Keck Observatory, which
  is operated jointly by Caltech, the University of California, and NASA.

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Title: The halo+cluster system of the Galactic globular cluster
    NGC 1851
Authors: Marino, A. F.; Milone, A. P.; Yong, D.; Dotter, A.; Da Costa,
   G.; Asplund, M.; Jerjen, H.; Mackey, D.; Norris, J.; Cassisi, S.;
   Sbordone, L.; Stetson, P. B.; Weiss, A.; Aparicio, A.; Bedin, L. R.;
   Lind, K.; Monelli, M.; Piotto, G.; Angeloni, R.; Buonanno, R.
2014MNRAS.442.3044M    Altcode: 2014arXiv1406.0944M
  NGC 1851 is surrounded by a stellar component that extends more
  than 10 times beyond the tidal radius. Although the nature of this
  stellar structure is not known, it has been suggested to be a sparse
  halo of stars or associated with a stellar stream. We analyse the
  nature of this intriguing stellar component surrounding NGC 1851
  by investigating its radial velocities and chemical composition, in
  particular in comparison with those of the central cluster analysed
  in a homogeneous manner. In total we observed 23 stars in the halo
  with radial velocities consistent with NGC 1851, and for 15 of them we
  infer [Fe/H] abundances. Our results show that (i) stars dynamically
  linked to NGC 1851 are present at least up to ∼2.5 tidal radii,
  supporting the presence of a halo of stars surrounding the cluster;
  (ii) apart from the NGC 1851 radial velocity-like stars, our observed
  velocity distribution agrees with that expected from Galactic models,
  suggesting that no other substructure (such as a stream) at different
  radial velocities is present in our field; (iii) the chemical abundances
  for the s-process elements Sr and Ba are consistent with the s-normal
  stars observed in NGC 1851; (iv) all halo stars have metallicities,
  and abundances for the other studied elements Ca, Mg and Cr, consistent
  with those exhibited by the cluster. The complexity of the whole NGC
  1851 cluster+halo system may agree with the scenario of a tidally
  disrupted dwarf galaxy in which NGC 1851 was originally embedded.

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Title: Solar twins in the open cluster M67: chemical signature of
    terrestrial planets or natal dust formation?
Authors: Asplund, Martin
2014koa..prop..367A    Altcode:
  No abstract at ADS

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Title: The Gaia-ESO Survey: the Galactic thick to thin disc transition
Authors: Recio-Blanco, A.; de Laverny, P.; Kordopatis, G.; Helmi,
   A.; Hill, V.; Gilmore, G.; Wyse, R.; Adibekyan, V.; Randich, S.;
   Asplund, M.; Feltzing, S.; Jeffries, R.; Micela, G.; Vallenari, A.;
   Alfaro, E.; Allende Prieto, C.; Bensby, T.; Bragaglia, A.; Flaccomio,
   E.; Koposov, S. E.; Korn, A.; Lanzafame, A.; Pancino, E.; Smiljanic,
   R.; Jackson, R.; Lewis, J.; Magrini, L.; Morbidelli, L.; Prisinzano,
   L.; Sacco, G.; Worley, C. C.; Hourihane, A.; Bergemann, M.; Costado,
   M. T.; Heiter, U.; Joffre, P.; Lardo, C.; Lind, K.; Maiorca, E.
2014A&A...567A...5R    Altcode: 2014arXiv1403.7568R
  <BR /> Aims: The nature of the thick disc and its relation to the
  thin disc is presently an important subject of debate. In fact, the
  structural and chemo-dynamical transition between disc populations can
  be used as a test of the proposed models of Galactic disc formation
  and evolution. <BR /> Methods: We used the atmospheric parameters,
  [α/Fe] abundances, and radial velocities, which were determined from
  the Gaia-ESO Survey GIRAFFE spectra of FGK-type stars (first nine months
  of observations) to provide a chemo-kinematical characterisation of
  the disc stellar populations. We focussed on a subsample of 1016 stars
  with high-quality parameters, covering the volume | Z | &lt; 4.5 kpc
  and R in the range 2-13 kpc. <BR /> Results: We have identified a thin
  to thick disc separation in the [α/Fe] vs. [M/H] plane, thanks to the
  presence of a low-density region in the number density distribution. The
  thick disc stars seem to lie in progressively thinner layers above the
  Galactic plane, as metallicity increases and [α/Fe] decreases. In
  contrast, the thin disc population presents a constant value of the
  mean distance to the Galactic plane at all metallicities. In addition,
  our data confirm the already known correlations between V<SUB>φ</SUB>
  and [M/H] for the two discs. For the thick disc sequence, a study of
  the possible contamination by thin disc stars suggests a gradient up
  to 64 ± 9 km s<SUP>-1</SUP> dex<SUP>-1</SUP>. The distributions of
  azimuthal velocity, vertical velocity, and orbital parameters are
  also analysed for the chemically separated samples. Concerning the
  gradients with galactocentric radius, we find, for the thin disc, a
  flat behaviour of the azimuthal velocity, a metallicity gradient equal
  to -0.058 ± 0.008 dex kpc<SUP>-1</SUP> and a very small positive
  [α/Fe] gradient. For the thick disc, flat gradients in [M/H] and
  [α/Fe] are derived. <BR /> Conclusions: Our chemo-kinematical analysis
  suggests a picture where the thick disc seems to have experienced a
  settling process, during which its rotation increased progressively
  and, possibly, the azimuthal velocity dispersion decreased. At [M/H]
  ≈ -0.25 dex and [α/Fe]≈ 0.1 dex, the mean characteristics of
  the thick disc in vertical distance to the Galactic plane, rotation,
  rotational dispersion, and stellar orbits' eccentricity agree with
  that of the thin disc stars of the same metallicity, suggesting
  a possible connection between these two populations at a certain
  epoch of the disc evolution. Finally, the results presented here,
  based only on the first months of the Gaia ESO Survey observations,
  confirm how crucial large high-resolution spectroscopic surveys
  outside the solar neighbourhood are today for our understanding of
  the Milky Way history. <P />Based on observations collected with the
  FLAMES spectrograph at the VLT/UT2 telescope (Paranal Observatory, ESO,
  Chile), for the Gaia-ESO Large Public Survey, programme 188.B-3002.Full
  Table 1 is only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/567/A5">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/567/A5</A>

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Title: Improvements to stellar structure models, based on a grid of
    3D convection simulations - I. T(τ) relations
Authors: Trampedach, Regner; Stein, Robert F.; Christensen-Dalsgaard,
   Jørgen; Nordlund, Åke; Asplund, Martin
2014MNRAS.442..805T    Altcode: 2014arXiv1405.0236T
  Relations between temperature, T, and optical depth, τ, are often
  used for describing the photospheric transition from optically thick
  to optically thin in stellar structure models. We show that this is
  well justified, but also that currently used T(τ) relations are often
  inconsistent with their implementation. As an outer boundary condition
  on the system of stellar structure equations, T(τ) relations have an
  undue effect on the overall structure of stars. In this age of precision
  asteroseismology, we need to re-assess both the method for computing
  and for implementing T(τ) relations, and the assumptions they rest
  on. We develop a formulation for proper and consistent evaluation
  of T(τ) relations from arbitrary 1D or 3D stellar atmospheres,
  and for their implementation in stellar structure and evolution
  models. We extract radiative T(τ) relations, as described by our
  new formulation, from 3D simulations of convection in deep stellar
  atmospheres of late-type stars from dwarfs to giants. These simulations
  employ realistic opacities and equation of state, and account for
  line blanketing. For comparison, we also extract T(τ) relations from
  1DMARCSmodel atmospheres using the same formulation. T(τ) relations
  from our grid of 3D convection simulations display a larger range of
  behaviours with surface gravity, compared with those of conventional
  theoretical 1D hydrostatic atmosphere models based on the mixing-length
  theory for convection. The 1D atmospheres show little dependence on
  gravity. 1D atmospheres of main-sequence stars also show an abrupt
  transition to the diffusion approximation at τ ≃ 2.5, whereas the
  3D simulations exhibit smooth transitions that occur at the same depth
  for M ≃ 0.8 M<SUB>⊙</SUB>, and higher in the atmosphere for both
  more and less massive main-sequence stars. Based on these results,
  we recommend no longer using scaled solar T(τ) relations. Files with
  T(τ) relations for our grid of simulations are made available to the
  community, together with routines for interpolating in this irregular
  grid. We also provide matching tables of atmospheric opacity, for
  consistent implementation in stellar structure models.

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Title: A high-precision chemical abundance analysis of the HAT-P-1
stellar binary: constraints on planet formation.
Authors: Liu, F.; Asplund, M.; Ramirez, I.; Yong, D.; Melendez, J.
2014MNRAS.442L..51L    Altcode: 2014arXiv1404.2112L
  We present a high-precision, differential elemental abundance
  analysis of the HAT-P-1 stellar binary based on high-resolution,
  high signal-to-noise ratio Keck/HIRES (High Resolution Echelle
  Spectrometer) spectra. The secondary star in this double system is
  known to host a transiting giant planet while no planets have yet been
  detected around the primary star. The derived metallicities ([Fe/H])
  of the primary and secondary stars are identical within the errors:
  0.146 ± 0.014 dex (σ = 0.033 dex) and 0.155 ± 0.007 dex (σ =
  0.023 dex), respectively. Extremely precise differential abundance
  ratios of 23 elements have been measured (mean error of σ([X/Fe])
  = 0.013 dex) and are found to be indistinguishable between the two
  stars: Δ[X/Fe] (secondary - primary) = +0.001 ± 0.006 dex (σ =
  0.008 dex). The striking similarity in the chemical composition of
  the two stellar components in HAT-P-1 is contrary to the possible
  0.04 dex level difference seen in 16 Cyg A+B, which also hosts a
  giant planet, at least three times more massive than the one around
  HAT-P-1 secondary star. We conclude that the presence of giant planets
  does not necessarily imply differences in the chemical compositions
  of the host stars. The elemental abundances of each star in HAT-P-1
  relative to the Sun show an identical, positive correlation with the
  condensation temperature of the elements; their abundance patterns
  are thus very similar to those observed in the majority of solar
  twins. In view of the Meléndez et al. interpretation of the peculiar
  solar abundance pattern, we conclude that HAT-P-1 experienced less
  efficient formation of terrestrial planets than the Sun. This is in
  line with the expectation that the presence of close-in giant planets
  preventing the formation or survival of terrestrial planets.

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Title: Planet transit and stellar granulation detection with
    interferometry. Using the three-dimensional stellar atmosphere
    Stagger-grid simulations
Authors: Chiavassa, A.; Ligi, R.; Magic, Z.; Collet, R.; Asplund,
   M.; Mourard, D.
2014A&A...567A.115C    Altcode: 2014arXiv1404.7049C
  Context. Stellar activity and, in particular, convection-related
  surface structures, potentially cause bias in planet detection and
  characterisation. In the latter, interferometry can help disentangle
  the signal of the transiting planet. <BR /> Aims: We used realistic
  three-dimensional (3D) radiative hydrodynamical (RHD) simulations
  from the Stagger-grid and synthetic images computed with the radiative
  transfer code Optim3D to provide interferometric observables to extract
  the signature of stellar granulation and transiting planets. <BR />
  Methods: We computed intensity maps from RHD simulations and produced
  synthetic stellar disk images as a nearby observer would see,
  thereby accounting for the centre-to-limb variations. We did this
  for twelve interferometric instruments covering wavelengths ranging
  from optical to infrared. We chose an arbitrary date and arbitrary
  star with coordinates, and this ensures observability throughout
  the night. This optimisation of observability allows for a broad
  coverage of spatial frequencies. The stellar surface asymmetries in
  the brightness distribution mostly affect closure phases, because of
  either convection-related structures or a faint companion. We then
  computed closure phases for all images and compared the system star
  with a transiting planet and the star alone. We considered the impact
  of magnetic spots with the construction of a hypothetical starspot
  image and compared the resulting closure phases with the system star
  that has a transiting planet. <BR /> Results: We analysed the impact
  of convection at different wavelengths. All the simulation depart from
  the axisymmetric case (closure phases not equal to 0 or ± π) at all
  wavelengths. The levels of asymmetry and inhomogeneity of stellar disk
  images reach high values with stronger effects from the 3rd visibility
  lobe on. We present two possible targets (Beta Com and Procyon)
  either in the visible or in the infrared and find that departures up
  to 16° can be detected on the 3rd lobe and higher. In particular,
  MIRC is the most appropriate instrument because it combines good
  UV coverage and long baselines. Moreover, we explored the impact of
  convection on interferometric planet signature for three prototypes
  of planets with sizes corresponding to one hot Jupiter, one hot
  Neptune, and a terrestrial planet. The signature of the transiting
  planet in the closure phase is mixed with the signal due to the
  convection-related surface structures, but it is possible to disentangle
  it at particular wavelengths (either in the infrared or in the optical)
  by comparing the closure phases of the star at difference phases of
  the planetary transit. It must be noted that starspots caused by the
  magnetic field may pollute the granulation and the transiting planet
  signals. However, it is possible to differentiate the transiting planet
  signal because the time scale of a planet crossing the stellar disk is
  much smaller than the typical rotational modulation of a star. <BR />
  Conclusions: Detection and characterisation of planets must be based
  on a comprehensive knowledge of the host star, and this includes the
  detailed study of the stellar surface convection with interferometric
  techniques. In this context, RHD simulations are crucial for this
  aim. We emphasise that interferometric observations should be pushed
  at high spatial frequencies by accumulating observations on closure
  phases at short and long baselines.

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Title: HIP 114328: a new refractory-poor and Li-poor solar twin
Authors: Meléndez, Jorge; Schirbel, Lucas; Monroe, TalaWanda R.;
   Yong, David; Ramírez, Iván; Asplund, Martin
2014A&A...567L...3M    Altcode: 2014arXiv1406.2385M
  Context. The standard solar model fails to predict the very low lithium
  abundance in the Sun, which is much lower than the proto-solar nebula
  (as measured in meteorites). This Li problem has been debated for
  decades, and it has been ascribed either to planet formation or to
  secular stellar depletion due to additional mixing below the convection
  zone, either during the pre-main sequence and thus possibly linked to
  planet formation, or additionally on secular time-scales during the
  main sequence. In order to test the evolution of Li, it is important to
  find solar twins in a range of ages, i.e., stars with about one solar
  mass and metallicity but in different evolutionary stages. Furthermore,
  the study of stars similar to the Sun is relevant in relation to the
  signature of terrestrial planet formation around the Sun, and for
  anchoring photometric and spectroscopic stellar parameter scales. <BR
  /> Aims: We aim to identify and analyse solar twins using high quality
  spectra, in order to study Li depletion in the Sun and the possible
  relation between chemical abundance anomalies and planet formation. <BR
  /> Methods: We acquired high-resolution (R ~ 110 000), high S/N (~300)
  ESO/VLT UVES spectra of several solar twin candidates and the Sun (as
  reflected from the asteroid Juno). Among the solar twin candidates
  we identify HIP 114328 as a solar twin and perform a differential
  line-by-line abundance analysis of this star relative to the Sun. <BR
  /> Results: HIP 114328 has stellar parameters T<SUB>eff</SUB> =
  5785 ± 10 K, log g = 4.38 ± 0.03, [ Fe/H] = -0.022 ± 0.009, and
  a microturbulent velocity 0.05 ± 0.03 km s<SUP>-1</SUP> higher than
  solar. The differential analysis shows that this star is chemically
  very similar to the Sun. The refractory elements seem slightly more
  depleted than in the Sun, meaning that HIP 114328 may be as likely to
  form terrestrial planets as the Sun. HIP 114328 is about 2 Gyr older
  than the Sun, and is thus the second oldest solar twin analysed at high
  precision. It has a Li abundance of A(Li)<SUB>NLTE</SUB> ≲ 0.46,
  which is about 4 times lower than in the Sun (A(Li)<SUB>NLTE</SUB> =
  1.07 dex), but close to the oldest solar twin known, HIP 102152. <BR
  /> Conclusions: Based on the lower abundances of refractory elements
  when compared to other solar twins, HIP 114328 seems an excellent
  candidate to host rocky planets. The low Li abundance of this star
  is consistent with its old age and fits very well the emerging
  Li-age relation among solar twins of different ages. <P />Based on
  observations obtained at the European Southern Observatory (ESO)
  Very Large Telescope (VLT) at Paranal Observatory, Chile (observing
  program 083.D-0871).Table 1 is available in electronic form at <A
  href="http://www.aanda.org/10.1051/0004-6361/201424172/olm">http://www.aanda.org</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: T(tau) relations code (Trampedach+,
    2014)
Authors: Trampedach, R.; Stein, R. F.; Christensen-Dalsgaard, J.;
   Nordlund, A.; Asplund, M.
2014yCat..74420805T    Altcode:
  Radiative T({tau})-relations, in the form of generalised Hopf functions,
  computed from a grid of 37, solar metallicity, realistic, 3D convection
  simulations with radiative transfer. <P />(6 data files).

---------------------------------------------------------
Title: Strömgren Survey for Asteroseismology and Galactic
Archaeology: Let the SAGA Begin
Authors: Casagrande, L.; Silva Aguirre, V.; Stello, D.; Huber, D.;
   Serenelli, A. M.; Cassisi, S.; Dotter, A.; Milone, A. P.; Hodgkin,
   S.; Marino, A. F.; Lund, M. N.; Pietrinferni, A.; Asplund, M.;
   Feltzing, S.; Flynn, C.; Grundahl, F.; Nissen, P. E.; Schönrich,
   R.; Schlesinger, K. J.; Wang, W.
2014ApJ...787..110C    Altcode: 2014arXiv1403.2754C
  Asteroseismology has the capability of precisely determining stellar
  properties that would otherwise be inaccessible, such as radii,
  masses, and thus ages of stars. When coupling this information with
  classical determinations of stellar parameters, such as metallicities,
  effective temperatures, and angular diameters, powerful new diagnostics
  for Galactic studies can be obtained. The ongoing Strömgren survey for
  Asteroseismology and Galactic Archaeology has the goal of transforming
  the Kepler field into a new benchmark for Galactic studies, similar to
  the solar neighborhood. Here we present the first results from a stripe
  centered at a Galactic longitude of 74° and covering latitude from
  about 8° to 20°, which includes almost 1000 K giants with seismic
  information and the benchmark open cluster NGC 6819. We describe the
  coupling of classical and seismic parameters, the accuracy as well
  as the caveats of the derived effective temperatures, metallicities,
  distances, surface gravities, masses, and radii. Confidence in the
  achieved precision is corroborated by the detection of the first and
  secondary clumps in a population of field stars with a ratio of 2 to 1
  and by the negligible scatter in the seismic distances among NGC 6819
  member stars. An assessment of the reliability of stellar parameters
  in the Kepler Input Catalog is also performed, and the impact of
  our results for population studies in the Milky Way is discussed,
  along with the importance of an all-sky Strömgren survey. <P />Based
  on observations made with the Isaac Newton Telescope operated on the
  island of La Palma by the Isaac Newton Group in the Spanish Observatorio
  del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.

---------------------------------------------------------
Title: Exploring the Origin of Lithium, Carbon, Strontium, and Barium
    with Four New Ultra Metal-poor Stars
Authors: Hansen, T.; Hansen, C. J.; Christlieb, N.; Yong, D.; Bessell,
   M. S.; García Pérez, A. E.; Beers, T. C.; Placco, V. M.; Frebel,
   A.; Norris, J. E.; Asplund, M.
2014ApJ...787..162H    Altcode: 2014arXiv1405.5846H
  We present an elemental abundance analysis for four newly discovered
  ultra metal-poor stars from the Hamburg/ESO survey, with [Fe/H] &lt;=
  -4. Based on high-resolution, high signal-to-noise spectra, we derive
  abundances for 17 elements in the range from Li to Ba. Three of
  the four stars exhibit moderate to large overabundances of carbon,
  but have no enhancements in their neutron-capture elements. The
  most metal-poor star in the sample, HE 0233-0343 ([Fe/H] = -4.68),
  is a subgiant with a carbon enhancement of [C/Fe] = +3.5, slightly
  above the carbon-enhancement plateau suggested by Spite et al. No
  carbon is detected in the spectrum of the fourth star, but the
  quality of its spectrum only allows for the determination of an
  upper limit on the carbon abundance ratio of [C/Fe] &lt; +1.7. We
  detect lithium in the spectra of two of the carbon-enhanced stars,
  including HE 0233-0343. Both stars with Li detections are Li-depleted,
  with respect to the Li plateau for metal-poor dwarfs found by Spite
  &amp; Spite. This suggests that whatever site(s) produced C either
  do not completely destroy lithium, or that Li has been astrated by
  early-generation stars and mixed with primordial Li in the gas that
  formed the stars observed at present. The derived abundances for the
  α elements and iron-peak elements of the four stars are similar to
  those found in previous large samples of extremely and ultra metal-poor
  stars. Finally, a large spread is found in the abundances of Sr and Ba
  for these stars, possibly influenced by enrichment from fast rotating
  stars in the early universe. <P />Based on observations made with the
  European Southern Observatory (ESO) Telescopes.

---------------------------------------------------------
Title: The Gaia-ESO Survey: processing FLAMES-UVES spectra
Authors: Sacco, G. G.; Morbidelli, L.; Franciosini, E.; Maiorca, E.;
   Randich, S.; Modigliani, A.; Gilmore, G.; Asplund, M.; Binney, J.;
   Bonifacio, P.; Drew, J.; Feltzing, S.; Ferguson, A.; Jeffries, R.;
   Micela, G.; Negueruela, I.; Prusti, T.; Rix, H. -W.; Vallenari, A.;
   Alfaro, E.; Allende Prieto, C.; Babusiaux, C.; Bensby, T.; Blomme,
   R.; Bragaglia, A.; Flaccomio, E.; Francois, P.; Hambly, N.; Irwin,
   M.; Koposov, S.; Korn, A.; Lanzafame, A.; Pancino, E.; Recio-Blanco,
   A.; Smiljanic, R.; Van Eck, S.; Walton, N.; Bergemann, M.; Costado,
   M. T.; de Laverny, P.; Heiter, U.; Hill, V.; Hourihane, A.; Jackson,
   R.; Jofre, P.; Lewis, J.; Lind, K.; Lardo, C.; Magrini, L.; Masseron,
   T.; Prisinzano, L.; Worley, C.
2014A&A...565A.113S    Altcode: 2014arXiv1403.4865S
  The Gaia-ESO Survey is a large public spectroscopic survey that
  aims to derive radial velocities and fundamental parameters
  of about 10<SUP>5</SUP> Milky Way stars in the field and in
  clusters. Observations are carried out with the multi-object optical
  spectrograph FLAMES, using simultaneously the medium-resolution (R ~
  20 000) GIRAFFE spectrograph and the high-resolution (R ~ 47 000) UVES
  spectrograph. In this paper we describe the methods and the software
  used for the data reduction, the derivation of the radial velocities,
  and the quality control of the FLAMES-UVES spectra. Data reduction
  has been performed using a workflow specifically developed for this
  project. This workflow runs the ESO public pipeline optimizing the
  data reduction for the Gaia-ESO Survey, automatically performs sky
  subtraction, barycentric correction and normalisation, and calculates
  radial velocities and a first guess of the rotational velocities. The
  quality control is performed using the output parameters from the ESO
  pipeline, by a visual inspection of the spectra and by the analysis
  of the signal-to-noise ratio of the spectra. Using the observations
  of the first 18 months, specifically targets observed multiple times
  at different epochs, stars observed with both GIRAFFE and UVES, and
  observations of radial velocity standards, we estimated the precision
  and the accuracy of the radial velocities. The statistical error on the
  radial velocities is σ ~ 0.4 km s<SUP>-1</SUP> and is mainly due to
  uncertainties in the zero point of the wavelength calibration. However,
  we found a systematic bias with respect to the GIRAFFE spectra (~0.9 km
  s<SUP>-1</SUP>) and to the radial velocities of the standard stars (~0.5
  km s<SUP>-1</SUP>) retrieved from the literature. This bias will be
  corrected in the future data releases, when a common zero point for all
  the set-ups and instruments used for the survey is be established. <P
  />Based on observations made with the ESO/VLT, at Paranal Observatory,
  under programme 188.B-3002 (The Gaia-ESO Public Spectroscopic Survey).

---------------------------------------------------------
Title: The Stagger-grid: A grid of 3D stellar atmosphere models -
    VI. Surface appearance of stellar granulation
Authors: Magic, Zazralt; Asplund, Martin
2014arXiv1405.7628M    Altcode:
  In the surface layers of late-type stars, stellar convection is
  manifested with its typical granulation pattern due to the presence
  of convective motions. The resulting photospheric up- and downflows
  leave imprints in the observed spectral line profiles. We perform
  a careful statistical analysis of stellar granulation and its
  properties for different stellar parameters. We employ realistic
  3D radiative hydrodynamic (RHD) simulations of surface convection
  from the Stagger-grid, a comprehensive grid of atmosphere models
  that covers a large parameter space in terms of Teff, logg, and
  [Fe/H]. Individual granules are detected from the (bolometric) intensity
  maps at disk center with an efficient granulation pattern recognition
  algorithm. From these we derive their respective properties: diameter,
  fractal dimension (area-perimeter relation), geometry, topology,
  variation of intensity, temperature, density and velocity with granule
  size. Also, the correlation of the physical properties at the optical
  surface are studied. We find in all of our 3D RHD simulations stellar
  granulation patterns imprinted, which are qualitatively similar to the
  solar case, despite the large differences in stellar parameters. The
  granules exhibit a large range in size, which can be divided into two
  groups - smaller and larger granules - by the mean granule size. These
  are distinct in their properties: smaller granules are regular shaped
  and dimmer, while the larger ones are increasingly irregular and more
  complex in their shapes and distribution in intensity contrast. This
  is reflected in their fractal dimensions, which is close to unity for
  the smaller granules, and close to two for larger granules, which is
  due to the fragmentation of granules. Stellar surface convection seems
  to operate scale-invariant over a large range in stellar parameters,
  which translates into a self-similar stellar granulation pattern.

---------------------------------------------------------
Title: Does SEGUE/SDSS indicate a dual Galactic halo?
Authors: Schönrich, Ralph; Asplund, Martin; Casagrande, Luca
2014ApJ...786....7S    Altcode: 2014arXiv1403.0937S
  We re-examine recent claims of observational evidence for a dual
  Galactic halo in SEGUE/SDSS data, and trace them back to improper
  error treatment and neglect of selection effects. In particular, the
  detection of a vertical abundance gradient in the halo can be explained
  as a metallicity bias in distance. A similar bias and the impact of disk
  contamination affect the sample of blue horizontal branch stars. These
  examples highlight why non-volume complete samples require forward
  modeling from theoretical models or extensive bias-corrections. We
  also show how observational uncertainties produce the specific
  non-Gaussianity in the observed azimuthal velocity distribution
  of halo stars, which can be erroneously identified as two Gaussian
  components. A single kinematic component yields an excellent fit to
  the observed data, when we model the measurement process including
  distance uncertainties. Furthermore, we show that sample differences
  in proper motion space are the direct consequence of kinematic cuts
  and are enhanced when distance estimates are less accurate. Thus,
  their presence is neither proof of a separate population nor a measure
  of reliability for the applied distances. We conclude that currently
  there is no evidence from SEGUE/SDSS that would favor a dual Galactic
  halo over a single halo that is full of substructure.

---------------------------------------------------------
Title: The Gaia-ESO Survey: radial metallicity gradients and
    age-metallicity relation of stars in the Milky Way disk
Authors: Bergemann, M.; Ruchti, G. R.; Serenelli, A.; Feltzing, S.;
   Alves-Brito, A.; Asplund, M.; Bensby, T.; Gruyters, P.; Heiter, U.;
   Hourihane, A.; Korn, A.; Lind, K.; Marino, A.; Jofre, P.; Nordlander,
   T.; Ryde, N.; Worley, C. C.; Gilmore, G.; Randich, S.; Ferguson,
   A. M. N.; Jeffries, R. D.; Micela, G.; Negueruela, I.; Prusti, T.; Rix,
   H. -W.; Vallenari, A.; Alfaro, E. J.; Allende Prieto, C.; Bragaglia,
   A.; Koposov, S. E.; Lanzafame, A. C.; Pancino, E.; Recio-Blanco, A.;
   Smiljanic, R.; Walton, N.; Costado, M. T.; Franciosini, E.; Hill,
   V.; Lardo, C.; de Laverny, P.; Magrini, L.; Maiorca, E.; Masseron,
   T.; Morbidelli, L.; Sacco, G.; Kordopatis, G.; Tautvaišienė, G.
2014A&A...565A..89B    Altcode: 2014arXiv1401.4437B
  We study the relationship between age, metallicity, and α-enhancement
  of FGK stars in the Galactic disk. The results are based upon the
  analysis of high-resolution UVES spectra from the Gaia-ESO large
  stellar survey. We explore the limitations of the observed dataset,
  i.e. the accuracy of stellar parameters and the selection effects
  that are caused by the photometric target preselection. We find that
  the colour and magnitude cuts in the survey suppress old metal-rich
  stars and young metal-poor stars. This suppression may be as high as
  97% in some regions of the age-metallicity relationship. The dataset
  consists of 144 stars with a wide range of ages from 0.5 Gyr to 13.5
  Gyr, Galactocentric distances from 6 kpcto 9.5 kpc, and vertical
  distances from the plane 0 &lt; |Z| &lt; 1.5 kpc. On this basis, we
  find that i) the observed age-metallicity relation is nearly flat in
  the range of ages between 0 Gyr and 8 Gyr; ii) at ages older than 9
  Gyr, we see a decrease in [Fe/H] and a clear absence of metal-rich
  stars; this cannot be explained by the survey selection functions;
  iii) there is a significant scatter of [Fe/H] at any age; and iv)
  [Mg/Fe] increases with age, but the dispersion of [Mg/Fe] at ages &gt;9
  Gyr is not as small as advocated by some other studies. In agreement
  with earlier work, we find that radial abundance gradients change as
  a function of vertical distance from the plane. The [Mg/Fe] gradient
  steepens and becomes negative. In addition, we show that the inner disk
  is not only more α-rich compared to the outer disk, but also older,
  as traced independently by the ages and Mg abundances of stars. <P
  />Based on observations made with the ESO/VLT, at Paranal Observatory,
  under programme 188.B-3002 (The Gaia-ESO Public Spectroscopic Survey).

---------------------------------------------------------
Title: Towards stellar effective temperatures and diameters at 1
    per cent accuracy for future surveys
Authors: Casagrande, L.; Portinari, L.; Glass, I. S.; Laney, D.; Silva
   Aguirre, V.; Datson, J.; Andersen, J.; Nordström, B.; Holmberg, J.;
   Flynn, C.; Asplund, M.
2014MNRAS.439.2060C    Altcode: 2014arXiv1401.3754C; 2014MNRAS.tmp..291C
  The apparent size of stars is a crucial benchmark for fundamental
  stellar properties such as effective temperatures, radii and surface
  gravities. While interferometric measurements of stellar angular
  diameters are the most direct method to gauge these, they are still
  limited to relatively nearby and bright stars, which are saturated
  in most of the modern photometric surveys. This dichotomy prevents
  us from safely extending well-calibrated relations to the faint
  stars targeted in large spectroscopic and photometric surveys. Here,
  we alleviate this obstacle by presenting South African Astronomical
  Observatory near-infrared JHK observations of 55 stars: 16 of them
  have interferometric angular diameters and the rest are in common
  with the 2 Micron All Sky Survey (2MASS, unsaturated) data set,
  allowing us to tie the effective temperatures and angular diameters
  derived via the infrared flux method to the interferometric scale. We
  extend the test to recent interferometric measurements of unsaturated
  2MASS stars, including giants, and the metal-poor benchmark target
  HD122563. With a critical evaluation of the systematics involved, we
  conclude that a 1 per cent accuracy in fundamental stellar parameters is
  usually within reach. Caution, however, must be used when indirectly
  testing a T<SUB>eff</SUB> scale via colour relations as well as
  when assessing the reliability of interferometric measurements,
  especially at submilliarcsec level. As a result, rather different
  effective temperature scales can be compatible with a given subset of
  interferometric data. We highlight some caveats to be aware of in such
  a quest and suggest a simple method to check against systematics in
  fundamental measurements. A new diagnostic combination seismic radii
  with astrometric distances is also presented.

---------------------------------------------------------
Title: Global and Nonglobal Parameters of Horizontal-branch Morphology
    of Globular Clusters
Authors: Milone, A. P.; Marino, A. F.; Dotter, A.; Norris, J. E.;
   Jerjen, H.; Piotto, G.; Cassisi, S.; Bedin, L. R.; Recio Blanco, A.;
   Sarajedini, A.; Asplund, M.; Monelli, M.; Aparicio, A.
2014ApJ...785...21M    Altcode: 2013arXiv1312.4169M
  The horizontal-branch (HB) morphology of globular clusters (GCs)
  is mainly determined by metallicity. However, the fact that GCs
  with almost the same metallicity exhibit different HB morphologies
  demonstrates that at least one more parameter is needed to explain
  the HB morphology. It has been suggested that one of these should be
  a global parameter that varies from GC to GC and the other a nonglobal
  parameter that varies within the GC. In this study we provide empirical
  evidence corroborating this idea. We used the photometric catalogs
  obtained with the Advanced Camera for Surveys of the Hubble Space
  Telescope and analyze the color-magnitude diagrams of 74 GCs. The HB
  morphology of our sample of GCs has been investigated on the basis of
  the two new parameters L1 and L2 that measure the distance between
  the red giant branch and the coolest part of the HB and the color
  extension of the HB, respectively. We find that L1 correlates with
  both metallicity and age, whereas L2 most strongly correlates with
  the mass of the hosting GC. The range of helium abundance among the
  stars in a GC, characterized by ΔY and associated with the presence
  of multiple stellar populations, has been estimated in a few GCs to
  date. In these GCs we find a close relationship among ΔY, GC mass, and
  L2. We conclude that age and metallicity are the main global parameters,
  while the range of helium abundance within a GC is the main nonglobal
  parameter defining the HB morphology of Galactic GCs. <P />Based on
  observations with the NASA/ESA Hubble Space Telescope, obtained at the
  Space Telescope Science Institute, which is operated by AURA, Inc.,
  under NASA contract NAS 5-26555.

---------------------------------------------------------
Title: The M 4 Core Project with HST - II. Multiple stellar
    populations at the bottom of the main sequence
Authors: Milone, A. P.; Marino, A. F.; Bedin, L. R.; Piotto, G.;
   Cassisi, S.; Dieball, A.; Anderson, J.; Jerjen, H.; Asplund, M.;
   Bellini, A.; Brogaard, K.; Dotter, A.; Giersz, M.; Heggie, D. C.;
   Knigge, C.; Rich, R. M.; van den Berg, M.; Buonanno, R.
2014MNRAS.439.1588M    Altcode: 2014arXiv1401.1091M; 2014MNRAS.tmp..278M
  The M 4 Core Project with HST is designed to exploit the Hubble
  Space Telescope (HST) to investigate the central regions of M 4, the
  Globular Cluster closest to the Sun. In this paper we combine optical
  and near-infrared photometry to study multiple stellar populations in
  M 4. We detected two sequences of M-dwarfs containing ∼38 per cent
  (MS<SUB>I</SUB>) and ∼62 per cent (MS<SUB>II</SUB>) of MS stars
  below the main-sequence (MS) knee. We compare our observations with
  those of NGC 2808, which is the only other GCs where multiple MSs of
  very low-mass stars have been studied to date. We calculate synthetic
  spectra for M-dwarfs, assuming the chemical composition mixture inferred
  from spectroscopic studies of stellar populations along the red giant
  branch, and different helium abundances, and we compare predicted and
  observed colours. Observations are consistent with two populations,
  one with primordial abundance and another with enhanced nitrogen and
  depleted oxygen.

---------------------------------------------------------
Title: The Gaia-ESO Survey: Abundance ratios in the inner-disk open
    clusters Trumpler 20, NGC 4815, NGC 6705
Authors: Magrini, L.; Randich, S.; Romano, D.; Friel, E.; Bragaglia,
   A.; Smiljanic, R.; Jacobson, H.; Vallenari, A.; Tosi, M.; Spina, L.;
   Donati, P.; Maiorca, E.; Cantat-Gaudin, T.; Sordo, R.; Bergemann, M.;
   Damiani, F.; Tautvaišienė, G.; Blanco-Cuaresma, S.; Jiménez-Esteban,
   F.; Geisler, D.; Mowlavi, N.; Munoz, C.; San Roman, I.; Soubiran, C.;
   Villanova, S.; Zaggia, S.; Gilmore, G.; Asplund, M.; Feltzing, S.;
   Jeffries, R.; Bensby, T.; Koposov, S.; Korn, A. J.; Flaccomio, E.;
   Pancino, E.; Recio-Blanco, A.; Sacco, G.; Costado, M. T.; Franciosini,
   E.; Jofre, P.; de Laverny, P.; Hill, V.; Heiter, U.; Hourihane, A.;
   Jackson, R.; Lardo, C.; Morbidelli, L.; Lewis, J.; Lind, K.; Masseron,
   T.; Prisinzano, L.; Worley, C.
2014A&A...563A..44M    Altcode: 2013arXiv1312.6472M
  Context. Open clusters are key tools to study the spatialdistribution
  of abundances in the disk and their evolution with time. <BR /> Aims:
  Using the first release of stellar parameters and abundances of the
  Gaia-ESO Survey, we analyse the chemical properties of stars in three
  old/intermediate-age open clusters, namely NGC 6705, NGC 4815, and
  Trumpler 20, which are all located in the inner part of the Galactic
  disk at Galactocentric radius R<SUB>GC</SUB> ~ 7 kpc. We aim to prove
  their homogeneity and to compare them with the field population. <BR
  /> Methods: We study the abundance ratios of elements belonging to
  two different nucleosynthetic channels: α-elements and iron-peak
  elements. For each element, we analyse the internal chemical homogeneity
  of cluster members, and we compare the cumulative distributions of
  cluster abundance ratios with those of solar neighbourhood turn-off
  stars and of inner-disk/bulge giants. We compare the abundance ratios of
  field and cluster stars with two chemical evolution models that predict
  different α-enhancement dependences on the Galactocentric distance due
  to different assumptions on the infall and star-formation rates. <BR
  /> Results: The main results can be summarised as follows: i) cluster
  members are chemically homogeneous within 3σ in all analysed elements;
  ii) the three clusters have comparable [El/Fe] patterns within ~1σ,
  but they differ in their global metal content [El/H] with NGC 4815
  having the lowest metallicity; their [El/Fe] ratios show differences
  and analogies with those of the field population, in both the solar
  neighbourhood and the bulge/inner disk; iii) comparing the abundance
  ratios with the results of two chemical evolution models and with field
  star abundance distributions, we find that the abundance ratios of Mg,
  Ni, and Ca in NGC 6705 might require an inner birthplace, implying a
  subsequent variation in its R<SUB>GC</SUB> during its lifetime, which is
  consistent with previous orbit determination. <BR /> Conclusions: Using
  the results of the first internal data release, we show the potential of
  the Gaia-ESO Survey through a homogeneous and detailed analysis of the
  cluster versus field populations to reveal the chemical structure of our
  Galaxy using a completely uniform analysis of different populations. We
  verify that the Gaia-ESO Survey data are able to identify the unique
  chemical properties of each cluster by pinpointing the composition of
  the interstellar medium at the epoch and place of formation. The full
  dataset of the Gaia-ESO Survey is a superlative tool to constrain the
  chemical evolution of our Galaxy by disentangling different formation
  and evolution scenarios. <P />Based on observations collected with
  the FLAMES spectrograph at the VLT/UT2 telescope (Paranal Observatory,
  ESO, Chile), for the Gaia-ESO Large Public Survey (188.B-3002).

---------------------------------------------------------
Title: VizieR Online Data Catalog: ARGOS line list λ8395-8830Å
    (Freeman+, 2013)
Authors: Freeman, K.; Ness, M.; Wylie-de-Boer, E.; Athanassoula, E.;
   Bland-Hawthorn, J.; Asplund, M.; Lewis, G.; Yong, D.; Lane, R.; Kiss,
   L.; Ibata, R.
2014yCat..74283660F    Altcode:
  The spectra were acquired with the fibre-fed AAOmega system on the
  Anglo-Australian Telescope in 2008-2011 May-August. <P />(1 data file).

---------------------------------------------------------
Title: The Stagger-grid: A grid of 3D stellar atmosphere models -
    V. Fe line shapes, shifts and asymmetries
Authors: Magic, Zazralt; Collet, Remo; Asplund, Martin
2014arXiv1403.6245M    Altcode:
  We present a theoretical study of the effects and signatures of
  realistic velocity field and atmospheric inhomogeneities associated
  with convective motions at the surface of cool late-type stars on
  the emergent profiles of iron spectral lines for a large range in
  stellar parameters. We compute 3D spectral line flux profiles under
  the assumption of local thermodynamic equilibrium (LTE) by employing
  state-of-the-art, time-dependent, 3D, radiative-hydrodynamical
  atmosphere models from the Stagger-grid. A set of 35 real unblended,
  optical FeI and FeII lines of varying excitation potential are
  considered. Additionally, fictitious Fe i and Fe ii lines (5000A
  and 0, 2, 4 eV) are used to construct general curves of growth and
  enable comparison of line profiles with the same line strength
  to illustrate systematical trends stemming from the intrinsic
  structural differences among 3D model atmospheres with different
  stellar parameters. Theoretical line shifts and bisectors are derived
  to analyze the shapes, shifts, and asymmetries imprinted in the full 3D
  line profiles emerging self-consistently from the convective simulations
  with velocity fields and atmospheric inhomogeneities. We find systematic
  variations in line strength, shift, width, and bisectors, that can be
  related to the respective physical conditions at the height of the line
  formation in the stellar atmospheric environment, in particular the
  amplitude of the vertical velocity field. Line shifts and asymmetries
  arise due to the presence of convective velocities and the granulation
  pattern that are ubiquitously found in observed stellar spectra of
  cool stars.

---------------------------------------------------------
Title: A single low-energy, iron-poor supernova as the source of
    metals in the star SMSS J031300.36-670839.3
Authors: Keller, S. C.; Bessell, M. S.; Frebel, A.; Casey, A. R.;
   Asplund, M.; Jacobson, H. R.; Lind, K.; Norris, J. E.; Yong, D.;
   Heger, A.; Magic, Z.; da Costa, G. S.; Schmidt, B. P.; Tisserand, P.
2014Natur.506..463K    Altcode: 2014arXiv1402.1517K
  The element abundance ratios of four low-mass stars with extremely
  low metallicities (abundances of elements heavier than helium)
  indicate that the gas out of which the stars formed was enriched
  in each case by at most a few--and potentially only one--low-energy
  supernova. Such supernovae yield large quantities of light elements
  such as carbon but very little iron. The dominance of low-energy
  supernovae seems surprising, because it had been expected that the
  first stars were extremely massive, and that they disintegrated
  in pair-instability explosions that would rapidly enrich galaxies
  in iron. What has remained unclear is the yield of iron from the
  first supernovae, because hitherto no star has been unambiguously
  interpreted as encapsulating the yield of a single supernova. Here we
  report the optical spectrum of SMSS J031300.36-670839.3, which shows no
  evidence of iron (with an upper limit of 10<SUP>-7.1</SUP> times solar
  abundance). Based on a comparison of its abundance pattern with those
  of models, we conclude that the star was seeded with material from a
  single supernova with an original mass about 60 times that of the Sun
  (and that the supernova left behind a black hole). Taken together with
  the four previously mentioned low-metallicity stars, we conclude that
  low-energy supernovae were common in the early Universe, and that
  such supernovae yielded light-element enrichment with insignificant
  iron. Reduced stellar feedback both chemically and mechanically from
  low-energy supernovae would have enabled first-generation stars to
  form over an extended period. We speculate that such stars may perhaps
  have had an important role in the epoch of cosmic reionization and
  the chemical evolution of early galaxies.

---------------------------------------------------------
Title: Detailed element abundances of SkyMapper EMP stars: first
    results of the high-resolution spectroscopic follow up
Authors: Jacobson, Heather R.; Asplund, Martin; Bessell, Michael S.;
   Casey, Andrew R.; Da Costa, Gary S.; Frebel, Anna; Keller, Stefan C.;
   Lind, Karin; Norris, John E.; Schmidt, Brian P.; Tisserand, Patrick;
   Yong, David
2014MmSAI..85..227J    Altcode:
  The multi band photometry of SkyMapper's Southern Sky Survey is
  designed to search for extremely metal-poor (EMP) stars. The best
  candidates have been observed with low-resolution spectroscopy
  to confirm their low metallicities, and then with high-resolution
  spectroscopy to determine their detailed element abundances. So far,
  high-resolution Magellan/MIKE spectra have been obtained for over
  200 EMP candidates. Here we present the results for the first ∼14
  months of this new effort, during which time the photometric candidate
  selection has been continuously improved. Of the 50 most recently
  observed EMP candidates, roughly half have [Fe/H] &lt; -3, with 3
  stars having [Fe/H] &lt; -3.5. Our analysis shows these metal-poor
  stars to have typical halo star abundance patterns. These results
  clearly demonstrate SkyMapper's capability to find large numbers of
  EMP stars which will vastly improve our understanding of the earliest
  star formation processes and the onset of chemical evolution.

---------------------------------------------------------
Title: The First Stars
Authors: Asplund, M.
2014fegb.confE...5A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Chemical signatures of planets: beyond solar-twins
Authors: Ramírez, I.; Meléndez, J.; Asplund, M.
2014A&A...561A...7R    Altcode: 2013arXiv1310.8581R
  Context. Elemental abundance studies of solar twin stars suggest that
  the solar chemical composition contains signatures of the formation of
  terrestrial planets in the solar system, namely small but significant
  depletions of the refractory elements. <BR /> Aims: To test whether
  these chemical signatures of planets are real, we study stars which,
  compared to solar twins, have less massive convective envelopes
  (therefore increasing the amplitude of the predicted effect) or are,
  arguably, more likely to host planets (thus increasing the frequency of
  signature detections). <BR /> Methods: We measure relative atmospheric
  parameters and elemental abundances of two groups of stars: a "warm"
  late-F type dwarf sample (52 stars), and a sample of "metal-rich"
  solar analogs (59 stars). The strict differential approach that we
  adopt allows us to determine with high precision (errors ~0.01 dex)
  the degree of refractory element depletion in our stars independently
  of Galactic chemical evolution. By examining relative abundance ratio
  versus condensation temperature plots we are able to identify stars with
  "pristine" composition in each sample and to determine the degree of
  refractory-element depletion for the rest of our stars. We calculate
  what mixture of Earth-like and meteorite-like material corresponds
  to these depletions. <BR /> Results: We detect refractory-element
  depletions with amplitudes up to about 0.15 dex. The distribution of
  depletion amplitudes for stars known to host gas giant planets is not
  different from that of the rest of stars. The maximum amplitude of
  depletion increases with effective temperature from 5650 K to 5950 K,
  while it appears to be constant for warmer stars (up to 6300 K). The
  depletions observed in solar twin stars have a maximum amplitude that
  is very similar to that seen here for both of our samples. <BR />
  Conclusions: Gas giant planet formation alone cannot explain the
  observed distributions of refractory-element depletions, leaving
  the formation of rocky material as a more likely explanation of our
  observations. More rocky material is necessary to explain the data of
  solar twins than metal-rich stars, and less for warm stars. However,
  the sizes of the stars' convective envelopes at the time of planet
  formation could be regulating these amplitudes. Our results could
  be explained if disk lifetimes were shorter in more massive stars,
  as independent observations indeed seem to suggest. Nevertheless,
  to reach stronger conclusions we will need a detailed knowledge of
  extrasolar planetary systems down to at least one Earth mass around a
  significant number of stars. <P />Based on observations collected at
  the European Organisation for Astronomical Research in the Southern
  Hemisphere, Chile, observing proposals 086.D0062 and 087.D0010.Full
  Tables 1 and 3-6 are only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/561/A7">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/561/A7</A>

---------------------------------------------------------
Title: Helium enhanced stars and multiple populations along the
horizontal branch of NGC 2808: direct spectroscopic measurements
Authors: Marino, A. F.; Milone, A. P.; Przybilla, N.; Bergemann,
   M.; Lind, K.; Asplund, M.; Cassisi, S.; Catelan, M.; Casagrande, L.;
   Valcarce, A. A. R.; Bedin, L. R.; Cortés, C.; D'Antona, F.; Jerjen,
   H.; Piotto, G.; Schlesinger, K.; Zoccali, M.; Angeloni, R.
2014MNRAS.437.1609M    Altcode: 2013MNRAS.tmp.2693M; 2013arXiv1310.4527M
  We present an abundance analysis of 96 horizontal branch (HB) stars
  in NGC 2808, a globular cluster exhibiting a complex multiple stellar
  population pattern. These stars are distributed in different portions
  of the HB and cover a wide range of temperature. By studying the
  chemical abundances of this sample, we explore the connection between
  HB morphology and the chemical enrichment history of multiple stellar
  populations. For stars lying on the red HB, we use GIRAFFE and UVES
  spectra to determine Na, Mg, Si, Ca, Sc, Ti, Cr, Mn, Fe, Ni, Zn, Y,
  Ba and Nd abundances. For colder, blue HB stars, we derive abundances
  for Na, primarily from GIRAFFE spectra. We were also able to measure
  direct non-local thermodynamic equilibrium He abundances for a subset
  of these blue HB stars with temperature higher than ∼9000 K. Our
  results show that: (i) HB stars in NGC 2808 show different content
  in Na depending on their position in the colour-magnitude diagram,
  with blue HB stars having higher Na than red HB stars; (ii) the red
  HB is not consistent with a uniform chemical abundance, with slightly
  warmer stars exhibiting a statistically significant higher Na content;
  and (iii) our subsample of blue HB stars with He abundances shows
  evidence of enhancement with respect to the predicted primordial
  He content by ΔY = +0.09 ± 0.01 ± 0.05 (internal plus systematic
  uncertainty). Our results strongly support theoretical models that
  predict He enhancement among second-generation(s) stars in globular
  clusters and provide observational constraints on the second-parameter
  governing HB morphology.

---------------------------------------------------------
Title: The GALAH survey
Authors: Anguiano, B.; Freeman, K.; Bland-Hawthorn, J.; De Silva,
   G.; Asplund, M.; Carollo, D.; D'Orazi, V.; Keller, S.; Martell, S.;
   Sharma, S.; Sneden, C.; de Boer, L. Wylie; Zucker, D.; Zwitter, T.
2014IAUS..298..322A    Altcode:
  HERMES is a new high-resolution multi-object spectrograph on the
  Anglo Australian Telescope. The primary science driver for HERMES is
  the GALAH survey, GALactic Archaeology with HERMES. We are planning a
  spectroscopic survey of about a million stars, aimed at using chemical
  tagging techniques to reconstruct the star-forming aggregates that
  built up the disk, the bulge and halo of the Galaxy. This project will
  benefit greatly from the stellar distances and transverse motions from
  the Gaia mission.

---------------------------------------------------------
Title: “Old” versus “New” Solar Chemical Composition
Authors: Grevesse, N.; Asplund, M.; Sauval, A. J.; Scott, P.
2013ASPC..479..481G    Altcode:
  We follow the evolution since 1989 of element abundance determinations
  in the solar photosphere. We describe how the largely used high
  metallicity mixtures (Z = 0.02 to 0.017) of Anders &amp; Grevesse
  (1989), Grevesse &amp; Noels (1993) and Grevesse &amp; Sauval (1998)
  have been obtained and explain why these mixtures should not be used
  anymore. They are to be replaced by the more recent mixture of Asplund
  et al. (2009) which results from the first comprehensive and homogeneous
  analysis for many decades. We describe the main characteristics of this
  work and discuss some impacts of this low Z (Z = 0.0134) mixture. We
  also comment on another recent analysis by Caffau et al. (2011) that
  leads to somewhat larger metal abundances.

---------------------------------------------------------
Title: The Stagger-grid: A Grid of 3D Stellar Atmosphere Models
Authors: Magic, Z.; Collet, R.; Asplund, M.
2013EAS....63..367M    Altcode: 2013arXiv1310.4996M
  Theoretical atmosphere models provide the basis for a variety of
  applications in astronomy. In simplified one-dimensional (1D) atmosphere
  models, convection is usually treated with the mixing length theory
  despite its well-known insufficiency, therefore, the superadiabatic
  regime is poorly rendered. Due to the increasing computational power
  over the last decades, we are now capable to compute large grids of
  realistic three-dimensional (3D) hydrodynamical model atmospheres with
  the realistic treatment of the radiative transfer. We have computed the
  Stagger-grid, a comprehensive grid of 3D atmosphere models for late-type
  stars. In the presented contribution, we discuss initial results of
  the grid by exploring global properties and mean stratifications of
  the 3D models. Furthermore, we also depict the differences to classic
  1D atmosphere models.

---------------------------------------------------------
Title: The Stagger-grid: A grid of 3D stellar atmosphere
    models. II. Horizontal and temporal averaging and spectral line
    formation
Authors: Magic, Z.; Collet, R.; Hayek, W.; Asplund, M.
2013A&A...560A...8M    Altcode: 2013arXiv1307.3273M
  <BR /> Aims: We study the implications of averaging methods with
  different reference depth scales for 3D hydrodynamical model atmospheres
  computed with the Stagger-code. The temporally and spatially averaged
  (hereafter denoted as ⟨3D⟩) models are explored in the light
  of local thermodynamic equilibrium (LTE) spectral line formation by
  comparing spectrum calculations using full 3D atmosphere structures
  with those from ⟨3D⟩ averages. <BR /> Methods: We explored methods
  for computing mean ⟨3D⟩ stratifications from the Stagger-grid
  time-dependent 3D radiative hydrodynamical atmosphere models by
  considering four different reference depth scales (geometrical depth,
  column-mass density, and two optical depth scales). Furthermore,
  we investigated the influence of alternative averages (logarithmic,
  enforced hydrostatic equilibrium, flux-weighted temperatures). For the
  line formation we computed curves of growth for Fe i and Fe ii lines in
  LTE. <BR /> Results: The resulting ⟨3D⟩ stratifications for the four
  reference depth scales can be very different. We typically find that in
  the upper atmosphere and in the superadiabatic region just below the
  optical surface, where the temperature and density fluctuations are
  highest, the differences become considerable and increase for higher
  T<SUB>eff</SUB>, lower log g, and lower [Fe / H]. The differential
  comparison of spectral line formation shows distinctive differences
  depending on which ⟨3D⟩ model is applied. The averages over
  layers of constant column-mass density yield the best mean ⟨3D⟩
  representation of the full 3D models for LTE line formation, while
  the averages on layers at constant geometrical height are the least
  appropriate. Unexpectedly, the usually preferred averages over layers of
  constant optical depth are prone to increasing interference by reversed
  granulation towards higher effective temperature, in particular at
  low metallicity. <P />Appendix A is available in electronic form
  at <A href="http://www.aanda.org">http://www.aanda.org</A>Mean
  ⟨3D⟩ models are available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/560/A8">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/560/A8</A>
  as well as at <A
  href="http://www.stagger-stars.net">http://www.stagger-stars.net</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: High-precision abundances for
    stars with planets (Ramirez+, 2014)
Authors: Ramirez, I.; Melendez, J.; Asplund, M.
2013yCat..35610007R    Altcode: 2013yCat..35619007R
  High-precision stellar parameters and chemical abundances are presented
  for 111 stars; 52 of them are late-F type dwarfs and 59 are metal-rich
  solar analogs. The atomic linelist employed in the derivation of
  chemical abundances is also given. This linelist includes hyperfine
  structure parameters for some species. The stars' isochrone masses
  and ages are also reported, along with estimates of chromospheric
  activity. <P />(5 data files).

---------------------------------------------------------
Title: A Community Science Case for E-ELT HIRES
Authors: Maiolino, R.; Haehnelt, M.; Murphy, M. T.; Queloz, D.;
   Origlia, L.; Alcala, J.; Alibert, Y.; Amado, P. J.; Allende Prieto, C.;
   Ammler-von Eiff, M.; Asplund, M.; Barstow, M.; Becker, G.; Bonfils, X.;
   Bouchy, F.; Bragaglia, A.; Burleigh, M. R.; Chiavassa, A.; Cimatti,
   D. A.; Cirasuolo, M.; Cristiani, S.; D'Odorico, V.; Dravins, D.;
   Emsellem, E.; Farihi, J.; Figueira, P.; Fynbo, J.; Gansicke, B. T.;
   Gillon, M.; Gustafsson, B.; Hill, V.; Israelyan, G.; Korn, A.; Larsen,
   S.; De Laverny, P.; Liske, J.; Lovis, C.; Marconi, A.; Martins, C.;
   Molaro, P.; Nisini, B.; Oliva, E.; Petitjean, P.; Pettini, M.; Recio
   Blanco, A.; Rebolo, R.; Reiners, A.; Rodriguez-Lopez, C.; Ryde, N.;
   Santos, N. C.; Savaglio, S.; Snellen, I.; Strassmeier, K.; Tanvir, N.;
   Testi, L.; Tolstoy, E.; Triaud, A.; Vanzi, L.; Viel, M.; Volonteri, M.
2013arXiv1310.3163M    Altcode:
  Building on the experience of the high-resolution community with the
  suite of VLT high-resolution spectrographs, which has been tremendously
  successful, we outline here the (science) case for a high-fidelity,
  high-resolution spectrograph with wide wavelength coverage at the
  E-ELT. Flagship science drivers include: the study of exo-planetary
  atmospheres with the prospect of the detection of signatures of life
  on rocky planets; the chemical composition of planetary debris on the
  surface of white dwarfs; the spectroscopic study of protoplanetary and
  proto-stellar disks; the extension of Galactic archaeology to the Local
  Group and beyond; spectroscopic studies of the evolution of galaxies
  with samples that, unlike now, are no longer restricted to strongly
  star forming and/or very massive galaxies; the unraveling of the
  complex roles of stellar and AGN feedback; the study of the chemical
  signatures imprinted by population III stars on the IGM during the
  epoch of reionization; the exciting possibility of paradigm-changing
  contributions to fundamental physics. The requirements of these science
  cases can be met by a stable instrument with a spectral resolution
  of R~100,000 and broad, simultaneous spectral coverage extending
  from 370nm to 2500nm. Most science cases do not require spatially
  resolved information, and can be pursued in seeing-limited mode,
  although some of them would benefit by the E-ELT diffraction limited
  resolution. Some multiplexing would also be beneficial for some of
  the science cases. (Abridged)

---------------------------------------------------------
Title: High precision differential abundance measurements in globular
clusters: chemical inhomogeneities in NGC 6752
Authors: Yong, David; Meléndez, Jorge; Grundahl, Frank; Roederer,
   Ian U.; Norris, John E.; Milone, A. P.; Marino, A. F.; Coelho, P.;
   McArthur, Barbara E.; Lind, K.; Collet, R.; Asplund, Martin
2013MNRAS.434.3542Y    Altcode: 2013MNRAS.tmp.1944Y; 2013arXiv1307.4486Y
  We report on a strictly differential line-by-line analysis of
  high-quality UVES spectra of bright giants in the metal-poor globular
  cluster NGC 6752. We achieved high precision differential chemical
  abundance measurements for Fe, Na, Si, Ca, Ti, Cr, Ni, Zn, Y, Zr, Ba,
  La, Ce, Pr, Nd, Sm, Eu and Dy with uncertainties as low as ∼0.01
  dex (∼2 per cent). We obtained the following main results. (1) The
  observed abundance dispersions are a factor of ∼2 larger than the
  average measurement uncertainty. (2) There are positive correlations, of
  high statistical significance, between all elements and Na. (3) For any
  pair of elements, there are positive correlations of high statistical
  significance, although the amplitudes of the abundance variations are
  small. Removing abundance trends with effective temperature and/or using
  a different pair of reference stars does not alter these results. These
  abundance variations and correlations may reflect a combination of (a)
  He abundance variations and (b) inhomogeneous chemical evolution in the
  pre- or protocluster environment. Regarding the former, the current
  constraints on ΔY from photometry likely preclude He as being the
  sole explanation. Regarding the latter, the nucleosynthetic source(s)
  must have synthesized Na, α, Fe-peak and neutron-capture elements and
  in constant amounts for species heavier than Si; no individual object
  can achieve such nucleosynthesis. We speculate that other, if not all,
  globular clusters may exhibit comparable abundance variations and
  correlations to NGC 6752 if subjected to a similarly precise analysis.

---------------------------------------------------------
Title: VizieR Online Data Catalog: STAGGER-grid of 3D stellar
    models. II. (Magic+, 2013)
Authors: Magic, Z.; Collet, R.; Hayek, W.; Asplund, M.
2013yCat..35600008M    Altcode: 2013yCat..35609008M
  More (updated) information and data available at:
  http://www.stagger-stars.net/ <P />(5 data files).

---------------------------------------------------------
Title: High Precision Abundances of the Old Solar Twin HIP 102152:
    Insights on Li Depletion from the Oldest Sun
Authors: Monroe, TalaWanda R.; Meléndez, Jorge; Ramírez, Iván; Yong,
   David; Bergemann, Maria; Asplund, Martin; Bedell, Megan; Tucci Maia,
   Marcelo; Bean, Jacob; Lind, Karin; Alves-Brito, Alan; Casagrande,
   Luca; Castro, Matthieu; do Nascimento, José-Dias; Bazot, Michael;
   Freitas, Fabrício C.
2013ApJ...774L..32M    Altcode: 2013arXiv1308.5744M
  We present the first detailed chemical abundance analysis of the old
  8.2 Gyr solar twin, HIP 102152. We derive differential abundances of
  21 elements relative to the Sun with precisions as high as 0.004 dex
  (lsim1%), using ultra high-resolution (R = 110,000), high S/N UVES
  spectra obtained on the 8.2 m Very Large Telescope. Our determined
  metallicity of HIP 102152 is [Fe/H] = -0.013 ± 0.004. The atmospheric
  parameters of the star were determined to be 54 K cooler than the Sun,
  0.09 dex lower in surface gravity, and a microturbulence identical to
  our derived solar value. Elemental abundance ratios examined versus
  dust condensation temperature reveal a solar abundance pattern for
  this star, in contrast to most solar twins. The abundance pattern
  of HIP 102152 appears to be the most similar to solar of any known
  solar twin. Abundances of the younger, 2.9 Gyr solar twin, 18 Sco,
  were also determined from UVES spectra to serve as a comparison for HIP
  102152. The solar chemical pattern of HIP 102152 makes it a potential
  candidate to host terrestrial planets, which is reinforced by the
  lack of giant planets in its terrestrial planet region. The following
  non-local thermodynamic equilibrium Li abundances were obtained for HIP
  102152, 18 Sco, and the Sun: log epsilon (Li) = 0.48 ± 0.07, 1.62 ±
  0.02, and 1.07 ± 0.02, respectively. The Li abundance of HIP 102152 is
  the lowest reported to date for a solar twin, and allows us to consider
  an emerging, tightly constrained Li-age trend for solar twin stars. <P
  />Based on observations obtained at the European Southern Observatory
  (observing programs 083.D-0871 and 188.C-0265).

---------------------------------------------------------
Title: The Stagger-grid: A grid of 3D stellar atmosphere
    models. I. Methods and general properties
Authors: Magic, Z.; Collet, R.; Asplund, M.; Trampedach, R.; Hayek,
   W.; Chiavassa, A.; Stein, R. F.; Nordlund, Å.
2013A&A...557A..26M    Altcode: 2013arXiv1302.2621M
  <BR /> Aims: We present the Stagger-grid, a comprehensive grid of
  time-dependent, three-dimensional (3D), hydrodynamic model atmospheres
  for late-type stars with realistic treatment of radiative transfer,
  covering a wide range in stellar parameters. This grid of 3D models is
  intended for various applications besides studies of stellar convection
  and atmospheres per se, including stellar parameter determination,
  stellar spectroscopy and abundance analysis, asteroseismology,
  calibration of stellar evolution models, interferometry, and extrasolar
  planet search. In this introductory paper, we describe the methods
  we applied for the computation of the grid and discuss the general
  properties of the 3D models as well as of their temporal and spatial
  averages (here denoted ⟨3D⟩ models). <BR /> Methods: All our models
  were generated with the Stagger-code, using realistic input physics for
  the equation of state (EOS) and for continuous and line opacities. Our ~
  220 grid models range in effective temperature, T<SUB>eff</SUB>, from
  4000 to 7000 K in steps of 500 K, in surface gravity, log g, from 1.5
  to 5.0 in steps of 0.5 dex, and metallicity, [Fe/H], from - 4.0 to +
  0.5 in steps of 0.5 and 1.0 dex. <BR /> Results: We find a tight scaling
  relation between the vertical velocity and the surface entropy jump,
  which itself correlates with the constant entropy value of the adiabatic
  convection zone. The range in intensity contrast is enhanced at lower
  metallicity. The granule size correlates closely with the pressure
  scale height sampled at the depth of maximum velocity. We compare the
  ⟨3D⟩ models with currently widely applied one-dimensional (1D)
  atmosphere models, as well as with theoretical 1D hydrostatic models
  generated with the same EOS and opacity tables as the 3D models, in
  order to isolate the effects of using self-consistent and hydrodynamic
  modeling of convection, rather than the classical mixing length theory
  approach. For the first time, we are able to quantify systematically
  over a broad range of stellar parameters the uncertainties of 1D
  models arising from the simplified treatment of physics, in particular
  convective energy transport. In agreement with previous findings,
  we find that the differences can be rather significant, especially
  for metal-poor stars. <P />Appendices A-C are available in electronic
  form at <A href="http://www.aanda.org">http://www.aanda.org</A>Full
  Table C.1 is available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/557/A26">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/557/A26</A>

---------------------------------------------------------
Title: The chemical signatures of planet formation: Kepler stars
    with rocky planets
Authors: Asplund, Martin
2013koa..prop..142A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: ARGOS - IV. The kinematics of the Milky Way bulge
Authors: Ness, M.; Freeman, K.; Athanassoula, E.; Wylie-de-Boer, E.;
   Bland-Hawthorn, J.; Asplund, M.; Lewis, G. F.; Yong, D.; Lane, R. R.;
   Kiss, L. L.; Ibata, R.
2013MNRAS.432.2092N    Altcode: 2013MNRAS.tmp.1344N; 2013arXiv1303.6656N
  We present the kinematic results from our ARGOS spectroscopic survey
  of the Galactic bulge of the Milky Way. Our aim is to understand the
  formation of the Galactic bulge. We examine the kinematics of about 17
  400 stars in the bulge located within 3.5 kpc of the Galactic Centre,
  identified from the 28 000 star ARGOS survey. We aim to determine
  if the formation of the bulge has been internally driven from disc
  instabilities as suggested by its boxy shape, or if mergers have
  played a significant role as expected from lambda cold dark matter
  simulations. From our velocity measurements across latitudes b =
  -5°, - 7.5° and -10° we find the bulge to be a cylindrically
  rotating system that transitions smoothly out into the disc. From
  observations of 3 fields at b = +10, the kinematics of the bulge
  show North-South symmetry about the major axis. Within the bulge,
  we find a kinematically distinct metal-poor population ([Fe/H] &lt;
  -1.0) that is not rotating cylindrically. The 5 per cent of our stars
  with [Fe/H] &lt; -1.0 are a slowly rotating spheroidal population,
  which we believe are stars of the metal-weak thick disc and halo
  which presently lie in the inner Galaxy. The kinematics of the two
  bulge components that we identified in ARGOS Paper III (mean [Fe/H]
  ≈ -0.25 and [Fe/H] ≈ +0.15, respectively) demonstrate that they
  are likely to share a common formation origin and are distinct from
  the more metal-poor populations of the thick disc and halo which are
  co-located inside the bulge. We do not exclude an underlying merger
  generated bulge component but our results favour bulge formation from
  instabilities in the early thin disc.

---------------------------------------------------------
Title: What 3D Hydrodynamical Stellar Model Atmospheres Can Do for
    Asteroseismology and Stellar Populations
Authors: Asplund, M.
2013aspm.confE..11A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: VizieR Online Data Catalog: STAGGER-grid of 3D stellar
    models. I. (Magic+, 2013)
Authors: Magic, Z.; Collet, R.; Asplund, M.; Trampedach, R.; Hayek,
   W.; Chiavassa, A.; Stein, R. F.; Nordlund, A.
2013yCat..35570026M    Altcode: 2013yCat..35579026M
  The 3D model atmospheres presented here were constructed with
  a custom version of the Stagger-code, a state-of-the-art,
  multipurpose, radiative-magnetohydrodynamics (R-MHD)
  code originally developed by Nordlund &amp; Galsgaard (1995,
  http://www.astro.ku.dk/~kg/Papers/MHD_code.ps.gz), and continuously
  improved over the years by its user community. <P />(1 data file).

---------------------------------------------------------
Title: The lithium isotopic ratio in very metal-poor stars
Authors: Lind, K.; Melendez, J.; Asplund, M.; Collet, R.; Magic, Z.
2013A&A...554A..96L    Altcode: 2013arXiv1305.6564L
  Context. Un-evolved, very metal-poor stars are the most
  important tracers of the cosmic abundance of lithium in the early
  universe. Combining the standard Big Bang nucleosynthesis model
  with Galactic production through cosmic ray spallation, these stars
  at [Fe / H] &lt; - 2 are expected to show an undetectably small
  <SUP>6</SUP>Li / <SUP>7</SUP>Li isotopic signature. Evidence to the
  contrary may necessitate an additional pre-galactic production source
  or a revision of the standard model of Big Bang nucleosynthesis. It
  would also cast doubts on Li depletion from stellar atmospheres as
  an explanation for the factor 3-5 discrepancy between the predicted
  primordial <SUP>7</SUP>Li from the Big Bang and the observed value in
  metal-poor dwarf/turn-off stars. <BR /> Aims: We revisit the isotopic
  analysis of four halo stars, two with claimed <SUP>6</SUP>Li-detections
  in the literature, to investigate the influence of improved model
  atmospheres and line formation treatment. <BR /> Methods: For the
  first time, a combined 3D, non-local thermodynamic equilibrium
  (NLTE) modelling technique for Li, Na, and Ca lines is utilised
  to constrain the intrinsic line-broadening and to determine the Li
  isotopic ratio. We discuss the influence of 3D NLTE effects on line
  profile shapes and assess the realism of our modelling using the Ca
  excitation and ionisation balance. <BR /> Results: By accounting for
  NLTE line formation in realistic 3D hydrodynamical model atmospheres,
  we can model the Li resonance line and other neutral lines with a
  consistency that is superior to LTE, with no need for additional
  line asymmetry caused by the presence of <SUP>6</SUP>Li. Contrary to
  the results from 1D and 3D LTE modelling, no star in our sample has a
  significant (2σ) detection of the lighter isotope in NLTE. Over a large
  parameter space, NLTE modelling systematically reduces the best-fit Li
  isotopic ratios by up to five percentage points. As a bi-product, we
  also present the first ever 3D NLTE Ca and Na abundances of halo stars,
  which reveal significant departures from LTE. <BR /> Conclusions: The
  observational support for a significant and non-standard <SUP>6</SUP>Li
  production source in the early universe is substantially weakened
  by our findings. <P />Appendix A is available in electronic form
  at <A href="http://www.aanda.org">http://www.aanda.org</A>The
  reduced spectra in the region around the Li line
  are only available at the CDS via anonymous ftp to <A
  href="http://cdsarc.u-strasbg.fr">cdsarc.u-strasbg.fr</A>
  (ftp://130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/554/A96">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/554/A96</A>

---------------------------------------------------------
Title: How realistic are solar model atmospheres?
Authors: Pereira, T. M. D.; Asplund, M.; Collet, R.; Thaler, I.;
   Trampedach, R.; Leenaarts, J.
2013A&A...554A.118P    Altcode: 2013arXiv1304.4932P
  Context. Recently, new solar model atmospheres have been developed
  to replace classical 1D local thermodynamical equilibrium (LTE)
  hydrostatic models and used to for example derive the solar chemical
  composition. <BR /> Aims: We aim to test various models against key
  observational constraints. In particular, a 3D model used to derive
  the solar abundances, a 3D magnetohydrodynamical (MHD) model (with an
  imposed 10 mT vertical magnetic field), 1D NLTE and LTE models from
  the PHOENIX project, the 1D MARCS model, and the 1D semi-empirical
  model of Holweger &amp; Müller. <BR /> Methods: We confronted the
  models with observational diagnostics of the temperature profile:
  continuum centre-to-limb variations (CLVs), absolute continuum fluxes,
  and the wings of hydrogen lines. We also tested the 3D models for the
  intensity distribution of the granulation and spectral line shapes. <BR
  /> Results: The predictions from the 3D model are in excellent agreement
  with the continuum CLV observations, performing even better than
  the Holweger &amp; Müller model (constructed largely to fulfil such
  observations). The predictions of the 1D theoretical models are worse,
  given their steeper temperature gradients. For the continuum fluxes,
  predictions for most models agree well with the observations. No
  model fits all hydrogen lines perfectly, but again the 3D model comes
  ahead. The 3D model also reproduces the observed continuum intensity
  fluctuations and spectral line shapes very well. <BR /> Conclusions:
  The excellent agreement of the 3D model with the observables reinforces
  the view that its temperature structure is realistic. It outperforms
  the MHD simulation in all diagnostics, implying that recent claims
  for revised abundances based on MHD modelling are premature. Several
  weaknesses in the 1D hydrostatic models (theoretical and semi-empirical)
  are exposed. The differences between the PHOENIX LTE and NLTE models
  are small. We conclude that the 3D hydrodynamical model is superior
  to any of the tested 1D models, which gives further confidence in the
  solar abundance analyses based on it.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Metal-poor star spectra of the
    LiI 670.8nm line (Lind+, 2013)
Authors: Lind, K.; Melendez, J.; Asplund, M.; Collet, R.; Magic, Z.
2013yCat..35540096L    Altcode: 2013yCat..35549096L
  Reduced spectra in the region around the LiI 670.8nm resonance
  line. Four stars have been observed: HD19445, HD84937, HD140283 and
  G64-12. For each star, wavelength and normalised flux are given. For
  the derivation of the Li isotopic ratio, the normalisation has been
  further fine-tuned in a spectral interval extending 0.17nm from the
  line centre. <P />(4 data files).

---------------------------------------------------------
Title: A Grid of Three-dimensional Stellar Atmosphere Models of Solar
    Metallicity. I. General Properties, Granulation, and Atmospheric
    Expansion
Authors: Trampedach, Regner; Asplund, Martin; Collet, Remo; Nordlund,
   Åke; Stein, Robert F.
2013ApJ...769...18T    Altcode: 2013arXiv1303.1780T
  Present grids of stellar atmosphere models are the workhorses in
  interpreting stellar observations and determining their fundamental
  parameters. These models rely on greatly simplified models of
  convection, however, lending less predictive power to such models of
  late-type stars. We present a grid of improved and more reliable stellar
  atmosphere models of late-type stars, based on deep, three-dimensional
  (3D), convective, stellar atmosphere simulations. This grid is to be
  used in general for interpreting observations and improving stellar
  and asteroseismic modeling. We solve the Navier Stokes equations in
  3D and concurrent with the radiative transfer equation, for a range
  of atmospheric parameters, covering most of stellar evolution with
  convection at the surface. We emphasize the use of the best available
  atomic physics for quantitative predictions and comparisons with
  observations. We present granulation size, convective expansion of the
  acoustic cavity, and asymptotic adiabat as functions of atmospheric
  parameters.

---------------------------------------------------------
Title: The SUMO project I. A survey of multiple populations in
    globular clusters
Authors: Monelli, M.; Milone, A. P.; Stetson, P. B.; Marino, A. F.;
   Cassisi, S.; del Pino Molina, A.; Salaris, M.; Aparicio, A.; Asplund,
   M.; Grundahl, F.; Piotto, G.; Weiss, A.; Carrera, R.; Cebrián, M.;
   Murabito, S.; Pietrinferni, A.; Sbordone, L.
2013MNRAS.431.2126M    Altcode: 2013arXiv1303.5187M
  We present a general overview and the first results of the SUMO project
  (a SUrvey of Multiple pOpulations in Globular Clusters). The objective
  of this survey is the study of multiple stellar populations in the
  largest sample of globular clusters homogeneously analysed to date. To
  this aim we obtained high signal-to-noise (S/N &gt; 50) photometry
  for main sequence stars with mass down to ∼0.5 M<SUB>⊙</SUB> in
  a large sample of clusters using both archival and proprietary U, B,
  V and I data from ground-based telescopes. <P />In this paper, we focus
  on the occurrence of multiple stellar populations in 23 clusters. We
  define a new photometric index, c<SUB>U, B, I</SUB> = (U - B) - (B - I),
  which turns out to be very effective for identifying multiple sequences
  along the red giant branch (RGB). We found that in the V-c<SUB>U, B,
  I</SUB> diagram all clusters presented in this paper show broadened
  or multimodal RGBs, with the presence of two or more components. We
  found a direct connection with the chemical properties of different
  sequences, which display different abundances of light elements (O, Na,
  C, N and Al). The c<SUB>U, B, I</SUB> index is also a powerful tool for
  identifying distinct sequences of stars along the horizontal branch and,
  for the first time in the case of NGC 104 (47 Tuc), along the asymptotic
  giant branch. Our results demonstrate that (i) the presence of more than
  two stellar populations is a common feature amongst globular clusters,
  as already highlighted in previous work; (ii) multiple sequences
  with different chemical contents can be easily identified by using
  standard Johnson photometry obtained with ground-based facilities;
  (iii) in the study of globular cluster multiple stellar populations
  the c<SUB>U, B, I</SUB> index is an alternative to spectroscopy,
  and has the advantage of larger statistics.

---------------------------------------------------------
Title: ARGOS - III. Stellar populations in the Galactic bulge of
    the Milky Way
Authors: Ness, M.; Freeman, K.; Athanassoula, E.; Wylie-de-Boer, E.;
   Bland-Hawthorn, J.; Asplund, M.; Lewis, G. F.; Yong, D.; Lane, R. R.;
   Kiss, L. L.
2013MNRAS.430..836N    Altcode: 2013MNRAS.tmp..635N; 2012arXiv1212.1540N
  We present the metallicity results from the ARGOS spectroscopic survey
  of the Galactic bulge. Our aim is to understand the formation of the
  Galactic bulge: did it form via mergers, as expected from Λ cold
  dark matter theory, or from disc instabilities, as suggested by its
  boxy/peanut shape, or both? Our stars are mostly red clump giants,
  which have a well-defined absolute magnitude from which distances
  can be determined. We have obtained spectra for 28 000 stars at
  a spectral resolution of R = 11 000. From these spectra, we have
  determined stellar parameters and distances to an accuracy of &lt;1.5
  kpc. The stars in the inner Galaxy span a large range in [Fe/H],
  -2.8 ≤ [Fe/H] ≤ +0.6. From the spatial distribution of the red
  clump stars as a function of [Fe/H], we propose that the stars with
  [Fe/H] &gt; -0.5 are part of the boxy/peanut bar/bulge. We associate
  the lower metallicity stars ([Fe/H] &lt; -0.5) with the thick disc,
  which may be puffed up in the inner region, and with the inner
  regions of the metal-weak thick disc and inner halo. For the bulge
  stars with [Fe/H] &gt; -0.5, we find two discrete populations: (i)
  stars with [Fe/H] ≈ -0.25 which provide a roughly constant fraction
  of the stars in the latitude interval b = -5° to -10°, and (ii)
  a kinematically colder, more metal-rich population with mean [Fe/H]
  ≈ +0.15 which is more prominent closer to the plane. The changing
  ratio of these components with latitude appears as a vertical abundance
  gradient of the bulge. We attribute both of these bulge components to
  instability-driven bar/bulge formation from the thin disc. We associate
  the thicker component with the stars of the early less metal-rich thin
  disc, and associate the more metal-rich population concentrated to the
  plane with the colder more metal-rich stars of the early thin disc,
  similar to the colder and younger more metal-rich stars seen in the
  thin disc in the solar neighbourhood today. We do not exclude a weak
  underlying classical merger-generated bulge component, but see no
  obvious kinematic association of any of our bulge stars with such a
  classical bulge component. The clear spatial and kinematic separation
  of the two bulge populations (i) and (ii) makes it unlikely that any
  significant merger event could have affected the inner regions of the
  Galaxy since the time when the bulge-forming instabilities occurred.

---------------------------------------------------------
Title: Why GN93 should not be used anymore
Authors: Grevesse, N.; Asplund, M.; Sauval, J.; Scott, P.
2013EPJWC..4301004G    Altcode:
  We show why the solar chemical composition of [1] (GN93) and the
  similar values of [2] (AG89) and [3] (GS98), characterized by values
  of the metallicity of the order of 0.017 to 0.020, largely used in
  solar and stellar modeling, are now obsolete. They should be replaced
  by the new and more precise results of [4] (AGSS09), with a much lower
  metallicity of 0.0134.

---------------------------------------------------------
Title: ARGOS - II. The Galactic bulge survey
Authors: Freeman, K.; Ness, M.; Wylie-de-Boer, E.; Athanassoula, E.;
   Bland-Hawthorn, J.; Asplund, M.; Lewis, G.; Yong, D.; Lane, R.; Kiss,
   L.; Ibata, R.
2013MNRAS.428.3660F    Altcode: 2012MNRAS.428.3660F; 2012arXiv1212.1541F; 2012MNRAS.tmp..296F
  We describe the motivation, field locations and stellar selection for
  the Abundances and Radial velocity Galactic Origins Survey (ARGOS)
  spectroscopic survey of 28 000 stars in the bulge and inner disc of the
  Milky Way galaxy across latitudes of b = -5° to -10°. The primary goal
  of this survey is to constrain the formation processes of the bulge
  and establish whether it is predominantly a merger or instability
  remnant. From the spectra (R = 11 000), we have measured radial
  velocities and determined stellar parameters, including metallicities
  and [α/Fe] ratios. Distances were estimated from the derived stellar
  parameters and about 14 000 stars are red giants within 3.5 kpc of
  the Galactic Centre. In this paper, we present the observations and
  analysis methods. Subsequent papers (III and IV) will discuss the
  stellar metallicity distribution and kinematics of the Galactic bulge
  and inner disc, and the implications for the formation of the bulge.

---------------------------------------------------------
Title: The Most Metal-poor Stars. II. Chemical Abundances of 190
    Metal-poor Stars Including 10 New Stars with [Fe/H] &lt;= -3.5
Authors: Yong, David; Norris, John E.; Bessell, M. S.; Christlieb,
   N.; Asplund, M.; Beers, Timothy C.; Barklem, P. S.; Frebel, Anna;
   Ryan, S. G.
2013ApJ...762...26Y    Altcode: 2012arXiv1208.3003Y
  We present a homogeneous chemical abundance analysis of 16 elements
  in 190 metal-poor Galactic halo stars (38 program and 152 literature
  objects). The sample includes 171 stars with [Fe/H] &lt;= -2.5, of
  which 86 are extremely metal poor, [Fe/H] &lt;= -3.0. Our program stars
  include 10 new objects with [Fe/H] &lt;= -3.5. We identify a sample
  of "normal" metal-poor stars and measure the trends between [X/Fe]
  and [Fe/H], as well as the dispersion about the mean trend for this
  sample. Using this mean trend, we identify objects that are chemically
  peculiar relative to "normal" stars at the same metallicity. These
  chemically unusual stars include CEMP-no objects, one star with high
  [Si/Fe], another with high [Ba/Sr], and one with unusually low [X/Fe]
  for all elements heavier than Na. The Sr and Ba abundances indicate
  that there may be two nucleosynthetic processes at lowest metallicity
  that are distinct from the main r-process. Finally, for many elements,
  we find a significant trend between [X/Fe] versus T <SUB>eff</SUB>,
  which likely reflects non-LTE and/or three-dimensional effects. Such
  trends demonstrate that care must be exercised when using abundance
  measurements in metal-poor stars to constrain chemical evolution and/or
  nucleosynthesis predictions. <P />This paper includes data gathered
  with the 6.5 m Magellan Telescopes located at Las Campanas Observatory,
  Chile. <P />Based on observations collected at the European Organisation
  for Astronomical Research in the Southern Hemisphere, Chile (proposal
  281.D-5015).

---------------------------------------------------------
Title: The Most Metal-poor Stars. I. Discovery, Data, and Atmospheric
    Parameters
Authors: Norris, John E.; Bessell, M. S.; Yong, David; Christlieb,
   N.; Barklem, P. S.; Asplund, M.; Murphy, Simon J.; Beers, Timothy C.;
   Frebel, Anna; Ryan, S. G.
2013ApJ...762...25N    Altcode: 2012arXiv1208.2999N
  We report the discovery of 34 stars in the Hamburg/ESO Survey for
  metal-poor stars and the Sloan Digital Sky Survey that have [Fe/H] &lt;~
  -3.0. Their median and minimum abundances are [Fe/H] = -3.1 and -4.1,
  respectively, while 10 stars have [Fe/H] &lt; -3.5. High-resolution,
  high signal-to-noise spectroscopic data—equivalent widths and
  radial velocities—are presented for these stars, together with
  an additional four objects previously reported or currently being
  investigated elsewhere. We have determined the atmospheric parameters,
  effective temperature (T <SUB>eff</SUB>), and surface gravity (log g),
  which are critical in the determination of the chemical abundances and
  the evolutionary status of these stars. Three techniques were used to
  derive these parameters. Spectrophotometric fits to model atmosphere
  fluxes were used to derive T <SUB>eff</SUB>, log g, and an estimate of
  E(B - V); Hα, Hβ, and Hγ profile fitting to model atmosphere results
  provided the second determination of T <SUB>eff</SUB> and log g; and
  finally, we used an empirical T <SUB>eff</SUB>-calibrated Hδ index,
  for the third, independent T <SUB>eff</SUB> determination. The three
  values of T <SUB>eff</SUB> are in good agreement, although the profile
  fitting may yield systematically cooler T <SUB>eff</SUB> values, by
  ~100 K. This collective data set will be analyzed in future papers
  in the present series to utilize the most metal-poor stars as probes
  of conditions in the early universe. <P />This paper includes data
  obtained with the ANU 2.3 m Telescope at Siding Spring Observatory,
  Australia; the Magellan Clay Telescope at Las Campanas Observatory,
  Chile; the Keck I Telescope at the W. M. Keck Observatory, Hawaii, USA;
  and the VLT (Kueyen) of the European Southern Observatory, Paranal,
  Chile (proposal 281.D-5015).

---------------------------------------------------------
Title: The SUMO project: a SUrvey of Multiple pOpulations in globular
    clusters
Authors: Monelli, M.; Milone, A. P.; Stetson, P. B.; Marino, A. F.;
   Cassisi, S.; Del Pino Molina, A.; Salaris, M.; Aparicio, A.; Asplund,
   M.; Grundahl, F.; Piotto, G.; Weiss, A.; Carrera, R.; Cebrián, M.;
   Murabito, S.; Pietrinferni, A.; Sbordone, L.
2013MmSAI..84...71M    Altcode:
  We present the first results of the SUMO project, aimed at studying
  multiple populations in globular clusters. For this purpose we obtained
  wide-field photometry in a large sample of clusters using both archival
  and proprietary U, B, V, and I data from ground-based telescopes. We
  have defined a new photometric index c_U,B,I=(U-B)-(B-I), that we
  show is very effective to split multiple sequences along the red
  giant branch (RGB). We found a direct connection with the chemical
  properties of different sequences, that display different abundances
  of light elements.

---------------------------------------------------------
Title: The Most Metal-poor Stars. III. The Metallicity Distribution
    Function and Carbon-enhanced Metal-poor Fraction
Authors: Yong, David; Norris, John E.; Bessell, M. S.; Christlieb,
   N.; Asplund, M.; Beers, Timothy C.; Barklem, P. S.; Frebel, Anna;
   Ryan, S. G.
2013ApJ...762...27Y    Altcode: 2012arXiv1208.3016Y
  We examine the metallicity distribution function (MDF) and fraction
  of carbon-enhanced metal-poor (CEMP) stars in a sample that includes
  86 stars with [Fe/H] &lt;= -3.0, based on high-resolution, high
  signal-to-noise spectroscopy, of which some 32 objects lie below [Fe/H]
  = -3.5. After accounting for the completeness function, the "corrected"
  MDF does not exhibit the sudden drop at [Fe/H] = -3.6 that was found in
  recent samples of dwarfs and giants from the Hamburg/ESO survey. Rather,
  the MDF decreases smoothly down to [Fe/H] = -4.1. Similar results are
  obtained from the "raw" MDF. We find that the fraction of CEMP objects
  below [Fe/H] = -3.0 is 23% ± 6% and 32% ± 8% when adopting the Beers
  &amp; Christlieb and Aoki et al. CEMP definitions, respectively. The
  former value is in fair agreement with some previous measurements,
  which adopt the Beers &amp; Christlieb criterion. <P />This paper
  includes data gathered with the 6.5 m Magellan Telescopes located at
  Las Campanas Observatory, Chile. <P />Based on observations collected
  at the European Organisation for Astronomical Research in the Southern
  Hemisphere, Chile (proposal 281.D-5015).

---------------------------------------------------------
Title: Chemical evolution of the Galactic bulge as traced by
    microlensed dwarf and subgiant stars. V. Evidence for a wide age
    distribution and a complex MDF
Authors: Bensby, T.; Yee, J. C.; Feltzing, S.; Johnson, J. A.; Gould,
   A.; Cohen, J. G.; Asplund, M.; Meléndez, J.; Lucatello, S.; Han, C.;
   Thompson, I.; Gal-Yam, A.; Udalski, A.; Bennett, D. P.; Bond, I. A.;
   Kohei, W.; Sumi, T.; Suzuki, D.; Suzuki, K.; Takino, S.; Tristram,
   P.; Yamai, N.; Yonehara, A.
2013A&A...549A.147B    Altcode: 2012arXiv1211.6848B
  Based on high-resolution spectra obtained during gravitational
  microlensing events we present a detailed elemental abundance analysis
  of 32 dwarf and subgiant stars in the Galactic bulge. Combined with
  the sample of 26 stars from the previous papers in this series,
  we now have 58 microlensed bulge dwarfs and subgiants that have been
  homogeneously analysed. The main characteristics of the sample and the
  findings that can be drawn are: (i) the metallicity distribution (MDF)
  is wide and spans all metallicities between [Fe/H] = -1.9 to +0.6;
  (ii) the dip in the MDF around solar metallicity that was apparent in
  our previous analysis of a smaller sample (26 microlensed stars) is no
  longer evident; instead it has a complex structure and indications of
  multiple components are starting to emerge. A tentative interpretation
  is that there could be different stellar populations at interplay,
  each with a different scale height: the thin disk, the thick disk,
  and a bar population; (iii) the stars with [Fe/H] ≲ -0.1 are old
  with ages between 10 and 12 Gyr; (iv) the metal-rich stars with [Fe/H]
  ≳ -0.1 show a wide variety of ages, ranging from 2 to 12 Gyr with a
  distribution that has a dominant peak around 4-5 Gyr and a tail towards
  higher ages; (v) there are indications in the [α/Fe]-[Fe/H] abundance
  trends that the "knee" occurs around [Fe/H] = -0.3to -0.2, which is
  a slightly higher metallicity as compared to the "knee" for the local
  thick disk. This suggests that the chemical enrichment of the metal-poor
  bulge has been somewhat faster than what is observed for the local thick
  disk. The results from the microlensed bulge dwarf stars in combination
  with other findings in the literature, in particular the evidence that
  the bulge has cylindrical rotation, indicate that the Milky Way could be
  an almost pure disk galaxy. The bulge would then just be a conglomerate
  of the other Galactic stellar populations (thin disk, thick disk,
  halo, and ...?), residing together in the central parts of the Galaxy,
  influenced by the Galactic bar. <P />Based on data obtained with the
  European Southern Observatory telescopes (Proposal ID:s 87.B-0600,
  88.B-0349, 89.B-0047, and 90.B-0204), the Magellan Clay telescope at
  the Las Campanas observatory, and the Keck I telescope at the W.M. Keck
  Observatory, which is operated as a scientific partnership among the
  California Institute of Technology, the University of California
  and the National Aeronautics and Space Administration.Tables 2-5
  are available in electronic form at the CDS via anonymous ftp to
  <A href="http://cdsarc.u-strasbg.fr"> cdsarc.u-strasbg.fr</A>
  (<A href="http://130.79.128.5">130.79.128.5</A>) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/549/A147">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/549/A147</A>

---------------------------------------------------------
Title: The Most Metal-poor Stars. IV. The Two Populations with [Fe/H]
    &lt;~ -3.0
Authors: Norris, John E.; Yong, David; Bessell, M. S.; Christlieb, N.;
   Asplund, M.; Gilmore, Gerard; Wyse, Rosemary F. G.; Beers, Timothy C.;
   Barklem, P. S.; Frebel, Anna; Ryan, S. G.
2013ApJ...762...28N    Altcode: 2012arXiv1211.3157N
  We discuss the carbon-normal and carbon-rich populations of Galactic
  halo stars having [Fe/H] lsim -3.0, utilizing chemical abundances from
  high-resolution, high signal-to-noise model-atmosphere analyses. The
  C-rich population represents ~28% of stars below [Fe/H] = -3.1, with the
  present C-rich sample comprising 16 CEMP-no stars, and two others with
  [Fe/H] ~ -5.5 and uncertain classification. The population is O-rich
  ([O/Fe] gsim +1.5); the light elements Na, Mg, and Al are enhanced
  relative to Fe in half the sample; and for Z &gt; 20 (Ca) there is
  little evidence for enhancements relative to solar values. These results
  are best explained in terms of the admixing and processing of material
  from H-burning and He-burning regions as achieved by nucleosynthesis in
  zero-heavy-element models in the literature of "mixing and fallback"
  supernovae (SNe); of rotating, massive, and intermediate-mass stars;
  and of Type II SNe with relativistic jets. The available (limited)
  radial velocities offer little support for the C-rich stars with
  [Fe/H] &lt; -3.1 being binary. More data are required before one
  could conclude that binarity is key to an understanding of this
  population. We suggest that the C-rich and C-normal populations result
  from two different gas cooling channels in the very early universe of
  material that formed the progenitors of the two populations. The first
  was cooling by fine-structure line transitions of C II and O I (to form
  the C-rich population); the second, while not well defined (perhaps
  dust-induced cooling?), led to the C-normal group. In this scenario,
  the C-rich population contains the oldest stars currently observed.

---------------------------------------------------------
Title: The Infrared Colors of the Sun
Authors: Casagrande, L.; Ramírez, I.; Meléndez, J.; Asplund, M.
2012ApJ...761...16C    Altcode: 2012arXiv1209.6127C
  Solar infrared colors provide powerful constraints on the stellar
  effective temperature scale, but they must be measured with both
  accuracy and precision in order to do so. We fulfill this requirement
  by using line-depth ratios to derive in a model-independent way the
  infrared colors of the Sun, and we use the latter to test the zero
  point of the Casagrande et al. effective temperature scale, confirming
  its accuracy. Solar colors in the widely used Two Micron All Sky
  Survey (2MASS) JHK<SUB>s</SUB> and WISE W1-4 systems are provided:
  (V - J)<SUB>⊙</SUB> = 1.198, (V - H)<SUB>⊙</SUB> = 1.484, (V -
  K<SUB>s</SUB> )<SUB>⊙</SUB> = 1.560, (J - H)<SUB>⊙</SUB> = 0.286,
  (J - K<SUB>s</SUB> )<SUB>⊙</SUB> = 0.362, (H - K<SUB>s</SUB>
  )<SUB>⊙</SUB> = 0.076, (V - W1)<SUB>⊙</SUB> = 1.608, (V -
  W2)<SUB>⊙</SUB> = 1.563, (V - W3)<SUB>⊙</SUB> = 1.552, and (V -
  W4)<SUB>⊙</SUB> = 1.604. A cross-check of the effective temperatures
  derived implementing 2MASS or WISE magnitudes in the infrared flux
  method confirms that the absolute calibration of the two systems agrees
  within the errors, possibly suggesting a 1% offset between the two, thus
  validating extant near- and mid-infrared absolute calibrations. While
  2MASS magnitudes are usually well suited to derive \textit {T}_{eff},
  we find that a number of bright, solar-like stars exhibit anomalous WISE
  colors. In most cases, this effect is spurious and can be attributed to
  lower-quality measurements, although for a couple of objects (3% ± 2%
  of the total sample) it might be real, and may hint at the presence
  of warm/hot debris disks.

---------------------------------------------------------
Title: The influence of electron collisions on non-LTE Li line
    formation in stellar atmospheres
Authors: Osorio, Yeisson; Barklem, Paul; Lind, Karin; Asplund, Martin
2012JPhCS.388d2018O    Altcode: 2011arXiv1102.1556O
  The influence of the uncertainties in the rate coefficient data for
  electron-impact excitation and ionization on non-LTE Li line formation
  in cool stellar atmospheres is investigated. We examine the electron
  collision data used in previous non-LTE calculations and compare them
  to our own calculations using the R-matrix with pseudostates (RMPS)
  method and to other calculations found in the literature.

---------------------------------------------------------
Title: Chemical evolution of the Galactic bulge as traced by
    microlensed dwarfs and subgiant stars. V. Evidence for a wide age
    distribution and a complex MDF.
Authors: Bensby, T.; Yee, J. C.; Feltzing, S.; Johnson, J. A.; Gould,
   A.; Cohen, J. G.; Asplund, M.; Melendez, J.; Lucatello, S.; Han, C.;
   Thompson, I.; Gal-Yam, A.; Udalski, A.; Benett, D. P.; Bond, I. A.;
   Kohei, W.; Sumi, T.; Suzuki, D.; Suzuki, K.; Takino, S.; Tristram,
   P.; Yamai, N.; Yonehara, A.
2012yCat..35490147B    Altcode: 2012yCat..35499147B
  For each spectral line we give the lower excitation potential,
  measured equivalent widths, and derived absolute abundances. We also
  give median abundances for each star, normalised to the Sun, and errors
  in the median abundances. These tables contain data for all so far 58
  microlensed dwarf stars, and superseeds the tables in Bensby+ (2009,
  Cat. J/A+A/499/737), Bensby+ (2010, Cat. J/A+A/512/A41), and Bensby+
  (2011, Cat. J/A+A/533/A134). <P />(4 data files).

---------------------------------------------------------
Title: Non-LTE line formation of Fe in late-type stars - II. 1D
    spectroscopic stellar parameters
Authors: Lind, K.; Bergemann, M.; Asplund, M.
2012MNRAS.427...50L    Altcode: 2012arXiv1207.2454L
  We investigate departures from local thermodynamic equilibrium (LTE)
  in the line formation of neutral and singly ionized iron lines and
  their impact on spectroscopic stellar parameters. The calculations were
  performed for an extensive grid of 1D MARCS models of metal-rich and
  metal-poor late-type dwarfs and giants. We find that iron abundances
  derived from Fe I lines are increasingly underestimated in hotter, lower
  surface gravity and more metal-poor stars, in a simple and well-defined
  pattern, while LTE is usually a realistic approximation for Fe II
  lines. For the vast majority of dwarfs and giants, the perturbed
  ionization balance of Fe I and Fe II is the main relevant non-LTE
  effect to consider in the determination of spectroscopic parameters,
  while for extremely metal-poor stars and hot giant stars significant
  impact is seen also on the excitation balance and on the microturbulence
  determination from Fe I lines.

---------------------------------------------------------
Title: Non-LTE line formation of Fe in late-type stars - I. Standard
    stars with 1D and &lt;3D&gt; model atmospheres
Authors: Bergemann, Maria; Lind, K.; Collet, R.; Magic, Z.; Asplund, M.
2012MNRAS.427...27B    Altcode: 2012arXiv1207.2455B
  We investigate departures from local thermodynamic equilibrium
  (LTE) in the line formation of Fe for a number of well-studied
  late-type stars in different evolutionary stages. A new model of
  the Fe atom was constructed from the most up-to-date theoretical
  and experimental atomic data available so far. Non-LTE (NLTE) line
  formation calculations for Fe were performed using 1D hydrostatic MARCS
  and MAFAGS-OS model atmospheres, as well as the spatial and temporal
  average stratifications from full 3D hydrodynamical simulations of
  stellar convection computed using the STAGGER code. It is shown that
  the Fe I/Fe II ionization balance can be well established with the 1D
  and mean 3D models under NLTE including calibrated inelastic collisions
  with H I calculated from Drawin's formulae. Strong low-excitation Fe
  I lines are very sensitive to the atmospheric structure; classical 1D
  models fail to provide consistent excitation balance, particularly
  so for cool metal-poor stars. A better agreement between Fe I lines
  spanning a range of excitation potentials is obtained with the mean
  3D models. Mean NLTE metallicities determined for the standard stars
  using the 1D and mean 3D models are fully consistent. Moreover,
  the NLTE spectroscopic effective temperatures and gravities from
  ionization balance agree with that determined by other methods,
  e.g. the infrared flux method and parallaxes, if one of the stellar
  parameters is constrained independently.

---------------------------------------------------------
Title: Integrating the HERMES spectrograph for the AAT
Authors: Heijmans, Jeroen; Asplund, Martin; Barden, Sam; Birchall,
   Michael; Carollo, Daniela; Bland-Hawthorn, Joss; Brzeski, Jurek; Case,
   Scott; Churilov, Vladimir; Colless, Matthew; Dean, Robert; De Silva,
   Gayandhi; Farrell, Tony; Fiegert, Kristin; Freeman, Kenneth; Gers,
   Luke; Goodwin, Michael; Gray, Doug; Heald, Ron; Heng, Anthony; Jones,
   Damien; Kobayashi, Chiaki; Klauser, Urs; Kondrat, Yuriy; Lawrence,
   Jon; Lee, Steve; Mathews, Darren; Mayfield, Don; Miziarski, Stan;
   Monnet, Guy J.; Muller, Rolf; Pai, Naveen; Patterson, Robert; Penny,
   Ed; Orr, David; Sheinis, Andrew; Shortridge, Keith; Smedley, Scott;
   Smith, Greg; Stafford, Darren; Staszak, Nicholas; Vuong, Minh; Waller,
   Lewis; Whittard, Denis; Wylie de Boer, Elisabeth; Xavier, Pascal;
   Zheng, Jessica; Zhelem, Ross; Zucker, Daniel
2012SPIE.8446E..0WH    Altcode:
  The High Efficiency and Resolution Multi Element Spectrograph,
  HERMES is an optical spectrograph designed primarily for the GALAH,
  Galactic Archeology Survey, the first major attempt to create a
  detailed understanding of galaxy formation and evolution by studying
  the history of our own galaxy, the Milky Way<SUP>1</SUP>. The goal of
  the GALAH survey is to reconstruct the mass assembly history of the of
  the Milky way, through a detailed spatially tagged abundance study of
  one million stars in the Milky Way. The spectrograph will be based at
  the Anglo Australian Telescope (AAT) and be fed with the existing 2dF
  robotic fibre positioning system. The spectrograph uses VPH-gratings
  to achieve a spectral resolving power of 28,000 in standard mode and
  also provides a high resolution mode ranging between 40,000 to 50,000
  using a slit mask. The GALAH survey requires a SNR greater than 100
  aiming for a star brightness of V=14. The total spectral coverage
  of the four channels is about 100nm between 370 and 1000nm for up to
  392 simultaneous targets within the 2 degree field of view. Current
  efforts are focused on manufacturing and integration. The delivery date
  of spectrograph at the telescope is scheduled for 2013. A performance
  prediction is presented and a complete overview of the status of the
  HERMES spectrograph is given. This paper details the following specific
  topics: The approach to AIT, the manufacturing and integration of the
  large mechanical frame, the opto-mechanical slit assembly, collimator
  optics and cameras, VPH gratings, cryostats, fibre cable assembly,
  instrument control hardware and software, data reduction.

---------------------------------------------------------
Title: The New Solar Chemical Composition — from Z = 0.02 to Z
    = 0.013
Authors: Grevesse, N.; Asplund, M.; Sauval, A. J.; Scott, P.
2012ASPC..462...41G    Altcode:
  We review the current status of our knowledge of the chemical
  composition of the sun and present a redetermination of the solar
  abundances of all available elements. These new results have recently
  been published by Asplund et al. (2009). The basic ingredients of
  this work, the main results and their implications are discussed. We
  show why the abundances of the main contributors to the metallicity
  have decreased and why the old high solar metallicity, Z ∼ 0.02,
  is definitely obsolete and should not be used anymore. We also show
  why other recent analyzes of the solar composition report solar
  metallicities somewhat larger than the one we recommend.

---------------------------------------------------------
Title: The Origin of the Split Red Clump in the Galactic Bulge of
    the Milky Way
Authors: Ness, M.; Freeman, K.; Athanassoula, E.; Wylie-De-Boer, E.;
   Bland-Hawthorn, J.; Lewis, G. F.; Yong, D.; Asplund, M.; Lane, R. R.;
   Kiss, L. L.; Ibata, R.
2012ApJ...756...22N    Altcode: 2012arXiv1207.0888N
  Near the minor axis of the Galactic bulge, at latitudes b &lt; -5°,
  the red giant clump stars are split into two components along the line
  of sight. We investigate this split using the three fields from the
  ARGOS survey that lie on the minor axis at (l, b) = (0°, -5°), (0°,
  -7fdg5), (0°, -10°). The separation is evident for stars with [Fe/H]
  &gt; - 0.5 in the two higher-latitude fields, but not in the field
  at b = -5°. Stars with [Fe/H] &lt; - 0.5 do not show the split. We
  compare the spatial distribution and kinematics of the clump stars with
  predictions from an evolutionary N-body model of a bulge that grew from
  a disk via bar-related instabilities. The density distribution of the
  peanut-shaped model is depressed near its minor axis. This produces
  a bimodal distribution of stars along the line of sight through the
  bulge near its minor axis, very much as seen in our observations. The
  observed and modeled kinematics of the two groups of stars are also
  similar. We conclude that the split red clump of the bulge is probably
  a generic feature of boxy/peanut bulges that grew from disks, and that
  the disk from which the bulge grew had relatively few stars with [Fe/H]
  &lt; - 0.5.

---------------------------------------------------------
Title: Chemically Tagging Disk Fossils: the Case of the Hyades
    Supercluster
Authors: De Silva, G. M.; Freeman, K. C.; Bland-Hawthorn, J.;
   Asplund, M.
2012ASPC..458..215D    Altcode:
  The Hyades supercluster is a kinematically defined group of stars,
  which are located across the Galactic disk. Advocated by Eggen in the
  1970's as part of the Hyades open cluster, recent simulations suggest
  the Hyades supercluster is a dynamical stream caused by spiral density
  waves. We present high resolution elemental abundances of probable
  supercluster members. We recover supercluster stars that share a
  similar chemical signature as the Hyades open cluster. Our results
  support the Hyades supercluster being at least partly the debris of
  an originally large star-forming event.

---------------------------------------------------------
Title: Signatures of an Intermediate-Age Metal-Rich Bulge Population
Authors: Bensby, T.; Feltzing, S.; Gould, A.; Johnson, J. A.; Asplund,
   M.; Adén, D.; Meléndez, J.; Cohen, J. G.; Thompson, I.; Lucatello,
   S.; Gal-Yam, A.
2012ASPC..458..203B    Altcode: 2012arXiv1201.2013B
  We have determined detailed elemental abundances and stellar ages
  for a sample of now 38 microlensed dwarf and subgiant stars in the
  Galactic bulge. Stars with sub-solar metallicities are all old and
  have enhanced α-element abundances - very similar to what is seen
  for local thick disk stars. The metal-rich stars on the other hand
  show a wide variety of stellar ages, ranging from 3-4 Gyr to 12 Gyr,
  and an average around 7-8 Gyr. The existence of young and metal-rich
  stars are in conflict with recent photometric studies of the bulge
  which claim that the bulge only contains old stars.

---------------------------------------------------------
Title: 3D and NLTE Effects on Spectroscopic Parameters of Late-Type
    Stars
Authors: Lind, K.; Bergemann, M.; Collet, R.; Asplund, M.; Magic, Z.
2012ASPC..458..109L    Altcode:
  We investigate the impact on spectroscopic effective temperatures
  (T<SUB>eff</SUB>), surface gravities (log (g)), and metallicites
  ([Fe/H]) of metal-poor stars, when departures from LTE are taken into
  account and the atmospheric model is constructed from realistic 3D,
  hydrodynamical simulations. We demonstrate that traditional 1D, LTE
  analysis underestimates the values for all three parameters in the
  metal-poor subgiant HD140283.

---------------------------------------------------------
Title: The Oxygen Abundance of the Ultra-metal-poor Star HE 0557-4840
Authors: Norris, John E.; Christlieb, N.; Bessell, M. S.; Asplund,
   M.; Eriksson, K.; Korn, A. J.
2012ApJ...753..150N    Altcode:
  We present a high-resolution ultraviolet (UV) spectrum of the
  ultra-metal-poor (UMP) carbon-enhanced red giant HE 0557-4840 (T
  <SUB> eff</SUB>/log g/[Fe/H] = 4900/2.2/-4.8). Combining these data
  with earlier observations, the radial velocity is 212.0 ± 0.4 km
  s<SUP>-1</SUP>, with no evidence of variability during 2006 February
  to 2007 December. One-dimensional (1D) LTE model-atmosphere analysis
  of UV Fe and CH lines confirms the iron and carbon abundances obtained
  previously ([Fe/H] = -4.8 and [C/Fe]<SUB>1D</SUB> = +1.7), and places
  a more stringent limit on nitrogen abundance of [N/Fe]<SUB>1D</SUB>
  &lt; +1.0. Analysis of the UV OH lines yields [O/Fe]<SUB>1D</SUB>
  = +2.3 ± 0.4. When corrections are made for three-dimensional (3D)
  effects we obtain [C/Fe]<SUB>3D</SUB> = +1.1, [N/Fe]<SUB>3D</SUB> &lt;
  +0.1, and [O/Fe]<SUB>3D</SUB> = +1.4. Comparison of the abundances
  of HE 0557-4840 with those of supernova models of Nomoto et al. and
  Joggerst et al. suggests that none is able to explain fully the observed
  abundance pattern. For HE 0557-4840, the Frebel et al. transition
  discriminant D <SUB>trans</SUB>(= log(10<SUP>[C/H]</SUP> + 0.3 ×
  10<SUP>[O/H]</SUP>) = -3.4 ± 0.2, consistent with fine-structure
  transitions of C II and O I being a major cooling mechanism of
  star-forming regions at the earliest times. Of the four stars known
  to have [Fe/H] &lt;~ -4.3, three are strongly carbon and oxygen
  enhanced. If the suggestion by Caffau et al. that SDSS J102915+172927
  ([Fe/H] = -4.7) does not belong to the class of C-rich, O-rich, UMP
  stars is supported by future similar discoveries, one will need to
  consider multiple channels for the production of stars having [Fe/H]
  &lt;~ -4.3. <P />Based on observations collected at European Southern
  Observatory, Paranal, Chile (proposal 380.D-0040).

---------------------------------------------------------
Title: The remarkable solar twin HIP 56948: a prime target in the
    quest for other Earths
Authors: Meléndez, J.; Bergemann, M.; Cohen, J. G.; Endl, M.;
   Karakas, A. I.; Ramírez, I.; Cochran, W. D.; Yong, D.; MacQueen,
   P. J.; Kobayashi, C.; Asplund, M.
2012A&A...543A..29M    Altcode: 2012arXiv1204.2766M
  Context. The Sun shows abundance anomalies relative to most solar
  twins. If the abundance peculiarities are due to the formation of inner
  rocky planets, that would mean that only a small fraction of solar
  type stars may host terrestrial planets. <BR /> Aims: In this work we
  study HIP 56948, the best solar twin known to date, to determine with
  an unparalleled precision how similar it is to the Sun in its physical
  properties, chemical composition and planet architecture. We explore
  whether the abundances anomalies may be due to pollution from stellar
  ejecta or to terrestrial planet formation. <BR /> Methods: We perform
  a differential abundance analysis (both in LTE and NLTE) using high
  resolution (R ~ 100 000) high S/N (600-650) Keck HIRES spectra of the
  Sun (as reflected from the asteroid Ceres) and HIP 56948. We use precise
  radial velocity data from the McDonald and Keck observatories to search
  for planets around this star. <BR /> Results: We achieve a precision
  of σ ≲ 0.003 dex for several elements. Including errors in stellar
  parameters the total uncertainty is as low as σ ≃ 0.005 dex (1%),
  which is unprecedented in elemental abundance studies. The similarities
  between HIP 56948 and the Sun are astonishing. HIP 56948 is only 17
  ± 7 K hotter than the Sun, and log g, [Fe/H] and microturbulence
  velocity are only + 0.02 ± 0.02 dex, +0.02 ± 0.01 dex and +0.01 ±
  0.01 km s<SUP>-1</SUP> higher than solar, respectively. Our precise
  stellar parameters and a differential isochrone analysis shows that
  HIP 56948 has a mass of 1.02 ± 0.02 M<SUB>⊙</SUB> and that it is ~1
  Gyr younger than the Sun, as constrained by isochrones, chromospheric
  activity, Li and rotation. Both stars show a chemical abundance
  pattern that differs from most solar twins, but the refractory elements
  (those with condensation temperature T<SUB>cond</SUB> ≳ 1000 K) are
  slightly (~0.01 dex) more depleted in the Sun than in HIP 56948. The
  trend with T<SUB>cond</SUB> in differential abundances (twins - HIP
  56948) can be reproduced very well by adding ~3 M<SUB>⊕</SUB> of a
  mix of Earth and meteoritic material, to the convection zone of HIP
  56948. The element-to-element scatter of the Earth/meteoritic mix for
  the case of hypothetical rocky planets around HIP 56948 is only 0.0047
  dex. From our radial velocity monitoring we find no indications of giant
  planets interior to or within the habitable zone of HIP 56948. <BR />
  Conclusions: We conclude that HIP 56948 is an excellent candidate to
  host a planetary system like our own, including the possible presence
  of inner terrestrial planets. Its striking similarity to the Sun and
  its mature age makes HIP 56948 a prime target in the quest for other
  Earths and SETI endeavors. <P />Based on observations obtained at the
  W.M. Keck Observatory, which is operated jointly by the California
  Institute of Technology, the University of California and the National
  Aeronautics and Space Administration (NASA). This paper also includes
  data taken at the McDonald Observatory of the University of Texas at
  Austin and with the European Southern Observatory (ESO) Very Large
  Telescope (VLT) at Paranal Observatory, Chile (observing program
  083.D-0871).Tables 1-6 and Appendices are available in electronic form
  at <A href="http://www.aanda.org">http://www.aanda.org</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: Abundances of M22 subgiants
    (Marino+, 2012)
Authors: Marino, A. F.; Milone, A. P.; Sneden, C.; Bergemann, M.;
   Kraft, R. P.; Wallerstein, G.; Cassisi, S.; Aparicio, A.; Asplund, M.;
   Bedin, R. L.; Hilker, M.; Lind, K.; Momany, Y.; Piotto, G.; Roederer,
   I. U.; Stetson, P. B.; Zoccali, M.
2012yCat..35410015M    Altcode: 2012yCat..35419015M
  Ground-based observations were used to analyze the CMD over a wide
  spatial field in the B and V bands and to estimate the atmospheric
  parameters of the spectroscopic targets. In addition, we used
  ground-based U images available for a smaller field, and images taken
  with the Advanced Camera for Surveys onboard the HST (ACS/HST) in
  the F606W and F814W bands to make our study of the double SGB extend
  from the ultraviolet to the infrared spectral regions. The HST ACS/WFC
  images were obtained under program GO-10775 (PI Sarajedini). <P />(2
  data files).

---------------------------------------------------------
Title: The double sub-giant branch of NGC 6656 (M 22): a chemical
    characterization
Authors: Marino, A. F.; Milone, A. P.; Sneden, C.; Bergemann, M.;
   Kraft, R. P.; Wallerstein, G.; Cassisi, S.; Aparicio, A.; Asplund, M.;
   Bedin, R. L.; Hilker, M.; Lind, K.; Momany, Y.; Piotto, G.; Roederer,
   I. U.; Stetson, P. B.; Zoccali, M.
2012A&A...541A..15M    Altcode: 2012arXiv1202.2825M
  We present an abundance analysis of 101 subgiant branch (SGB) stars
  in the globular cluster M 22. Using low-resolution FLAMES/GIRAFFE
  spectra we have determined abundances of the neutron-capture strontium
  and barium and the light element carbon. With these data we explore
  relationships between the observed SGB photometric split in this cluster
  and two stellar groups characterized by different contents of iron,
  slow neutron-capture process (s-process) elements, and the α element
  calcium, which we previously discovered in M 22's red-giant stars. We
  show that the SGB stars correlate in chemical composition and the
  color-magnitude diagram position. The stars with higher metallicity
  and relative s-process abundances define a fainter SGB, while stars
  with lower metallicity and s-process content reside on a relatively
  brighter SGB. This result has implications for the relative ages of
  the two stellar groups of M 22. In particular, it is inconsistent
  with a broad spread in ages of the two SGBs. By accounting for the
  chemical content of the two stellar groups, isochrone fitting of
  the double SGB suggests that their agesare not different by more
  than ~300 Myr. <P />Based on data collected at the European Southern
  Observatory with the FLAMES/GIRAFFE spectrograph under the program
  085.D-0698A.Tables 2 and 3 are available in electronic form at <A
  href="http://www.aanda.org">http://www.aanda.org</A>

---------------------------------------------------------
Title: Commission 29: Stellar Spectra
Authors: Piskunov, Nikolai; Cunha, Katia; Parthasarathy, Mudumba; Aoki,
   Wako; Asplund, Martin; Bohlender, David; Carpenter, Kenneth; Melendez,
   Jorge; Rossi, Silvia; Smith, Verne; Soderblom, David; Wahlgren, Glenn
2012IAUTA..28..157P    Altcode:
  Commission 29 consists of members of the International Astronomical
  Union carrying out theoretical and observational studies of stars
  using spectroscopy, developing instrumentation for spectroscopy and
  producing and collecting data for interpretation of spectra.

---------------------------------------------------------
Title: Division Iv: Stars
Authors: Corbally, Christopher; D'Antona, Francesca; Spite, Monique;
   Asplund, Martin; Charbonnel, Corinne; Docobo, Jose Angel; Gray,
   Richard O.; Piskunov, Nikolai E.
2012IAUTA..28..147C    Altcode:
  This Division IV was started on a trial basis at the General Assembly
  in The Hague 1994 and was formally accepted at the Kyoto General
  Assembly in 1997. Its broad coverage of “Stars” is reflected in
  its relatively large number of Commissions and so of members (1266 in
  late 2011). Its kindred Division V, “Variable Stars”, has the same
  history of its beginning. The thinking at the time was to achieve
  some kind of balance between the number of members in each of the 12
  Divisions. Amid the current discussion of reorganizing the number of
  Divisions into a more compact form it seems advisable to make this
  numerical balance less of an issue than the rationalization of the
  scientific coverage of each Division, so providing more effective
  interaction within a particular field of astronomy. After all, every
  star is variable to a certain degree and such variability is becoming
  an ever more powerful tool to understand the characteristics of every
  kind of normal and peculiar star. So we may expect, after hearing the
  reactions of members, that in the restructuring a single Division will
  result from the current Divisions IV and V.

---------------------------------------------------------
Title: Three-dimensional interferometric, spectrometric, and planetary
    views of Procyon
Authors: Chiavassa, A.; Bigot, L.; Kervella, P.; Matter, A.; Lopez,
   B.; Collet, R.; Magic, Z.; Asplund, M.
2012A&A...540A...5C    Altcode: 2012arXiv1201.3264C
  Context. Procyon is one of the brightest stars in the sky and one
  of our nearest neighbours. It is therefore an ideal benchmark
  object for stellar astrophysics studies using interferometric,
  spectroscopic, and asteroseismic techniques. <BR /> Aims: We use a
  new realistic three-dimensional (3D) radiative-hydrodynamical (RHD)
  model atmosphere of Procyon generated with the Stagger Code and
  synthetic spectra computed with the radiative transfer code Optim3D
  to re-analyze interferometric and spectroscopic data from the optical
  to the infrared. We provide synthetic interferometric observables
  that can be validated using observations. <BR /> Methods: We computed
  intensity maps from a RHD simulation in two optical filters centered
  on 500 and 800 nm (Mark III) and one infrared filter centered on 2.2
  μm (Vinci). We constructed stellar disk images accounting for the
  center-to-limb variations and used them to derive visibility amplitudes
  and closure phases. We also computed the spatially and temporally
  averaged synthetic spectrum from the ultraviolet to the infrared. We
  compare these observables to Procyon data. <BR /> Results: We study the
  impact of the granulation pattern on center-to-limb intensity profiles
  and provide limb-darkening coefficients in the optical as well as in the
  infrared. We show how the convection-related surface structures affect
  the visibility curves and closure phases with clear deviations from
  circular symmetry, from the 3rd lobe on. These deviations are detectable
  with current interferometers using closure phases. We derive new angular
  diameters at different wavelengths with two independent methods based
  on 3D simulations. We find that θ<SUB>Vinci</SUB> = 5.390 ± 0.03
  mas, which we confirm by comparison with an independent asteroseismic
  estimation (θ<SUB>seismic</SUB> = 5.360 ± 0.07 mas. The resulting
  T<SUB>eff</SUB> is 6591 K (or 6556 K depending on the bolometric
  flux used), which is consistent with the value of T<SUB>eff,IR</SUB>
  = 6621 K found with the infrared flux method. We measure a surface
  gravity log g = 4.01 ± 0.03 [cm/s<SUP>2</SUP>] that is higher by
  0.05 dex than literature values. Spectrophotometric comparisons with
  observations provide very good agreement with the spectral energy
  distribution and photometric colors, allowing us to conclude that the
  thermal gradient in the simulation matches Procyon fairly well. Finally,
  we show that the granulation pattern of a planet-hosting Procyon-like
  star has a non-negligible impact on the detection of hot Jupiters in
  the infrared using interferometry closure phases. It is then crucial
  to have a comprehensive knowledge of the host star to directly detect
  and characterize hot Jupiters. In this respect, RHD simulations are
  very important to achieving this aim.

---------------------------------------------------------
Title: Commission 12: Solar Radiation and Structure
Authors: Kosovichev, Alexander; Cauzzi, Gianna; Pillet, Valentin
   Martinez; Asplund, Martin; Brandenburg, Axel; Chou, Dean-Yi;
   Christensen-Dalsgaard, Jorgen; Gan, Weiqun; Kuznetsov, Vladimir D.;
   Rovira, Marta G.; Shchukina, Nataliya; Venkatakrishnan, P.
2012IAUTA..28...81K    Altcode: 2012IAUTB..28...81K
  Commission 12 of the International Astronomical Union encompasses
  investigations of the internal structure and dynamics of the Sun, mostly
  accessible through the techniques of local and global helioseismology,
  the quiet solar atmosphere, solar radiation and its variability, and
  the nature of relatively stable magnetic structures like sunspots,
  faculae and the magnetic network. The Commission sees participation
  of over 350 scientists worldwide.

---------------------------------------------------------
Title: The Gaia-ESO Public Spectroscopic Survey
Authors: Gilmore, G.; Randich, S.; Asplund, M.; Binney, J.; Bonifacio,
   P.; Drew, J.; Feltzing, S.; Ferguson, A.; Jeffries, R.; Micela, G.;
   Negueruela, I.; Prusti, T.; Rix, H. -W.; Vallenari, A.; Alfaro, E.;
   Allende-Prieto, C.; Babusiaux, C.; Bensby, T.; Blomme, R.; Bragaglia,
   A.; Flaccomio, E.; François, P.; Irwin, M.; Koposov, S.; Korn, A.;
   Lanzafame, A.; Pancino, E.; Paunzen, E.; Recio-Blanco, A.; Sacco,
   G.; Smiljanic, R.; Van Eck, S.; Walton, N.; Aden, D.; Aerts, C.;
   Affer, L.; Alcala, J. -M.; Altavilla, G.; Alves, J.; Antoja, T.;
   Arenou, F.; Argiroffi, C.; Asensio Ramos, A.; Bailer-Jones, C.;
   Balaguer-Nunez, L.; Bayo, A.; Barbuy, B.; Barisevicius, G.; Barrado
   y Navascues, D.; Battistini, C.; Bellas Velidis, I.; Bellazzini, M.;
   Belokurov, V.; Bergemann, M.; Bertelli, G.; Biazzo, K.; Bienayme, O.;
   Bland-Hawthorn, J.; Boeche, C.; Bonito, S.; Boudreault, S.; Bouvier,
   J.; Brandao, I.; Brown, A.; de Bruijne, J.; Burleigh, M.; Caballero,
   J.; Caffau, E.; Calura, F.; Capuzzo-Dolcetta, R.; Caramazza, M.;
   Carraro, G.; Casagrande, L.; Casewell, S.; Chapman, S.; Chiappini,
   C.; Chorniy, Y.; Christlieb, N.; Cignoni, M.; Cocozza, G.; Colless,
   M.; Collet, R.; Collins, M.; Correnti, M.; Covino, E.; Crnojevic,
   D.; Cropper, M.; Cunha, M.; Damiani, F.; David, M.; Delgado, A.;
   Duffau, S.; Edvardsson, B.; Eldridge, J.; Enke, H.; Eriksson, K.;
   Evans, N. W.; Eyer, L.; Famaey, B.; Fellhauer, M.; Ferreras, I.;
   Figueras, F.; Fiorentino, G.; Flynn, C.; Folha, D.; Franciosini,
   E.; Frasca, A.; Freeman, K.; Fremat, Y.; Friel, E.; Gaensicke, B.;
   Gameiro, J.; Garzon, F.; Geier, S.; Geisler, D.; Gerhard, O.; Gibson,
   B.; Gomboc, A.; Gomez, A.; Gonzalez-Fernandez, C.; Gonzalez Hernandez,
   J.; Gosset, E.; Grebel, E.; Greimel, R.; Groenewegen, M.; Grundahl,
   F.; Guarcello, M.; Gustafsson, B.; Hadrava, P.; Hatzidimitriou, D.;
   Hambly, N.; Hammersley, P.; Hansen, C.; Haywood, M.; Heber, U.; Heiter,
   U.; Held, E.; Helmi, A.; Hensler, G.; Herrero, A.; Hill, V.; Hodgkin,
   S.; Huelamo, N.; Huxor, A.; Ibata, R.; Jackson, R.; de Jong, R.;
   Jonker, P.; Jordan, S.; Jordi, C.; Jorissen, A.; Katz, D.; Kawata,
   D.; Keller, S.; Kharchenko, N.; Klement, R.; Klutsch, A.; Knude,
   J.; Koch, A.; Kochukhov, O.; Kontizas, M.; Koubsky, P.; Lallement,
   R.; de Laverny, P.; van Leeuwen, F.; Lemasle, B.; Lewis, G.; Lind,
   K.; Lindstrom, H. P. E.; Lobel, A.; Lopez Santiago, J.; Lucas, P.;
   Ludwig, H.; Lueftinger, T.; Magrini, L.; Maiz Apellaniz, J.; Maldonado,
   J.; Marconi, G.; Marino, A.; Martayan, C.; Martinez-Valpuesta, I.;
   Matijevic, G.; McMahon, R.; Messina, S.; Meyer, M.; Miglio, A.;
   Mikolaitis, S.; Minchev, I.; Minniti, D.; Moitinho, A.; Momany, Y.;
   Monaco, L.; Montalto, M.; Monteiro, M. J.; Monier, R.; Montes, D.;
   Mora, A.; Moraux, E.; Morel, T.; Mowlavi, N.; Mucciarelli, A.; Munari,
   U.; Napiwotzki, R.; Nardetto, N.; Naylor, T.; Naze, Y.; Nelemans, G.;
   Okamoto, S.; Ortolani, S.; Pace, G.; Palla, F.; Palous, J.; Parker, R.;
   Penarrubia, J.; Pillitteri, I.; Piotto, G.; Posbic, H.; Prisinzano,
   L.; Puzeras, E.; Quirrenbach, A.; Ragaini, S.; Read, J.; Read, M.;
   Reyle, C.; De Ridder, J.; Robichon, N.; Robin, A.; Roeser, S.; Romano,
   D.; Royer, F.; Ruchti, G.; Ruzicka, A.; Ryan, S.; Ryde, N.; Santos,
   N.; Sanz Forcada, J.; Sarro Baro, L. M.; Sbordone, L.; Schilbach, E.;
   Schmeja, S.; Schnurr, O.; Schoenrich, R.; Scholz, R. -D.; Seabroke, G.;
   Sharma, S.; De Silva, G.; Smith, M.; Solano, E.; Sordo, R.; Soubiran,
   C.; Sousa, S.; Spagna, A.; Steffen, M.; Steinmetz, M.; Stelzer, B.;
   Stempels, E.; Tabernero, H.; Tautvaisiene, G.; Thevenin, F.; Torra,
   J.; Tosi, M.; Tolstoy, E.; Turon, C.; Walker, M.; Wambsganss, J.;
   Worley, C.; Venn, K.; Vink, J.; Wyse, R.; Zaggia, S.; Zeilinger, W.;
   Zoccali, M.; Zorec, J.; Zucker, D.; Zwitter, T.; Gaia-ESO Survey Team
2012Msngr.147...25G    Altcode:
  The Gaia-ESO Public Spectroscopic Survey has begun and will obtain high
  quality spectroscopy of some 100000 Milky Way stars, in the field and
  in open clusters, down to magnitude 19, systematically covering all the
  major components of the Milky Way. This survey will provide the first
  homogeneous overview of the distributions of kinematics and chemical
  element abundances in the Galaxy. The motivation, organisation and
  implementation of the Gaia-ESO Survey are described, emphasising the
  complementarity with the ESA Gaia mission. Spectra from the very first
  observing run of the survey are presented.

---------------------------------------------------------
Title: Limb darkening laws for two exoplanet host stars derived
    from 3D stellar model atmospheres. Comparison with 1D models and
    HST light curve observations
Authors: Hayek, W.; Sing, D.; Pont, F.; Asplund, M.
2012A&A...539A.102H    Altcode: 2012arXiv1202.0548H
  We compare limb darkening laws derived from 3D hydrodynamical model
  atmospheres and 1D hydrostatic MARCS models for the host stars of
  two well-studied transiting exoplanet systems, the late-type dwarfs
  <ASTROBJ>HD 209458</ASTROBJ> and <ASTROBJ>HD 189733</ASTROBJ>. The
  surface brightness distribution of the stellar disks is calculated
  for a wide spectral range using 3D LTE spectrum formation and opacity
  sampling<SUP>⋆</SUP>. We test our theoretical predictions using
  least-squares fits of model light curves to wavelength-integrated
  primary eclipses that were observed with the Hubble Space Telescope
  (HST). The limb darkening law derived from the 3D model of HD 209458 in
  the spectral region between 2900 Å and 5700 Å produces significantly
  better fits to the HST data, removing systematic residuals that were
  previously observed for model light curves based on 1D limb darkening
  predictions. This difference arises mainly from the shallower mean
  temperature structure of the 3D model, which is a consequence of the
  explicit simulation of stellar surface granulation where 1D models
  need to rely on simplified recipes. In the case of HD 189733, the
  model atmospheres produce practically equivalent limb darkening curves
  between 2900 Å and 5700 Å, partly due to obstruction by spectral
  lines, and the data are not sufficient to distinguish between the
  light curves. We also analyze HST observations between 5350 Å and
  10 500 Å for this star; the 3D model leads to a better fit compared
  to 1D limb darkening predictions. The significant improvement of fit
  quality for the HD 209458 system demonstrates the higher degree of
  realism of 3D hydrodynamical models and the importance of surface
  granulation for the formation of the atmospheric radiation field of
  late-type stars. This result agrees well with recent investigations of
  limb darkening in the solar continuum and other observational tests of
  the 3D models. The case of HD 189733 is no contradiction as the model
  light curves are less sensitive to the temperature stratification
  of the stellar atmosphere and the observed data in the 2900-5700
  Å region are not sufficient to distinguish more clearly between
  the 3D and 1D limb darkening predictions. <P />Full theoretical
  spectra for both stars are available in electronic form at the
  CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/539/A102">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/539/A102</A>,
  as well as at <A
  href="http://www.astro.ex.ac.uk/people/sing">www.astro.ex.ac.uk/people/sing</A>.

---------------------------------------------------------
Title: Simulations of the solar near-surface layers with the CO5BOLD,
    MURaM, and Stagger codes
Authors: Beeck, B.; Collet, R.; Steffen, M.; Asplund, M.; Cameron,
   R. H.; Freytag, B.; Hayek, W.; Ludwig, H. -G.; Schüssler, M.
2012A&A...539A.121B    Altcode: 2012arXiv1201.1103B
  Context. Radiative hydrodynamic simulations of solar and stellar surface
  convection have become an important tool for exploring the structure and
  gas dynamics in the envelopes and atmospheres of late-type stars and for
  improving our understanding of the formation of stellar spectra. <BR
  /> Aims: We quantitatively compare results from three-dimensional,
  radiative hydrodynamic simulations of convection near the solar surface
  generated with three numerical codes (CO<SUP>5</SUP>BOLD, MURaM,
  and Stagger) and different simulation setups in order to investigate
  the level of similarity and to cross-validate the simulations. <BR
  /> Methods: For all three simulations, we considered the average
  stratifications of various quantities (temperature, pressure, flow
  velocity, etc.) on surfaces of constant geometrical or optical depth,
  as well as their temporal and spatial fluctuations. We also compared
  observables, such as the spatially resolved patterns of the emerging
  intensity and of the vertical velocity at the solar optical surface
  as well as the center-to-limb variation of the continuum intensity
  at various wavelengths. <BR /> Results: The depth profiles of the
  thermodynamical quantities and of the convective velocities as well as
  their spatial fluctuations agree quite well. Slight deviations can be
  understood in terms of differences in box size, spatial resolution
  and in the treatment of non-gray radiative transfer between the
  simulations. <BR /> Conclusions: The results give confidence in the
  reliability of the results from comprehensive radiative hydrodynamic
  simulations.

---------------------------------------------------------
Title: VizieR Online Data Catalog: HD 209458 and HD 189733 theoretical
    spectra (Hayek+, 2012)
Authors: Hayek, W.; Sing, D.; Pont, F.; Asplund, M.
2012yCat..35390102H    Altcode: 2012yCat..35399102H
  Theoretical spectrum computations for the G-type dwarf HD 209458 and
  the K-type dwarf HD 189733 are presented, based on 3D hydrodynamical
  models of the stellar atmospheres. Surface intensities were computed
  in LTE using the SCATE spectrum formation code and cover the wavelength
  region between about 910 Angstroem and 20 micron with constant sampling
  of R=λ/δ_λ=20,000. The stellar disk was sampled at the disk center
  (μ=cos(θ)=1.0) and at angles μ = 0.90, 0.80, 0.70, 0.60, 0.50,
  0.40, 0.30, 0.25, 0.20, 0.15, 0.125, 0.1, 0.075, 0.05, 0.025, 0.01
  towards the limb. Use integration weights 0.05, 0.1, 0.1, 0.1, 0.1,
  0.1, 0.1, 0.075, 0.05, 0.05, 0.0375, 0.025, 0.025, 0.025, 0.025, 0.02,
  0.0125 to obtain fluxes. <P />(2 data files).

---------------------------------------------------------
Title: The detection and treatment of distance errors in kinematic
    analyses of stars
Authors: Schönrich, Ralph; Binney, James; Asplund, Martin
2012MNRAS.420.1281S    Altcode: 2011MNRAS.tmp.2130S; 2011arXiv1111.0204S
  We present a new method for detecting and correcting systematic errors
  in the distances to stars when both proper motions and line-of-sight
  velocities are available. The method, which is applicable for samples
  of 200 or more stars that have a significant extension on the sky,
  exploits correlations between the measured U, V and W velocity
  components that are introduced by distance errors. We deliver a
  formalism to describe and interpret the specific imprints of distance
  errors including spurious velocity correlations and shifts of mean
  motion in a sample. We take into account correlations introduced by
  measurement errors, Galactic rotation and changes in the orientation
  of the velocity ellipsoid with position in the Galaxy. Tests on
  pseudo-data show that the method is more robust and sensitive than
  traditional approaches to this problem. We investigate approaches
  to characterizing the probability distribution of distance errors,
  in addition to the mean distance error, which is the main theme of the
  paper. Stars with the most overestimated distances bias our estimate of
  the overall distance scale, leading to the corrected distances being
  slightly too small. We give a formula that can be used to correct for
  this effect. We apply the method to samples of stars from the Sloan
  Extension for Galactic Understanding and Exploration (SEGUE) survey,
  exploring optimal gravity cuts, sample contamination, and correcting
  the used distance relations.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Elemental abundances in Hyades
    supercluster (De Silva+, 2011)
Authors: de Silva, G. M.; Freeman, K. C.; Bland-Hawthorn, J.; Asplund,
   M.; Williams, M.; Holmberg, J.
2012yCat..74150563D    Altcode:
  High-resolution and high signal-to-noise ratio spectra of probable
  members of the Hyades supercluster were observed using the VLT UV-Visual
  Echelle Spectrograph (UVES) at UT2 in the framework of programmes
  080.D-0094(A) and 381.B-0045(A). A total of 45 probable member stars
  were submitted for service mode observations, using the UVES Red arm
  standard setting at 520 nm which provides complete spectral coverage
  from 4200 to 6200Å, and employed a 0.8-arcsec slit to achieve a
  spectral resolving power of 60000. <P />(3 data files).

---------------------------------------------------------
Title: The chemical evolution of the Galactic Bulge seen through
    micro-lensing events
Authors: Feltzing, S.; Bensby, T.; Meléndez, J.; Adén, D.; Asplund,
   M.; Gould, A.; Johnson, J.; Lucatello, S.; Gal-Yam, A.
2012EPJWC..1906002F    Altcode: 2011arXiv1110.4465F
  Galactic bulges are central to understanding galaxy formation and
  evolution. Here we report on recent studies using micro-lensing events
  to obtain spectra of high resolution and moderately high signal-to-noise
  ratios of dwarf stars in the Galactic bulge. Normally this is not
  feasible for the faint turn-off stars in the Galactic bulge, but
  micro-lensing offers this possibility. Elemental abundance trends
  in the Galactic bulge as traced by dwarf stars are very similar to
  those seen for dwarf stars in the solar neighbourhood. We discuss the
  implications of the ages and metallicity distribution function derived
  for the micro-lensed dwarf stars in the Galactic bulge.

---------------------------------------------------------
Title: Spectral diagnostics of late-type stars: Non-LTE and &lt;3D&gt;
    approach
Authors: Bergemann, M.; Lind, K.; Collet, R.; Asplund, M.; Magic, Z.
2012EPJWC..1905013B    Altcode:
  We determine effective temperature, metallicity, and microturbulence for
  a number of well-studied late-type stars. We use the new NLTE atomic
  model of Fe, and discuss the results for the MARCS models, as well
  as for the spatial and temporal averages of full 3D hydrodynamical
  simulations of stellar convection. It is shown that, contrary to
  the mean 3D models, certain limitations shall be imposed on the line
  formation and spectrum synthesis calculations with classical hydrostatic
  1D models to obtain physically-realistic results.

---------------------------------------------------------
Title: Evidence for a vanishing <SUP>6</SUP>Li/<SUP>7</SUP>Li isotopic
    signature in the metal-poor halo star HD 84937
Authors: Lind, K.; Asplund, M.; Collet, R.; Meléndez, J.
2012MSAIS..22..142L    Altcode:
  The claimed detections of <SUP>6</SUP>Li in the atmospheres of
  some metal-poor halo stars have lead to speculative additions
  to the standard model of Big Bang nucleosynthesis and the early
  Universe, as the inferred abundances cannot be explained by Galactic
  cosmic ray production. A prominent example of a so far un-disputed
  <SUP>6</SUP>Li-detection is that of the metal-poor turn-off star
  HD 84937, for which at least three different groups obtain very
  similar results. We revisit the lithium isotopic analysis for this
  star and two other halo stars, G 64-12 and HD 140283, using spectra
  of superiour quality and applying for the first time a combined 3D,
  NLTE synthesis to both the Li line and to Ca lines that are used to
  constrain the external line broadening. We demonstrate how differential
  NLTE effects between the Li and Ca line profiles can lead to spurious
  <SUP>6</SUP>Li-detections in LTE, compatible with previously reported
  values of <SUP>6</SUP>Li/<SUP>7</SUP>Li≈5%. With our new analysis
  technique, none of the three analysed stars have a significant detection
  of <SUP>6</SUP>Li in NLTE. We discuss which further progress is needed
  to firmly establish these results.

---------------------------------------------------------
Title: The cosmological Li problems: Big Bang in crisis perhaps
Authors: Asplund, Martin
2012cemw.confE...2A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: NLTE effects on Fe I/II in the atmospheres of FGK stars and
    application to the abundance analysis of their spectra
Authors: Bergemann, Maria; Lind, Karin; Collet, Remo; Asplund, Martin
2011JPhCS.328a2002B    Altcode: 2011arXiv1109.2601B
  We describe the first results from our project aimed at large-scale
  calculations of NLTE abundance corrections for important astrophysical
  atoms and ions. In this paper, the focus is on Fe which is a proxy
  of stellar metallicity and is commonly used to derive effective
  temperature and surface gravity. We present a small grid of NLTE
  abundance corrections for a sample of Fe I lines and discuss how the
  NLTE effects influence the determination of effective temperature,
  surface gravity, and metallicity for late-type stars.

---------------------------------------------------------
Title: The StaggerGrid project: a grid of 3-D model atmospheres for
    high-precision spectroscopy
Authors: Collet, Remo; Magic, Zazralt; Asplund, Martin
2011JPhCS.328a2003C    Altcode: 2011arXiv1110.5475C
  In this contribution, we present the STAGGERGRID, a collaborative
  project for the construction of a comprehensive grid of time-dependent,
  three-dimensional (3-D), hydrodynamic model atmospheres of solar-
  and late-type stars with different effective temperatures,
  surface gravities, and chemical compositions. We illustrate the
  main characteristics of these 3-D models and their effects on the
  predicted strengths, wavelength-shifts, and shapes of spectral lines,
  highlighting the differences with respect to calculations based on
  classical, one-dimensional, hydrostatic models, and discuss some of
  their possible applications to elemental abundance analysis of stellar
  spectra in the context of large observational surveys.

---------------------------------------------------------
Title: Effects of Scattering on the Temperature Stratification in
    3D Model Atmospheres of Late-Type Stars
Authors: Collet, R.; Hayek, W.; Asplund, M.
2011ASPC..448..819C    Altcode: 2011csss...16..819C
  Three-dimensional (3D) radiative hydrodynamic model atmospheres
  of metal-poor late-type stars predict cooler upper photospheric
  stratifications than their one-dimensional (1D) counterparts. This
  property of 3D model atmospheres affects the determination of
  elemental abundances from temperature-sensitive spectral features, with
  important consequences for galactic chemical evolution studies. In this
  contribution, we investigate the impact of different approximations
  of scattering in the solution of the radiative transfer equation on
  the temperature stratification of 3D model atmospheres of metal-poor
  red giants. We use the BIFROST code to construct 3D model atmospheres
  of metal-poor red giants using three different approximations of
  scattering. First, we self-consistently solve the radiative transfer
  equation for the general case of a source function with a coherent
  scattering term; second, we solve the radiative transfer equation
  assuming a Planckian source function and neglecting altogether
  the contribution of continuum scattering to extinction in the
  optically thin layers; third, we assume a Planckian source function
  and treat continuum scattering as pure absorption everywhere in the
  simulation's domain. We find that the second approach produces very
  similar temperature structures with cool upper photospheric layers as
  when treating scattering correctly, and at a much lower computational
  cost. In contrast, treating scattering as pure absorption leads to
  significantly hotter and shallower temperature stratifications.

---------------------------------------------------------
Title: 3-D hydrodynamical model atmospheres: a tool to correct radial
    velocities and parallaxes for Gaia
Authors: Chiavassa, A.; Bigot, L.; Thévenin, F.; Collet, R.;
   Jasniewicz, G.; Magic, Z.; Asplund, M.
2011JPhCS.328a2012C    Altcode: 2011arXiv1111.5515C
  Convection plays an essential role in the emerging intensity for
  many stars that will be observed by Gaia. Convective-related surface
  structures affect the shape, shift, and asymmetry of absorption lines,
  the photocentric and photometric variability causing bias in Gaia
  measurements. Regarding the importance of Gaia mission and its goals,
  it is mandatory to have the best models of the observed stars. 3-D
  time-dependent hydrodynamical simulations of surface convection are
  crucial to model the photosphere of late type stars in a very realistic
  way. These simulations are an important tool to correct the radial
  velocities and to better estimate the parallaxes and photometric
  variability.

---------------------------------------------------------
Title: Spectroscopic Microvariability Induced by Convective Motions
Authors: Porter, L.; Asplund, M.
2011ASPC..448.1013P    Altcode: 2011csss...16.1013P
  Convection reaches the atmospheres of cool stars creating detectable
  variability in the photometry and spectrum of the star. Current 3D
  hydro-dynamical models of dwarfs and red giants simulate only a small
  representative volume of the stellar atmosphere, typically covering
  some 10 granules horizontally. To derive observable quantities it is
  necessary to integrate these 'Box-in-a-star' models over the stellar
  disk. The disk-integrated variability caused by convective motions can
  be constrained using the statistical properties of spatial and temporal
  fluctuations from a time-series of these models. Previously suggested
  for white light and photometric centroid (Ludwig 2006), we extend this
  method to spectral lines, including the effects of stellar rotation. We
  believe a better characterisation of this convective microvariability
  would benefit velocity diagnostics for helioseismology, eg NiI 6768 Å,
  used by SOHO MDI (Jones 1989) and could be used to remove the 'noise'
  induced by convective motions in radial velocity planet searches.

---------------------------------------------------------
Title: Is the solar spectrum latitude-dependent?. An investigation
    with SST/TRIPPEL
Authors: Kiselman, D.; Pereira, T. M. D.; Gustafsson, B.; Asplund,
   M.; Meléndez, J.; Langhans, K.
2011A&A...535A..14K    Altcode: 2011arXiv1108.4527K
  Context. In studies of the solar spectrum compared to spectra of solar
  twin stars, it has been found that the chemical composition of the Sun
  seems to depart systematically from those of the twins. One possible
  explanation could be that the effect is caused by the special aspect
  angle of the Sun when observed from Earth compared with the aspect
  angles of the twins. This means that a latitude dependence of the
  solar spectrum, even with the heliocentric angle constant, could
  lead to the observed effects. <BR /> Aims: We explore a possible
  variation in the strength of certain spectral lines that are used
  in the comparisons between the composition of the Sun and the twins
  at loci on the solar disk with different latitudes but at constant
  heliocentric angle. <BR /> Methods: We use the TRIPPEL spectrograph at
  the Swedish 1-m Solar Telescope on La Palma to record spectra in five
  spectral regions to compare different locations on the solar disk at
  a heliocentric angle of 45°. Equivalent widths and other parameters
  are measured for fifteen different lines representing nine atomic
  species. Spectra acquired at different times are used in averaging the
  line parameters for each line and observing position. <BR /> Results:
  The relative variations in equivalent widths at the equator and at
  solar latitude ~45° are found to be less than 1.5% for all spectral
  lines studied. Translated into elemental abundances as they would be
  measured from a terrestrial and a hypothetical pole-on observer, the
  difference is estimated to be within 0.005 dex in all cases. <BR />
  Conclusions: It is very unlikely that latitude effects could cause the
  reported abundance difference between the Sun and the solar twins. The
  accuracy obtainable in measurements of small differences in spectral
  line strengths between different solar disk positions is very high,
  and can be exploited in studies of, e.g. weak magnetic fields or
  effects of solar activity on atmospheric structure.

---------------------------------------------------------
Title: Chemical evolution of the Galactic bulge as traced by
    microlensed dwarf and subgiant stars. IV. Two bulge populations
Authors: Bensby, T.; Adén, D.; Meléndez, J.; Gould, A.; Feltzing,
   S.; Asplund, M.; Johnson, J. A.; Lucatello, S.; Yee, J. C.; Ramírez,
   I.; Cohen, J. G.; Thompson, I.; Bond, I. A.; Gal-Yam, A.; Han, C.;
   Sumi, T.; Suzuki, D.; Wada, K.; Miyake, N.; Furusawa, K.; Ohmori,
   K.; Saito, To.; Tristram, P.; Bennett, D.
2011A&A...533A.134B    Altcode: 2011arXiv1107.5606B
  Based on high-resolution (R ≈ 42 000 to 48 000) and high
  signal-to-noise (S/N ≈ 50 to 150) spectra obtained with UVES/VLT, we
  present detailed elemental abundances (O, Na, Mg, Al, Si, Ca, Ti, Cr,
  Fe, Ni, Zn, Y, and Ba) and stellar ages for 12 new microlensed dwarf and
  subgiant stars in the Galactic bulge. Including previous microlensing
  events, the sample of homogeneously analysed bulge dwarfs has now
  grown to 26. The analysis is based on equivalent width measurements
  and standard 1-D LTE MARCS model stellar atmospheres. We also present
  NLTE Li abundances based on line synthesis of the <SUP>7</SUP>Li
  line at 670.8 nm. The results from the 26 microlensed dwarf and
  subgiant stars show that the bulge metallicity distribution (MDF)
  is double-peaked; one peak at [Fe/H] ≈ -0.6 and one at [Fe/H] ≈ +
  0.3, and with a dearth of stars around solar metallicity. This is in
  contrast to the MDF derived from red giants in Baade's window, which
  peaks at this exact value. A simple significance test shows that it is
  extremely unlikely to have such a gap in the microlensed dwarf star
  MDF if the dwarf stars are drawn from the giant star MDF. To resolve
  this issue we discuss several possibilities, but we can not settle on a
  conclusive solution for the observed differences. We further find that
  the metal-poor bulge dwarf stars arepredominantly old with ages greater
  than 10 Gyr, while the metal-rich bulge dwarf stars show a wide range
  of ages. The metal-poor bulge sample is very similar to the Galactic
  thick disk in terms of average metallicity, elemental abundance trends,
  and stellar ages. Speculatively, the metal-rich bulge population might
  be the manifestation of the inner thin disk. If so, the two bulge
  populations could support the recent findings, based on kinematics,
  that there are no signatures of a classical bulge and that the Milky Way
  is a pure-disk galaxy. Also, recent claims of a flat IMF in the bulge
  based on the MDF of giant stars may have to be revised based on the MDF
  and abundance trends probed by our microlensed dwarf stars. <P />Based
  on observations made with the European Southern Observatory telescopes
  (84.B-0837, 85.B-0399, and 86.B-0757). This paper also includes data
  gathered with the 6.5 m Magellan Telescopes located at the Las Campanas
  Observatory, Chile, and data obtained at the W. M. Keck Observatory,
  which is operated as a scientific partnership among the California
  Institute of Technology, the University of California and the National
  Aeronautics and Space Administration.Tables 4 and 5 are available at the
  CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/533/A134">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/533/A134</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: Abundances of microlensed stars
    in the Bulge (Bensby+, 2011)
Authors: Bensby, T.; Aden, D.; Melendez, J.; Gould, A.; Feltzing, S.;
   Asplund, M.; Johnson, J. A.; Lucatello, S.; Yee, J. C.; Ramirez, I.;
   Cohen, J. G.; Thompson, I.; Gal-Yam, A.; Han, C.; Sumi, T.; Suzuki, D.;
   Wada, K.; Miyake, N.; Furusawa, K.; Ohmori, K.; Saito, To.; Tristram,
   P.; Bennett, D.
2011yCat..35330134B    Altcode: 2011yCat..35339134B
  For each spectral line we give the lower excitation potential, measured
  equivalent widths, and derived absolute abundances. We also give
  median abundances for each star, normalised to the Sun, and errors
  in the median abundances. These tables contain data for the last 12
  microlensed dwarf stars. Data for the first 14 microlensed dwarfs can
  be found in Bensby et al. (2009, Cat. J/A+A/499/737) and Bensby et
  al. (2010, Cat. J/A+A/512/A41). <P />(5 data files).

---------------------------------------------------------
Title: On the alleged duality of the Galactic halo
Authors: Schönrich, Ralph; Asplund, Martin; Casagrande, Luca
2011MNRAS.415.3807S    Altcode: 2010arXiv1012.0842S; 2011MNRAS.tmp.1011S
  We examine the kinematics of the Galactic halo based on SDSS/SEGUE data
  by Carollo et al. We find that their claims of a counter-rotating
  halo are the result of substantial biases in distance estimates
  (of the order of 50 per cent): the claimed retrograde component,
  which makes up only a tiny fraction of the entire sample, prone to
  contaminations, is identified as the tail of distance overestimates. The
  strong overestimates also result in a lift in the vertical velocity
  component, which explains the large altitudes those objects were
  claimed to reach. Errors are worst for the lowest metallicity stars,
  which explains the metal-poor nature of the artificial component. We
  also argue that measurement errors were not properly accounted for
  and that the use of Gaussian fitting on intrinsically non-Gaussian
  Galactic components invokes the identification of components that are
  distorted or even artificial. Our evaluation of the data leads to a
  revision of the estimated velocity ellipsoids and does not yield any
  reliable evidence for a counter-rotating halo component. If a distinct
  counter-rotating halo component exists, then it must be far weaker
  than claimed by Carollo et al. Finally, we note that their revised
  analysis presented in Beers et al. does not alleviate our main concerns.

---------------------------------------------------------
Title: The Effect of Scattering on the Temperature Stratification
    of 3D Model Atmospheres of Metal-Poor Red Giants
Authors: Collet, Remo; Hayek, Wolfgang; Asplund, Martin
2011IAUS..271..373C    Altcode:
  We study the effects of different approximations of scattering in 3D
  radiation-hydrodynamics simulations on the photospheric temperature
  stratification of metal-poor red giant stars. We find that assuming a
  Planckian source function and neglecting the contribution of scattering
  to extinction in optically thin layers provides a good approximation
  of the effects of coherent scattering on the photospheric temperature
  balance.

---------------------------------------------------------
Title: High-resolution elemental abundance analysis of the Hyades
    supercluster
Authors: de Silva, G. M.; Freeman, K. C.; Bland-Hawthorn, J.; Asplund,
   M.; Williams, M.; Holmberg, J.
2011MNRAS.415..563D    Altcode: 2011MNRAS.tmp..794D; 2011arXiv1103.2588D
  The existence of a kinematically defined moving group of stars
  centred at U=-40, V=-17 km s<SUP>-1</SUP>, referred to as the Hyades
  supercluster, has been suggested to be the debris of an originally
  large star-forming event, with its core being the present-day Hyades
  open cluster. Using high-resolution UV-Visual Echelle Spectrograph
  (UVES) spectra, we present the elemental abundances for a range
  of alpha, Fe-peak and neutron-capture elements for 26 proposed
  supercluster stars. Our results show that the sample stars display
  a heterogeneous abundance distribution, with a clump around [Fe/H]
  =+0.15. We also calculate stellar radial velocities and U, V, W space
  velocities. Enforcing strict chemical and kinematical membership
  criteria, we find that four supercluster stars share the Hyades open
  cluster abundances and kinematics, while many of the remaining stars
  fit the disc field kinematics and abundance range. We discuss our
  findings in the context of the Hyades supercluster being a dispersed
  star-forming remnant, a stellar stream of purely dynamical origin or a
  result of several processes. Based on observations made at the European
  Southern Observatory, Paranal, Chile (ESO programmes 080.D-0094(A)
  and 381.B-0045(A)).

---------------------------------------------------------
Title: Sulphur abundances in halo giants from the [S I] line at 1082
    nm and the [S I] triplet around 1045 nm
Authors: Jönsson, H.; Ryde, N.; Nissen, P. E.; Collet, R.; Eriksson,
   K.; Asplund, M.; Gustafsson, B.
2011A&A...530A.144J    Altcode: 2011arXiv1104.2148J
  Context. It is still debated whether or not the Galactic chemical
  evolution of sulphur in the halo follows the flat trend with [Fe/H]
  that is ascribed to the result of explosive nucleosynthesis in type
  II SNe. It has been suggested that the disagreement between different
  investigations of sulphur abundances in halo stars might be owing
  to problems with the diagnostics used, that a new production source
  of sulphur might be needed in the early Universe, like hypernovae, or
  that the deposition of supernova ejecta into the interstellar medium is
  time-delayed. <BR /> Aims: The aim of this study is to try to clarify
  this situation by measuring the sulphur abundance in a sample of halo
  giants using two diagnostics: the S i triplet around 1045 nm and the
  [S i] line at 1082 nm. The latter of the two is not believed to be
  sensitive to non-LTE effects. We can thereby minimize the uncertainties
  in the diagnostic used and estimate the usefulness of the triplet for
  the sulphur determination in halo K giants. We will also be able to
  compare our sulphur abundance differences from the two diagnostics
  with the expected non-LTE effects in the 1045 nm triplet previously
  calculated by others. <BR /> Methods: High-resolution near-infrared
  spectra of ten K giants were recorded using the spectrometer CRIRES
  mounted at VLT. Two standard settings were used, one covering the S i
  triplet and one covering the [S i] line. The sulphur abundances were
  individually determined with equivalent widths and synthetic spectra
  for the two diagnostics using tailored 1D model atmospheres and relying
  on non-LTE corrections from the litterature. Effects of convective
  inhomogeneities in the stellar atmospheres are investigated. <BR />
  Results: The sulphur abundances derived from both the [S i] line and the
  non-LTE corrected 1045 nm triplet favor a flat trend for the evolution
  of sulphur. In contrast to some previous studies, we saw no "high"
  values of [S/Fe] in our sample. <BR /> Conclusions: We corroborate
  the flat trend in the [S/Fe] vs. [Fe/H] plot for halo stars found in
  some previous studies but do not find a scatter or a rise in [S/Fe]
  as obtained in other works. We find the sulphur abundances deduced
  from the non-LTE corrected triplet to be somewhat lower than the
  abundances from the [S i] line, possibly indicating too large non-LTE
  corrections. Considering 3D modeling, however, they might instead
  be too small. Moreover, we show that the [S i] line can be used as
  a sulphur diagnostic down to [Fe/H] ~ -2.3 in giants. <P />Based on
  observations collected at the European Southern Observatory, Chile
  (ESO program 080.D-0675(A)).

---------------------------------------------------------
Title: New constraints on the chemical evolution of the solar
    neighbourhood and Galactic disc(s). Improved astrophysical parameters
    for the Geneva-Copenhagen Survey
Authors: Casagrande, L.; Schönrich, R.; Asplund, M.; Cassisi, S.;
   Ramírez, I.; Meléndez, J.; Bensby, T.; Feltzing, S.
2011A&A...530A.138C    Altcode: 2011arXiv1103.4651C
  We present a re-analysis of the Geneva-Copenhagen survey, which
  benefits from the infrared flux method to improve the accuracy of the
  derived stellar effective temperatures and uses the latter to build a
  consistent and improved metallicity scale. Metallicities are calibrated
  on high-resolution spectroscopy and checked against four open clusters
  and a moving group, showing excellent consistency. The new temperature
  and metallicity scales provide a better match to theoretical isochrones,
  which are used for a Bayesian analysis of stellar ages. With respect to
  previous analyses, our stars are on average 100 K hotter and 0.1 dex
  more metal rich, which shift the peak of the metallicity distribution
  function around the solar value. From Strömgren photometry we are
  able to derive for the first time a proxy for [α/Fe] abundances,
  which enables us to perform a tentative dissection of the chemical
  thin and thick disc. We find evidence for the latter being composed
  of an old, mildly but systematically alpha-enhanced population that
  extends to super solar metallicities, in agreement with spectroscopic
  studies. Our revision offers the largest existing kinematically
  unbiased sample of the solar neighbourhood that contains full
  information on kinematics, metallicities, and ages and thus provides
  better constraints on the physical processes relevant in the build-up
  of the Milky Way disc, enabling a better understanding of the Sun in
  a Galactic context. <P />Catalogue (Table 2) is only available at the
  CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/530/A138">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/530/A138</A>

---------------------------------------------------------
Title: 3D LTE spectral line formation with scattering in red giant
    stars
Authors: Hayek, W.; Asplund, M.; Collet, R.; Nordlund, Å.
2011A&A...529A.158H    Altcode: 2011arXiv1108.3366H
  <BR /> Aims: We investigate the effects of coherent isotropic continuum
  scattering on the formation of spectral lines in local thermodynamic
  equilibrium (LTE) using 3D hydrodynamical and 1D hydrostatic model
  atmospheres of red giant stars. <BR /> Methods: Detailed radiative
  transfer with coherent and isotropic continuum scattering is computed
  for 3D hydrodynamical and 1D hydrostatic models of late-type stellar
  atmospheres using the SCATE code. Opacities are computed in LTE, while
  a coherent and isotropic scattering term is added to the continuum
  source function. We investigate the effects of scattering by comparing
  continuum flux levels, spectral line profiles and curves of growth
  for different species with calculations that treat scattering as
  absorption. <BR /> Results: Rayleigh scattering is the dominant source
  of scattering opacity in the continuum of red giant stars. Photons
  may escape from deeper, hotter layers through scattering, resulting in
  significantly higher continuum flux levels beneath a wavelength of λ
  ≲ 5000 Å. The magnitude of the effect is determined by the importance
  of scattering opacity with respect to absorption opacity; we observe
  the largest changes in continuum flux at the shortest wavelengths
  and lowest metallicities; intergranular lanes of 3D models are more
  strongly affected than granules. Continuum scattering acts to increase
  the profile depth of LTE lines: continua gain more brightness than line
  cores due to their larger thermalization depth in hotter layers. We
  thus observe the strongest changes in line depth for high-excitation
  species and ionized species, which contribute significantly to photon
  thermalization through their absorption opacity near the continuum
  optical surface. Scattering desaturates the line profiles, leading to
  larger abundance corrections for stronger lines, which reach -0.5 dex
  at 3000 Å for Fe ii lines in 3D with excitation potential χ = 2 eV at
  [Fe/H] = -3.0. The corrections are less severe for low-excitation lines,
  longer wavelengths, and higher metallicity. Velocity fields increase
  the effects of scattering by separating emission from granules and
  intergranular lanes in wavelength. 1D calculations exhibit similar
  scattering abundance corrections for weak lines, but those for
  strong lines are generally smaller compared to 3D models and depend
  on the choice of microturbulence. <BR /> Conclusions: Continuum
  scattering should be taken into account for computing realistic
  spectral line profiles at wavelengths λ ≲ 4000 Å in metal-poor
  giant stars. Profile shapes are strongly affected by velocity fields
  and horizontal inhomogeneities, requiring a treatment based on 3D
  hydrodynamical rather than classical 1D hydrostatic model atmospheres.

---------------------------------------------------------
Title: The influence of electron collisions on non-LTE Li line
    formation in stellar atmospheres
Authors: Osorio, Y.; Barklem, P. S.; Lind, K.; Asplund, M.
2011A&A...529A..31O    Altcode:
  The influence of the uncertainties in the rate coefficient data for
  electron-impact excitation and ionization on non-LTE Li line formation
  in cool stellar atmospheres is investigated. We examine the electron
  collision data used in previous non-LTE calculations and compare them to
  recent calculations that use convergent close-coupling (CCC) techniques
  and to our own calculations using the R-matrix with the pseudostates
  (RMPS) method. We find excellent agreement between rate coefficients
  from the CCC and RMPS calculations, and reasonable agreement between
  these data and the semi-empirical data used in non-LTE calculations
  up to now. The results of non-LTE calculations using the old and new
  data sets are compared and only small differences found: about 0.01
  dex (~2%) or less in the abundance corrections. We therefore conclude
  that the influence on non-LTE calculations of uncertainties in the
  electron collision data is negligible. Indeed, together with the
  collision data for the charge exchange process Li(3s) + H ⇌ Li<SUP>
  + </SUP> + H<SUP> - </SUP> now available, and barring the existence
  of an unknown important collisional process, the collisional data in
  general is not a source of significant uncertainty in non-LTE Li line
  formation calculations.

---------------------------------------------------------
Title: Non-LTE calculations for neutral Na in late-type stars using
    improved atomic data
Authors: Lind, K.; Asplund, M.; Barklem, P. S.; Belyaev, A. K.
2011A&A...528A.103L    Altcode: 2011arXiv1102.2160L
  Neutral sodium is a minority species in the atmospheres of late-type
  stars, and line formation in local thermodynamic equilibrium (LTE) is
  often a poor assumption, in particular for strong lines. We present
  an extensive grid of non-LTE calculations for several Na I lines in
  cool stellar atmospheres, including metal-rich and metal-poor dwarfs
  and giants. For the first time, we constructed a Na model atom that
  incorporates accurate quantum mechanical calculations for collisional
  excitation and ionisation by electrons as well as collisional excitation
  and charge exchange reactions with neutral hydrogen. Similar to Li
  I, the new rates for hydrogen impact excitation do not affect the
  statistical equilibrium calculations, while charge exchange reactions
  have a small but non-negligible influence. The presented LTE and non-LTE
  curves-of-growth can be interpolated to obtain non-LTE abundances and
  abundance corrections for arbitrary stellar parameter combinations and
  line strengths. The typical corrections for weak lines are -0.1... -0.2
  dex, whereas saturated lines may overestimate the abundance in LTE by
  more than 0.5 dex. The non-LTE Na abundances appear very robust with
  respect to uncertainties in the input collisional data.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Geneva-Copenhagen survey
    re-analysis (Casagrande+, 2011)
Authors: Casagrande, L.; Schoenrich, R.; Asplund, M.; Cassisi, S.;
   Ramirez, I.; Melendez, J.; Bensby, T.; Feltzing, S.
2011yCat..35300138C    Altcode: 2011yCat..35309138C
  We present a re-analysis of the Geneva-Copenhagen survey, benefiting
  from the infrared flux method to improve upon the accuracy of the
  derived stellar effective temperatures and using the latter to build a
  consistent and improved metallicity scale. Metallicities are calibrated
  on high-resolution spectroscopy and checked against four open clusters
  and a moving group, showing excellent consistency. The new temperature
  and metallicity scales provide a better match to theoretical isochrones,
  which are used for a Bayesian analysis of stellar ages. With respect
  to previous analyses, our stars are on average 100K hotter and 0.1dex
  more metal rich, shifting the peak of the metallicity distribution
  function around the solar value. From Stromgren photometry we are
  able to derive for the first time a proxy for [Fe] abundances, which
  enables for a tentative dissection of the chemical thin and thick
  disc. We find evidence for the latter being composed of an old, mildly
  but systematically alpha-enhanced population extending to super solar
  metallicities, in agreement with spectroscopic studies. Our revision
  offers the largest existing kinematically unbiased sample of the
  solar neighbourhood that contains full information on kinematics,
  metallicities and ages and thus provides better constraints on the
  physical processes relevant in the build-up of the Milky Way disc,
  enabling a better understanding of the Sun in a Galactic context. <P
  />(1 data file).

---------------------------------------------------------
Title: The chemical composition of the sun
Authors: Grevesse, N.; Asplund, M.; Sauval, A. J.; Scott, P.
2011CaJPh..89..327G    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Three-dimensional surface convection simulations of metal-poor
    stars. The effect of scattering on the photospheric temperature
    stratification
Authors: Collet, R.; Hayek, W.; Asplund, M.; Nordlund, Å.; Trampedach,
   R.; Gudiksen, B.
2011A&A...528A..32C    Altcode: 2011arXiv1101.3265C
  Context. Three-dimensional (3D) radiative hydrodynamic model atmospheres
  of metal-poor late-type stars are characterized by cooler upper
  photospheric layers than their one-dimensional counterparts. This
  property of 3D model atmospheres can dramatically affect the
  determination of elemental abundances from temperature-sensitive
  spectral features, with profound consequences on galactic chemical
  evolution studies. <BR /> Aims: We investigate whether the cool surface
  temperatures predicted by 3D model atmospheres of metal-poor stars
  can be ascribed to approximations in the treatment of scattering
  during the modelling phase. <BR /> Methods: We use the Bifrost
  code to construct 3D model atmospheres of metal-poor stars and test
  three different ways to handle scattering in the radiative transfer
  equation. As a first approach, we solve iteratively the radiative
  transfer equation for the general case of a source function with
  a coherent scattering term, treating scattering in a correct and
  consistent way. As a second approach, we solve the radiative transfer
  equation in local thermodynamic equilibrium approximation, neglecting
  altogether the contribution of continuum scattering to extinction in the
  optically thin layers; this has been the default mode in our previous
  3D modelling as well as in present Stagger-Code models. As our third
  and final approach, we treat continuum scattering as pure absorption
  everywhere, which is the standard case in the 3D modelling by the
  CO<SUP>5</SUP>BOLD collaboration. <BR /> Results: For all simulations,
  we find that the second approach produces temperature structures
  with cool upper photospheric layers very similar to the case in which
  scattering is treated correctly. In contrast, treating scattering as
  pure absorption leads instead to significantly hotter and shallower
  temperature stratifications. The main differences in temperature
  structure between our published models computed with the Stagger-
  and Bifrost codes and those generated with the CO<SUP>5</SUP>BOLD
  code can be traced to the different treatments of scattering. <BR />
  Conclusions: Neglecting the contribution of continuum scattering to
  extinction in optically thin layers provides a good approximation
  to the full, iterative solution of the radiative transfer equation
  in metal-poor stellar surface convection simulations, and at a much
  lower computational cost. Our results also demonstrate that the cool
  temperature stratifications predicted for metal-poor late-type stars
  by previous models by our collaboration are not an artifact of the
  approximated treatment of scattering.

---------------------------------------------------------
Title: Tracing the evolution of NGC 6397 through the chemical
    composition of its stellar populations
Authors: Lind, K.; Charbonnel, C.; Decressin, T.; Primas, F.; Grundahl,
   F.; Asplund, M.
2011A&A...527A.148L    Altcode: 2010arXiv1012.0477L
  Context. The chemical compositions of globular clusters provide
  important information on the star formation that occurred at very
  early times in the Galaxy. In particular the abundance patterns of
  elements with atomic number z ≤ 13 may shed light on the properties
  of stars that early on enriched parts of the star-forming gas with the
  rest-products of hydrogen-burning at high temperatures. <BR /> Aims:
  We analyse and discuss the chemical compositions of a large number of
  elements in 21 red giant branch stars in the metal-poor globular cluster
  NGC 6397. We compare the derived abundance patterns with theoretical
  predictions in the framework of the "wind of fast rotating massive
  star"-scenario. <BR /> Methods: High-resolution spectra were obtained
  with the FLAMES/UVES spectrograph on the VLT. We determined non-LTE
  abundances of Na, and LTE abundances for the remaining 21 elements,
  including O (from the [OI] line at 630 nm), Mg, Al, α, iron-peak,
  and neutron-capture elements, many of which had not been previously
  analysed for this cluster. We also considered the influence of possible
  He enrichment in the analysis of stellar spectra. <BR /> Results:
  We find that the Na abundances of evolved, as well as unevolved,
  stars in NGC 6397 show a distinct bimodality, which is indicative
  of two stellar populations: one primordial stellar generation of
  composition similar to field stars, and a second generation that
  is polluted with material processed during hydrogen-burning, i.e.,
  enriched in Na and Al and depleted in O and Mg. The red giant branch
  exhibits a similar bimodal distribution in the Strömgren colour
  index c<SUB>y</SUB> = c<SUB>1</SUB> - (b - y), implying that there
  are also large differences in the N abundance. The two populations
  have the same composition for all analysed elements heavier than Al,
  within the measurement uncertainty of the analysis, with the possible
  exception of [Y/Fe]. Using two stars with almost identical stellar
  parameters, one from each generation, we estimate the difference
  in He content, ΔY = 0.01 ± 0.06, given the assumption that the
  mass fraction of iron is the same for the stars. <BR /> Conclusions:
  NGC 6397 hosts two stellar populations that have different chemical
  compositions of N, O, Na, Mg, and probably Al. The cluster is dominated
  (75%) by the second generation. We show that massive stars of the
  first generation can be held responsible for the abundance patterns
  observed in the second generation long-lived stars of NGC 6397. We
  estimate that the initial mass of this globular cluster is at least
  ten times higher than its present-day value. <P />Based on data
  collected at European Southern Observatory (ESO), Paranal, Chile,
  under program IDs 077.A-0018(A) and 281.D-5028(A), as well as data
  collected with the Danish 1.54 m at European Southern Observatory
  (ESO), La Silla.Tables A.1 and A.2 are only available in electronic
  form at <A href="http://www.aanda.org">http://www.aanda.org</A>Two
  tables with line equivalent widths, chemical abundances, and stellar
  parameters are only available in electronic form at the CDS via
  anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A
  href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/527/A148">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/527/A148</A>

---------------------------------------------------------
Title: The radius and mass of the close solar twin 18 Scorpii derived
    from asteroseismology and interferometry
Authors: Bazot, M.; Ireland, M. J.; Huber, D.; Bedding, T. R.;
   Broomhall, A. -M.; Campante, T. L.; Carfantan, H.; Chaplin, W. J.;
   Elsworth, Y.; Meléndez, J.; Petit, P.; Théado, S.; Van Grootel,
   V.; Arentoft, T.; Asplund, M.; Castro, M.; Christensen-Dalsgaard,
   J.; Do Nascimento, J. D.; Dintrans, B.; Dumusque, X.; Kjeldsen, H.;
   McAlister, H. A.; Metcalfe, T. S.; Monteiro, M. J. P. F. G.; Santos,
   N. C.; Sousa, S.; Sturmann, J.; Sturmann, L.; ten Brummelaar, T. A.;
   Turner, N.; Vauclair, S.
2011A&A...526L...4B    Altcode: 2012arXiv1209.0217B
  The growing interest in solar twins is motivated by the possibility of
  comparing them directly to the Sun. To carry on this kind of analysis,
  we need to know their physical characteristics with precision. Our
  first objective is to use asteroseismology and interferometry on
  the brightest of them: 18 Sco. We observed the star during 12 nights
  with HARPS for seismology and used the PAVO beam-combiner at CHARA
  for interferometry. An average large frequency separation 134.4 ±
  0.3 μHz and angular and linear radiuses of 0.6759 ± 0.0062 mas and
  1.010 ± 0.009 R<SUB>⊙</SUB> were estimated. We used these values
  to derive the mass of the star, 1.02 ± 0.03 M<SUB>⊙</SUB>. <P
  />Based on observations collected at the European Southern Observatory
  (ID 183.D-0729(A)) and at the CHARA Array, operated by Georgia State
  University.

---------------------------------------------------------
Title: VizieR Online Data Catalog: NGC6397 red giants chemical
    composition (Lind+, 2011)
Authors: Lind, K.; Charbonnel, C.; Decressin, T.; Primas, F.; Grundahl,
   F.; Asplund, M.
2011yCat..35270148L    Altcode: 2011yCat..35279148L
  The tables contain stellar parameters, equivalent widths, and
  line-by-line abundances for stars in the metal-poor globular cluster
  NGC6397. All abundances are given in logarithmic units relative to
  hydrogen, according to A(x)=log(N(x)/N(H))+12, where N(x) is the number
  density of element x and N(H) the number density of hydrogen. For
  photometric data, Li abundances, and equivalent widths of Fe lines
  we refer to Lind et al. (2009, Cat. J/A+A/503/545). Table 2 contains
  improved non-LTE Na abundances for the targets presented in Lind et al
  (2009,, Cat. J/A+A/503/545). <P />(2 data files).

---------------------------------------------------------
Title: The New Solar Composition and the Solar Metallicity
Authors: Grevesse, Nicolas; Asplund, Martin; Sauval, A. Jacques;
   Scott, Pat
2011sswh.book...51G    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Three-dimensional hydrodynamical simulations of red
giant stars: semi-global models for interpreting interferometric
    observations
Authors: Chiavassa, A.; Collet, R.; Casagrande, L.; Asplund, M.
2010A&A...524A..93C    Altcode: 2010arXiv1009.1745C
  Context. Theoretical predictions from models of red giant branch
  stars are a valuable tool for various applications in astrophysics
  ranging from galactic chemical evolution to studies of exoplanetary
  systems. <BR /> Aims: We use the radiative transfer code Optim3D
  and realistic 3D radiative-hydrodynamical (RHD) surface convection
  simulations of red giants to explore the impact of granulation on
  interferometric observables. We assess how 3D simulations of surface
  convection can be validated against observations. <BR /> Methods: We
  computed intensity maps for the 3D simulation snapshots in two filters,
  the optical at 5000 ± 300 Å and the K band 2.14 ± 0.26 μm FLUOR
  filter, corresponding to the wavelength-range of instruments mounted on
  the CHARA interferometer. From the intensity maps, we constructed images
  of the stellar disks and account for center-to-limb variations. We
  then derived interferometric visibility amplitudes and phases. We
  study their behavior with position angle and wavelength, and compare
  them with CHARA observations of the red giant star HD 214868. <BR />
  Results: We provide average limb darkening coefficients for different
  metallicities and wavelengths ranges. We explain prospects for detecting
  and characterizing granulation and center-to-limb variations of red
  giant stars with today's interferometers. Regarding interferometric
  observables, we find that the effect of convective-related surface
  structures depends on metallicity and surface gravity. We provide
  theoretical closure-phases that should be incorporated into the analysis
  of red giant planet companion closure phase signals. We estimate
  3D-1D corrections to stellar radii determination: 3D models are ~3.5%
  smaller to ~1% larger in the optical than 1D, and roughly 0.5 to 1.5%
  smaller in the infrared. Even if these corrections are small, they are
  needed to properly set the zero point of effective temperature scale
  derived by interferometry and to strengthen the confidence of existing
  red giant catalogs of calibrating stars for interferometry. Finally,
  we show that our RHD simulations provide an excellent fit to the red
  giant HD 214868 even though more observations are needed at higher
  spatial frequencies and shorter wavelength.

---------------------------------------------------------
Title: Granulation Signatures in the Spectrum of the Very Metal-poor
    Red Giant HD 122563
Authors: Ramírez, I.; Collet, R.; Lambert, D. L.; Allende Prieto,
   C.; Asplund, M.
2010ApJ...725L.223R    Altcode: 2010arXiv1011.4077R
  A very high resolution (R = λ/Δλ = 200, 000), high signal-to-noise
  ratio (S/N ~= 340) blue-green spectrum of the very metal-poor ([Fe/H]
  ~= -2.6) red giant star HD 122563 has been obtained by us at McDonald
  Observatory. We measure the asymmetries and core wavelengths of a set
  of unblended Fe I lines covering a wide range of line strength. Line
  bisectors exhibit the characteristic C-shape signature of surface
  convection (granulation) and they span from about 100 m s<SUP>-1</SUP>
  in the strongest Fe I features to 800 m s<SUP>-1</SUP> in the
  weakest ones. Core wavelength shifts range from about -100 to -900
  m s<SUP>-1</SUP>, depending on line strength. In general, larger
  blueshifts are observed in weaker lines, but there is increasing
  scatter with increasing residual flux. Assuming local thermodynamic
  equilibrium (LTE), we synthesize the same set of spectral lines using
  a state-of-the-art three-dimensional (3D) hydrodynamic simulation
  for a stellar atmosphere of fundamental parameters similar to those
  of HD 122563. We find good agreement between model predictions and
  observations. This allows us to infer an absolute zero point for
  the line shifts and radial velocity. Moreover, it indicates that
  the structure and dynamics of the simulation are realistic, thus
  providing support to previous claims of large 3D-LTE corrections to
  elemental abundances and fundamental parameters of very metal-poor
  red giant stars obtained with standard 1D-LTE spectroscopic analyses,
  as suggested by the hydrodynamic model used here.

---------------------------------------------------------
Title: Chemical evolution of the Galactic bulge as traced by
    microlensed dwarf and subgiant stars. III. Detection of lithium in
    the metal-poor bulge dwarf MOA-2010-BLG-285S
Authors: Bensby, T.; Asplund, M.; Johnson, J. A.; Feltzing, S.;
   Meléndez, J.; Dong, S.; Gould, A.; Han, C.; Adén, D.; Lucatello,
   S.; Gal-Yam, A.
2010A&A...521L..57B    Altcode: 2010arXiv1009.5792B
  Context. To study the evolution of Li in the Galaxy it is necessary
  to observe dwarf or subgiant stars. These are the only long-lived
  stars whose present-day atmospheric chemical composition reflects
  their natal Li abundances according to standard models of stellar
  evolution. Although Li has been extensively studied in the Galactic
  disk and halo, to date there has only been one uncertain detection of
  Li in an unevolved bulge star. <BR /> Aims: Our aim with this study
  is to provide the first clear detection of Li in the Galactic bulge,
  based on an analysis of a dwarf star that has largely retained its
  initial Li abundance. <BR /> Methods: We performed a detailed elemental
  abundance analysis of the bulge dwarf star MOA-2010-BLG-285S using a
  high-resolution and high signal-to-noise spectrum obtained with the UVES
  spectrograph at the VLT when the object was optically magnified during
  a gravitational microlensing event (visual magnification A~550 during
  observation). The Li abundance was determined through synthetic line
  profile fitting of the <SUP>7</SUP>Li resonance doublet line at 670.8
  nm. The results have been corrected for departures from LTE. <BR />
  Results: MOA-2010-BLG-285S is, at [Fe/H] = -1.23, the most metal-poor
  dwarf star detected so far in the Galactic bulge. Its old age (12.5 Gyr)
  and enhanced [α/Fe] ratios agree well with stars in the thick disk
  at similar metallicities. This star represents the first unambiguous
  detection of Li in a metal-poor dwarf star in the Galactic bulge. We
  find an NLTE corrected Li abundance of logɛ(Li) = 2.16, which is
  consistent with values derived for Galactic disk and halo dwarf stars
  at similar metallicities and temperatures. <BR /> Conclusions: Our
  results show that there are no signs of Li enrichment or production
  in the Galactic bulge during its earliest phases. Observations of Li
  in other galaxies (ω Cen) and other components of the Galaxy suggest
  further that the Spite plateau is universal. <P />Based on observations
  carried out at the European Southern Observatory telescopes on Paranal,
  Chile, Program ID 085.B-0399.

---------------------------------------------------------
Title: A possible signature of terrestrial planet formation in the
    chemical composition of solar analogs
Authors: Ramírez, I.; Asplund, M.; Baumann, P.; Meléndez, J.;
   Bensby, T.
2010A&A...521A..33R    Altcode: 2010arXiv1008.3161R
  Recent studies have shown that the elemental abundances in the
  Sun are anomalous when compared to most (about 85%) nearby solar
  twin stars. Compared to its twins, the Sun exhibits a deficiency of
  refractory elements (those with condensation temperatures T<SUB>C</SUB>
  ≳ 900 K) relative to volatiles (T<SUB>C</SUB> ≲ 900 K). This finding
  is speculated to be a signature of the planet formation that occurred
  more efficiently around the Sun compared with the majority of solar
  twins. Furthermore, within this scenario, it seems more likely that
  the abundance patterns found are specifically related to the formation
  of terrestrial planets. In this work we analyze abundance results from
  six large independent stellar abundance surveys to determine whether
  they confirm or reject this observational finding. We show that the
  elemental abundances derived for solar analogs in these six studies
  are consistent with the T<SUB>C</SUB> trend suggested as a planet
  formation signature. The same conclusion is reached when those results
  are averaged heterogeneously. We also investigate the dependency of the
  abundances with first ionization potential (FIP), which correlates well
  with T<SUB>C</SUB>. A trend with FIP would suggest a different origin
  for the abundance patterns found, but we show that the correlation
  with T<SUB>C</SUB> is statistically more significant. We encourage
  similar investigations of metal-rich solar analogs and late F-type
  dwarf stars, for which the hypothesis of a planet formation signature
  in the elemental abundances makes very specific predictions. Finally,
  we examine a recent paper that claims that the abundance patterns of two
  stars hosting super-Earth like planets contradict the planet formation
  signature hypothesis. Instead, we find that the chemical compositions
  of these two stars are fully compatible with our hypothesis.

---------------------------------------------------------
Title: Lithium depletion in solar-like stars: no planet connection
Authors: Baumann, P.; Ramírez, I.; Meléndez, J.; Asplund, M.;
   Lind, K.
2010A&A...519A..87B    Altcode: 2010arXiv1008.0575B
  We have determined precise stellar parameters and lithium abundances
  in a sample of 117 stars with basic properties very similar to the
  Sun. This sample selection reduces biasing effects and systematic errors
  in the analysis. We estimate the ages of our sample stars mainly from
  isochrone fitting but also from measurements of rotation period and
  X-ray luminosity and test the connection between lithium abundance, age,
  and stellar parameters. We find strong evidence for increasing lithium
  depletion with age. Our sample includes 14 stars that are known to
  host planets and it does not support recent claims that planet-host
  stars have experienced more lithium depletion than stars without
  planets. We find the solar lithium abundance normal for a star of its
  age, mass, and metallicity. Furthermore, we analyze published data for
  82 stars that were reported to support an enhanced lithium depletion
  in planet hosts. We show that those stars in fact follow an age trend
  very similar to that found with our sample and that the presence of
  giant planets is not related to low lithium abundances. Finally, we
  discuss the systematic biases that led to the incorrect conclusion of
  an enhanced lithium depletion in planet-host stars.

---------------------------------------------------------
Title: The chemical composition of the Sun
Authors: Grevesse, N.; Asplund, M.; Sauval, A. J.; Scott, P.
2010Ap&SS.328..179G    Altcode: 2010Ap&SS.tmp...48G
  We present a redetermination of the solar abundances of all available
  elements. The new results have very recently been published by
  Asplund et al. (Annu. Rev. Astron. Astrophys. 47:481, 2009). The
  basic ingredients of this work, the main results and some of their
  implications are summarized hereafter.

---------------------------------------------------------
Title: The solar, exoplanet and cosmological lithium problems
Authors: Meléndez, J.; Ramírez, I.; Casagrande, L.; Asplund, M.;
   Gustafsson, B.; Yong, D.; Do Nascimento, J. D.; Castro, M.; Bazot, M.
2010Ap&SS.328..193M    Altcode: 2009Ap&SS.tmp..221M; 2009arXiv0910.5845M
  We review three Li problems. First, the Li problem in the Sun, for which
  some previous studies have argued that it may be Li-poor compared to
  other Suns. Second, we discuss the Li problem in planet hosting stars,
  which are claimed to be Li-poor when compared to field stars. Third,
  we discuss the cosmological Li problem, i.e. the discrepancy between
  the Li abundance in metal-poor stars (Spite plateau stars) and the
  predictions from standard Big Bang Nucleosynthesis. In all three cases
  we find that the “problems” are naturally explained by non-standard
  mixing in stars.

---------------------------------------------------------
Title: Radiative transfer with scattering for domain-decomposed 3D
    MHD simulations of cool stellar atmospheres. Numerical methods and
    application to the quiet, non-magnetic, surface of a solar-type star
Authors: Hayek, W.; Asplund, M.; Carlsson, M.; Trampedach, R.; Collet,
   R.; Gudiksen, B. V.; Hansteen, V. H.; Leenaarts, J.
2010A&A...517A..49H    Altcode: 2010arXiv1007.2760H
  <BR /> Aims: We present the implementation of a radiative
  transfer solver with coherent scattering in the new BIFROST
  code for radiative magneto-hydrodynamical (MHD) simulations of
  stellar surface convection. The code is fully parallelized using
  MPI domain decomposition, which allows for large grid sizes and
  improved resolution of hydrodynamical structures. We apply the code
  to simulate the surface granulation in a solar-type star, ignoring
  magnetic fields, and investigate the importance of coherent scattering
  for the atmospheric structure. <BR /> Methods: A scattering term
  is added to the radiative transfer equation, requiring an iterative
  computation of the radiation field. We use a short-characteristics-based
  Gauss-Seidel acceleration scheme to compute radiative flux divergences
  for the energy equation. The effects of coherent scattering are
  tested by comparing the temperature stratification of three 3D
  time-dependent hydrodynamical atmosphere models of a solar-type star:
  without scattering, with continuum scattering only, and with both
  continuum and line scattering. <BR /> Results: We show that continuum
  scattering does not have a significant impact on the photospheric
  temperature structure for a star like the Sun. Including scattering in
  line-blanketing, however, leads to a decrease of temperatures by about
  350 K below log<SUB>10</SUB> τ<SUB>5000</SUB> ⪉ -4. The effect is
  opposite to that of 1D hydrostatic models in radiative equilibrium,
  where scattering reduces the cooling effect of strong LTE lines in
  the higher layers of the photosphere. Coherent line scattering also
  changes the temperature distribution in the high atmosphere, where
  we observe stronger fluctuations compared to a treatment of lines as
  true absorbers.

---------------------------------------------------------
Title: The chemical composition of solar-type stars in comparison
    with that of the Sun
Authors: Gustafsson, Bengt; Meléndez, Jorge; Asplund, Martin;
   Yong, David
2010Ap&SS.328..185G    Altcode: 2010Ap&SS.tmp...36G
  The question whether the solar chemical composition is typical for
  solar-type stars is analysed by comparing the Sun with different stellar
  samples, including a sample of stars with very similar parameters,
  solar twins. Although typical in terms of overall metallicity for
  stars of solar age and galactic orbit, the solar atmosphere is found to
  have abundances, as compared with solar twins, that indicate that its
  gas has once been affected by dust formation and dust separation. It
  is concluded that this may be related to the formation of the solar
  planetary system and its special properties.

---------------------------------------------------------
Title: Observational evidence for a broken Li Spite plateau and
    mass-dependent Li depletion
Authors: Meléndez, J.; Casagrande, L.; Ramírez, I.; Asplund, M.;
   Schuster, W. J.
2010A&A...515L...3M    Altcode: 2010arXiv1005.2944M
  We present NLTE Li abundances for 88 stars in the metallicity range
  -3.5 &lt; [Fe/H] &lt; -1.0. The effective temperatures are based on the
  infrared flux method with improved E(B-V) values obtained mostly from
  interstellar Na I D lines. The Li abundances were derived through MARCS
  models and high-quality UVES+VLT, HIRES+Keck and FIES+NOT spectra, and
  complemented with reliable equivalent widths from the literature. The
  less-depleted stars with [Fe/H] &lt; -2.5 and [Fe/H] &gt; -2.5 fall
  into two well-defined plateaus of A<SUB>Li</SUB> = 2.18 (σ = 0.04) and
  A<SUB>Li</SUB> = 2.27 (σ = 0.05), respectively. We show that the two
  plateaus are flat, unlike previous claims for a steep monotonic decrease
  in Li abundances with decreasing metallicities. At all metallicities we
  uncover a fine-structure in the Li abundances of Spite plateau stars,
  which we trace to Li depletion that depends on both metallicity and
  mass. Models including atomic diffusion and turbulent mixing seem to
  reproduce the observed Li depletion assuming a primordial Li abundance
  A<SUB>Li</SUB> = 2.64, which agrees well with current predictions
  (A<SUB>Li</SUB> = 2.72) from standard Big Bang nucleosynthesis. Adopting
  the Kurucz overshooting model atmospheres increases the Li abundance
  by +0.08 dex to A<SUB>Li</SUB> = 2.72, which perfectly agrees with
  BBN+WMAP. <P />Based in part on observations obtained at the W. M. Keck
  Observatory, the Nordic Optical Telescope on La Palma, and on data from
  the HIRES/Keck archive and the European Southern Observatory ESO/ST-ECF
  Science Archive Facility.Table 1 is only available in electronic form
  at <A href="http://www.aanda.org">http://www.aanda.org</A>

---------------------------------------------------------
Title: Commission 29: Stellar Spectra
Authors: Piskunov, Nikolai; Cunha, Katia; Parthasarathy, Mudumba;
   Aoki, Wako; Asplund, Martin; Bohlender, David; Carpenter, Kenneth;
   Melendez, Jorge; Parthasarathy, Mudumba; Rossi, Silvia; Smith, Verne;
   Soderblom, David; Wahlgren, Glenn
2010IAUTB..27..193P    Altcode:
  The business meeting was attended by 23 members of the Commission. The
  meeting started at 16:00 a short report of the activities during the
  triennium 2006-2009. The focus of the activities was the sharing
  of expertise between spectroscopic techniques in various areas of
  astronomical research. In particular, the progress in instrumentation,
  detectors, data reduction, data analysis and archiving. The second
  activity was the analysis of to IAU meeting proposals followed by
  recommendations for improvements and eventually support. The sponsored
  symposia included Sponsoring symposia The Ages of Stars and The Disk
  Galaxy Evolution in the Cosmological Context. The Commission was also
  disseminating information about the Commission activities and relevant
  meetings to the Commission members. In this respect the Commission
  web page is playing a crucial role.

---------------------------------------------------------
Title: Commission 36: Theory of Stellar Atmospheres
Authors: Asplund, Martin; Puls, Joachim; Landstreet, John; Allende
   Prieto, Carlos; Ayres, Thomas; Berdyugina, Svetlana; Gustafsson,
   Bengt; Hubeny, Ivan; Ludwig, Hans Günter; Mashonkina, Lyudmila;
   Randich, Sofia
2010IAUTB..27..197A    Altcode:
  The members of the Commission 36 Organizing Committee attending the IAU
  General Assembly in Rio de Janeiro met for a business session on August
  7. Both members from the previous (2006-2009) and the new (2009-2012)
  Organizing Committee partook in the discussions. Past president John
  Landstreet described the work he had done over the past three years
  in terms of supporting proposed conferences on the topic. He has
  also spent significant amount of time establishing an updated mailing
  list of all &gt;350 members of the commission, which is unfortunately
  not provided automatically by the IAU. Such a list is critical for a
  rapid dissemination of information to the commission members and for
  a correct and smooth running of elections of IAU officials. Everyone
  present thanked John effusively for all of his hard work over the past
  three years to stimulate a high level of activity within the discipline.

---------------------------------------------------------
Title: Lithium in other Suns: no connection between stars and planets
Authors: Meléndez, Jorge; Ramírez, Iván; Asplund, Martin; Baumann,
   Patrick
2010IAUS..268..341M    Altcode:
  An unbiased sample of solar twins shows that the Sun has a normal
  Li abundance for its age and that a low Li abundance does not imply
  the presence of planets. We find a tight correlation between Li and
  age, which holds for all stars analyzed in our sample: solar twins,
  stars with and without detected giant planets, and stars that may host
  terrestrial planets.

---------------------------------------------------------
Title: Chemical similarities between Galactic bulge and local thick
disk red giants: O, Na, Mg, Al, Si, Ca, and Ti
Authors: Alves-Brito, A.; Meléndez, J.; Asplund, M.; Ramírez, I.;
   Yong, D.
2010A&A...513A..35A    Altcode: 2010arXiv1001.2521A
  Context. The formation and evolution of the Galactic bulge and its
  relationship with the other Galactic populations is still poorly
  understood. <BR /> Aims: To establish the chemical differences and
  similarities between the bulge and other stellar populations, we
  performed an elemental abundance analysis of α- (O, Mg, Si, Ca, and
  Ti) and Z-odd (Na and Al) elements of red giant stars in the bulge
  as well as of local thin disk, thick disk and halo giants. <BR />
  Methods: We use high-resolution optical spectra of 25 bulge giants in
  Baade's window and 55 comparison giants (4 halo, 29 thin disk and 22
  thick disk giants) in the solar neighborhood. All stars have similar
  stellar parameters but cover a broad range in metallicity (-1.5 &lt;
  [Fe/H] &lt; +0.5). A standard 1D local thermodynamic equilibrium
  analysis using both Kurucz and MARCS models yielded the abundances
  of O, Na, Mg, Al, Si, Ca, Ti and Fe. Our homogeneous and differential
  analysis of the Galactic stellar populations ensured that systematic
  errors were minimized. <BR /> Results: We confirm the well-established
  differences for [α/Fe] at a given metallicity between the local thin
  and thick disks. For all the elements investigated, we find no chemical
  distinction between the bulge and the local thick disk, in agreement
  with our previous study of C, N and O but in contrast to other groups
  relying on literature values for nearby disk dwarf stars. For -1.5
  &lt; [Fe/H] &lt; -0.3 exactly the same trend is followed by both the
  bulge and thick disk stars, with a star-to-star scatter of only 0.03
  dex. Furthermore, both populations share the location of the knee
  in the [α/Fe] vs. [Fe/H] diagram. It still remains to be confirmed
  that the local thick disk extends to super-solar metallicities as is
  the case for the bulge. These are the most stringent constraints to
  date on the chemical similarity of these stellar populations. <BR />
  Conclusions: Our findings suggest that the bulge and local thick disk
  stars experienced similar formation timescales, star formation rates
  and initial mass functions, confirming thus the main outcomes of our
  previous homogeneous analysis of [O/Fe] from infrared spectra for nearly
  the same sample. The identical α-enhancements of thick disk and bulge
  stars may reflect a rapid chemical evolution taking place before the
  bulge and thick disk structures we see today were formed, or it may
  reflect Galactic orbital migration of inner disk/bulge stars resulting
  in stars in the solar neighborhood with thick-disk kinematics. <P
  />Tables 8-15 are only available in electronic form at the CDS
  via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A
  href="http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/513/A35">http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/513/A35</A>

---------------------------------------------------------
Title: The light elements in the light of 3D and non-LTE effects
Authors: Asplund, Martin; Lind, Karin
2010IAUS..268..191A    Altcode: 2010arXiv1002.1993A
  In this review we discuss possible systematic errors inherent
  in classical 1D LTE abundance analyses of late-type stars for
  the light elements (here: H, He, Li, Be and B). The advent of
  realistic 3D hydrodynamical model atmospheres and the availability
  of non-LTE line formation codes place the stellar analyses on a
  much firmer footing and indeed drastically modify the astrophysical
  interpretations in many cases, especially at low metallicities. For
  the T<SUB>eff</SUB>-sensitive hydrogen lines both stellar granulation
  and non-LTE are likely important but the combination of the two has not
  yet been fully explored. A fortuitous near-cancellation of significant
  but opposite 3D and non-LTE effects leaves the derived <SUP>7</SUP>Li
  abundances largely unaffected but new atomic collisional data should
  be taken into account. We also discuss the impact on 3D non-LTE line
  formation on the estimated lithium isotopic abundances in halo stars
  in light of recent claims that convective line asymmetries can mimic
  the presence of <SUP>6</SUP>Li. While Be only have relatively minor
  non-LTE abundance corrections, B is sensitive even if the latest
  calculations imply smaller non-LTE effects than previously thought.

---------------------------------------------------------
Title: Observational signatures of lithium depletion in the metal-poor
    globular cluster NGC6397
Authors: Lind, Karin; Primas, Francesca; Charbonnel, Corinne; Grundahl,
   Frank; Asplund, Martin
2010IAUS..268..263L    Altcode: 2010arXiv1001.5153L
  The “stellar” solution to the cosmological lithium problem proposes
  that surface depletion of lithium in low-mass, metal-poor stars can
  reconcile the lower abundances found for Galactic halo stars with
  the primordial prediction. Globular clusters are ideal environments
  for studies of the surface evolution of lithium, with large number
  statistics possible to obtain for main sequence stars as well as
  giants. We discuss the Li abundances measured for &gt;450 stars in
  the globular cluster NGC 6397, focusing on the evidence for lithium
  depletion and especially highlighting how the inferred abundances
  and interpretations are affected by early cluster self-enrichment and
  systematic uncertainties in the effective temperature determination.

---------------------------------------------------------
Title: Observational signatures for depletion in the Spite plateau:
    solving the cosmological Li discrepancy?
Authors: Meléndez, Jorge; Casagrande, Luca; Ramírez, Iván; Asplund,
   Martin; Schuster, William J.
2010IAUS..268..211M    Altcode: 2009arXiv0912.2949M
  We present Li abundances for 73 stars in the metallicity range -3.5
  &lt; [Fe/H] &lt; -1.0 using improved IRFM temperatures (Casagrande et
  al. 2010) with precise E(B-V) values obtained mostly from interstellar
  NaI D lines, and high-quality equivalent widths (σ<SUB>EW</SUB>
  ~ 3%). At all metallicities we uncover a fine-structure in the Li
  abundances of Spite plateau stars, which we trace to Li depletion that
  depends on both metallicity and mass. Models including atomic diffusion
  and turbulent mixing seem to reproduce the observed Li depletion
  assuming a primordial Li abundance A<SUB>Li</SUB> = 2.64 dex (MARCS
  models) or 2.72 (Kurucz overshooting models), in good agreement with
  current predictions (A<SUB>Li</SUB> = 2.72) from standard BBN. We are
  currently expanding our sample to have a better coverage of different
  evolutionary stages at the high and low metallicity ends, in order to
  verify our findings.

---------------------------------------------------------
Title: Chemical similarities between the Galactic bulge and local
thick disk red giant stars: analysis from optical data
Authors: Alves-Brito, Alan; Meléndez, Jorge; Asplund, Martin
2010IAUS..265..342A    Altcode:
  The Galactic structure and composition remain as one of the greatest
  open problems in modern astrophysics. We show here that there are
  chemical similarities between the Galactic bulge and local thick disk
  red giant stars. This finding puts strong constraints on the IMF,
  SFR and chemical enrichment timescale of the bulge and thick disk. Our
  results are based upon a detailed elemental abundance analysis of 80
  high S/N and high resolution optical spectra of giant stars, in the
  range -1.5 &lt; [Fe/H] &lt; +0.5.

---------------------------------------------------------
Title: A Puzzle Involving Galactic Bulge Microlensing Events
Authors: Cohen, Judith G.; Gould, Andrew; Thompson, Ian B.; Feltzing,
   Sofia; Bensby, Thomas; Johnson, Jennifer A.; Huang, Wenjin; Meléndez,
   Jorge; Lucatello, Sara; Asplund, Martin
2010ApJ...711L..48C    Altcode: 2009arXiv0911.5081C
  We study a sample of 16 microlensed Galactic bulge main-sequence turnoff
  region stars for which high-dispersion spectra have been obtained with
  detailed abundance analyses. We demonstrate that there is a very strong
  and highly statistically significant correlation between the maximum
  magnification of the microlensed bulge star and the value of the [Fe/H]
  deduced from the high resolution spectrum of each object. Physics
  demands that this correlation, assuming it to be real, be the result
  of some sample bias. We suggest several possible explanations, but are
  forced to reject them all, and are left puzzled. To obtain a reliable
  metallicity distribution in the Galactic bulge based on microlensed
  dwarf stars, it will be necessary to resolve this issue through the
  course of additional observations. <P />Based in part on observations
  obtained at the W. M. Keck Observatory, which is operated jointly by
  the California Institute of Technology, the University of California,
  and the National Aeronautics and Space Administration.

---------------------------------------------------------
Title: Unprecedented accurate abundances: signatures of other Earths?
Authors: Meléndez, Jorge; Asplund, Martin; Gustafsson, Bengt; Yong,
   David; Ramírez, Iván
2010IAUS..265..412M    Altcode: 2009arXiv0910.0875M
  For more than 140 years the chemical composition of our Sun has
  been considered typical of solar-type stars. Our highly differential
  elemental abundance analysis of unprecedented accuracy (~0.01 dex)
  of the Sun relative to solar twins, shows that the Sun has a peculiar
  chemical composition with a ≈20% depletion of refractory elements
  relative to the volatile elements in comparison with solar twins. The
  abundance differences correlate strongly with the condensation
  temperatures of the elements. A similar study of solar analogs from
  planet surveys shows that this peculiarity also holds in comparisons
  with solar analogs known to have close-in giant planets while the
  majority of solar analogs without detected giant planets show the solar
  abundance pattern. The peculiarities in the solar chemical composition
  can be explained as signatures of the formation of terrestrial planets
  like our own Earth.

---------------------------------------------------------
Title: Chemical evolution of the Galactic bulge as traced by
    microlensed dwarf and subgiant stars. II. Ages, metallicities,
    detailed elemental abundances, and connections to the Galactic
    thick disc
Authors: Bensby, T.; Feltzing, S.; Johnson, J. A.; Gould, A.; Adén,
   D.; Asplund, M.; Meléndez, J.; Gal-Yam, A.; Lucatello, S.; Sana,
   H.; Sumi, T.; Miyake, N.; Suzuki, D.; Han, C.; Bond, I.; Udalski, A.
2010A&A...512A..41B    Altcode: 2009arXiv0911.5076B
  Context. The Bulge is the least understood major stellar population of
  the Milky Way. Most of what we know about the formation and evolution
  of the Bulge comes from bright giant stars. The underlying assumption
  that giants represent all the stars, and accurately trace the chemical
  evolution of a stellar population, is under debate. In particular,
  recent observations of a few microlensed dwarf stars give a very
  different picture of the evolution of the Bulge from that given by the
  giant stars. <BR /> Aims: We aim to resolve the apparent discrepancy
  between Bulge metallicity distributions derived from microlensed
  dwarf stars and giant stars. Additionally, we aim to put observational
  constraints on the elemental abundance trends and chemical evolution
  of the Bulge. <BR /> Methods: We perform a detailed elemental abundance
  analysis of dwarf stars in the Galactic bulge, based on high-resolution
  spectra that were obtained while the stars were optically magnified
  during gravitational microlensing events. The analysis method is
  the same as for a large sample of F and G dwarf stars in the Solar
  neighbourhood, enabling a fully differential comparison between the
  Bulge and the local stellar populations in the Galactic disc. <BR />
  Results: We present detailed elemental abundances and stellar ages
  for six new dwarf stars in the Galactic bulge. Combining these with
  previous events, here re-analysed with the same methods, we study a
  homogeneous sample of 15 stars, which constitute the largest sample to
  date of microlensed dwarf stars in the Galactic bulge. We find that the
  stars span the full range of metallicities from [Fe/H] = -0.72 to +0.54,
  and an average metallicity of &lt; [Fe/H]&gt; = -0.08 ± 0.47, close to
  the average metallicity based on giant stars in the Bulge. Furthermore,
  the stars follow well-defined abundance trends, that for [Fe/H]&lt;0
  are very similar to those of the local Galactic thick disc. This
  suggests that the Bulge and the thick disc have had, at least partially,
  comparable chemical histories. At sub-solar metallicities we find the
  Bulge dwarf stars to have consistently old ages, while at super-solar
  metallicities we find a wide range of ages. Using the new age and
  abundance results from the microlensed dwarf stars we investigate
  possible formation scenarios for the Bulge. <P />Based on observations
  made with the European Southern Observatory telescopes, Program IDs
  082.B-0453 and 083.B-0265.Table 5 is also available in electronic form
  at the CDS and full Table 4 is only available in electronic form at the
  CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A
  href="http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/512/A41">http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/512/A41</A>

---------------------------------------------------------
Title: Elemental abundances in the Galactic bulge from microlensed
    dwarf stars
Authors: Bensby, T.; Feltzing, S.; Johnson, J. A.; Gould, A.; Sana,
   H.; Gal-Yam, A.; Asplund, M.; Lucatello, S.; Melendez, J.; Udalski,
   A.; Kubas, D.; James, G.; Adén, D.; Simmerer, J.
2010IAUS..265..346B    Altcode: 2009arXiv0908.2779B
  We present elemental abundances of 13 microlensed dwarf and subgiant
  stars in the Galactic bulge, which constitute the largest sample to
  date. We show that these stars span the full range of metallicity from
  Fe/H= -0.8 to +0.4, and that they follow well-defined abundance trends,
  coincident with those of the Galactic thick disc.

---------------------------------------------------------
Title: A possible signature of terrestrial planet formation in the
    chemical composition of solar twins
Authors: Ramírez, I.; Meléndez, J.; Asplund, M.; Baumann, P.
2010iac..talk....2R    Altcode: 2010iac..talk..148R
  No abstract at ADS

---------------------------------------------------------
Title: VizieR Online Data Catalog: Abundances in solar analogs
    (Ramirez+, 2009)
Authors: Ramirez, I.; Melendez, J.; Asplund, M.
2010yCat..35089017R    Altcode:
  Our sample stars were selected from the Hipparcos catalog (I/239) by
  applying constraints on color, based on the color-Teff calibrations by
  Ramirez &amp; Melendez (2005ApJ...626..465R), corrected by suspected
  zero point errors (Casagrande et al., 2009, submitted), trigonometric
  parallaxes, and literature values for [Fe/H] and chromospheric activity,
  if available. About 100 stars satisfied our selection criteria
  and, given our observational constraints, data for 64 of them were
  acquired. We also observed the asteroids Vesta and Ceres as solar
  reference. <P />(2 data files).

---------------------------------------------------------
Title: Precise Li abundances in metal-poor stars: depletion in the
    Spite plateau
Authors: Meléndez, J.; Casagrande, L.; Ramírez, I.; Asplund, M.
2010IAUS..265...71M    Altcode:
  We present Li abundances for 73 stars in the metallicity range -3.5
  &lt; [Fe/H] &lt; -1.0 using improved IRFM temperatures (Casagrande et
  al. 2009) with precise E(B-V) values obtained mostly from interstellar
  NaI D lines, and high-quality equivalent widths (σ<SUB>EW</SUB>
  ~ 3%). At all metallicities we uncover a fine-structure in the Li
  abundances of Spite plateau stars, which we trace to Li depletion
  that depends on both metallicity and mass. Models including atomic
  diffusion and turbulent mixing seem to reproduce the observed Li
  depletion assuming a primordial Li abundance A<SUB>Li</SUB> = 2.64 dex
  (MARCS models) or 2.72 (Kurucz overshooting models), in good agreement
  with current predictions (A<SUB>Li</SUB> = 2.72) from standard BBN.

---------------------------------------------------------
Title: An absolutely calibrated T<SUB>eff</SUB> scale from the
    infrared flux method. Dwarfs and subgiants
Authors: Casagrande, L.; Ramírez, I.; Meléndez, J.; Bessell, M.;
   Asplund, M.
2010A&A...512A..54C    Altcode: 2010arXiv1001.3142C
  Various effective temperature scales have been proposed over the
  years. Despite much work and the high internal precision usually
  achieved, systematic differences of order 100 K (or more) among
  various scales are still present. We present an investigation based
  on the infrared flux method aimed at assessing the source of such
  discrepancies and pin down their origin. We break the impasse among
  different scales by using a large set of solar twins, stars which
  are spectroscopically and photometrically identical to the Sun,
  to set the absolute zero point of the effective temperature scale
  to within few degrees. Our newly calibrated, accurate and precise
  temperature scale applies to dwarfs and subgiants, from super-solar
  metallicities to the most metal-poor stars currently known. At solar
  metallicities our results validate spectroscopic effective temperature
  scales, whereas for [Fe/H]⪉ -2.5 our temperatures are roughly 100
  K hotter than those determined from model fits to the Balmer lines
  and 200 K hotter than those obtained from the excitation equilibrium
  of Fe lines. Empirical bolometric corrections and useful relations
  linking photometric indices to effective temperatures and angular
  diameters have been derived. Our results take full advantage of the
  high accuracy reached in absolute calibration in recent years and
  are further validated by interferometric angular diameters and space
  based spectrophotometry over a wide range of effective temperatures and
  metallicities. <P />Table 8 is only available in electronic form at the
  CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A
  href="http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/512/A54">http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/512/A54</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: Teff and Fbol from Infrared Flux
    Method (Casagrande+, 2010)
Authors: Casagrande, L.; Ramirez, I.; Melendez, J.; Bessell, M.;
   Asplund, M.
2010yCat..35120054C    Altcode: 2010yCat..35129054C
  Sample stars used and fundamental physical parameters (Teff, Fbol, diam)
  derived via IRFM. The apparent bolometric magnitudes (mBol) have been
  computed according to Casagrande et al. (2006MNRAS.373...13C), where the
  absolute bolometric magnitude of the Sun MBol<SUB>⊙</SUB>=4.74. For
  each star mBol is obtained using its bolometric flux (Fbol) and
  effective temperature (Teff) and therefore it is already corrected for
  reddening, if present. Notice however that the observed magnitudes
  given here are not: before computing bolometric corrections,
  the observed magnitudes should be dereddened using the E(B-V)
  given here. The correction into dereddened magnitudes as been done
  iteratively, as described in Section 2.1 of the paper. However,
  average relations between E(B-V) and various photometric bands can
  be found in literature e.g. McCall (2004AJ....128.2144M). Bolometric
  corrections in each band can be readily obtained using the dereddened
  magnitudes. E.g. BC<SUB>V</SUB>=mBol-V0, where BC<SUB>V</SUB> is the
  bolometric correction in V band, mBol is thw apparent bolometric
  magnitude, V0 is the dereddened apparent V magnitude (=Vmag if
  E(B-V)=0). Errors have been computed as described in the paper, without
  accounting for the uncertainty in E(B-V): changing it by +/-0.01 would
  affect Teff by approximately +/-50K. <P />(1 data file).

---------------------------------------------------------
Title: VizieR Online Data Catalog: Abundances of microlensed stars
    in the Bulge (Bensby+, 2010)
Authors: Bensby, T.; Feltzing, S.; Johnson, J. A.; Gould, A.; Aden,
   D.; Asplund, M.; Melendez, J.; Gal-Yam, A.; Lucatello, S.; Sana, H.;
   Sumi, T.; Miyake, N.; Suzuki, N.; Han, C.; Bond, I.; Udalski, A.
2010yCat..35120041B    Altcode: 2010yCat..35129041B
  For each spectral line we give the lower excitation potential, measured
  equivalent widths, and derived absolute abundances. We also give median
  abundances for each star, normalised to the Sun, and errors in the
  median abundances. <P />(3 data files).

---------------------------------------------------------
Title: Searching for Signatures of Radial Mixing in The Chemically
    Divided Galactic Disks
Authors: Lee, Young S.; Schonrich, R.; Beers, T. C.; Heather, M. L.;
   An, D.; Allende Prieto, C.; Asplund, M.; Carollo, D.; Rockosi, C. M.
2010AAS...21541303L    Altcode: 2010BAAS...42R.250L
  The Milky Way's thick disk was originally identified by fitting
  the vertical density distribution of stars to a double exponential
  profile. Recent investigations have shown that, in addition to being
  older, thick disk stars show chemical and kinematical properties
  distinct from the thin disk. Most scenarios of thick disk formation
  discussed to date emphasize mergers, e.g., heating of a pre-existing
  thin disk, accretion of stars from disrupted <P />satellites, or in-situ
  formation induced by infalling gas-rich systems. Recently, however,
  growing observational and theoretical evidence has suggested that the
  thick disk might be the result of the cumulative radial migration
  of disk stars over the history of the Galaxy. According to these
  models, disk stars move radially over their lifetimes, spreading the
  chemical signatures associated with their birth place at a range of
  galactocentric distances and giving rise to chemical and kinematical
  signatures corresponding to the common thin and thick disk divisions. In
  this study we search for observational signatures of radial mixing in
  the disk populations based on a large sample of F-and G-type dwarfs
  observed by SEGUE-1, divided into thin and thick disk populations
  characterized by low (-0.1 &lt;[α/Fe] &lt; +0.2) and high (+0.3 &lt;
  [α/Fe] &lt; +0.6) α-abundances, respectively. We also demonstrate
  that we are able to determine [α/Fe] with an accuracy of &lt; 0.1
  dex down to S/N = 20/1 for the SEGUE stellar spectra. <P />This work
  was supported in part by grants PHY 02-16783 and PHY <P />08-22648:
  Physics Frontiers Center / Joint Institute for Nuclear <P />Astrophysics
  (JINA), awarded by the U.S. National Science Foundation.

---------------------------------------------------------
Title: The lithium history of NGC 6397
Authors: Primas, Francesca; Lind, Karin; Charbonnel, Corinne; Grundahl,
   Frank; Asplund, Martin
2010IAUS..266..143P    Altcode:
  The primordial lithium abundance inferred from WMAP and standard Big
  Bang nucleosysnthesis is approximately three times higher than the
  plateau value measured in old metal-poor Population II stars, suggesting
  that these stars have undergone atmospheric Li depletion. To constrain
  the physics responsible for such depletion, we conducted a homogeneous
  analysis of a large sample of stars in the metal-poor globular cluster
  NGC 6397, covering all evolutionary phases from below the main-sequence
  turnoff to high up the red-giant branch (RGB). The dwarf, turnoff,
  and early subgiant stars form a thin abundance plateau, with a sharpe
  edge in the middle of the subgiant branch, where Li dilution caused by
  the inward extension of the convective envelope starts (the beginning
  of the so-called first dredge up). A second steep abundance drop
  is seen at the RGB bump, again highlighting the need for the onset
  of nonstandard mixing in this evolutionary phase. Moreover, by also
  measuring the sodium abundances of the targets, we have gained insight
  into the degree of pollution by early cluster self-enrichement, and may
  separate highly polluted, Li-poor and Na-rich stars from stars formed
  from pristine material. Our observational findings strictly limit both
  the extent of lithium surface depletion, which in turn constrains the
  efficiency of mixing below the outer convection zone, and the resulting
  spread in lithium abundance in metal-poor turn-off stars.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Abundances of Galactic red giants
    (Alves-Brito+, 2010)
Authors: Alves-Brito, A.; Melendez, J.; Asplund, M.; Ramirez, I.;
   Yong, D.
2010yCat..35130035A    Altcode: 2010yCat..35139035A
  Line list and equivalent widths (EWs) of a sample of 80 giant stars
  in the Galactic bulge, halo, thin- and thick disk. The list includes
  lines of [OI], NaI, MgI, AlI, SiI, CaI, TiI, FeI and FeII. The adopted
  oscillator strengths (loggfs) and excitation potential (EP) are also
  listed. For the bulge stars, the EWs were taken from Fulbrigth et
  al. (2006, Cat. &lt;J/ApJ/636/821&gt;, 2007ApJ...661.1152F). Refer to
  the paper's text for more detail. <P />(2 data files).

---------------------------------------------------------
Title: Chemical abundances of 11 bulge stars from high-resolution,
    near-IR spectra
Authors: Ryde, N.; Gustafsson, B.; Edvardsson, B.; Meléndez, J.;
   Alves-Brito, A.; Asplund, M.; Barbuy, B.; Hill, V.; Käufl, H. U.;
   Minniti, D.; Ortolani, S.; Renzini, A.; Zoccali, M.
2010A&A...509A..20R    Altcode: 2009arXiv0910.0448R
  Context. It is debated whether the Milky Way bulge has characteristics
  more similar to those of a classical bulge than those of a
  pseudobulge. Detailed abundance studies of bulge stars are important
  when investigating the origin, history, and classification of the
  bulge. These studies provide constraints on the star-formation
  history, initial mass function, and differences between stellar
  populations. Not many similar studies have been completed because
  of the large distance and high variable visual extinction along the
  line-of-sight towards the bulge. Therefore, near-IR investigations
  can provide superior results. <BR /> Aims: To investigate the origin
  of the bulge and study its chemical abundances determined from
  near-IR spectra for bulge giants that have already been investigated
  with optical spectra. The optical spectra also provide the stellar
  parameters that are very important to the present study. In particular,
  the important CNO elements are determined more accurately in the
  near-IR. Oxygen and other α elements are important for investigating
  the star-formation history. The C and N abundances are important for
  determining the evolutionary stage of the giants and the origin of C
  in the bulge. <BR /> Methods: High-resolution, near-infrared spectra
  in the H band were recorded using the CRIRES spectrometer mounted on
  the Very Large Telescope. The CNO abundances are determined from the
  numerous molecular lines in the wavelength range observed. Abundances
  of the α elements Si, S, and Ti are also determined from the near-IR
  spectra. <BR /> Results: The abundance ratios [O/Fe], [Si/Fe], and
  [S/Fe] are enhanced to metallicities of at least [Fe/H] = -0.3, after
  which they decline. This suggests that the Milky Way bulge experienced a
  rapid and early burst of star formation similar to that of a classical
  bulge. However, a similarity between the bulge trend and the trend of
  the local thick disk seems to be present. This similarity suggests that
  the bulge could have had a pseudobulge origin. The C and N abundances
  suggest that our giants are first-ascent red-giants or clump stars,
  and that the measured oxygen abundances are those with which the
  stars were born. Our [C/Fe] trend does not show any increase with
  [Fe/H], which is expected if W-R stars contributed substantially to
  the C abundances. No “cosmic scatter” can be traced around our
  observed abundance trends: the measured scatter is expected, given the
  observational uncertainties. <P />Based on observations collected at
  the European Southern Observatory, Chile (ESO program 079.B-0338(A)).

---------------------------------------------------------
Title: Improved log(gf) Values Of Selected Lines In Mn I And Mn II
    For Studies Of Non-equilibrium Effects In Stellar Photospheres
Authors: Den Hartog, Elizabeth; Lawler, J. E.; Sobeck, J.; Sneden,
   C.; Cowan, J. J.; Asplund, M.
2010AAS...21542403D    Altcode: 2010BAAS...42..330D
  The work presents transition probabilities with very low uncertainties
  for a selected set of multiplets of Mn I and Mn II. Multiplets are
  chosen which are accessible to ground-based observation, are relatively
  unblended and unsaturated in stellar spectra and which are amenable
  to accurate branching fraction determination. These lab measurements
  provide a foundation for studies of non-LTE and 3-dimensional effects in
  stellar photospheres. We report on new radiative lifetime measurements
  for 22 levels of Mn I from the e<SUP>8</SUP>D, z<SUP>6</SUP>P,
  z<SUP>6</SUP>D, z<SUP>4</SUP>F, e<SUP>8</SUP>S and e<SUP>6</SUP>S
  multiplets and 3 levels of Mn II from the z<SUP>5</SUP>P multiplet using
  time-resolved laser-induced fluorescence on a slow atomic beam. New
  branching fractions for transitions from these levels, measured using
  a Fourier-transform spectrometer, are also reported. When combined,
  these measurements yield transition probabilities for 47 transitions
  of Mn I and 12 transitions of Mn II. Comparisons are made to data
  from the literature and to simple Russell-Saunders or LS theory. Final
  recommended values, which are weighted averages of all available modern
  measurements and in some cases LS theory, are given for the transition
  probabilities. These recommended log(gf) values are accurate to +/-
  0.02 dex with high ( 2 sigma) confidence. The companion paper applies
  these new lab results to studies of departures from both LTE in Mn I
  and Saha equilibrium between Mn I and Mn II on a variety of stellar
  photospheres. This research is supported in part by NASA Grant
  NNX08AQ09G and NSF Grant AST-0907732.

---------------------------------------------------------
Title: Accurate abundance patterns of solar twins and analogs. Does
    the anomalous solar chemical composition come from planet formation?
Authors: Ramírez, I.; Meléndez, J.; Asplund, M.
2009A&A...508L..17R    Altcode:
  We derive the abundance of 19 elements in a sample of 64 stars with
  fundamental parameters very similar to solar, which minimizes the
  impact of systematic errors in our spectroscopic 1D-LTE differential
  analysis, using high-resolution (R≃60 000), high signal-to-noise ratio
  (S/N≃200) spectra. The estimated errors in the elemental abundances
  relative to solar are as small as ≃0.025 dex. The abundance ratios
  [X/Fe] as a function of [Fe/H] agree closely with previously established
  patterns of Galactic thin-disk chemical evolution. Interestingly, the
  majority of our stars show a significant correlation between [X/Fe]
  and condensation temperature (T_C). In the sample of 22 stars with
  parameters closest to solar, we find that, on average, low T<SUB>C</SUB>
  elements are depleted with respect to high T<SUB>C</SUB> elements in
  the solar twins relative to the Sun by about 0.08 dex (≃20%). An
  increasing trend is observed for the abundances as a function of
  T<SUB>C</SUB> for 900&lt;T_C&lt;1800 K, while abundances of lower
  T<SUB>C</SUB> elements appear to be roughly constant. We speculate that
  this is a signature of the planet formation that occurred around the Sun
  but not in the majority of solar twins. If this hypothesis is correct,
  stars with planetary systems like ours, although rare (frequency of
  ≃15%), may be identified through a very detailed inspection of the
  chemical compositions of their host stars. <P />Figure 1 and Tables
  1-4 are only available in electronic form at http://www.aanda.org

---------------------------------------------------------
Title: Oxygen lines in solar granulation. II. Centre-to-limb
    variation, NLTE line formation, blends, and the solar oxygen abundance
Authors: Pereira, T. M. D.; Asplund, M.; Kiselman, D.
2009A&A...508.1403P    Altcode: 2009arXiv0909.2310P
  Context: There is a lively debate about the solar oxygen abundance and
  the role of 3D models in its recent downward revision. These models
  have been tested using high-resolution solar atlases of flux and
  disk-centre intensity. Further testing can be done using centre-to-limb
  variations.<BR /> Aims: Using high-resolution and high S/N observations
  of neutral oxygen lines across the solar surface, we seek to test
  that the 3D and 1D models reproduce their observed centre-to-limb
  variation. In particular we seek to assess whether the latest generation
  of 3D hydrodynamical solar model atmospheres and NLTE line formation
  calculations are appropriate to derive the solar oxygen abundance.<BR />
  Methods: We use our recent observations of O i 777 nm, O i 615.81 nm,
  [O i] 630.03 nm, and nine lines of other elements for five viewing
  angles 0.2≤μ≤ 1 of the quiet solar disk. We compared them with
  the predicted line profiles from the 3D and 1D models computed with
  the most up-to-date line formation codes and line data and allowing
  for departures of LTE. The centre-to-limb variation of the O i 777 nm
  lines is also used to obtain an empirical correction for the poorly
  known efficiency of the inelastic collisions with H i.<BR /> Results:
  The 3D model generally reproduces the centre-to-limb observations of
  the lines very well, particularly the oxygen lines. From the O i 777 nm
  lines we find that the classical Drawin recipe slightly overestimates
  H i collisions (S_H≈ 0.85 agrees best with the observations). The
  limb observations of the O i 615.82 nm line allow us to identify a
  previously unknown contribution of molecules for this line, prevalent
  at the solar limb. A detailed treatment of the [O i] 630.03 nm line
  that includes the recent nickel abundance shows that the 3D modelling
  closely agrees with the observations. The derived oxygen abundances
  with the 3D model are 8.68 (777 nm lines), 8.66 (630.03 nm line), and
  8.62 (615.82 nm line).<BR /> Conclusions: These additional tests have
  reinforced the trustworthiness of the 3D model and line formation for
  abundance analyses. <P />SST spectra are available in electronic form
  at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)
  or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/508/1403

---------------------------------------------------------
Title: Solar Surface Convection
Authors: Nordlund, Åke; Stein, Robert F.; Asplund, Martin
2009LRSP....6....2N    Altcode:
  We review the properties of solar convection that are directly
  observable at the solar surface, and discuss the relevant underlying
  physics, concentrating mostly on a range of depths from the temperature
  minimum down to about 20 Mm below the visible solar surface.

---------------------------------------------------------
Title: Does the anomalous solar chemical composition come from
    planet formation?
Authors: Ramirez, I.; Melendez, J.; Asplund, M.
2009arXiv0911.1893R    Altcode:
  We derive the abundance of 19 elements in a sample of 64 stars with
  fundamental parameters very similar to solar, which minimizes the impact
  of systematic errors in our spectroscopic 1D-LTE differential analysis,
  using high-resolution (R=60,000), high signal-to-noise ratio (S/N=200)
  spectra. The estimated errors in the elemental abundances relative
  to solar are as small as 0.025 dex. The abundance ratios [X/Fe] as a
  function of [Fe/H] agree closely with previously established patterns
  of Galactic thin-disk chemical evolution. Interestingly, the majority of
  our stars show a significant correlation between [X/Fe] and condensation
  temperature (Tc). In the sample of 22 stars with parameters closest
  to solar, we find that, on average, low Tc elements are depleted with
  respect to high Tc elements in the solar twins relative to the Sun by
  about 0.08 dex (20%). An increasing trend is observed for the abundances
  as a function of Tc for 900&lt;Tc&lt;1800 K, while abundances of lower
  Tc elements appear to be roughly constant. We speculate that this is a
  signature of the planet formation that occurred around the Sun but not
  in the majority of solar twins. If this hypothesis is correct, stars
  with planetary systems like ours, although rare (frequency of 15%),
  may be identified through a very detailed inspection of the chemical
  compositions of their host stars.

---------------------------------------------------------
Title: Oxygen lines in solar granulation. I. Testing 3D models
    against new observations with high spatial and spectral resolution
Authors: Pereira, T. M. D.; Kiselman, D.; Asplund, M.
2009A&A...507..417P    Altcode: 2009arXiv0909.2307P
  Aims: We seek to provide additional tests of the line formation of
  theoretical 3D solar photosphere models. In particular, we set out
  to test the spatially-resolved line formation at several viewing
  angles, from the solar disk-centre to the limb and focusing on atomic
  oxygen lines. The purpose of these tests is to provide additional
  information on whether the 3D model is suitable to derive the solar
  oxygen abundance. We also aim to empirically constrain the NLTE
  recipes for neutral hydrogen collisions, using the spatially-resolved
  observations of the O i 777 nm lines. <BR />Methods: Using the Swedish
  1-m Solar Telescope we obtained high-spatial-resolution observations of
  five atomic oxygen lines (as well as several lines for other species,
  mainly Fe i) for five positions on the solar disk. These observations
  have a high spatial (sub-arcsecond) and spectral resolution, and
  a continuum intensity contrast up to 9% at 615 nm. The theoretical
  line profiles were computed using the 3D model, with a full 3D NLTE
  treatment for oxygen and LTE for the other lines. <BR />Results:
  At disk-centre we find an excellent agreement between predicted
  and observed line shifts, strengths, FWHM and asymmetries. At other
  viewing angles the agreement is also good, but the smaller continuum
  intensity contrast makes a quantitative comparison harder. We use the
  disk-centre observations we constrain S<SUB>H</SUB>, the scaling factor
  for the efficiency of collisions with neutral hydrogen. We find that
  S<SUB>H</SUB>=1 provides the best match to the observations, although
  this method is not as robust as the centre-to-limb line variations to
  constrain S<SUB>H</SUB>. <BR />Conclusions: Overall there is a very
  good agreement between predicted and observed line properties over
  the solar granulation. This further reinforces the view that the 3D
  model is realistic and a reliable tool to derive the solar oxygen
  abundance. <P />2D spectrograms are available in electronic form at
  the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or
  via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/507/417

---------------------------------------------------------
Title: New Solar Composition: The Problem with Solar Models Revisited
Authors: Serenelli, Aldo M.; Basu, Sarbani; Ferguson, Jason W.;
   Asplund, Martin
2009ApJ...705L.123S    Altcode: 2009arXiv0909.2668S
  We construct updated solar models with different sets of solar
  abundances, including the most recent determinations by Asplund et
  al. The latter work predicts a larger (~10%) solar metallicity compared
  to previous measurements by the same authors but significantly lower
  (~25%) than the recommended value from a decade ago by Grevesse &amp;
  Sauval. We compare the results of our models with determinations of the
  solar structure inferred through helioseismology measurements. The
  model that uses the most recent solar abundance determinations
  predicts the base of the solar convective envelope to be located
  at R <SUB>CZ</SUB> = 0.724 R <SUB>sun</SUB> and a surface helium
  mass fraction of Y <SUB>surf</SUB> = 0.231. These results are in
  conflict with helioseismology data (R <SUB>CZ</SUB> = 0.713 ± 0.001
  R <SUB>sun</SUB> and Y <SUB>surf</SUB> = 0.2485 ± 0.0035) at 5σ and
  11σ levels, respectively. Using the new solar abundances, we calculate
  the magnitude by which radiative opacities should be modified in order
  to restore agreement with helioseismology. We find that a maximum
  change of ~15% at the base of the convective zone is required with a
  smooth decrease toward the core, where the change needed is ~5%. The
  required change at the base of the convective envelope is about half
  the value estimated previously. We also present the solar neutrino
  fluxes predicted by the new models. The most important changes brought
  about by the new solar abundances are the increase by ~10% in the
  predicted <SUP>13</SUP>N and <SUP>15</SUP>O fluxes that arise mostly
  due to the increase in the C and N abundances in the newly determined
  solar composition.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Oxygen lines in solar
    granulation. II. (Pereira+, 2009)
Authors: Pereira, T. M. D.; Asplund, M.; Kiselman, D.
2009yCat..35081403P    Altcode:
  We obtained solar observations of several lines at several positions
  of the solar disk. Data were obtained in May 2007 with the TRIPPEL
  spectrograph at the Swedish 1-m Solar Telescope (SST). The spectra
  were obtained for three distinct wavelength windows at ~615, 630 and
  777nm. Each window covers approx. 1nm. Here we provide the spatially and
  temporally averaged spectra. Each spectrum was the average of 50 frames
  (mu=1.0) or 25 frames (other positions). The frames were selected by
  the highest continuum contrast, and thus are not regularly spaced in
  time between the start and end Julian dates. <P />The observations are
  given for five positions in the solar disk, ordered by mu, the cosine
  of the heliocentric angle. The objective was to study the centre-to-limb
  variation of the lines. Active sun regions were avoided. <P />Important
  note: the wavelength scales have NOT been corrected for solar rotation
  or gravitational redshift. <P />(4 data files).

---------------------------------------------------------
Title: The Peculiar Solar Composition and Its Possible Relation to
    Planet Formation
Authors: Meléndez, J.; Asplund, M.; Gustafsson, B.; Yong, D.
2009ApJ...704L..66M    Altcode: 2009arXiv0909.2299M
  We have conducted a differential elemental abundance analysis of
  unprecedented accuracy (~0.01 dex) of the Sun relative to 11 solar twins
  from the Hipparcos catalog and 10 solar analogs from planet searches. We
  find that the Sun shows a characteristic signature with a ≈20%
  depletion of refractory elements relative to the volatile elements in
  comparison with the solar twins. The abundance differences correlate
  strongly with the condensation temperatures of the elements. This
  peculiarity also holds in comparisons with solar analogs known to have
  close-in giant planets while the majority of solar analogs found not
  to have such giant planets in radial velocity monitoring show the solar
  abundance pattern. We discuss various explanations for this peculiarity,
  including the possibility that the differences in abundance patterns
  are related to the formation of planetary systems like our own, in
  particular to the existence of terrestrial planets.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Equivalent widths of Li, Na, Fe,
    Ca in NGC 6397 (Lind+, 2009)
Authors: Lind, K.; Primas, F.; Charbonnel, C.; Grundahl, F.;
   Asplund, M.
2009yCat..35030545L    Altcode:
  The tables contain coordinates, photometry, derived stellar parameters,
  equivalent widths, and abundances for a large number of dwarfs,
  subgiant branch stars, and red giant branch stars in the metal-poor
  globular cluster NGC6397. All abundances are given in logarithmic units
  relative to hydrogen, according to A(x)=log(N(x)/N(H))+12, where N(x)
  is the number density of element x and N(H) the number density of
  hydrogen. Table 3 contains only a subset (32) of all targets. The
  oscillator strengths adopted are listed in the paper. <P />(3 data
  files).

---------------------------------------------------------
Title: The Barium Isotopic Abundance in the Metal-Poor Star HD140283
Authors: Collet, R.; Asplund, M.; Nissen, P. E.
2009PASA...26..330C    Altcode: 2008arXiv0811.4586C
  We derive the mixture of odd to even barium isotopes in the atmosphere
  of the metal-poor subgiant HD140283 from the analysis of the Ba
  ii transition at 4554 Å in a high-resolution high signal-to-noise
  spectrum of the star. The detailed shape of this spectral line depends
  on the relative contributions of odd and even isotopes via isotopic
  and hyperfine splitting. We measure the fractional abundance of odd Ba
  isotopes by modelling the formation of the Ba ii 4554-Å line profile
  with the use of both a classical 1D hydrostatic and a 3D hydrodynamical
  model atmosphere of HD140283. We interpret the results in terms of
  contributions by the slow (s) and rapid (r) neutron-capture processes
  to the isotopic mix. While the result of the 1D analysis of the Ba
  ii feature indicates a 64 +/- 36% contribution of the r-process to
  the isotopic mix, the 3D analysis points toward a mere 15 +/- 34%
  contribution from this process, that is consistent with a solar-like
  mixture of barium isotopes.

---------------------------------------------------------
Title: Testing 3D solar models against observations
Authors: Pereira, Tiago M. D.; Asplund, Martin; Kiselman, Dan
2009arXiv0909.4121P    Altcode:
  We present results from a series of observational tests to 3D and 1D
  solar models. In particular, emphasis is given to the line formation
  of atomic oxygen lines, used to derive the much debated solar oxygen
  photospheric abundance. Using high-quality observations obtained
  with the Swedish Solar Telescope (SST) we study the centre-to-limb
  variation of the O I lines, testing the models and line formation
  (LTE and non-LTE). For the O I 777 nm triplet, the centre-to-limb
  variation sets strong constraints in the non-LTE line formation, and
  is used to derive an empirical correction factor (S_H) to the classical
  Drawin recipe for neutral hydrogen collisions. Taking advantage of the
  spatially-resolved character of the SST data, an additional framework
  for testing the 3D model and line formation is also studied. From
  the tests we confirm that the employed 3D model is realistic and its
  predictions agree very well with the observations.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Oxygen lines in solar
    granulation. I. (Pereira+, 2009)
Authors: Pereira, T. M. D.; Kiselman, D.; Asplund, M.
2009yCat..35070417P    Altcode:
  We obtained solar observations of several lines at several positions
  of the solar disk. Data were obtained in May 2007 with the TRIPPEL
  spectrograph at the Swedish 1-m Solar Telescope (SST). The spectra were
  obtained for three distinct wavelength windows at approx 615, 630 and
  777nm. Each window covers ~1nm. The spectra are spatially-resolved
  in the solar surface, hence are given as 2D spectrograms. One axis
  covers the wavelength and the other spatial position. <P />The
  observations are given for five positions in the solar disk, ordered
  by mu, the cosine of the heliocentric angle. The objective was to
  study the centre-to-limb variation of the lines. Active sun regions
  were avoided. In total 150 spectrograms are given for each wavelength
  window: 50 for the solar disk-centre (mu=1) and 25 for the other four
  positions (mu=0.8, 0.6, 0.4, 0.2). The images were selected by continuum
  contrast, hence their observed times are not the same for the three
  windows. <P />The spectrograms are given as FITS files. Each file
  has two Header/Data Units (HDU). The first HDU contains the reduced
  spectrogram, a 2D array. The first dimension of the array contains
  (FITS NAXIS1) corresponds to wavelength, and the second (FITS NAXIS2)
  to spatial coordinate. The second HDU contains the continuum levels
  obtained for each spatial point (1D array, length equal to the number
  of spatial points in the spectrogram). To obtain the normalized reduced
  spectrogram one has to divide each spectrum in the spectrogram by the
  corresponding continuum level. The spectrograms have been corrected
  for stray light and to minimize noise a Fourier filter has been applied
  (details in the paper). <P />Important note: the wavelength scales have
  NOT been corrected for solar rotation or gravitational redshift. <P
  />(3 data files).

---------------------------------------------------------
Title: The Chemical Composition of the Sun
Authors: Asplund, Martin; Grevesse, Nicolas; Sauval, A. Jacques;
   Scott, Pat
2009ARA&A..47..481A    Altcode: 2009arXiv0909.0948A
  The solar chemical composition is an important ingredient in our
  understanding of the formation, structure, and evolution of both the
  Sun and our Solar System. Furthermore, it is an essential reference
  standard against which the elemental contents of other astronomical
  objects are compared. In this review, we evaluate the current
  understanding of the solar photospheric composition. In particular,
  we present a redetermination of the abundances of nearly all available
  elements, using a realistic new three-dimensional (3D), time-dependent
  hydrodynamical model of the solar atmosphere. We have carefully
  considered the atomic input data and selection of spectral lines, and
  accounted for departures from local thermodynamic equilibrium (LTE)
  whenever possible. The end result is a comprehensive and homogeneous
  compilation of the solar elemental abundances. Particularly noteworthy
  findings are significantly lower abundances of C, N, O, and Ne compared
  to the widely used values of a decade ago. The new solar chemical
  composition is supported by a high degree of internal consistency
  between available abundance indicators, and by agreement with
  values obtained in the Solar Neighborhood and from the most pristine
  meteorites. There is, however, a stark conflict with standard models
  of the solar interior according to helioseismology, a discrepancy that
  has yet to find a satisfactory resolution.

---------------------------------------------------------
Title: Signatures of intrinsic Li depletion and Li-Na anti-correlation
    in the metal-poor globular cluster NGC 6397
Authors: Lind, K.; Primas, F.; Charbonnel, C.; Grundahl, F.;
   Asplund, M.
2009A&A...503..545L    Altcode: 2009arXiv0906.2876L
  Context: To alleviate the discrepancy between the prediction of
  the primordial lithium abundance in the universe and the abundances
  observed in Pop II dwarfs and subgiant stars, it has been suggested
  that the stars observable today have undergone photospheric depletion
  of lithium. <BR />Aims: To identify the cause of this depletion,
  it is important to accurately establish the behaviour of lithium
  abundance with effective temperature and evolutionary phase. Stars in
  globular clusters are ideal objects for such an abundance analysis,
  because relative stellar parameters can be determined precisely. <BR
  />Methods: We conducted a homogeneous analysis of a very large sample
  of stars in the metal-poor globular cluster NGC 6397, covering all
  evolutionary phases from below the main sequence turn-off to high up
  on the red giant branch. Non-LTE Li abundances or abundance upper
  limits were obtained for all stars, and for a sizeable subset of
  the targets sodium abundances were also obtained. The Na abundances
  were used to distinguish stars formed out of pristine material from
  stars formed out of material affected by pollution from a previous
  generation of more massive stars. <BR />Results: The dwarf, turn-off,
  and early subgiant stars in our sample form a thin abundance plateau,
  disrupted in the middle of the subgiant branch by the Li dilution caused
  by the first dredge-up. A second steep abundance drop is seen at the
  luminosity of the red giant branch bump. The turn-off stars are more
  Li-poor, by up to 0.1 dex, than subgiants that have not yet undergone
  dredge-up. In addition, hotter dwarfs are slightly more Li-poor than
  cooler dwarfs, which may be a signature of the so-called Li dip in
  the cluster, commonly seen among Pop I stars. The feature is however
  weak. A considerably wide spread in Na abundance confirms that NGC 6397
  has suffered from intracluster pollution in its infancy and a limited
  number of Na-enhanced and Li-deficient stars strongly contribute to
  forming a significant anti-correlation between the abundances of Na
  and Li. It is nevertheless seen that Li abundances are unaffected
  by relatively high degrees of pollution. Lithium abundance trends
  with effective temperature and stellar luminosity are compared to
  predictions from stellar structure models including atomic diffusion
  and ad-hoc turbulence below the convection zone. We confirm previous
  findings that some turbulence, with strict limits to its efficiency,
  is necessary for explaining the observations. <P />Based on data
  collected at European Southern Observatory (ESO), Paranal, Chile,
  under program IDs 077.A-0018(A) and 281.D-5028(A), as well as data
  collected with the Danish 1.54 m at European Southern Observatory
  (ESO), La Silla. Full Tables 2-4 are only available in electronic form
  at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)
  or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/503/545

---------------------------------------------------------
Title: Subaru High-Resolution Spectroscopy of Star G in the Tycho
    Supernova Remnant
Authors: Kerzendorf, Wolfgang E.; Schmidt, Brian P.; Asplund, M.;
   Nomoto, Ken'ichi; Podsiadlowski, Ph.; Frebel, Anna; Fesen, Robert A.;
   Yong, David
2009ApJ...701.1665K    Altcode: 2009arXiv0906.0982K
  It is widely believed that Type Ia supernovae (SNe Ia) originate in
  binary systems where a white dwarf accretes material from a companion
  star until its mass approaches the Chandrasekhar mass and carbon is
  ignited in the white dwarf's core. This scenario predicts that the
  donor star should survive the supernova (SNe) explosion, providing
  an opportunity to understand the progenitors of SNe Ia. In this
  paper, we argue that rotation is a generic signature expected of
  most nongiant donor stars that is easily measurable. Ruiz-Lapuente
  et al. examined stars in the center of the remnant of SN 1572 (Tycho
  SN) and showed evidence that a subgiant star (Star G by their naming
  convention) near the remnant's center was the system's donor star. We
  present high-resolution (R sime 40, 000) spectra taken with the High
  Dispersion Spectrograph on Subaru of this candidate donor star and
  measure the star's radial velocity as 79 ± 2 km s<SUP>-1</SUP> with
  respect to the local standard of rest and put an upper limit on the
  star's rotation of 7.5 km s<SUP>-1</SUP>. In addition, by comparing
  images that were taken in 1970 and 2004, we measure the proper motion
  of Star G to be μ<SUB> l </SUB> = -1.6 ± 2.1 mas yr<SUP>-1</SUP> and
  μ<SUB> b </SUB> = -2.7 ± 1.6 mas yr<SUP>-1</SUP>. We demonstrate
  that all of the measured properties of Star G presented in this
  paper are consistent with those of a star in the direction of Tycho
  SN that is not associated with the SN event. However, we discuss an
  unlikely, but still viable scenario for Star G to be the donor star,
  and suggest further observations that might be able to confirm or
  refute it. <P />Based in part on data collected at Subaru telescope,
  which is operated by the National Astronomical Observatory of Japan.

---------------------------------------------------------
Title: How Carbon Enhanced are Carbon-Enhanced Metal-Poor Stars?
Authors: Schuler, Simon C.; Asplund, Martin; Sivarani, Thirupathi;
   Smith, Verne V.; Cunha, Katia; Beers, Timothy C.; Margheim, Steven J.
2009noao.prop...99S    Altcode:
  Carbon-Enhanced Metal-Poor (CEMP) stars make up a large fraction of
  very metal-poor (VMP) stars in the Galactic halo, and they are proving
  to be important to our understanding of a wide range of astrophysical
  phenomena. Accurate abundance determinations of these stars are
  needed to both fully delineate their formation and evolution, and to
  firmly place them into a greater astrophysical context. Our group
  has recently demonstrated that CEMP star C abundances derived from
  the blue bands of CH and the C_2 Swan system, the principal features
  used for this purpose, may be systematically overestimated at [Fe/H]
  &lt;=- 3.0. We have also shown that the (lambda) 8727 forbidden [C I]
  line is an accurate abundance indicator for CEMP stars. Here we propose
  an observational program to obtain Keck/HIRES spectra of six CEMP
  stars, four of which have Fe abundances ranging from -4.0 &lt;=[Fe/H]
  &lt;=-3.12, in order to derive accurate C abundances of the targets
  from the [C I] line. With the proposed observations we will determine
  if indeed molecular line-based C abundances of CEMP stars are too high
  at very low metallicities and if so, provide empirically determined
  corrections for those abundances.

---------------------------------------------------------
Title: Departures from LTE for neutral Li in late-type stars
Authors: Lind, K.; Asplund, M.; Barklem, P. S.
2009A&A...503..541L    Altcode: 2009arXiv0906.0899L
  We perform non-LTE calculations of lithium in late-type stars for
  a wide range of stellar parameters, including quantum mechanical
  cross-sections for collisions with neutral hydrogen and the negative
  hydrogen ion. Non-LTE abundance corrections for the lithium resonance
  line at 670.7 nm and the subordinate line at 610.3 nm, are calculated
  using 1D MARCS model atmospheres spanning a grid T_eff = [4000, 8000]
  K, log g = [1.0, 5.0], and [Fe/H] = [0.0, -3.0], for lithium abundances
  in the range A(Li) = [-0.3, 4.2]. The competing effects of ultraviolet
  over-ionization and photon losses in the resonance line govern the
  behaviour of the non-LTE effects with stellar parameters and lithium
  abundance. The size and sign of the non-LTE abundance corrections
  vary significantly over the grid for the 670.7 nm line, but are
  typically positive and below 0.15 dex for the 610.3 nm, line. The new
  collisional data play a significant role in determining the abundance
  corrections. <P />Complete Tables [see full textsee full textsee full
  textsee full textsee full text] and [see full textsee full textsee
  full textsee full textsee full text] are only available in electronic
  form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)
  or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/503/541

---------------------------------------------------------
Title: Granulation in K-type dwarf stars. II. Hydrodynamic simulations
    and 3D spectrum synthesis
Authors: Ramírez, I.; Allende Prieto, C.; Koesterke, L.; Lambert,
   D. L.; Asplund, M.
2009A&A...501.1087R    Altcode: 2009arXiv0905.3101R
  Aims: To explore the impact of surface inhomogeneities on stellar
  spectra, granulation models need to be computed. Ideally, the most
  fundamental characteristics of these models should be carefully
  tested before applying them to the study of more practical matters,
  such as the derivation of photospheric abundances. Our goal is to
  analyze the particular case of a K-dwarf. <BR />Methods: We construct a
  three-dimensional radiative-hydrodynamic model atmosphere of parameters
  T_eff=4820 K, log g=4.5, and solar chemical composition. Using this
  model and 3D spectrum synthesis, we computed a number of Fe i and Fe
  ii line profiles. The observations presented in the first paper of this
  series were used to test the model predictions. The effects of stellar
  rotation and instrumental imperfections are carefully taken into account
  in the synthesis of spectral lines. <BR />Results: The theoretical
  line profiles show the typical signatures of granulation: the lines
  are asymmetric, with their bisectors having a characteristic C-shape
  and their core wavelengths shifted with respect to their laboratory
  values. The line bisectors span from about 10 to 250 m s<SUP>-1</SUP>,
  depending on line strength, with the stronger features showing larger
  span. The corresponding core wavelength shifts range from about -200 m
  s<SUP>-1</SUP> for the weak Fe i lines to almost +100 m s<SUP>-1</SUP>
  in the strong Fe i features. Based on observational results for the Sun,
  we argue that there should be no core wavelength shift for Fe i lines
  of EW≳100 mÅ. The cores of the strongest lines show contributions
  from the uncertain top layers of the model, where non-LTE effects
  and the presence of the chromosphere, which are important in real
  stars, are not accounted for. The Fe ii lines suffer from stronger
  granulation effects due to their deeper formation depth which makes them
  experience stronger temperature and velocity contrasts. For example,
  the core wavelength shifts of the weakest Fe ii lines are about -600
  m s<SUP>-1</SUP>. The comparison of model predictions to observed Fe
  i line bisectors and core wavelength shifts for our reference star,
  HIP 86 400, shows excellent agreement, with the exception of the core
  wavelength shifts of the strongest features, for which we suspect
  inaccurate theoretical values. Since this limitation does not affect
  the predicted line equivalent widths significantly, we consider our
  3D model validated for photospheric abundance work.

---------------------------------------------------------
Title: Experimental and theoretical radiative decay rates for highly
    excited ruthenium atomic levels and the solar abundance of ruthenium
Authors: Fivet, V.; Quinet, P.; Palmeri, P.; Biémont, É.; Asplund,
   M.; Grevesse, N.; Sauval, A. J.; Engström, L.; Lundberg, H.; Hartman,
   H.; Nilsson, H.
2009MNRAS.396.2124F    Altcode: 2009MNRAS.tmp..738F
  The solar photospheric abundance of ruthenium is revised on the basis
  of a new set of oscillator strengths derived for RuI transitions with
  wavelengths in the spectral range 2250-4710 Å. The new abundance value
  (in the usual logarithmic scale where the solar hydrogen abundance
  is equal to 12.00), A<SUB>Ru</SUB> = 1.72 +/- 0.10, is in agreement
  with the most recent meteoritic result, A<SUB>Ru</SUB> = 1.76 +/-
  0.03. The accuracy of the transition probabilities, obtained using a
  relativistic Hartree-Fock model including core-polarization effects,
  has been assessed by comparing the theoretical lifetimes with previous
  experimental results. A comparison is also made with new measurements
  performed in this work by the time-resolved laser-induced fluorescence
  spectroscopy for 10 highly excited odd-parity levels of RuI.

---------------------------------------------------------
Title: The C/O ratio at low metallicity: constraints on early chemical
    evolution from observations of Galactic halo stars
Authors: Fabbian, D.; Nissen, P. E.; Asplund, M.; Pettini, M.;
   Akerman, C.
2009A&A...500.1143F    Altcode: 2008arXiv0810.0281F
  Aims: We present new measurements of the abundances of carbon and
  oxygen derived from high-excitation C i and O i absorption lines in
  metal-poor halo stars, with the aim of clarifying the main sources
  of these two elements in the early stages of the chemical enrichment
  of the Galaxy. <BR />Methods: We target 15 new stars compared to our
  previous study, with an emphasis on additional C/O determinations
  in the crucial metallicity range -3 ⪉ [Fe/H]⪉ -2. The stellar
  effective temperatures were estimated from the profile of the Hβ
  line. Departures from local thermodynamic equilibrium were accounted
  for in the line formation for both carbon and oxygen. The non-LTE
  effects are very strong at the lowest metallicities but, contrary
  to what has sometimes been assumed in the past due to a simplified
  assessment, of different degrees for the two elements. In addition,
  for the 28 stars with [Fe/H] &lt; -1 previously analysed, stellar
  parameters were re-derived and non-LTE corrections applied in the same
  fashion as for the rest of our sample, giving consistent abundances
  for 43 halo stars in total. <BR />Results: The new observations and
  non-LTE calculations strengthen previous suggestions of an upturn in
  C/O towards lower metallicity (particularly for [O/H] ⪉ -2). The
  C/O values derived for these very metal-poor stars are, however,
  sensitive to excitation via the still poorly quantified inelastic
  H collisions. While these do not significantly affect the non-LTE
  results for C i, they greatly modify the O i outcome. Adopting the
  H collisional cross-sections estimated from the classical Drawin
  formula leads to [C/O] ≈ 0 at [O/H] ≈ -3. To remove the upturn
  in C/O, near-LTE formation for O i lines would be required, which
  could only happen if the H collisional efficiency with the Drawin
  recipe is underestimated by factors of up to several tens of times,
  a possibility which we consider unlikely. <BR />Conclusions: The high
  C/O values derived at the lowest metallicities may be revealing the
  fingerprints of Population III stars or may signal rotationally-aided
  nucleosynthesis in more normal Population II stars. <P />Based on data
  collected with the European Southern Observatory's Very Large Telescope
  (VLT) at the Paranal, Chile (programmes No. 67.D-0106 and 73.D-0024)
  and with the Magellan Telescope at Las Campanas Observatory, Chile.

---------------------------------------------------------
Title: On and Na abundance patterns in open clusters of the Galactic
    disk
Authors: de Silva, G. M.; Gibson, B. K.; Lattanzio, J.; Asplund, M.
2009A&A...500L..25D    Altcode: 2009arXiv0905.4354D
  Aims: A global O-Na abundance anti-correlation is observed in globular
  clusters, which is not present in the Galactic field population. Open
  clusters are thought to be chemically homogeneous internally. We aim to
  explore the O and Na abundance pattern among the open cluster population
  of the Galactic disk. <BR />Methods: We combine open cluster abundance
  ratios of O and Na from high-resolution spectroscopic studies in the
  literature and normalize them to a common solar scale. We compare
  the open cluster abundances against the globular clusters and disk
  field. <BR />Results: We find that the different environments show
  different abundance patterns. The open clusters do not show the
  O-Na anti-correlation at the extreme O-depletion/Na-enhancement as
  observed in globular clusters. Furthermore, the high Na abundances in
  open clusters do not match the disk field stars. If real, it may be
  suggesting that the dissolution of present-day open clusters is not a
  significant contribution to building the Galactic disk. Large-scale
  homogeneous studies of clusters and field will further confirm the
  reality of the Na enhancement.

---------------------------------------------------------
Title: Neutral oxygen spectral line formation revisited with new
collisional data: large departures from LTE at low metallicity
Authors: Fabbian, D.; Asplund, M.; Barklem, P. S.; Carlsson, M.;
   Kiselman, D.
2009A&A...500.1221F    Altcode: 2009arXiv0902.4472F
  Aims: A detailed study is presented, including estimates of the
  impact on elemental abundance analysis, of the non-local thermodynamic
  equilibrium (non-LTE) formation of the high-excitation neutral oxygen
  777 nm triplet in model atmospheres representative of stars with
  spectral types F to K. <BR />Methods: We have applied the statistical
  equilibrium code MULTI to a number of plane-parallel MARCS atmospheric
  models covering late-type stars (4500 ≤ T_eff ≤ 6500 K, 2 ≤ log
  g ≤ 5 [cgs], and -3.5 ≤ [Fe/H] ≤ 0). The atomic model employed
  includes, in particular, recent quantum-mechanical electron collision
  data. <BR />Results: We confirm that the O i triplet lines form under
  non-LTE conditions in late-type stars, suffering negative abundance
  corrections with respect to LTE. At solar metallicity, the non-LTE
  effect, mainly attributed in previous studies to photon losses in the
  triplet itself, is also driven by an additional significant contribution
  from line opacity. At low metallicity, the very pronounced departures
  from LTE are due to overpopulation of the lower level (3s ^5S^o) of the
  transition. Large line opacity stems from triplet-quintet intersystem
  electron collisions, a form of coupling previously not considered or
  seriously underestimated. The non-LTE effects generally become severe
  for models (both giants and dwarfs) with higher T_eff. Interestingly,
  in metal-poor turn-off stars, the negative non-LTE abundance corrections
  tend to rapidly become more severe towards lower metallicity. When
  neglecting H collisions, they amount to as much as |Δlog ɛ_O|
  ~ 0.9 dex and ~1.2 dex, respectively at [Fe/H] = -3 and [Fe/H]
  = -3.5. Even when such collisions are included, the LTE abundance
  remains a serious overestimate, correspondingly by |Δlog ɛ_O| ~ 0.5
  dex and ~0.9 dex at such low metallicities. Although the poorly known
  inelastic hydrogen collisions thus remain an important uncertainty,
  the large metallicity-dependent non-LTE effects seem to point to
  a resulting “low” (compared to LTE) [O/Fe] in metal-poor halo
  stars. <BR />Conclusions: Our results may be important in solving
  the long-standing [O/Fe] debate. When applying the derived non-LTE
  corrections, the LTE oxygen abundance inferred from the 777 nm permitted
  triplet will be decreased substantially at low metallicity. If the
  classical Drawin formula is employed for O+H collisions, the derived
  [O/Fe] trend becomes almost flat below [Fe/H] ~ -1, in better agreement
  with recent literature estimates generally obtained from other oxygen
  abundance indicators. A value of [O/Fe] ⪉ +0.5 may therefore be
  appropriate, as suggested by standard theoretical models of type II
  supernovae nucleosynthetic yields. If neglecting impacts with H atoms
  instead, [O/Fe] decreases towards lower [Fe/H], which would open new
  questions. Our tests using ATLAS model atmospheres show that, though
  non-LTE corrections for metal-poor dwarfs are smaller (by ~0.2 dex
  when adopting efficient H collisions) than in the MARCS case, our
  main conclusions are preserved, and that the LTE approach tends to
  seriously overestimate the O abundance at low metallicity. However,
  in order to finally reach consistency between oxygen abundances from
  the different available spectral features, it is of high priority to
  reduce the large uncertainty regarding H collisions, to undertake a
  full investigation of the interplay of non-LTE and 3D effects, and to
  clarify the issue of the temperature scale at low metallicity.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Neutral Li in late-type stars
    non-LTE calculations (Lind+, 2009)
Authors: Lind, K.; Asplund, M.; Barklem, P. S.
2009yCat..35030541L    Altcode:
  Non-LTE abundance corrections and equivalent widths for atmospheric
  models in the stellar parameter range Teff=[4000,8000]K,
  log(g)=[1.0,5.0], [Fe/H]=[0.0,-3.0], and microturbulence
  [1.0,5.0]km/s. The lithium abundance ranges between A(Li)=[-0.3,4.2]. An
  IDL-code for interpolation between table-values can be obtained on
  request to klind(at)eso.org. <P />(2 data files).

---------------------------------------------------------
Title: Metal-poor Globular Clusters of the Galactic bulge
Authors: Barbuy, B.; Dias, B.; Alves-Brito, A.; Zoccali, M.; Minniti,
   D.; Meléndez, J.; Asplund, M.; Ortolani, S.; Renzini, A.; Hill, V.;
   Gómez, A.; Bica, E.
2009RMxAC..35..150B    Altcode:
  We are carrying studies on the metal-poor globular clusters of the
  Galactic bulge. These objects appear to be very old, and might be
  relics of the first objects in the Galaxy. High resolution observations
  carried out with VLT-UVES, VLT-FLAMES and Gemini-PHOENIX are presented,
  and the abundance pattern of these globulars is studied.

---------------------------------------------------------
Title: Stellar abundances tracing the formation of the Galactic Bulge
Authors: Barbuy, Beatriz; Zoccali, Manuela; Ortolani, Sergio; Hill,
   Vanessa; Renzini, Alvio; Meléndez, Jorge; Gómez, Anita; Asplund,
   Martin; Minniti, Dante; Bica, Eduardo; Alves-Brito, Alan
2009IAUS..254..153B    Altcode:
  The metallicity distribution and abundance ratios of the Galactic
  bulge are reviewed. Issues raised by different groups in recent
  work, in particular the high metallicity end, a comparison between
  the oxygen abundances derived from different indicators, the [OI]
  630nm and IR OH lines, and the issue of measuring giants vs. dwarfs,
  are discussed. Finally, abundances in bulge globular clusters are
  briefly described.

---------------------------------------------------------
Title: On the Solar Nickel and Oxygen Abundances
Authors: Scott, Pat; Asplund, Martin; Grevesse, Nicolas; Sauval,
   A. Jacques
2009ApJ...691L.119S    Altcode: 2008arXiv0811.0815S
  Determinations of the solar oxygen content relying on the neutral
  forbidden transition at 630 nm depend upon the nickel abundance,
  due to a Ni I blend. Here, we rederive the solar nickel abundance,
  using the same ab initio three-dimensional hydrodynamic model of the
  solar photosphere employed in the recent revision of the abundances
  of C, N, O, and other elements. Using 17 weak, unblended lines of
  Ni I together with the most accurate atomic and observational data
  available, we find log epsilon<SUB>Ni</SUB> = 6.17 ± 0.02(statistical)
  ± 0.05(systematic), a downward shift of 0.06-0.08 dex relative to
  previous abundances based on one-dimensional model atmospheres. We
  investigate the implications of the new nickel abundance for studies of
  the solar oxygen abundance based on the [O I] 630 nm line in the quiet
  Sun. Furthermore, we demonstrate that the oxygen abundance implied
  by the recent sunspot spectropolarimetric study of Centeno &amp;
  Socas-Navarro needs to be revised downward from log epsilon<SUB>O</SUB>
  = 8.86 ± 0.07 to 8.71 ± 0.10. This revision is based on the new
  nickel abundance, the application of the best available gf value for
  the 630 nm forbidden oxygen line, and a more transparent treatment of
  CO formation. Determinations of the solar oxygen content relying on
  forbidden lines now appear to converge around log epsilon<SUB>O</SUB>
  = 8.7.

---------------------------------------------------------
Title: Commission 36: Theory of Stellar Atmospheres
Authors: Landstreet, John D.; Asplund, Martin; Spite, Monique;
   Balachandran, Suchitra B.; Berdyugina, Svetlana V.; Hauschildt, Peter
   H.; Ludwig, Hans G.; Mashonkina, Lyudmila I.; Nagendra, K. N.; Puls,
   Joachim; Randich, M. Sofia; Tautvaisiene, Grazina
2009IAUTA..27..222L    Altcode:
  Commission 36 covers the whole field of the physics of stellar
  atmospheres. The scientific activity in this large subject has been very
  intense during the last triennium and led to the publication of a large
  number of papers, which makes a complete report quite impractical. We
  have therefore decided to keep the format of the preceding report:
  first a list of areas of current research, then Web links for obtaining
  further information.

---------------------------------------------------------
Title: Carbon Abundances Of Three Cemp Stars From High-resolution
    Gemini-s/bHROS Spectra Of The [c I] Forbidden Line
Authors: Schuler, Simon C.; Margheim, S. J.; Sivarani, T.; Asplund,
   M.; Smith, V. V.; Cunha, K.; Beers, T. C.
2009AAS...21340608S    Altcode: 2009BAAS...41..199S
  We present the results from a LTE analysis of the [C I] Forbidden line
  at 8727 angstroms in high-resolution Gemini-S/bHROS spectra of three
  Carbon-Enhanced Metal-Poor (CEMP) stars. Carbon abundances of CEMP stars
  are primarily derived from CH and C2 features, lines that are expected
  to be highly sensitive to photospheric temperature inhomogeneities,
  the so-called 3D effects. We find the [C/Fe] ratios based on the [C I]
  abundances of the two most Fe-rich stars in our sample (HE 0506-1653:
  [Fe/H] = -1.42 and HE 0054-2542: [Fe/H] = -2.66) to be in good agreement
  with previously determined molecular line-based values. The [C/Fe]
  ratio of the most Fe-poor star in our sample (HE 1005-1439: [Fe/H]
  = -3.08), however, is 0.34 dex lower than the published molecular
  line-based abundance. This result is in line with expectations
  that 3D effects on the molecular lines become more severe toward
  lower metallicities. We have carried out 3D LTE calculations for
  [C I], and the resulting corrections for all three stars are found
  to be modest, suggesting the discrepancy between the [C I] line and
  molecular line-based abundances of HE 1005-1439 is due to more severe
  3D effects on the molecular lines. <P />S.C.S. is supported by the
  NOAO Leo Goldberg Fellowship; NOAO is operated by the Association of
  Universities for Research Astronomy (AURA), Inc., under cooperative
  agreement with the National Science Foundation (NSF). V.V.S. and
  K.C. gratefully acknowledge support from the NSF under grant AST
  06-46790. T.C.B. and T.S. acknowledge partial support for this work
  from the NSF under grants AST 04-06784, AST 07-07776, and PHY 02-16783;
  Physics Frontier Center/Joint Institute for Nuclear Astrophysics (JINA).

---------------------------------------------------------
Title: Granulation across the HR diagram
Authors: Ramírez, I.; Allende Prieto, C.; Lambert, D. L.; Koesterke,
   L.; Asplund, M.
2009MmSAI..80..618R    Altcode: 2009arXiv0908.4571R
  We have obtained ultra-high quality spectra (R=180,000; S/N&gt;300)
  with unprecedented wavelength coverage (4400 to 7400 Å) for a
  number of stars covering most of the HR diagram in order to test the
  predictions of models of stellar surface convection. Line bisectors
  and core wavelength shifts are both measured and modeled, allowing
  us to validate and/or reveal the limitations of state-of-the-art
  hydrodynamic model atmospheres of different stellar parameters. We
  show the status of our project and preliminary results.

---------------------------------------------------------
Title: Accounting for convective blue-shifts in the determination
    of absolute stellar radial velocities.
Authors: Allende Prieto, C.; Koesterke, L.; Ramírez, I.; Ludwig,
   H. -G.; Asplund, M.
2009MmSAI..80..622A    Altcode: 2009arXiv0909.0470A
  For late-type non-active stars, gravitational redshifts and convective
  blueshifts are the main source of biases in the determination of
  radial velocities. If ignored, these effects can introduce systematic
  errors of the order of ∼ 0.5 km s<SUP>-1</SUP>. We demonstrate that
  three-dimensional hydrodynamical simulations of solar surface convection
  can be used to predict the convective blue-shifts of weak spectral
  lines in solar-like stars to ∼ 0.070 km s<SUP>-1</SUP>. Using accurate
  trigonometric parallaxes and stellar evolution models, the gravitational
  redshifts can be constrained with a similar uncertainty, leading to
  absolute radial velocities accurate to ∼ 0.1 km s<SUP>-1</SUP>.

---------------------------------------------------------
Title: Abundance analysis of the halo giant HD 122563 with
    three-dimensional model stellar atmospheres
Authors: Collet, R.; Nordlund, Å.; Asplund, M.; Hayek, W.;
   Trampedach, R.
2009MmSAI..80..719C    Altcode: 2009arXiv0909.0690C
  We present a preliminary local thermodynamic equilibrium (LTE) abundance
  analysis of the template halo red giant HD122563 based on a realistic,
  three-dimensional (3D), time-dependent, hydrodynamical model atmosphere
  of the very metal-poor star. We compare the results of the 3D analysis
  with the abundances derived by means of a standard LTE analysis based
  on a classical, 1D, hydrostatic model atmosphere of the star. Due to
  the different upper photospheric temperature stratifications predicted
  by 1D and 3D models, we find large, negative, 3D-1D LTE abundance
  differences for low-excitation OH and Fe I lines. We also find trends
  with lower excitation potential in the derived Fe LTE abundances
  from Fe I lines, in both the 1D and 3D analyses. Such trends may be
  attributed to the neglected departures from LTE in the spectral line
  formation calculations.

---------------------------------------------------------
Title: Testing 3D solar models against observations . Center-to-limb
    variations of oxygen lines, spatially-resolved line formation and
    probing for departures from LTE
Authors: Pereira, T. M. D.; Asplund, M.; Kiselman, D.
2009MmSAI..80..650P    Altcode:
  We present results from a series of observational tests to 3D and 1D
  solar models. In particular, emphasis is given to the line formation
  of atomic oxygen lines, used to derive the much debated solar oxygen
  photospheric abundance. Using high-quality observations obtained
  with the Swedish Solar Telescope (SST) we study the center-to-limb
  variation of the O I lines, testing the models and line formation
  (LTE and non-LTE). For the O I 777 nm triplet, the center-to-limb
  variation sets strong constraints in the non-LTE line formation, and
  is used to derive an empirical correction factor (S<SUB>H</SUB>) to
  the classical Drawin recipe for neutral hydrogen collisions. Taking
  advantage of the spatially-resolved character of the SST data, an
  additional framework for testing the 3D model and line formation is
  also studied. From the tests we confirm that the employed 3D model is
  realistic and its predictions agree very well with the observations.

---------------------------------------------------------
Title: Spectroscopic Properties of Granulation in K-type Dwarf Stars
Authors: Ramirez, Ivan; Allende Prieto, C.; Asplund, M.; Koesterke,
   L.; Lambert, D. L.
2009AAS...21340601R    Altcode: 2009BAAS...41..198R
  The presence of surface convection in K-type dwarfs is revealed in very
  high quality spectra of nine bright stars. The observed asymmetries and
  wavelength shifts of the Fe I absorption line profiles are mainly due
  to granulation. The bisectors of the strongest Fe I lines have a span
  of about 100 m/s and the central wavelengths of the weakest Fe I lines
  are shifted by up to -200 m/s. The blueshifts decrease for stronger Fe
  I lines, but they become independent of line strength for equivalent
  widths larger than about 100 mA. The detection of this "plateau"
  in the velocity shifts of the strongest Fe I lines is necessary to
  remove the non-negligible uncertainty introduced by granulation in the
  determination of absolute radial velocities. Line profiles computed
  using a 3D model atmosphere accurately reproduce the observations, with
  statistical tests showing an agreement at the 95 % confidence level,
  which validates the 3D model for spectroscopic studies of abundances
  and fundamental parameters of K-dwarfs. We find that 3D effects reduce
  the difference in the iron abundance determined separately from Fe II
  and Fe I lines, which is about 0.15 dex for 1D models, by two thirds,
  thus alleviating significantly the iron ionization imbalance problem in
  K-dwarfs. However, the 3D iron abundances from Fe I lines show a small
  dependence with excitation potential, similar to the 1D case, possibly
  due to non-LTE effects that have not been taken into account. We also
  find that the 3D correction to the effective temperatures of solar
  metallicity K-dwarfs derived with the infrared flux method is about +30
  K. Finally, we show that the 3D spectrum synthesis of molecular bands
  greatly improves the agreement with the observational data compared
  to the 1D analysis, which overestimates the abundances derived from
  molecular features by a factor of 2.

---------------------------------------------------------
Title: Commission 12: Solar Radiation and Structure
Authors: Martínez Pillet, Valentin; Kosovichev, Alexander;
   Mariska, John T.; Bogdan, Thomas J.; Asplund, Martin; Cauzzi, Gianna;
   Christensen-Dalsgaard, Jørgen; Cram, Lawrence E.; Gan, Weiqun; Gizon,
   Laurent; Heinzl, Petr; Rovira, Marta G.; Venkatakrishnan, P.
2009IAUTA..27..104M    Altcode:
  Commission 12 encompasses investigations on the internal structure
  and dynamics of the Sun, mostly accessible through the techniques of
  local and global helioseismology, the quiet solar atmosphere, solar
  radiation and its variability, and the nature of relatively stable
  magnetic structures like sunspots, faculae and the magnetic network. A
  revision of the progress made in these fields is presented. For some
  specific topics, the review has counted with the help of experts
  outside the Commission Organizing Committee that are leading and/or
  have recently presented relevant works in the respective fields. In
  this cases the contributor's name is given in parenthesis.

---------------------------------------------------------
Title: Carbon Abundances of Three Carbon-Enhanced Metal-Poor Stars
    from High-Resolution Gemini-S/bHROS Spectra of the λ8727 [C I] Line
Authors: Schuler, Simon C.; Margheim, Steven J.; Sivarani, Thirupathi;
   Asplund, Martin; Smith, Verne V.; Cunha, Katia; Beers, Timothy C.
2008AJ....136.2244S    Altcode: 2008arXiv0809.1377S
  We present the results from an analysis of the λ8727 forbidden
  [C I] line in high-resolution Gemini-S/bHROS spectra of three
  Carbon-Enhanced Metal-Poor (CEMP) stars. Previous derivations of C
  abundances in CEMP stars have primarily used the blue bands of CH
  and the C<SUB>2</SUB> Swan system, features which are suspected to be
  sensitive to photospheric temperature inhomogeneities (the so-called
  three-dimensional effects). We find the [C/Fe] ratios based on the [C I]
  abundances of the two most Fe-rich stars in our sample (HE 0507-1653:
  [Fe/H] = -1.42 and HE 0054-2542: [Fe/H] = -2.66) to be in good agreement
  with previously determined values. For the most Fe-deficient star in
  our sample (HE 1005-1439: [Fe/H] = -3.08), however, the [C/Fe] ratio is
  found to be 0.34 dex lower than the published molecular-based value. We
  have carried out three-dimensional local thermodynamic equilibrium (LTE)
  calculations for [C I], and the resulting corrections are found to be
  modest for all three stars, suggesting that the discrepancy between
  the [C I] and molecular-based C abundances of HE 1005-1439 is due to
  more severe three-dimensional effects on the molecular lines. Carbon
  abundances are also derived from C I high-excitation lines and are found
  to be 0.45-0.64 dex higher than the [C I]-based abundances. Previously
  published non-LTE (NLTE) C I abundance corrections bring the [C I]
  and C I abundances into better agreement; however, targeted NLTE
  calculations for CEMP stars are clearly needed. We have also derived
  the abundances of nitrogen, potassium, and iron for each star. The
  Fe abundances agree well with previously derived values, and the K
  abundances are similar to those of C-normal metal-poor stars. Nitrogen
  abundances have been derived from resolved lines of the CN red system
  assuming the C abundances derived from the [C I] feature. The abundances
  are found to be approximately 0.44 dex larger than literature values,
  which have been derived from CN blue bands near 3880 and 4215 Å. We
  discuss evidence that suggests that analyses of the CN blue system
  bands underestimate the N abundances of metal-poor giants.

---------------------------------------------------------
Title: A new sample of extremely/ultra metal-poor stars
Authors: García Pérez, A. E.; Christlieb, N.; Ryan, S. G.; Beers,
   T. C.; Aoki, W.; Asplund, M.; Barklem, P. S.; Bessell, M. S.; Eriksson,
   K.; Frebel, A.; Gustafsson, B.; Korn, A. J.; Nordström, B.; Norris,
   J. E.
2008PhST..133a4036G    Altcode:
  A sample of 30 very metal-poor stars from the Hamburg-European
  Southern Observatory (ESO) objective-prism survey have been observed
  at high spectral resolution at the Very Large Telescope (VLT) using the
  Ultraviolet and Visual Echelle Spectrograph (UVES). Two of the observed
  stars are very interesting not only because of their very low iron
  content, approximately four orders of magnitude lower than the solar
  value, but also because we detected the neutral lithium resonance line
  at 670.8 nm. Hydrogen lines suggest that the two observed stars have
  effective temperatures around 6000 6250 K and according to isochrones,
  they are either on the main sequence or on the subgiant branch, in
  which case they would probably be the most metal-poor dwarfs or warm
  subgiants with lithium detections known. These detections would allow
  to determine more accurately the slope of the trend of the lithium
  abundance with [Fe/H] than was possible with samples of unevolved
  stars restricted to higher metallicities.

---------------------------------------------------------
Title: Abundances in the Galactic bulge
Authors: Barbuy, B.; Alves-Brito, A.; Ortolani, S.; Zoccali, M.;
   Hill, V.; Meléndez, J.; Asplund, M.; Bica, E.; Renzini, A.; Gómez,
   A.; Minniti, D.
2008PhST..133a4032B    Altcode:
  The metallicity distribution and abundance ratios of the Galactic bulge
  are reviewed. Issues raised by recent work of different groups, in
  particular the high metallicity end, the overabundance of α-elements in
  the bulge relative to the thick disc and the measurement of giants
  versus dwarfs, are discussed. Abundances in the old moderately
  metal-poor bulge globular clusters are described.

---------------------------------------------------------
Title: Another forbidden solar oxygen abundance: the [O I] 5577
    Å line
Authors: Meléndez, J.; Asplund, M.
2008A&A...490..817M    Altcode: 2008arXiv0808.2796M
  Context: Recent works with improved model atmospheres, line formation,
  atomic and molecular data, and detailed treatment of blends have
  resulted in a significant downward revision of the solar oxygen
  abundance. <BR />Aims: Considering the importance of the Sun as an
  astrophysical standard and the current conflict of standard solar models
  using the new solar abundances with helioseismological observations we
  have performed a new study of the solar oxygen abundance based on the
  forbidden [O I] line at 5577.34 Å, not previously considered. <BR
  />Methods: High-resolution (R &gt; 500 000), high signal-to-noise
  (S/N &gt; 1000) solar spectra of the [O I] 5577.34 Å line have been
  analyzed employing both three-dimensional (3D) and a variety of 1D
  (spatially and temporally averaged 3D, Holweger &amp; Müller, MARCS
  and Kurucz models with and without convective overshooting) model
  atmospheres. <BR />Results: The oxygen abundance obtained from the
  [O I] 5577.3 Å forbidden line is almost insensitive to the input
  model atmosphere and has a mean value of log ɛ<SUB>O</SUB> = 8.71
  ± 0.02 (σ from using the different model atmospheres). The total
  error (0.07 dex) is dominated by uncertainties in the log gf value
  (0.03 dex), apparent line variation (0.04 dex) and uncertainties in
  the continuum and line positions (0.05 dex). <BR />Conclusions: The
  oxygen abundance derived here is close to the 3D-based estimates from
  the two other [O I] lines at 6300 and 6363 Å, the permitted O I lines
  and vibrational and rotational OH transitions in the infrared. Our
  study thus supports a low solar oxygen abundance (log ɛ<SUB>O</SUB>
  ≈ 8.7), independent of the adopted model atmosphere.

---------------------------------------------------------
Title: PREFACE: A Stellar Journey A Stellar Journey
Authors: Asplund, M.
2008PhST..133a1002A    Altcode:
  The conference A Stellar Journey was held in Uppsala, Sweden, 23 27June
  2008, in honour of Professor Bengt Gustafsson's 65th birthday. The
  choice of Uppsala as the location for this event was obvious given
  Bengt's long-standing association with the city stemming back to
  his school days. With the exception of a two-year postdoc stint in
  Copenhagen, five years as professor at Stockholm University and two
  years as director of the Sigtuna foundation, Bengt has forged his
  illustrious professional career at Uppsala University. The symposium
  venue was Museum Gustavianum, once the main building of the oldest
  university in Scandinavia. <P />The title of the symposium is a
  paraphrasing of Bengt's popular astronomy book Kosmisk Resa (in
  English: Cosmic Journey) written in the early eighties. I think this
  aptly symbolizes his career that has been an astronomical voyage
  from near to far, from the distant past to the present. The original
  book title was modified slightly to reflect that most of his work
  to date has dealt with stars in one way or another. In addition
  it also gives credit to Bengt's important role as a guiding light
  for a very large number of students, colleagues and collaborators,
  indeed for several generations of astronomers. For me personally,
  the book Kosmisk Resa bears particular significance as it has shaped
  my life rather profoundly. Although I had already decided to become
  an astronomer, when I first read the book as a 14-year-old I made up
  my mind then and there that I would study under Bengt Gustafsson and
  work on stars. Indeed I have remained true to this somewhat audacious
  resolution. I suspect that a great number of us have similar stories
  how Bengt has had a major influence on our lives, whether on the
  professional or personal level. <P />Perhaps Bengt's most outstanding
  characteristic is his enthralling enthusiasm. This is equally true
  whether he is pondering some scientific conundrum, supervising students
  or performing in front of an audience, be it an astronomical talk,
  student lecture, musical concert or theatre play. Another attribute of
  Bengt is his boundless optimism, which not the least has helped many
  of his students overcome the unavoidable moments of despair (this
  is only true as long as one is aware of the well-known BG factor:
  multiply any of Bengt's estimates for the time required to complete a
  task by at least a factor of three). His personal traits make working
  with Bengt always very enjoyable as well as highly educating. Bengt's
  work also extends well beyond the domain of astronomy, including
  music, literature, theatre, religion, research ethics, science
  policy and science popularization. Bengt is an excellent role model
  for a successful scientist with a rich and rewarding life outside of
  academia. <P />The symposium A Stellar Journey was divided into five
  sessions covering basically the main research areas Bengt has worked on:
  Stellar atmospheres, Solar/stellar spectroscopy, Stellar parameters,
  Stellar evolution and nucleosynthesis and Stellar populations. In
  addition, one afternoon was devoted to a session entitled Anything
  but astronomy (see the symposium program), which tried to showcase
  Bengt's diverse interests outside of astronomy with talks ranging
  from religion and history of science over science popularization
  and future studies to literature and music. <P />My task, as chair
  of the Scientific Organizing Committee, to put together an exciting
  scientific program of invited reviews and talks was made considerably
  easier thanks to the excellent suggestions by the other SOC members:
  Ann Boesgaard, Sofia Feltzing, John Lattanzio, Andre Maeder, Bertrand
  Plez and Monique Spite. I believe in the end we were successful in
  achieving our charge, an impression corroborated by the many encouraging
  comments from various participants during and after the conference. I am
  particularly grateful to Nils Bergvall, Bengt Edvardsson and Bertrand
  Plez for their time-consuming efforts in arranging the extraordinary
  and greatly appreciated non-astronomical session on Tuesday afternoon;
  Sigbritt Ernald provided a rich source of suggestions for suitable
  interesting persons to invite for the stimulating and highly enjoyable
  oral and musical presentations. <P />While the responsibilities of
  the SOC are quite pleasant and frankly not particularly demanding,
  the heavy burden with organizing a conference falls squarely with
  the Local Organizing Committee, which has to deal with a seemingly
  never-ending stream of practicalities and more mundane chores. The main
  reason the Stellar Journey conference was such an astounding success
  and ran so smoothly is the tireless work by the whole LOC. All of us
  owe a great deal of gratitude to Paul Barklem, Nils Bergvall, Norbert
  Christlieb, Bengt Edvardsson (Chair), Kjell Eriksson, Ulrike Heiter,
  Susanne Höfner, Andreas Korn, Nikolai Piskunov, Bertrand Plez and
  Astrid Wachter for their extensive efforts. I'd like to also extend a
  special acknowledgement to all of the Uppsala students who helped out
  during the reception, registration and various sessions. <P />Last but
  not the least, I'd like to thank all of the conference participants for
  giving such excellent talks and for providing stimulating discussions
  throughout the week. It is telling that essentially everyone invited
  to participate in the conference almost immediately accepted while
  the very few who declined did so only reluctantly due to other prior
  commitments. Bengt is a highly regarded colleague and friend, whom we
  all wished to celebrate this special occasion with. This conference
  represented merely one brief stop on a marvellous and truly stellar
  journey. I dare say that without exception we are all deeply thankful
  for having been able to join Bengt Gustafsson on at least some of his
  many cosmic adventures during the past decades. We trust that this
  exciting odyssey will continue for many years.

---------------------------------------------------------
Title: Does the Sun have a subsolar metallicity?
Authors: Asplund, Martin
2008IAUS..252...13A    Altcode:
  The solar chemical composition has recently undergone a drastic
  revision, in particular in terms of the C, N, O and Ne abundances that
  have been lowered by almost a factor of two. In this invited review
  I will describe the different compounding reasons for this change (3D
  model atmospheres, non-LTE line formation, improved atomic/molecular
  data) and discuss some astrophysical implications thereof, which
  fall under both good (solar neighborhood) and bad (helioseismology)
  news. The most recent literature regarding the solar O abundance is
  surveyed and a critical evaluation whether or not these support the
  low solar abundance scale is presented. Finally I venture to make some
  predictions to what the real solar O abundance may be.

---------------------------------------------------------
Title: Reality of Moving Groups in the Galaxy and Chemically Tagging
    the Galactic Disk
Authors: de Silva, G. M.; Freeman, K. C.; Bland-Hawthorn, J.;
   Asplund, M.
2008ASPC..396...59D    Altcode:
  The existence of old dispersed stellar groups within the Milky Way disk
  is still controversial. Are they the debris of ancient star-forming
  aggregates, or short-lived artifacts of dynamical origin? With detailed
  elemental abundance measurements from high quality spectroscopic data,
  we show that at least one such old dispersed stellar group is a true
  relic of an earlier phase of star formation. The identification of
  other such relic structures will provide essential information for
  probing the evolutionary history of the Milky Way disk.

---------------------------------------------------------
Title: Reality of Moving Groups in the Galaxy
Authors: De Silva, G. M.; Freeman, K. C.; Bland-Hawthorn, J.;
   Asplund, M.
2008arXiv0810.3346D    Altcode:
  The existence of old dispersed stellar groups within the Milky Way disk
  is still controversial. Are they the debris of ancient star-forming
  aggregates, or short-lived artifacts of dynamical origin? With detailed
  elemental abundance measurements from high quality spectroscopic data,
  we show that at least one such old dispersed stellar group is a true
  relic of an earlier phase of star formation. The identification of
  other such relic structures will provide essential information for
  probing the evolutionary history of the Milky Way disk.

---------------------------------------------------------
Title: Nitrogen Abundances in Giant Stars of the Globular Cluster
    NGC 6752
Authors: Yong, David; Grundahl, Frank; Johnson, Jennifer A.; Asplund,
   Martin
2008ApJ...684.1159Y    Altcode: 2008arXiv0806.0187Y
  We present N abundances for 21 bright giants in the globular cluster NGC
  6752 based on high-resolution UVES spectra of the 3360 Å NH lines. We
  confirm that the Strömgren c<SUB>1</SUB> index traces the N abundance
  and find that the star-to-star N abundance variation is 1.95 dex, at the
  sample's luminosity. We find statistically significant correlations,
  but small-amplitude variations, between the abundances of N and α-,
  Fe-peak, and s-process elements. Analyses using model atmospheres with
  appropriate N, O, Na, and Al abundances would strengthen, rather than
  mute, these correlations. If the small variations of heavy elements are
  real, then the synthesis of the N anomalies must take place in stars
  which also synthesize α-, Fe-peak, and s-process elements. These
  correlations offer support for contributions from both asymptotic
  giant branch and massive stars to the globular cluster abundance
  anomalies. <P />Based on observations made with ESO Telescopes at the
  Paranal Observatories under program 65.L-0165(A).

---------------------------------------------------------
Title: Signatures of Granulation in the Spectra of K-Dwarfs
Authors: Ramírez, I.; Allende Prieto, C.; Lambert, D. L.; Asplund, M.
2008ASPC..393..255R    Altcode: 2007arXiv0712.0387R
  Very high resolution (R&gt;150,000) spectra of a small sample of
  nearby K-dwarfs have been acquired to measure the line asymmetries
  and central wavelength shifts caused by convective motions present
  in stellar photospheres. This phenomenon of granulation is modeled
  by 3D hydrodynamical simulations but they need to be confronted with
  accurate observations to test their realism before they are used in
  stellar abundance studies. We find that the line profiles computed
  with a 3D model agree reasonably well with the observations. The line
  bisectors and central wavelength shifts on K-dwarf spectra have a
  maximum amplitude of only about 200 m s<SUP>-1</SUP> and we have been
  able to resolve these granulation effects with a very careful observing
  strategy. By computing a number of iron lines with 1D and 3D models
  (assuming local thermodynamic equilibrium), we find that the impact of
  3D-LTE effects on classical iron abundance determinations is negligible.

---------------------------------------------------------
Title: <SUP>18</SUP>O and the Origins of HdC and R CrB Stars
Authors: Geballe, T. R.; Clayton, G. C.; Asplund, M.; Herwig, F.;
   Fryer, C. L.
2008ASPC..391...51G    Altcode:
  We have detected enormously enhanced <SUP>18</SUP>O and correspondingly
  small values of <SUP>16</SUP>O/<SUP>18</SUP>O in many hydrogen-deficient
  carbon (HdC) stars and R Coronae Borealis (R CrB) stars. The similar
  ratios suggest a common origin for the two types of stars. Of the two
  leading candidates for the origin of R CrB stars, white dwarf mergers
  and final helium flashes, the former appears more likely to produce
  this and other observed isotopic anomalies.

---------------------------------------------------------
Title: Chemical similarities between Galactic bulge and local thick
    disk red giant stars
Authors: Meléndez, J.; Asplund, M.; Alves-Brito, A.; Cunha, K.;
   Barbuy, B.; Bessell, M. S.; Chiappini, C.; Freeman, K. C.; Ramírez,
   I.; Smith, V. V.; Yong, D.
2008A&A...484L..21M    Altcode: 2008arXiv0804.4124M
  Context: The evolution of the Milky Way bulge and its relationship with
  the other Galactic populations is still poorly understood. The bulge
  has been suggested to be either a merger-driven classical bulge or
  the product of a dynamical instability of the inner disk. <BR />Aims:
  To probe the star formation history, the initial mass function and
  stellar nucleosynthesis of the bulge, we performed an elemental
  abundance analysis of bulge red giant stars. We also completed an
  identical study of local thin disk, thick disk and halo giants to
  establish the chemical differences and similarities between the various
  populations. <BR />Methods: High-resolution infrared spectra of 19 bulge
  giants and 49 comparison giants in the solar neighborhood were acquired
  with Gemini/Phoenix. All stars have similar stellar parameters but
  cover a broad range in metallicity. A standard 1D local thermodynamic
  equilibrium analysis yielded the abundances of C, N, O and Fe. A
  homogeneous and differential analysis of the bulge, halo, thin disk and
  thick disk stars ensured that systematic errors were minimized. <BR
  />Results: We confirm the well-established differences for [O/Fe]
  (at a given metallicity) between the local thin and thick disks. For
  the elements investigated, we find no chemical distinction between
  the bulge and the local thick disk, which is in contrast to previous
  studies relying on literature values for disk dwarf stars in the solar
  neighborhood. <BR />Conclusions: Our findings suggest that the bulge
  and local thick disk experienced similar, but not necessarily shared,
  chemical evolution histories. We argue that their formation timescales,
  star formation rates and initial mass functions were similar.

---------------------------------------------------------
Title: Primordial and Pre-Galactic Origins of the Lithium Isotopes
Authors: Asplund, Martin; Meléndez, Jorge
2008AIPC..990..342A    Altcode:
  There are currently two cosmological lithium problems: compared with
  predictions from Big Bang Nucleosynthesis and models for Galactic
  cosmic ray production, the observed <SUP>7</SUP>Li abundance in
  Galactic halo stars is too low while the <SUP>6</SUP>Li content is
  too high. Here we report on new Keck/HIRES observations of the two
  extremely metal-poor stars G064-012 and G064-37, which both show
  distortions of the Li I 670.8 nm line consistent with a significant
  (~3σ) presence of <SUP>6</SUP>Li. If confirmed, these are the
  lowest metallicity <SUP>6</SUP>Li detections and would suggest a
  cosmological or pre-Galactic origin for the isotope. Invoking stellar
  Li depletion to solve the above-mentioned <SUP>7</SUP>Li discrepancy
  would further increase the inferred initial <SUP>6</SUP>Li abundance
  by a factor of ~10. Possible <SUP>6</SUP>Li production scenarios
  are decaying/annihilating supersymmetric particles within the first
  few minutes of the Big Bang and cosmological cosmic rays from the
  first stars, although stellar flare production can not be ruled out
  either. Work still remains, however, before one can unequivocally
  say that <SUP>6</SUP>Li really has been detected in these and other
  halo stars, in particular whether convective atmospheric motions and
  non-LTE line formation can mimic the presence of <SUP>6</SUP>Li in
  the observed line profiles.

---------------------------------------------------------
Title: A dedicated northern search for the first stars
Authors: Beers, Timothy; Norris, John; Allende Prieto, Carlos;
   Aoki, Wako; Asplund, Martin; Bessell, Michael; Christlieb, Norbert;
   Frebel, Anna; Johnson, Jennifer; Melendez, Jorge; Sneden, Christopher;
   Yong, David
2008noao.prop..179B    Altcode:
  We propose to continue a northern sky program using high resolution,
  moderate S/N spectra to discover the chemically oldest stars - ultra
  metal-poor dwarfs and giants drawn from the Hamburg/ESO and SEGUE
  surveys. With these data we seek to (1) discover more stars with [Fe/H]
  &lt; -4.0 (only three of which are known and all of which our group
  has discovered) to constrain the nature of the first stars; (2) measure
  the Li abundance for more stars with [Fe/H] &lt; -4.0, to investigate
  further the non-detection on this element in the subgiant HE1327-2326
  ([Fe/H] = -5.4) and its implication for Big Bang Nucleosynthesis;
  and (3) discover further r-process enhanced metal-poor stars with
  detectable Th and U, for cosmo-chronometric age determinations.

---------------------------------------------------------
Title: Comparing 3D Solar Model Atmospheres with Observations:
    Hydrogen Lines and Centre-to-limb Variations
Authors: Pereira, Tiago M. D.; Asplund, Martin; Trampedach, Regner
2008psa..conf..313P    Altcode:
  Three dimensional hydrodynamical stellar model atmospheres
  represent a major step forward in stellar spectroscopy. Making use
  of radiative-hydrodynamical convection simulations that contain no
  adjustable free parameters, the model atmospheres provide a robust
  and realistic treatment of convection. These models have been applied
  to several lines in the Sun and other stars, yielding an excellent
  agreement with observations (e.g., Asplund et al. (2000) [1]).

---------------------------------------------------------
Title: [C/O] Observations in Low-[Fe/H] Halo Stars
Authors: Fabbian, D.; Nissen, P. E.; Asplund, M.; Akerman, C. J.;
   Pettini, M.
2008psa..conf...45F    Altcode:
  We have observed 15 halo stars to determine the [C/O] behaviour at low
  [Fe/H]. Making use of our recent non-LTE calculations, which show
  that the high excitation C and O lines used in previous studies in
  the literature are affected by very significant departures from LTE,
  we aim to obtain accurate [C/O] ratios down to [Fe/H]∼ —3.2, which
  will enable us to shed light on the possible presence of an upturn of
  [C/O] at low metallicities.

---------------------------------------------------------
Title: Beyond 1D: spectral line formation with 3D hydrodynamical
    model atmospheres of red giants
Authors: Collet, R.; Asplund, M.; Trampedach, R.
2008MmSAI..79..649C    Altcode: 2007arXiv0711.3186C
  We present the results of realistic, 3D, hydrodynamical, simulations
  of surface convection in red giant stars with varying effective
  temperatures and metallicities. We use the convection simulations as
  time-dependent, hydrodynamical, model atmospheres to compute spectral
  line profiles for a number of ions and molecules under the assumption
  of local thermodynamic equilibrium (LTE). We compare the results with
  the predictions of line formation calculations based on 1D, hydrostatic,
  model stellar atmospheres in order to estimate the impact of 3D models
  on the derivation of elemental abundances. We find large negative
  3D-1D LTE abundance corrections (typically -0.5 to -1 dex) for weak
  low-excitation lines from molecules and neutral species in the very
  low metallicity cases. Finally, we discuss the extent of departures
  from LTE in the case of neutral iron spectral line formation.

---------------------------------------------------------
Title: Sulphur Abundances in Metal-poor Stars
Authors: Nissen, P. E.; Akerman, C.; Asplund, M.; Fabbian, D.;
   Pettini, M.
2008psa..conf...51N    Altcode:
  We report on sulphur abundances in halo stars as derived from near-IR
  UVES spectra. The importance of removing telluric lines and residual
  CCD fringing patterns by using early B-type stars as calibrators is
  emphasized. Comparison of data from the weak λ8694.6 and the stronger
  λ9212.9, 9237.5 pair of S I lines provides important constraints on
  non-LTE effects. We do not confirm the high sulphur abundances reported
  by others for some metal-poor stars; our results instead indicate that
  sulphur behaves like other typical α-capture elements with a plateau at
  [S/Fe] ∼ +0.3 dex in the Galactic halo.

---------------------------------------------------------
Title: Lithium Isotopic Abundances in Stars
Authors: Nissen, Poul Erik; Asplund, Martin
2008psa..conf....3N    Altcode:
  The Li isotope ratio, <SUP>6</SUP>Li/<SUP>7</SUP>Li, in stars can
  be determined from the isotopic shift in the Li I 670.8 nm resonance
  line. Because of the small effect this however requires truly precision
  spectroscopy: spectral resolving power R ≥ 10<SUP>5</SUP> and S/N ≥
  500. In this review we discuss the method and what one can learn from
  Li isotopic abundances in terms of Big-Bang nucleosynthesis, cosmic
  ray production of Li, stellar structure, and planet formation. Some
  instrumental problems and the need for new instrumentation are briefly
  discussed.

---------------------------------------------------------
Title: Lithium Isotopic Abundances in the Early Galaxy
Authors: Asplund, M.
2007ASPC..374..119A    Altcode:
  The lithium isotopes are potent probes of cosmic, galactic and
  stellar evolution. Herein I describe the challenging method used to
  derive Li isotopic abundances in metal-poor halo stars and their
  associated uncertainties. The results from our VLT-based program
  using extraordinarily high-quality spectra points to two cosmological
  Li problems: the observed ^7Li abundance is too low while the ^6Li
  abundance is too large compared with standard models for Big Bang
  nucleosynthesis and Galactic cosmic ray spallation.

---------------------------------------------------------
Title: Commission 36: Theory of Stellar Atmospheres
Authors: Spite, Monique; Landstreet, John D.; Asplund, Martin; Ayres,
   Thomas R.; Balachandran, Suchitra C.; Dravins, Dainis; Hauschildt,
   Peter H.; Kiselman, Dan; Nagendra, K. N.; Sneden, Christopher;
   Tautvaišiené, Grazina; Werner, Klaus
2007IAUTB..26..160S    Altcode:
  The business meeting of Commission 36 was held during the General
  Assembly in Prague on 16 August. It was attended by about 15
  members. The issues presented included a review of the work made
  by members of Commission 36, and the election of the new Organising
  Committee. We note that a comprehensive report on the activities of
  the commission during the last triennium has been published in Reports
  on Astronomy, Transactions IAU Volume XXVIA. The scientific activity
  of the members of the commission has been very intense, and has led
  to the publication of a large number of papers.

---------------------------------------------------------
Title: Three-dimensional hydrodynamical simulations of surface
    convection in red giant stars. Impact on spectral line formation
    and abundance analysis
Authors: Collet, R.; Asplund, M.; Trampedach, R.
2007A&A...469..687C    Altcode: 2007astro.ph..3652C
  Aims:We investigate the impact of realistic three-dimensional (3D)
  hydrodynamical model atmospheres of red giant stars at different
  metallicities on the formation of spectral lines of a number of ions
  and molecules. <BR />Methods: We carry out realistic, ab initio, 3D,
  hydrodynamical simulations of surface convection at the surface of red
  giant stars with varying effective temperatures and metallicities. We
  use the convection simulations as time-dependent hydrodynamical model
  stellar atmospheres to calculate spectral lines of a number of ions (Li
  I, O I, Na I, Mg I, Ca I, Fe I, and Fe II) and molecules (CH, NH, and
  OH) under the assumption of local thermodynamic equilibrium (LTE). We
  carry out a differential comparison of the line strengths computed
  in 3D with the results of analogous line formation calculations for
  classical, 1D, hydrostatic, plane-parallel marcs model atmospheres in
  order to estimate the impact of 3D models on the derivation of elemental
  abundances. <BR />Results: The temperature and density inhomogeneities
  and correlated velocity fields in 3D models, as well as the differences
  between the mean 3D stratifications and corresponding 1D model
  atmospheres significantly affect the predicted strengths of spectral
  lines. Under the assumption of LTE, the low atmospheric temperatures
  encountered in 3D model atmospheres of very metal-poor giant stars
  cause spectral lines from neutral species and molecules to appear
  stronger than within the framework of 1D models. As a consequence,
  elemental abundances derived from these lines using 3D models are
  significantly lower than according to 1D analyses. In particular,
  the differences between 3D and 1D abundances of C, N, and O derived
  from CH, NH, and OH weak low-excitation lines are found to be in the
  range -0.5 dex to -1.0 dex for the the red giant stars at [Fe/H]=-3
  considered here. At this metallicity, large negative corrections
  (about -0.8 dex) are also found, in LTE, for weak low-excitation Fe
  I lines. We caution, however, that the neglected departures from LTE
  might be significant for these and other elements and comparable to
  the effects due to stellar granulation.

---------------------------------------------------------
Title: Sulphur and zinc abundances in Galactic halo stars revisited
Authors: Nissen, P. E.; Akerman, C.; Asplund, M.; Fabbian, D.; Kerber,
   F.; Kaufl, H. U.; Pettini, M.
2007A&A...469..319N    Altcode: 2007astro.ph..2689N
  Aims:Based on a new set of sulphur abundances in very metal-poor stars
  and an improved analysis of previous data, we aim at resolving current
  discrepancies on the trend of S/Fe vs. Fe/H and thereby gain better
  insight into the nucleosynthesis of sulphur. The trends of Zn/Fe and
  S/Zn will also be studied. <BR />Methods: High resolution VLT/UVES
  spectra of 40 main-sequence stars with -3.3 &lt; [Fe/H] &lt; -1.0 are
  used to derive S abundances from the weak λ 8694.6 S I line and the
  stronger λ λ 9212.9,9237.5 pair of S I lines. For one star, the S
  abundance is also derived from the S I triplet at 1.046 μm recently
  observed with the VLT infrared echelle spectrograph CRIRES. Fe and
  Zn abundances are derived from lines in the blue part of the UVES
  spectra, and effective temperatures are obtained from the profile
  of the Hβ line. <BR />Results: Comparison of sulphur abundances
  from the weak and strong S I lines provides important constraints on
  non-LTE effects. The high sulphur abundances reported by others for
  some metal-poor stars are not confirmed; instead, when taking non-LTE
  corrections into account, the Galactic halo stars distribute around a
  plateau at [S/Fe] ~ +0.2 dex with a scatter of 0.07 dex only. [Zn/Fe]
  is close to zero for metallicities in the range -2.0 &lt; [Fe/H]
  &lt; -1.0 but increases to a level of [Zn/Fe] ~ +0.1 to +0.2 dex in
  the range -2.7 &lt; [Fe/H] &lt; -2.0. At still lower metallicities
  [Zn/Fe] rises steeply to a value of [Zn/Fe] ~ +0.5 dex at [Fe/H] =
  -3.2. <BR />Conclusions: The trend of S/Fe vs. Fe/H corresponds to
  the trends of Mg/Fe, Si/Fe, and Ca/Fe and indicates that sulphur in
  Galactic halo stars has been made by α-capture processes in massive
  SNe. The observed scatter in S/Fe is much smaller than predicted from
  current stochastic models of the chemical evolution of the early Galaxy,
  suggesting that either the models or the calculated yields of massive
  SNe should be revised. We also examine the behaviour of S/Zn and find
  that departures from the solar ratio are significantly reduced at
  all metallicities if non-LTE corrections to the abundances of these
  two elements are adopted. This effect, if confirmed, would reduce the
  usefulness of the S/Zn ratio as a diagnostic of past star-formation
  activity, but would bring closer together the values measured in damped
  Lyman-alpha systems and in Galactic stars. <P />Based on observations
  collected at the European Southern Observatory at Paranal, Chile
  (programmes No. 67.D-0106, 73.D-0024 and CRIRES science verification
  program 60.A-9072). Table 1 and Appendices are only available in
  electronic form at http://www.aanda.org

---------------------------------------------------------
Title: Sulphur Abundances in Metal-Poor Stars   First Result from
    CRIRES Science Verification
Authors: Nissen, Poul Erik; Asplund, Martin; Fabbian, Damian; Kerber,
   Florian; Käufl, Hans Ulrich; Pettini, Max
2007Msngr.128...38N    Altcode:
  Sulphur is the tenth most abundant element in the Universe and plays an
  im-portant role in studies of the chemical enrichment and star formation
  history of distant galaxies. Due to the lack of suitable sulphur lines
  in the visible part of stellar spectra there is, however, still no
  agreement on the abundance of sulphur in Galactic metal poor stars,
  and we are therefore uncertain about the nucleosynthetic origin of
  sulphur. New observations of infrared sulphur lines with the cryogenic
  high resolution infrared echelle spectrograph (CRIRES) at ESO's VLT
  are helping to solve this problem.

---------------------------------------------------------
Title: Uniquely Large Excesses of 18O in HdC and RCB Stars: Evidence
    for White Dwarf Mergers
Authors: Clayton, G. C.; Geballe, T. R.; Herwig, F.; Fryer, C.;
   Asplund, M.
2007apn4.confE..83C    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Solar Chemical Composition
Authors: Grevesse, N.; Asplund, M.; Sauval, A. J.
2007SSRv..130..105G    Altcode: 2007SSRv..tmp..105G
  We present our current knowledge of the solar chemical composition
  based on the recent significant downward revision of the solar
  photospheric abundances of the most abundant metals. These new solar
  abundances result from the use of a 3D hydrodynamic model of the solar
  atmosphere instead of the classical 1D hydrostatic models, accounting
  for departures from LTE, and improved atomic and molecular data. With
  these abundances, the new solar metallicity, Z, decreases to Z=0.012,
  almost a factor of two lower than earlier widely used values. We
  compare our values with data from other sources and analyse a number
  of impacts of these new photospheric abundances. While resolving a
  number of longstanding problems, the new 3D-based solar photospheric
  composition also poses serious challenges for the standard solar model
  as judged by helioseismology.

---------------------------------------------------------
Title: Very Large Excesses of <SUP>18</SUP>O in Hydrogen-deficient
Carbon and R Coronae Borealis Stars: Evidence for White Dwarf Mergers
Authors: Clayton, Geoffrey C.; Geballe, T. R.; Herwig, Falk; Fryer,
   Christopher; Asplund, Martin
2007ApJ...662.1220C    Altcode: 2007astro.ph..3453C
  We have found that at least seven hydrogen-deficient carbon (HdC) and R
  Coronae Borealis (RCB) stars, have <SUP>16</SUP>O/<SUP>18</SUP>O ratios
  close to and in some cases less than unity, values that are orders
  of magnitude lower than measured in other stars (the solar value is
  500). Greatly enhanced <SUP>18</SUP>O is evident in every HdC and RCB
  we have measured that is cool enough to have detectable CO bands. The
  three HdC stars measured have <SUP>16</SUP>O/<SUP>18</SUP>O&lt;1,
  lower values than any of the RCB stars. These discoveries are
  important clues in determining the evolutionary pathways of HdC
  and RCB stars, for which two models have been proposed: the double
  degenerate (white dwarf [WD] merger) and the final helium-shell flash
  (FF). No overproduction of <SUP>18</SUP>O is expected in the FF
  scenario. We have quantitatively explored the idea that HdC and RCB
  stars originate in the mergers of CO- and He-WDs. The merger process
  is estimated to take only a few days, with accretion rates of 150
  M<SUB>solar</SUB> yr<SUP>-1</SUP> producing temperatures at the base
  of the accreted envelope of (1.2-1.9)×10<SUP>8</SUP> K. Analysis of
  a simplified one-zone calculation shows that nucleosynthesis in the
  dynamically accreting material may provide a suitable environment for
  a significant production of <SUP>18</SUP>O, leading to very low values
  of <SUP>16</SUP>O/<SUP>18</SUP>O, similar to those observed. We also
  find qualitative agreement with observed values of <SUP>12</SUP>C/<SUP>
  13</SUP>C and with the CNO elemental ratios. H-admixture during the
  accretion process from the small H-rich C/O WD envelope may play
  an important role in producing the observed abundances. Overall,
  our analysis shows that WD mergers may very well be the progenitors
  of O<SUP>18</SUP>-rich RCB and HdC stars, and that more detailed
  simulations and modeling are justified.

---------------------------------------------------------
Title: Convection and the solar abundances: Does the sun have a
    sub-solar metallicity?
Authors: Asplund, Martin
2007IAUS..239..122A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Commission 36: Theory of Stellar Atmospheres
Authors: Spite, Monique; Landstreet, John; Asplund, M.; Ayres, T.;
   Balachandran, S.; Dravins, D.; Hauschildt, P.; Kiselman, D.; Nagendra,
   K. N.; Sneden, C.; Tautvaišiené, G.; Werner, K.
2007IAUTA..26..215S    Altcode:
  Commission 36 covers all the physics of stellar atmospheres. The
  scientific activity in this large field has been very intense during
  the last triennium and led to the publication of a large number of
  papers which makes an exhaustive report practically not feasible. As
  a consequence we decided to keep the format of the preceding report:
  first a list of areas of current research, then web links for obtaining
  further information.

---------------------------------------------------------
Title: Soils Ain't Soils: The Preservation of Solar Wind in Metal
    Grains from the Lunar Regolith
Authors: Ireland, T. R.; Holden, P.; Norman, M. D.; Mya, J.;
   Asplund, M.
2007LPI....38.1449I    Altcode:
  Oxygen isotopes from two more lunar soils have been analysed. Neither
  has an implanted component and all oxygen isotope compositions measured
  are normal. Solar wind exposure must be independently ascertained for
  each grain.

---------------------------------------------------------
Title: Commission 12: Solar Radiation &amp; Structure
Authors: Bogdan, Thomas. J.; Martínez Pillet, Valentin; Asplund,
   M.; Christensen-Dalsgaard, J.; Cauzzi, G.; Cram, L. E.; Dravins, D.;
   Gan, W.; Henzl, P.; Kosovichev, A.; Mariska, J. T.; Rovira, M. G.;
   Venkatakrishnan, P.
2007IAUTA..26...89B    Altcode:
  Commission 12 covers research on the internal structure and dynamics
  of the Sun, the "quiet" solar atmosphere, solar radiation and its
  variability, and the nature of relatively stable magnetic structures
  like sunspots, faculae and the magnetic network. There is considerable
  productive overlap with the other Commissions of Division II as
  investigations move progressively toward the fertile intellectual
  boundaries between traditional research disciplines. In large part,
  the solar magnetic field provides the linkage that connects these
  diverse themes. The same magnetic field that produces the more subtle
  variations of solar structure and radiative output over the 11 yr
  activity cycle is also implicated in rapid and often violent phenomena
  such as flares, coronal mass ejections, prominence eruptions, and
  episodes of sporadic magnetic reconnection.The last three years have
  again brought significant progress in nearly all the research endeavors
  touched upon by the interests of Commission 12. The underlying causes
  for this success remain the same: sustained advances in computing
  capabilities coupled with diverse observations with increasing levels
  of spatial, temporal and spectral resolution. It is all but impossible
  to deal with these many advances here in anything except a cursory and
  selective fashion. Thankfully, the Living Reviews in Solar Physics; has
  published several extensive reviews over the last two years that deal
  explicitly with issues relevant to the purview of Commission 12. The
  reader who is eager for a deeper and more complete understanding of
  some of these advances is directed to http://www.livingreviews.org
  for access to these articles.

---------------------------------------------------------
Title: Chemical Homogeneity in Collinder 261 and Implications for
    Chemical Tagging
Authors: De Silva, G. M.; Freeman, K. C.; Asplund, M.; Bland-Hawthorn,
   J.; Bessell, M. S.; Collet, R.
2007AJ....133.1161D    Altcode: 2006astro.ph.11832D
  This paper presents abundances for 12 red giants of the old open
  cluster Collinder 261 based on spectra from the Very Large Telescope
  UVES. Abundances were derived for Na, Mg, Si, Ca, Mn, Fe, Ni, Zr,
  and Ba. We find that the cluster has a solar-level metallicity of
  [Fe/H]=-0.03 dex. However, most α- and s-process elements were found to
  be enhanced. The star-to-star scatter was consistent with the expected
  measurement uncertainty for all elements. The observed rms scatter
  is as follows: Na=0.07, Mg=0.05, Si=0.06, Ca=0.05, Mn=0.03, Fe=0.02,
  Ni=0.04, Zr=0.12, and Ba=0.03 dex. The intrinsic scatter was estimated
  to be less than 0.05 dex. Such high levels of homogeneity indicate that
  chemical information remains preserved in this old open cluster. We use
  the chemical homogeneity we have now established in Cr 261, the Hyades,
  and the HR 1614 moving group to examine the uniqueness of the individual
  cluster abundance patterns, i.e., chemical signatures. We demonstrate
  that the three studied clusters have unique chemical signatures and
  discuss how other such signatures may be searched for in the future. Our
  findings support the prospect of chemically tagging disk stars to common
  formation sites in order to unravel the dissipative history of the
  Galactic disk. <P />Based on observations collected during ESO VLT-UT2
  Program 73.D-0716A at the European Southern Observatory, Paranal, Chile.

---------------------------------------------------------
Title: Chemically Tagging the HR 1614 Moving Group
Authors: De Silva, G. M.; Freeman, K. C.; Bland-Hawthorn, J.; Asplund,
   M.; Bessell, M. S.
2007AJ....133..694D    Altcode: 2006astro.ph.10041D
  We present abundances for a sample of F, G, and K dwarfs of the HR
  1614 moving group based on high-resolution, high signal-to-noise ratio
  spectra from the Anglo-Australian Telescope UCLES instrument. Our
  sample includes stars from Feltzing and Holmberg, as well as from
  Eggen. Abundances were derived for Na, Mg, Al, Si, Ca, Mn, Fe, Ni, Zr,
  Ba, Ce, Nd, and Eu. The α, Fe, and Fe-peak element abundances show a
  bimodal distribution, with four stars having solar metallicities, while
  the remaining 14 stars are metal-rich, [Fe/H]&gt;=0.25 dex. However,
  the abundances of these two groups converge for the heavier n-capture
  elements. Based on their photometry and kinematics, three of the
  four deviating stars are likely nonmembers or binaries. Although
  one star cannot be excluded on these grounds, we do expect low-level
  contamination from field stars within the HR 1614 moving group's range
  of magnitude, color, and space velocities. Disregarding these four
  stars, the abundance scatter across the group members for all elements
  is low. We find that there is an 80% probability that the intrinsic
  scatter does not exceed the following values: Fe, 0.01 dex; Na, 0.08
  dex; Mg, 0.02 dex; Al, 0.06 dex; Si, 0.02 dex; Ca, 0.02 dex; Mn, 0.01
  dex; Ni, 0.01 dex; Zr, 0.03 dex; Ba, 0.03 dex; Ce, 0.04 dex; Nd, 0.01
  dex; and Eu, 0.02 dex. The homogeneity of the HR 1614 group in age and
  abundance suggests that it is the remnant of a dispersed star-forming
  event. Its kinematical coherence shows that such a dispersing system
  need not be significantly perturbed by external dynamical influences
  such as Galactic spiral structure or giant molecular clouds, at least
  over a period of 2 Gyr.

---------------------------------------------------------
Title: The Solar Chemical Composition
Authors: Grevesse, N.; Asplund, M.; Sauval, A. J.
2007coma.book..105G    Altcode:
  We present our current knowledge of the solar chemical composition
  based on the recent significant downward revision of the solar
  photospheric abundances of the most abundant metals. These new solar
  abundances result from the use of a 3D hydrodynamic model of the solar
  atmosphere instead of the classical 1D hydrostatic models, accounting
  for departures from LTE, and improved atomic and molecular data. With
  these abundances, the new solar metallicity, Z, decreases to Z=0.012,
  almost a factor of two lower than earlier widely used values. We
  compare our values with data from other sources and analyse a number
  of impacts of these new photospheric abundances. While resolving a
  number of longstanding problems, the new 3D-based solar photospheric
  composition also poses serious challenges for the standard solar model
  as judged by helioseismology.

---------------------------------------------------------
Title: Evidence that R Coronae Borealis Stars Evolve from a White
    Dwarf Merger rather than a Final Helium Shell Flash
Authors: Clayton, Geoffrey C.; Geballe, T. R.; Herwig, F.; Fryer,
   C.; Tenenbaum, E.; Asplund, M.
2006AAS...20916812C    Altcode: 2006BAAS...38.1140C
  We have discovered, mainly using Gemini/GNIRS, that several
  hydrogen-deficient carbon (HdC) and R Coronae Borealis (RCB) stars,
  have 18O/16O ratios close to and sometimes exceeding unity, a value
  orders of magnitude greater than measured in other known stars
  (the Solar value is 1/500). This discovery is an important step in
  determining the evolutionary pathway of HdC and RCB stars in general,
  for which two models have been proposed: double degenerate (white dwarf
  (WD) merger), and the final helium-shell flash (FF). The FF model for
  producing RCB stars has been discredited recently due to a mismatch
  of abundances and timescales needed to produce the RCB stars. We have
  explored the idea that HdC and RCB stars originate in the merger of
  COand He-WDs in the light of the new observations. Understanding the
  RCB and HdC stars is a key test for any theory that aims to explain
  hydrogen deficiency in post-AGB stars. These new results on the 18O/16O
  ratio and our work on the FF star V605 Aql represent an opportunity for
  a huge breakthrough. Confirmation of the WD merger scenario, which is
  suggested, by both the models and these observations, will allow the use
  of RCB and HdC stars as probes for WD merger simulations. The ability to
  model the rates of these low-mass WD mergers will help us to understand
  the rates of more massive mergers that may make some type Ia supernovae.

---------------------------------------------------------
Title: The non-LTE line formation of neutral carbon in late-type stars
Authors: Fabbian, D.; Asplund, M.; Carlsson, M.; Kiselman, D.
2006A&A...458..899F    Altcode: 2006astro.ph..8284F
  Aims.We investigate the non-Local Thermodynamic Equilibrium (non-LTE)
  line formation of neutral carbon in late-type stars in order to remove
  some of the potential systematic errors in stellar abundance analyses
  employing C i features.<BR /> Methods: .The statistical equilibrium
  code MULTI was used on a grid of plane-parallel 1D MARCS atmospheric
  models.<BR /> Results: .Within the parameter space explored, the
  high-excitation C i lines studied are stronger in non-LTE due to
  the combined effect of line source function drop and increased line
  opacity due to overpopulation of the lower level for the transitions
  considered; the relative importance of the two effects depends on
  the particular combination of T<SUB>{eff</SUB>}, log g, [Fe/H] and
  [C/Fe] and on the analysed C i line. As a consequence, the non-LTE
  abundance corrections are negative and can be substantially so,
  for example ∼ -0.4 dex in halo turn-off stars at [Fe/H]∼ -3. The
  magnitude of the non-LTE corrections is rather insensitive to whether
  inelastic H collisions are included or not.<BR /> Conclusions: .Our
  results have implications on studies of nucleosynthetic processes and
  on Galactic chemical evolution models. When applying our calculated
  corrections to recent observational data, the upturn in [C/O] at low
  metallicity might still be present (thus apparently still necessitating
  contributions from massive Pop. III stars for the carbon production),
  but at a lower level and possibly with a rather shallow trend of ∼
  -0.2 dex/dex below [O/H]∼ -1.

---------------------------------------------------------
Title: The solar chemical composition
Authors: Asplund, Martin; Grevesse, Nicolas; Jacques Sauval, A.
2006NuPhA.777....1A    Altcode: 2004astro.ph.10214A
  We present what we believe to be the best estimates of the chemical
  compositions of the solar photosphere and the most pristine meteorites.

---------------------------------------------------------
Title: Line formation in solar granulation. VII. CO lines and the
    solar C and O isotopic abundances
Authors: Scott, P. C.; Asplund, M.; Grevesse, N.; Sauval, A. J.
2006A&A...456..675S    Altcode: 2006astro.ph..5116S
  CO spectral line formation in the Sun has long been a source of
  consternation for solar physicists, as have the elemental abundances
  it seems to imply. We modelled solar CO line formation using a
  realistic, ab initio, time-dependent 3D radiative-hydrodynamic model
  atmosphere. Results were compared with space-based observations
  from the ATMOS space shuttle experiment. We employed weak
  <SUP>12</SUP>C<SUP>16</SUP>O, <SUP>13</SUP>C<SUP>16</SUP>O and
  <SUP>12</SUP>C<SUP>18</SUP>O lines from the fundamental (Δ v =
  1) and first overtone (Δ v = 2) bands to determine the solar
  carbon abundance, as well as the <SUP>12</SUP>C/<SUP>13</SUP>C
  and <SUP>16</SUP>O/<SUP>18</SUP>O isotopic ratios. A weighted
  solar carbon abundance of logɛ_C=8.39 ± 0.05 was found. We
  note with satisfaction that the derived abundance is identical to
  our recent 3D determination based on C i, [C i], C2 and CH lines,
  increasing our confidence in the accuracy of both results. Identical
  calculations were carried out using 1D models, but only the 3D
  model was able to produce abundance agreement between different
  CO lines and the other atomic and molecular diagnostics. Solar
  <SUP>12</SUP>C/<SUP>13</SUP>C and <SUP>16</SUP>O/<SUP>18</SUP>O ratios
  were measured as 86.8<SUP>+3.9</SUP><SUB>-3.7</SUB> (δ<SUP>13</SUP>C
  = 30<SUP>+46</SUP><SUB>-44</SUB>) and 479<SUP>+29</SUP><SUB>-28</SUB>
  (δ<SUP>18</SUP>O = 41<SUP>+67</SUP><SUB>-59</SUB>), respectively. These
  values may require current theories of solar system formation, such as
  the CO self-shielding hypothesis, to be revised. Excellent agreement
  was seen between observed and predicted weak CO line shapes, without
  invoking micro- or macroturbulence. Agreement breaks down for the
  strongest CO lines however, which are formed in very high atmospheric
  layers. Whilst the line asymmetries (bisectors) were reasonably
  well reproduced, line strengths predicted on the basis of C and O
  abundances from other diagnostics were weaker than observed. The
  simplest explanation is that temperatures are overestimated in the
  highest layers of the 3D simulation. Thus, our analysis supports
  the presence of a COmosphere above the traditional photospheric
  temperature minimum, with an average temperature of less than 4000
  K. This shortcoming of the 3D model atmosphere is not surprising,
  given that it was never intended to properly describe such high layers.

---------------------------------------------------------
Title: New and improved experimental oscillator strengths in Zr II
    and the solar abundance of zirconium
Authors: Ljung, G.; Nilsson, H.; Asplund, M.; Johansson, S.
2006A&A...456.1181L    Altcode:
  Using the Fourier Transform Spectrometer at Lund Observatory, intensity
  calibrated spectra of singly ionized zirconium have been recorded and
  analyzed. Oscillator strengths for 263 Zr II spectral lines in the
  region 2500-5400 Å have been derived by combining new experimental
  branching fractions with previously measured radiative lifetimes. The
  transitions combine 34 odd parity levels with 29 low metastable levels
  between 0 and 2.4 eV. The experimental branching fractions have been
  compared with theoretical values and the oscillator strengths with
  previously published data when available. The oscillator strengths
  have been employed to derive the solar photospheric Zr abundance
  based on both 1D and 3D model atmospheres. Based on the seven best
  and least perturbed Zr II lines in the solar disk-center spectrum, we
  determine the solar Zr abundance to log ɛ_Zr=2.58±0.02 when using a
  3D hydrodynamical solar model atmosphere. The new value is in excellent
  agreement with the meteoritic Zr abundance.

---------------------------------------------------------
Title: Isotopic Analysis of the Sun
Authors: Ireland, T. R.; Asplund, M.
2006M&PSA..41.5176I    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Oxygen isotope reservoirs in the solar system
Authors: Ireland, T. R.; Asplund, M.
2006GeCAS..70Q.278I    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Chemically tagging the HR moving group
Authors: de Silva, G.; Freeman, K.; Bland-Hawthorn, J.; Asplund, M.;
   Bessell, M.
2006AAONw.110...13D    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The solar model problem: helioseismology vs the new solar
    chemical composition
Authors: Asplund, M.
2006IAUJD..17E...3A    Altcode:
  Recently the solar photospheric abundances of C, N and O have been
  significantly revised downward as a consequence of 3D hydrodynamical
  solar model atmosphere, non-LTE line formation, and improved
  atomic/molecular data. While this new solar chemical composition solves
  many long-standing problems in astrophysics such as the apparent high
  metallicity of the Sun relative to the current-day solar neighbourhood,
  it wrecks havoc with standard solar interior models as judged by
  helioseismology. In this review I will describe the background of this
  solar model problem, the new 3D solar abundance analysis, and possible
  solutions to the discrepancy.

---------------------------------------------------------
Title: An abundance study of the most iron-poor star HE1327-2326
    with Subaru/HDS
Authors: Aoki, W.; Frebel, A.; Christlieb, N.; Norris, J. E.; Beers,
   T. C.; Minezaki, T.; Barklem, P. S.; Honda, S.; Takada-Hidai, M.;
   Asplund, M.; Ryan, S. G.; Tsangarides, S.; Eriksson, K.; Steinhauer,
   A.; Deliyannis, C. P.; Nomoto, K.; Fujimoto, M. Y.; Ando, H.; Yoshii,
   Y.; Kajino, T.
2006AIPC..847...53A    Altcode:
  We present an elemental abundance analysis of HE 1327-2326, the most
  iron-deficient star known, based on a comprehensive investigation of
  spectra obtained with the Subaru Telescope. HE 1327-2326 is either
  in its main sequence or subgiant phase of evolution, hence it is
  essentially unevolved. The chemical abundances of this star have
  the following properties, which provide new constraints on models of
  nucleosynthesis processes that occurred in first-generation objects: <P
  />(1)The iron abundance (NLTE) is [Fe/H]= -5.45. This value is 0.2 dex
  lower than that of HE 0107-5240, the previously most iron-poor object
  known. No object having [Fe/H]= -5 ~ -4 is known to date. <P />(2)This
  star, as well as HE 0107-5240, exhibits extremely large overabundances
  of carbon relative to solar ratios ([C/Fe]~ +4). <P />(3)HE 1327-2326
  exhibits remarkable overabundances of the light elements (N, Na, Mg
  and Al), while HE 0107-5240 shows only relatively small excesses of N
  and Na. <P />(4)A large overabundance of Sr is found in HE 1327-2326
  as compared to other extremely low metallicity stars. <P />(5)The Li
  I 6707 Å line, which is detected in the great majority of metal-poor
  dwarfs and warm subgiants, is not found in HE 1327-2326. The upper
  limit on the Li abundance we determine (log ɛ (Li) &lt; 1.5) is
  clearly lower than the expected value from the Spite plateau.

---------------------------------------------------------
Title: Lithium Isotopic Abundances in Metal-poor Halo Stars
Authors: Asplund, Martin; Lambert, David L.; Nissen, Poul Erik;
   Primas, Francesca; Smith, Verne V.
2006ApJ...644..229A    Altcode: 2005astro.ph.10636A
  Very high quality spectra of 24 metal-poor halo dwarfs and subgiants
  have been acquired with ESO's VLT/UVES for the purpose of determining
  Li isotopic abundances. The derived one-dimensional, non-LTE <SUP>
  7</SUP>Li abundances from the Li I 670.8 nm line reveal a pronounced
  dependence on metallicity but with negligible scatter around this
  trend. Very good agreement is found between the abundances from the Li I
  670.8 nm line and the Li I 610.4 nm line. The estimated primordial <SUP>
  7</SUP>Li abundance is <SUP>7</SUP>Li/H=(1.1-1.5)×10<SUP>-10</SUP>,
  which is a factor of 3-4 lower than predicted from standard big bang
  nucleosynthesis with the baryon density inferred from the cosmic
  microwave background. Interestingly, <SUP>6</SUP>Li is detected in 9
  of our 24 stars at the &gt;=2 σ significance level. Our observations
  suggest the existence of a <SUP> 6</SUP>Li plateau at the level
  of logɛ<SUB><SUP>6</SUP>Li</SUB>~0.8 however, taking into account
  predictions for <SUP>6</SUP>Li destruction during the pre-main-sequence
  evolution tilts the plateau such that the <SUP>6</SUP>Li abundances
  apparently increase with metallicity. Our most noteworthy result is the
  detection of <SUP>6</SUP>Li in the very metal-poor star LP 815-43. Such
  a high <SUP>6</SUP>Li abundance during these early Galactic epochs
  is very difficult to achieve by Galactic cosmic-ray spallation and
  α-fusion reactions. It is concluded that both Li isotopes have a
  pre-Galactic origin. Possible <SUP>6</SUP>Li production channels include
  protogalactic shocks and late-decaying or annihilating supersymmetric
  particles during the era of big bang nucleosynthesis. The presence of
  <SUP>6</SUP>Li limits the possible degree of stellar <SUP> 7</SUP>Li
  depletion and thus sharpens the discrepancy with standard big bang
  nucleosynthesis. <P />Based on observations collected at the European
  Southern Observatory, Paranal, Chile (observing programs 65.L-0131,
  68.D-0091, and 273.D-5043).

---------------------------------------------------------
Title: The Chemical Compositions of the Extreme Halo Stars
    HE 0107-5240 and HE 1327-2326 Inferred from Three-dimensional
    Hydrodynamical Model Atmospheres
Authors: Collet, R.; Asplund, M.; Trampedach, R.
2006ApJ...644L.121C    Altcode: 2006astro.ph..5219C
  We investigate the impact of realistic three-dimensional (3D)
  hydrodynamical model stellar atmospheres on the determination of
  elemental abundances in the carbon-rich, hyper-iron-poor stars HE
  0107-5240 and HE 1327-2326. We derive the chemical compositions of the
  two stars by means of a detailed 3D analysis of spectral lines under
  the assumption of local thermodynamic equilibrium (LTE). The lower
  temperatures of the line-forming regions of the hydrodynamical models
  cause changes in the predicted spectral line strengths. In particular,
  we find the 3D abundances of C, N, and O to be lower by about -0.8 dex
  (or more) than estimated from a 1D analysis. The 3D abundances of iron
  peak elements are also decreased but by smaller factors (about -0.2
  dex). We caution, however, that the neglected non-LTE effects might
  actually be substantial for these metals. We finally discuss possible
  implications for studies of early Galactic chemical evolution.

---------------------------------------------------------
Title: Oxygen abundances in metal-poor subgiants as determined from
    [O I], O I and OH lines
Authors: García Pérez, A. E.; Asplund, M.; Primas, F.; Nissen,
   P. E.; Gustafsson, B.
2006A&A...451..621G    Altcode: 2005astro.ph.12290G
  The debate on the oxygen abundances of metal-poor stars has its
  origin in contradictory results obtained using different abundance
  indicators. To achieve a better understanding of the problem we
  have acquired high quality spectra with the Ultraviolet and Visual
  Echelle Spectrograph at VLT, with a signal-to-noise of the order of
  100 in the near ultraviolet and 500 in the optical and near infrared
  wavelength range. Three different oxygen abundance indicators,
  OH ultraviolet lines around 310.0 nm, the [O i] line at 630.03 nm
  and the O i lines at 777.1-5 nm were observed in the spectra of 13
  metal-poor subgiants with -3.0≤[Fe/H]≤-1.5. Oxygen abundances
  were obtained from the analysis of these indicators which was carried
  out assuming local thermodynamic equilibrium and plane-parallel
  model atmospheres. Abundances derived from O i were corrected for
  departures from local thermodynamic equilibrium. Stellar parameters
  were computed using T_eff-vs.-color calibrations based on the infrared
  flux method and Balmer line profiles, Hipparcos parallaxes and Fe II
  lines. [O/Fe] values derived from the forbidden line at 630.03 nm are
  consistent with an oxygen/iron ratio that varies linearly with [Fe/H] as
  [O/Fe]=-0.09(±0.08)[Fe/H]+0.36(±0.15). Values based on the O i triplet
  are on average 0.19±0.22 dex(s.d.) higher than the values based on the
  forbidden line while the agreement between OH ultraviolet lines and the
  forbidden line is much better with a mean difference of the order of
  -0.09±0.25 dex(s.d.). In general, our results follow the same trend
  as previously published results with the exception of the ones based
  on OH ultraviolet lines. In that case our results lie below the values
  which gave rise to the oxygen abundance debate for metal-poor stars.

---------------------------------------------------------
Title: HE 1327-2326, an Unevolved Star with [Fe/H]&lt;-5.0. I. A
    Comprehensive Abundance Analysis
Authors: Aoki, W.; Frebel, A.; Christlieb, N.; Norris, J. E.; Beers,
   T. C.; Minezaki, T.; Barklem, P. S.; Honda, S.; Takada-Hidai, M.;
   Asplund, M.; Ryan, S. G.; Tsangarides, S.; Eriksson, K.; Steinhauer,
   A.; Deliyannis, C. P.; Nomoto, K.; Fujimoto, M. Y.; Ando, H.; Yoshii,
   Y.; Kajino, T.
2006ApJ...639..897A    Altcode: 2005astro.ph..9206A
  We present the elemental abundances of HE 1327-2326, the most
  iron-deficient star known, determined from a comprehensive analysis
  of spectra obtained with the Subaru Telescope High Dispersion
  Spectrograph. HE 1327-2326 is either in its main-sequence or
  subgiant phase of evolution. Its non-LTE-corrected iron abundance is
  [Fe/H]=-5.45, 0.2 dex lower than that of HE 0107-5240, the previously
  most iron-poor object known, and more than 1 dex lower than those
  of all other metal-poor stars. Both HE 1327-2326 and HE 0107-5240
  exhibit extremely large overabundances of carbon ([C/Fe]~+4). The
  combination of extremely high carbon abundance with outstandingly
  low iron abundance in these objects clearly distinguishes them from
  other metal-poor stars. The large carbon excesses in these two stars
  are not the result of a selection effect. There also exist important
  differences between HE 1327-2326 and HE 0107-5240. While the former
  shows remarkable overabundances of the light elements (N, Na, Mg,
  and Al), the latter shows only relatively small excesses of N and
  Na. The neutron-capture element Sr is detected in HE 1327-2326,
  but not in HE 0107-5240 its Sr abundance is significantly higher
  than the upper limit for HE 0107-5240. The Li I λ6707 line, which is
  detected in most metal-poor dwarfs and warm subgiants having the same
  temperature as HE 1327-2326, is not found in this object. The upper
  limit of its Li abundance [logɛ(Li)&lt;1.5] is clearly lower than the
  Spite plateau value. These data provide new constraints on models of
  nucleosynthesis processes in the first-generation objects that were
  responsible for metal enrichment at the earliest times. We discuss
  possible scenarios to explain the observed abundance patterns. <P
  />Based on data collected with the Subaru Telescope, which is operated
  by the National Astronomical Observatory of Japan.

---------------------------------------------------------
Title: The Oxygen Abundance of HE 1327-2326
Authors: Frebel, Anna; Christlieb, Norbert; Norris, John E.; Aoki,
   Wako; Asplund, Martin
2006ApJ...638L..17F    Altcode: 2005astro.ph.12543F
  From a newly obtained VLT/UVES spectrum, we have determined the
  oxygen abundance of HE 1327-2326, the most iron-poor star known to
  date. Ultraviolet OH lines yield one-dimensional LTE abundances of
  [O/Fe]<SUB>OH</SUB> =3.7 (subgiant case) and [O/Fe]<SUB>OH</SUB>=3.4
  (dwarf case). Using a correction of -1.0 dex to account for
  three-dimensional (3D) effects on OH line formation, the abundances
  are lowered to [O/Fe]=2.8 and [O/Fe]=2.5, respectively, which we
  adopt. Without 3D corrections, the UV OH-based abundance would be in
  disagreement with the upper limits derived from the O I triplet lines:
  [O/Fe]<SUB>trip</SUB>&lt;2.8 (subgiant) and [O/Fe]<SUB>trip</SUB>&lt;3.0
  (dwarf). We also correct the previously determined carbon and nitrogen
  abundances for 3D effects. Knowledge of the O abundance of HE 1327-2326
  has implications for the interpretation of its abundance pattern. A
  large O abundance is in accordance with HE 1327-2326 being an early
  Population II star that formed from material chemically enriched by
  a first-generation supernova. Our derived abundances, however, do
  not exclude other possibilities such as a Population III scenario. <P
  />Based on observations collected at the European Southern Observatory,
  Paranal, Chile (proposal 075.D-0048).

---------------------------------------------------------
Title: Getting a handle on the origin of the Galactic Bulge
Authors: Lambert, David L.; Ryde, Nils; Hinkle, Kenneth; Smith, Verne
   V.; Gustafsson, Bengt; Edvardsson, Bengt; Asplund, Martin; Johansson,
   Sveneric; Wahlin, Rurik
2006noao.prop..268L    Altcode:
  The origin, chemical properties, and evolution history of the
  Galactic Bulge remain poorly understood. Abundance ratios of bulge
  stars, especially in the [(alpha)/Fe] vs [Fe/H] diagram, serve to
  constrain the evolutionary models. Measuring, for instance, a high
  (alpha) over-abundance indicates rapid and early star-formation. Thus,
  we propose an infrared based study of the (alpha) elements, including
  oxygen, of ten stars in two low-extinction windows towards the bulge. We
  will also re-investigate the oxygen abundance trends found from optical
  spectra of K giants in Baade's window by McWilliam &amp; Rich (2004),
  which indicate a surprising cession of oxygen production in the bulge
  for metallicities larger than -0.5. The infrared, with lower extinction
  and molecular rather than atomic abundance indicators, is a preferred
  wavelength region to study abundances in bulge stars.

---------------------------------------------------------
Title: Ci Non-LTE Spectral Line Formation in Late-Type Stars
Authors: Fabbian, D.; Asplund, M.; Carlsson, M.
2006cams.book...52F    Altcode:
  We present the results from our non-LTE investigation for neutral
  carbon, which was carried out to remove potential systematic errors
  in stellar abundance analyses. The calculations were performed for
  late-type stars and give substantial negative non-LTE abundance
  corrections. When applied to observations of extremely metal-poor
  stars, which within the LTE framework seem to suggest a possible [C/O]
  uprise at low metallicities (Akerman et al. 2004), these improvements
  will have important implications, enabling us to understand if the
  standard chemical evolution model is adequate, with no need to invoke
  signatures by Pop. III stars for the carbon nucleosynthesis.

---------------------------------------------------------
Title: Chemical Homogeneity in the Hyades
Authors: De Silva, G. M.; Sneden, C.; Paulson, D. B.; Asplund, M.;
   Bland-Hawthorn, J.; Bessell, M. S.; Freeman, K. C.
2006AJ....131..455D    Altcode: 2005astro.ph..9241D
  We present an abundance analysis of the heavy elements Zr, Ba,
  La, Ce, and Nd for Hyades F-K dwarfs based on high-resolution, high
  signal-to-noise ratio spectra from Keck HIRES. The derived abundances
  show the stellar members to be highly uniform, although some elements
  show a small residual trend with temperature. The rms scatter for each
  element for the cluster members is as follows: Zr=0.055, Ba=0.049,
  Ce=0.025, La=0.025, and Nd=0.032 dex. This is consistent with the
  measurement errors and implies that there is little or no intrinsic
  scatter among the Hyades members. Several stars thought to be nonmembers
  of the cluster based on their kinematics are found to deviate from the
  cluster mean abundances by about 2 σ. Establishing chemical homogeneity
  in open clusters is the primary requirement for the viability of
  chemically tagging Galactic disk stars to common formation sites in
  order to unravel the dissipative history of early disk formation.

---------------------------------------------------------
Title: The new solar abundances - Part I: the observations
Authors: Asplund, M.; Grevesse, N.; Sauval, A. J.
2006CoAst.147...76A    Altcode:
  The new solar abundances have been derived from analyses of the
  photospheric spectrum. They result from the use of a 3D hydrodynamical
  model of the solar atmosphere instead of the classical 1D hydrostatic
  models, accounting for departures from LTE when possible and improved
  atomic and molecular data. The new solar abundances are lower than
  previously recommended values and the present solar metallicity, Z,
  and Z/X, decrease to Z = 0.0122 and Z/X = 0.0165 respectively, almost
  a factor of two lower than earlier widely used values. We briefly
  discuss the new results for the most abundant elements, show why they
  are trustworthy and discuss some implications (see also Montalban et
  al. 2006, Part II).

---------------------------------------------------------
Title: 3D Hydrodynamical Simulations of Convection in Red-Giants
    Stellar Atmospheres
Authors: Collet, R.; Asplund, M.; Trampedach, R.
2006cams.book..306C    Altcode:
  We present preliminary results of 3D hydrodynamical simulations
  of surface convection in red giants stars. We investigate the main
  differences between static 1D and 3D time-dependent model stellar
  atmospheres of red giants for a range of metallicities between solar
  and [Fe/H] = -3 focusing in particular on the impact of 3D spectral
  line formation on the derivation of stellar abundances.

---------------------------------------------------------
Title: Chemical abundance patterns of extremely metal-poor stars
Authors: Aoki, Wako; Beers, Timothy C.; Christlieb, Norbert; Frebel,
   Anna; Norris, John E.; Honda, Satoshi; Takada-Hidai, Masahide; Asplund,
   Martin; Ando, Hiroyasu; Ryan, Sean G.; Tsangarides, Stelios
2006isna.confE.210A    Altcode: 2006PoS....28E.210A
  We have obtained high resolution (R =60,000), high quality (S/N
  &gt;100) spectroscopy using Subaru/HDS for 20 candidate extremely
  metal-poor stars ([Fe/H]&lt; -3) to determine their chemical abundance
  patterns. In the observing program we found HE1327-2326, which has
  [Fe/H]= -5.4, the lowest Fe abundance known in normal stars. This
  star shows extremely large excesses of C and N, and also excesses
  of other light elements (e.g. O, Na). The low iron abundance and the
  peculiar abundance pattern provide a signature of the nucleosynthesis
  by the first generation stars in the Universe. We also present the
  preliminary results for other stars: (1) The iron abundances of our
  sample, except for HE 1327-2326, are higher than [Fe/H]= -4. There is
  a gap of iron abundance between [Fe/H]= -4 and -5. This would indicate
  that the nucleosynthesis, or formation processes that are responsible
  for the stars with [Fe/H]&lt; -5 and others are quite different. (2)
  Six stars of our sample, including HE1327-2326, show clear excesses
  of carbon. Only two of them show excesses of the heavy neutron-capture
  element Ba, suggesting a large contribution of AGB nucleosynthesis. The
  origin of carbon-excesses in other stars are still unclear, but the
  existence of these stars is a remarkable feature only found at the
  extremely low metallicity.

---------------------------------------------------------
Title: Highlights from the Search for Bright Extremely Metal-poor
    Stars
Authors: Frebel, A.; Norris, J. E.; Christlieb, N.; Beers, T. C.;
   Asplund, M.; Bessell, M. S.; Aoki, W.
2005AAS...207.6910F    Altcode: 2005BAAS...37.1272F
  We present very recent work on bright (10 &lt; B &lt; 14) extremely
  metal-poor stars selected from the Hamburg/ESO survey. Detailed
  knowledge about the most metal-poor objects found in the halo
  of the Galaxy is crucial for a comprehensive understanding of
  the early Universe since they are the closest relatives to true
  first stars (“Population III" objects). In a sample of 1777 bright
  metal-poor candidate stars we identified ∼ 100 star with [Fe/H] &lt;
  -2.5. This sample is currently being observed with high-resolution
  spectroscopy to reveal any unusual abundance patterns which are
  of astrophysical interest (e.g. ultra metal-poor, s- or r-process
  enhanced). So far, we have found the bright dwarf or subgiant HE
  1327-2326 which has a new low record iron abundance of [Fe/H] =
  -5.4. Most characteristically, this star displays huge amounts of CNO
  elements with respect to iron ( ∼ 4 dex) as well as an enhancement
  of the neutron-capture element Sr. Despite its evolutinary status,
  no Li could be detected. The interpretation of the abundance pattern
  of HE 1327-2326 challenges the current theoretical understanding of
  the first stars. Furthermore, we are searching for stars with strong
  enhancement of r-process abundances. Potential abundance measurements
  of the the heavy elements Th and U allow the determination of
  stellar ages. These are independent lower limits for the age of the
  Universe. A.F, J.E.N., M.S.B and M.A. acknowledge funding from the
  Australian Research Council. N.C. acknowledges funding from Deutsche
  Forschungsgemeinschaft. T.C.B. acknowledges funding from the US National
  Science Foundation Physics and Frontiers Center/JINA: Joint Institute
  for Nuclear Astrophysics, awarded by the US National Science Foundation.

---------------------------------------------------------
Title: Lithium Isotopic Abundances in Metal-Poor Stars: A Problem
    for Standard Big Bang Nucleosynthesis?
Authors: Nissen, Poul E.; Asplund, Martin; Lambert, David L.; Primas,
   Francesca; Smith, Verne V.
2005Msngr.122...32N    Altcode:
  Spectra obtained with VLT/UVES suggest the existence of the Li isotope
  in several metal-poor stars at a level that challenges ideas about its
  synthesis. The Li abundance is, on the other hand, a factor of three
  lower than predicted by standard Big Bang nucleosynthesis theory. Both
  problems may be explained if decaying supersymmetric particles affect
  the synthesis of light elements in the Big Bang.

---------------------------------------------------------
Title: Effects of line-blocking on the non-LTE Fe I spectral line
    formation
Authors: Collet, R.; Asplund, M.; Thévenin, F.
2005A&A...442..643C    Altcode: 2005astro.ph..7375C
  The effects of background line opacity (line-blocking) in statistical
  equilibrium calculations for Fe in late-type stellar atmospheres have
  been investigated using an extensive and up-to-date model atom with
  radiative data primarily from the iron Project. The background metal
  line opacities have been computed using data from the marcs stellar
  model atmospheres. While accounting for this line opacity is important
  at solar metallicity, the differences between calculations including
  and excluding line-blocking at low metallicity are insignificant for
  the non-local thermodynamic equilibrium (non-LTE) abundance corrections
  for Fe I lines. The line-blocking has no impact on the non-LTE effects
  of Fe II lines. The dominant uncertainty in Fe non-LTE calculations
  for metal-poor stars is still the treatment of the inelastic H I
  collisions, which here have been included using scaling factors to the
  classical Drawin formalism, and whether or not thermalisation of the
  high Fe I levels to Fe II ground state should be enforced. Without such
  thermalisation, the Fe I non-LTE abundance corrections are substantial
  in metal-poor stars: about 0.3 dex with efficient (i.e. Drawin-like)
  H I collisions and ⪉0.5 dex without. Without both thermalisation and
  H I collisions, even Fe II lines show significant non-LTE effects in
  such stars.

---------------------------------------------------------
Title: The solar model problem resurrected
Authors: Asplund, M.; Grevesse, N.; Guedel, M.; Sauval, A. J.
2005astro.ph.10377A    Altcode:
  The new solar composition, when applied to compute a model of the Sun,
  leads to serious disagreement between the predictions of the model
  and the observations obtained by helioseismology. New measurements of
  the coronal Ne/O abundance ratio in nearby stars using X-ray spectra
  typically find high values of Ne/O=0.4 rather than 0.15 normally adopted
  for the Sun. Drake &amp; Testa (2005) suggest that this high Ne/O ratio
  is appropriate also for the Sun, which would bring the solar models
  back in agreement with the helioseismological observations. Here we
  present arguments why the high Ne/O ratio is unlikely to be applicable
  to the Sun.

---------------------------------------------------------
Title: Trends and Scatter of Abundance Ratios for Metal-poor
    Turnoff Stars
Authors: Nissen, P. E.; Asplund, M.; Lambert, D. L.; Primas, F.;
   Smith, V. V.
2005ASPC..336...55N    Altcode:
  Trends and scatter of abundances of Li, O, Ca and Fe in metal-poor
  stars are discussed with particular emphasis on new results obtained
  by analyzing high resolution ESO VLT/UVES spectra of 23 turnoff stars
  using effective temperatures derived from the Hα line. Evidence of a
  significant cosmic scatter in O/Fe and Ca/Fe at a given metallicity is
  found, whereas the scatter in Li/H is very small, i.e. less than 0.03
  dex. The results are compared to previous data for halo, thick and
  thin disk stars, and to the prediction of the primordial Li abundance
  from WMAP.

---------------------------------------------------------
Title: New Light on Stellar Abundance Analyses: Departures from LTE
    and Homogeneity
Authors: Asplund, Martin
2005ARA&A..43..481A    Altcode:
  The information on the chemical compositions of stars encoded in their
  spectra plays a central role in contemporary astrophysics. Stellar
  element abundances are, however, not observed: to decipher the spectral
  fingerprints in terms of abundances requires realistic models for the
  stellar atmospheres and the line-formation processes. Still today,
  the vast majority of abundance analyses of late-type stars rely on
  one-dimensional (1D), hydrostatic model atmospheres and the assumption
  of local thermodynamic equilibrium (LTE). In this review possible
  systematic errors in studies of F-, G- and K-type stars introduced by
  these questionable approximations are discussed. Departures from LTE
  are commonplace and often quite severe, in particular for low surface
  gravities or metallicities, with minority species and low-excitation
  transitions being the most vulnerable. Recently, time-dependent, 3D,
  hydrodynamical model atmospheres have started to be employed for stellar
  abundance purposes, with large differences compared with 1D modeling
  found in particular for metal-poor stars. An assessment of non-LTE
  and 3D effects for individual elements as well as on the estimated
  stellar parameters is presented.

---------------------------------------------------------
Title: Chemical abundances in 43 metal-poor stars
Authors: Jonsell, K.; Edvardsson, B.; Gustafsson, B.; Magain, P.;
   Nissen, P. E.; Asplund, M.
2005A&A...440..321J    Altcode: 2005astro.ph..5118J
  We have derived abundances of O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe,
  Ni, and Ba for 43 metal-poor field stars in the solar neighbourhood,
  most of them subgiants or turn-off-point stars with iron abundances
  [Fe/H] ranging from -0.4 to -3.0. About half of this sample has not been
  spectroscopically analysed in detail before. Effective temperatures
  were estimated from uvby photometry, and surface gravities primarily
  from Hipparcos parallaxes. The analysis is differential relative to
  the Sun, and was carried out with plane-parallel MARCS models. Various
  sources of error are discussed and found to contribute a total error
  of about 0.1-0.2 dex for most elements, while relative abundances,
  such as [Ca/Fe], are most probably more accurate. For the oxygen
  abundances, determined in an NLTE analysis of the 7774 Å triplet
  lines, the errors may be somewhat larger. We made a detailed comparison
  with similar studies and traced the reasons for the, in most cases,
  relatively small differences. Among the results we find that [O/Fe]
  possibly increases beyond [Fe/H] = -1.0, though considerably less so
  than in results obtained by others from abundances based on OH lines. We
  did not trace any tendency toward strong overionization of iron, and
  find the excesses, relative to Fe and the Sun, of the α elements Mg,
  Si, and Ca to be smaller than those of O. We discuss some indications
  that also the abundances of different α elements relative to Fe vary
  and the possibility that some of the scatter around the trends in
  abundances relative to iron may be real. This may support the idea that
  the formation of Halo stars occurred in smaller systems with different
  star formation rates. We verify the finding by Gratton et al. (2003b,
  A&amp;A, 406, 131) that stars that do not participate in the rotation
  of the galactic disk show a lower mean and larger spread in [ α/Fe]
  than stars participating in the general rotation. The latter stars also
  seem to show some correlation between [ α/Fe] and rotation speed. We
  trace some stars with peculiar abundances, among these two Ba stars,
  <ASTROBJ>HD 17072</ASTROBJ> and <ASTROBJ>HD 196944</ASTROBJ>, the
  second already known to be rich in s elements. Finally we advocate
  that a spectroscopic study of a larger sample of halo stars with
  well-defined selection criteria is very important, in order to add to
  the very considerable efforts that various groups have already made.

---------------------------------------------------------
Title: The Solar Chemical Composition
Authors: Asplund, M.; Grevesse, N.; Sauval, A. J.
2005ASPC..336...25A    Altcode:
  We review our current knowledge of the solar chemical composition
  as determined from photospheric absorption lines. In particular we
  describe the recent significant revisions of the solar abundances as a
  result of the application of a time-dependent, 3D hydrodynamical model
  of the solar atmosphere instead of 1D hydrostatic models. This has
  decreased the metal content in the solar convection zone by almost a
  factor of two compared with the widely used compilation by Anders &amp;
  Grevesse (1989). While resolving a number of long-standings problems,
  the new 3D-based element abundances also pose serious challenges,
  most notably for helioseismology.

---------------------------------------------------------
Title: Lithium isotopic abundances in very metal-poor halo stars
Authors: Asplund, Martin
2005noao.prop..186A    Altcode:
  In our VLT/UVES survey of 6Li and 7Li isotopic abundances in Galactic
  halo stars, we have boosted the number of positive 6Li detections in
  such stars from the previous single case to at least ten. No doubt
  the most exciting result stemming from our program is a detection
  of 6Li in LP815-43, one of the most metal-poor stars in our sample
  ([Fe/H]=-2.7). If high 6Li abundances at low [Fe/H] is a general
  feature, it would have important ramifications for light element
  production in the early Universe, Li depletion in metal-poor stars, Big
  Bang nucleosynthesis and possibly even non-standard particle physics. We
  here request Keck/HIRES time to observe a sufficiently large sample of
  very metal-poor stars to test whether such a 6Li plateau indeed exists.

---------------------------------------------------------
Title: Detection of Near-Infrared CO Absorption Bands in R Coronae
    Borealis Stars
Authors: Tenenbaum, Emily D.; Clayton, Geoffrey C.; Asplund, Martin;
   Engelbracht, C. W.; Gordon, Karl D.; Hanson, M. M.; Rudy, Richard J.;
   Lynch, David K.; Mazuk, S.; Venturini, Catherine C.; Puetter, R. C.
2005AJ....130..256T    Altcode: 2005astro.ph..3497T
  R Coronae Borealis (RCB) stars are hydrogen-deficient, carbon-rich,
  pulsating, post-asymptotic giant branch stars that experience
  massive irregular declines in brightness caused by circumstellar dust
  formation. The mechanism of dust formation around RCB stars is not well
  understood. It has been proposed that CO molecules play an important
  role in cooling the circumstellar gas so that dust may form. We report
  on a survey for CO in a sample of RCB stars. We obtained H- and K-band
  spectra including the first- and second-overtone CO bands for eight
  RCB stars, the RCB-like star DY Per, and the final-helium-flash star FG
  Sge. The first- and second-overtone CO bands were detected in the cooler
  (T<SUB>eff</SUB>&lt;6000 K) RCB stars, Z Umi, ES Aql, SV Sge, and DY
  Per. The bands are not present in the warmer (T<SUB>eff</SUB>&gt;6000
  K) RCB stars, R CrB, RY Sgr, SU Tau, and XX Cam. In addition,
  first-overtone bands are seen in FG Sge, a final-helium-flash star
  that is in an RCB-like phase at present. Effective temperatures of the
  eight RCB stars range from 4000 to 7250 K. The observed photospheric
  CO absorption bands were compared to line-blanketed model spectra of
  RCB stars. As predicted by the models, the CO bands are strongest in
  the coolest RCB stars and not present in the warmest. No correlation
  was found between the presence or strength of the CO bands and dust
  formation activity in the stars.

---------------------------------------------------------
Title: Line formation in solar granulation. IV. [O I], O I and OH
    lines and the photospheric O abundance
Authors: Asplund, M.; Grevesse, N.; Sauval, A. J.; Allende Prieto,
   C.; Kiselman, D.
2005A&A...435..339A    Altcode:
  A&amp;A, 417, 751-768 (2004), DOI:10.1051/0004-6361:20034328

---------------------------------------------------------
Title: VizieR Online Data Catalog: Chemical abundances in 43
    metal-poor stars (Jonsell+, 2005)
Authors: Jonsell, K.; Edvardsson, B.; Gustafsson, B.; Magain, P.;
   Nissen, P. E.; Asplund, M.
2005yCat..34400321J    Altcode:
  Data from an analysis of 43 metal-poor field stars with iron abundances
  [Fe/H] ranging from -0.4 to -3.0dex are presented here. Photometric
  data, stellar velocities, masses, fundamental parameters, spectral
  classifications and notations of possible binarity are given. Tables
  with line data for O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe, Ni and
  Ba, equivalent widths and resulting abundances are also given. <P />(4
  data files).

---------------------------------------------------------
Title: Nucleosynthetic signatures of the first stars
Authors: Frebel, Anna; Aoki, Wako; Christlieb, Norbert; Ando, Hiroyasu;
   Asplund, Martin; Barklem, Paul S.; Beers, Timothy C.; Eriksson,
   Kjell; Fechner, Cora; Fujimoto, Masayuki Y.; Honda, Satoshi; Kajino,
   Toshitaka; Minezaki, Takeo; Nomoto, Ken'ichi; Norris, John E.; Ryan,
   Sean G.; Takada-Hidai, Masahide; Tsangarides, Stelios; Yoshii, Yuzuru
2005Natur.434..871F    Altcode: 2005astro.ph..3021F
  The chemically most primitive stars provide constraints on the nature
  of the first stellar objects that formed in the Universe; elements
  other than hydrogen, helium and traces of lithium present within
  these objects were generated by nucleosynthesis in the very first
  stars. The relative abundances of elements in the surviving primitive
  stars reflect the masses of the first stars, because the pathways of
  nucleosynthesis are quite sensitive to stellar masses. Several models
  have been suggested to explain the origin of the abundance pattern
  of the giant star HE0107-5240, which hitherto exhibited the highest
  deficiency of heavy elements known. Here we report the discovery of
  HE1327-2326, a subgiant or main-sequence star with an iron abundance
  about a factor of two lower than that of HE0107-5240. Both stars
  show extreme overabundances of carbon and nitrogen with respect to
  iron, suggesting a similar origin of the abundance patterns. The
  unexpectedly low Li and high Sr abundances of HE1327-2326, however,
  challenge existing theoretical understanding: no model predicts the
  high Sr abundance or provides a Li depletion mechanism consistent with
  data available for the most metal-poor stars.

---------------------------------------------------------
Title: An Extremely Large Excess of <SUP>18</SUP>O in the
    Hydrogen-deficient Carbon Star HD 137613
Authors: Clayton, Geoffrey C.; Herwig, Falk; Geballe, T. R.; Asplund,
   Martin; Tenenbaum, Emily D.; Engelbracht, C. W.; Gordon, Karl D.
2005ApJ...623L.141C    Altcode: 2005astro.ph..3198C
  We report the discovery of a uniquely large excess of <SUP>18</SUP>O in
  the hydrogen-deficient carbon (HdC) star HD 137613 based on a spectrum
  of the first-overtone bands of CO at 2.3-2.4 μm in which three
  strong absorption bands of <SUP>12</SUP>C<SUP>18</SUP>O are clearly
  present. Bands of <SUP>12</SUP>C<SUP>16</SUP>O also are present, but no
  bands of <SUP>13</SUP>C<SUP>16</SUP>O or <SUP>12</SUP>C<SUP>17</SUP>O
  are seen. We estimate an isotopic ratio <SUP>16</SUP>O/<SUP>18</SUP>O
  &lt;~ 1. The solar value of this ratio is ~500. Neither He-core burning
  nor He-shell flash burning can produce the isotopic ratios of oxygen and
  carbon observed in HD 137613. However, a remarkable similarity exists
  between the observed abundances and those found in the outer layers of
  the broad He shell of early-asymptotic giant branch (AGB) stars, soon
  after the end of He-core burning. It is not known how the outer envelope
  down to the He shell could be lost, but some mechanism of enhanced mass
  loss must be involved. HD 137613 may be a post-early-AGB star with the
  outer layers of the former He-burning shell as its photosphere. The
  unusual elemental abundances of the HdC stars resemble those of the
  R Coronae Borealis (RCB) stars, but HdC stars do not produce clouds
  of dust that produce declines in brightness. None of the other RCB or
  HdC stars observed show significant <SUP>18</SUP>O.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Center-to-limb variation of quiet
    Sun (Allende+, 2004)
Authors: Allende Prieto, C.; Asplund, M.; Fabiani Bendicho, P.
2005yCat..34231109A    Altcode:
  Solar observations of the center-to-limb variation of several spectral
  lines were carried out in October 22-23, 1997, with the Gregory Coude
  Telescope (GCT) and its Czerny-Turner echelle spectrograph at the
  Observatorio del Teide (Tenerife, Spain). <P />We secured spectra
  for 8 spectral setups in 6 different positions across the solar
  disk, as summarized in Table 1. <P />Positions #1 to #5 were always
  at heliocentric angles theta = 0, 15, 30, 45, and 60 degrees (mu =
  cos(theta) = 1.00, 0.97, 0.87, 0.71, and 0.50) along a straight line
  crossing the center of the solar disk. Position #6 was also selected
  along the same direction, sometimes at theta = 75 degrees and others
  at 80 degrees (mu = 0.26 or 0.17). <P />(2 data files).

---------------------------------------------------------
Title: Line formation in solar granulation. VI. [C I], C I, CH and
    C<SUB>2</SUB> lines and the photospheric C abundance
Authors: Asplund, M.; Grevesse, N.; Sauval, A. J.; Allende Prieto,
   C.; Blomme, R.
2005A&A...431..693A    Altcode: 2004astro.ph.10681A
  The solar photospheric carbon abundance has been determined from [C
  I], C I, CH vibration-rotation, CH A-X electronic and C<SUB>2</SUB>
  Swan electronic lines by means of a time-dependent, 3D, hydrodynamical
  model of the solar atmosphere. Departures from LTE have been considered
  for the C I lines. These turned out to be of increasing importance for
  stronger lines and are crucial to remove a trend in LTE abundances
  with the strengths of the lines. Very gratifying agreement is found
  among all the atomic and molecular abundance diagnostics in spite of
  their widely different line formation sensitivities. The mean value
  of the solar carbon abundance based on the four primary abundance
  indicators ([C I], C I, CH vibration-rotation, C<SUB>2</SUB> Swan)
  is log ɛ<SUB>C</SUB> = 8.39 ± 0.05, including our best estimate of
  possible systematic errors. Consistent results also come from the CH
  electronic lines, which we have relegated to a supporting role due
  to their sensitivity to the line broadening. The new 3D based solar C
  abundance is significantly lower than previously estimated in studies
  using 1D model atmospheres.

---------------------------------------------------------
Title: Lithium isotopic abundances in metal-poor stars
Authors: Asplund, Martin; Nissen, Poul Erik; Lambert, David L.;
   Primas, Francesca; Smith, Verne V.
2005IAUS..228...53A    Altcode:
  We report on a survey of <SUP>7</SUP>Li and <SUP>6</SUP>Li isotopic
  abundances in metal-poor halo stars. The spectra of the 24 stars
  observed with VLT/UVES are of exceptionally high quality: S/N&gt;400
  and resolving power R ≃ 120 000. The <SUP>7</SUP>Li abundances on
  our Hα T<SUB>eff</SUB>-scale show very small intrinsic scatter and
  a pronounced [Fe/H]-dependence. The resulting estimated primordial
  <SUP>7</SUP>Li abundance is about 0.5 dex lower than predicted from
  Big Bang nucleosynthesis and the baryon density inferred by the cosmic
  microwave background. Nine of the stars yield a positive detection
  (&gt;2σ) of <SUP>6</SUP>Li, which suggests the existence of a
  <SUP>6</SUP>Li plateau for halo stars. The most interesting result is
  the presence of <SUP>6</SUP>Li in the very metal-poor ([Fe/H]=-2.74)
  dwarf LP815-43 at the level of <SUP>6</SUP>Li/<SUP>7</SUP>Li ≃
  0.05±0.02. According to models for stellar Li depletion due to
  diffusion or rotationally-induced mixing, a 0.5 dex <SUP>7</SUP>Li
  depletion would require an unrealistic high initial <SUP>6</SUP>Li
  abundance (log <SUP>6</SUP>Li ≥ 2.0). Simultaneously, the
  observed high <SUP>6</SUP>Li abundance at such low [Fe/H] can not be
  reconciled with existing models for Galactic cosmic ray spallation and
  α-fusion reactions. This opens up exciting prospects of pre-Galactic
  <SUP>6</SUP>Li production, possibly due to cosmological cosmic rays
  or late-decaying massive particles such as the gravitino or neutralino
  in the Big Bang.

---------------------------------------------------------
Title: Globular cluster abundances in the light of 3D hydrodynamical
    model atmospheres
Authors: Asplund, Martin
2005HiA....13..151A    Altcode:
  Recently realistic time-dependent 3D hydrodynamical simulations of
  stellar surface convection have become feasible. Such 3D hydrodynamical
  model atmospheres often show significant differences in their
  atmospheric structures compared with existing hydrostatic 1D model
  atmospheres which directly propagate to differences in the emergent
  spectrum and the inferred interpretations in terms of for example
  elemental abundances. In this review I will discuss the impact of the
  new generation of 3D model atmospheres on the derived abundances for
  globular clusters concentrating on elements of specific importance for
  the understanding of the formation and evolution of globular clusters.

---------------------------------------------------------
Title: Effective temperatures and lithium abundances of halo
    turnoff stars
Authors: Nissen, P. E.; Akerman, C.; Asplund, M.; Fabbian, D.;
   Pettini, M.
2005IAUS..228..101N    Altcode:
  Effective temperatures of 30 turnoff stars with -3.2 {[Fe/H]{
  have been derived from the profiles of Balmer lines in high S/N,
  VLT/UVES spectra. While the systematic error of T<SUB>eff</SUB> may
  be of the order of 100K, the differential values of T<SUB>eff</SUB>
  are determined with a one-sigma precision of ∼25K. These precise
  T<SUB>eff</SUB> values are used in a study of the slope and dispersion
  of the Li abundance as a function of [Fe/H]. A small, but significant
  cosmic dispersion in A(Li) appears to be present exemplified by the
  two very metal-poor stars G64-12 and G64-37.

---------------------------------------------------------
Title: The evolution of the C/O ratio in metal-poor halo stars
Authors: Akerman, C. J.; Carigi, L.; Nissen, P. E.; Pettini, M.;
   Asplund, M.
2005HiA....13Q.578A    Altcode:
  Whilst it is known that oxygen is produced in massive stars and is
  dispersed into the ISM by type II supernovae the origins and yields of
  carbon are less certain. Carbon is produced during helium burning in
  both massive intermediate-mass and low-mass stars but the dependence
  of the carbon yield on stellar mass and initial composition is not
  well known. A reliable determination of the C/O abundance ratio as
  a function of the oxygen abundance for main-sequence stars will be
  helpful in gaining an understanding of these problems. <P />Previous
  studies have measured the C/O ratio for disk stars using forbidden lines
  ([CI] 8727.1 A [OI] 6300.3 A). In halo main-sequence stars with [Fe/H]
  &lt; -1 the forbidden carbon line is too weak to be measured. Tomkin
  et al. (1992) use instead four high excitation CI lines around 9100A
  together with the oxygen triplet at 7774 A. To test and expand on
  their results which hint at interesting features in the trend of [C/O]
  we derive C and O abundances for 35 metal-poor halo stars from high
  resolution near-IR VLT/UVES spectra. Combined with the previous [C/O]
  measurements a more detailed trend with oxygen abundance is derived.

---------------------------------------------------------
Title: Sulphur and zinc abundances in halo and disk stars
Authors: Nissen, P. E.; Chen, Y. Q.; Asplund, M.; Pettini, M.
2005HiA....13..587N    Altcode:
  Sulphur and zinc are key elements in studies of the chemical evolution
  of DLAs because they are undepleted on interstellar dust. It is often
  assumed that S is an ""alpha""-element made by Type II supernovae
  whereas Zn follows iron in its chemical evolution. If correct the S/Zn
  ratio can be used as ""a chemical clock"" to date the star formation
  process in DLAs. Recent studies of S/Fe and Zn/Fe in Galactic stars
  have however questioned these assumptions. <P />In order to advance
  the study of the chemical evolution of S and Zn in our Galaxy we have
  obtained high resolution ESO VLT/UVES spectra for 35 halo stars and
  the Xinglong 2.16m telescope has been used to observe disk stars. From
  a model atmosphere analysis of these spectra including estimates of
  3D effects we have derived the trends of S/Fe and Zn/Fe for Galactic
  stars in the metallicity range -3.2 &lt; [Fe/H] &lt; +0.2. Preliminary
  results suggest that S behaves like an ""alpha""-element whereas Zn
  may show small deviations from the trend of iron.

---------------------------------------------------------
Title: Uncertainties in Stellar Abundance Analyses
Authors: Asplund, Martin
2005HiA....13..542A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Oxygen abundances in metal-poor subgiants
Authors: García Pérez, A. E.; Asplund, M.; Primas, F.; Nissen,
   P. E.; Gustafsson, B.
2005IAUS..228..257G    Altcode: 2005IAUS..228..257P
  There seems to be no consensus on the [O/Fe] values found in
  metal-poor stars nor their trend with metallicity: different
  indicators give different results. We present here [O/Fe] derived
  from three different oxygen abundance indicators ([OI], OI and OH UV
  lines) for a sample of thirteen subgiant stars with metallicities
  in the range -3≤[Fe/H]≤-1.5. Oxygen and iron abundances were
  determined from the analysis of high S/N spectra acquired with
  the UVES spectrograph at VLT. We found good agreement between
  [O/Fe] estimates based on OH and the estimates based on [Oi]
  (mean difference∼-0.09±0.25(s.d.)), although the scatter is not
  insignificant. Unfortunately, good agreement is not reached for
  the third indicator (mean difference∼0.19±0.22(s.d.)). Our [OI]
  and OH-based estimates do not show a well defined linear trend with
  metallicity. Another interesting result is that the abundances based
  on molecular lines ([O/Fe]∼0.45) are in general lower than previous
  published results for turn-off stars even though a lower solar oxygen
  abundance (A(O)=8.74) was assumed.

---------------------------------------------------------
Title: Chemical Abundance Patterns of Extremely Metal-Poor Stars with
    [Fe/H]≲ -3.5
Authors: Aoki, W.; Beers, T. C.; Christlieb, N.; Frebel, A.; Norris,
   J. E.; Honda, S.; Takada-Hidai, M.; Asplund, M.; Ando, H.; Ryan, S. G.;
   Tsangarides, S.; Nomoto, K.; Fujimoto, M. Y.; Kajino, T.; Yoshii, Y.
2005IAUS..228..195A    Altcode:
  We present preliminary results on the chemical abundance patterns of
  extremely metal-poor stars obtained during an ongoing observing program
  with Subaru/HDS. High-resolution, high signal-to-noise spectra have
  been obtained for 14 stars with [Fe/H]≲ -3. Five of them exhibit
  clear overabundances of carbon, a remarkable characteristic found
  only in the most metal-poor range. One of the carbon-rich stars,
  HE 1327-2326, has [Fe/H]<SUB>NLTE</SUB>=-5.4, the lowest Fe abundance
  known. No stars with {-}5 {[Fe/H] { have yet been found in our program,
  suggesting that quite different enrichment processes were responsible
  for stars with [Fe/H] { and [Fe/H] {&gt;} {-}4. While neutron-capture
  elements are deficient in most of our stars, one star (BS 16550-087)
  exhibits large enhancements of its light neutron-capture elements (Sr,
  Y and Zr), providing a strong constraint on models for the production
  of such elements in the very early Galaxy.

---------------------------------------------------------
Title: CI non LTE spectral line formation in late-type stars
Authors: Fabbian, D.; Asplund, M.; Carlsson, M.; Kiselman, D.
2005IAUS..228..255F    Altcode: 2005astro.ph..8063F
  We present non-Local Thermodynamic Equilibrium (non-LTE) calculations
  for neutral carbon spectral line formation, carried out for a grid
  of model atmospheres covering the range of late-type stars. The
  results of our detailed calculations suggest that the carbon
  non-LTE corrections in these stars are higher than usually adopted,
  remaining substantial even at low metallicity. For the most metal-poor
  stars in the sample of Akerman et al (2004), the effects are of the
  order of Δlogɛ<SUB>C</SUB> ≃ -0.35ldots-0.45 (when neglecting H
  collisions). Applying our results to those observations, the apparent
  [C/O] upturn seen in their LTE analysis is no longer present, thus
  revealing no need to invoke contributions from Pop. III stars to the
  carbon nucleosynthesis.

---------------------------------------------------------
Title: The new record holder for the most iron-poor star: HE 1327
    2326, a dwarf or subgiant with [Fe/H[=[minus sign]5.4
Authors: Frebel, A.; Aoki, W.; Christlieb, N.; Ando, H.; Asplund, M.;
   Barklem, P. S.; Beers, T. C.; Eriksson, K.; Fechner, C.; Fujimoto,
   M. Y.; Honda, S.; Kajino, T.; Minezaki, T.; Nomoto, K.; Norris, J. E.;
   Ryan, S. G.; Takada-Hidai, M.; Tsangarides, S.; Yoshii, Y.
2005IAUS..228..207F    Altcode: 2005astro.ph..9658F
  We describe the discovery of HE 1327-2326, a dwarf or subgiant with
  [Fe/H]=-5.4. The star was found in a sample of bright metal-poor
  stars selected from the Hamburg/ESO survey. Its abundance pattern is
  characterized by very high C and N abundances. The detection of Sr
  which is overabundant by a factor of 10 as compared to iron and the
  Sun, suggests that neutron-capture elements had already been produced
  in the very early Galaxy. A puzzling Li depletion is observed in this
  unevolved star which contradicts the value of the primordial Li derived
  from WMAP and other Li studies. Possible scenarios for the origin of
  the abundance pattern (Pop. II or Pop. III) are presented as well as
  an outlook on future observations.

---------------------------------------------------------
Title: The Impact of Non-LTE Effects and Granulation Inhomogeneities
    on the Derived Iron and Oxygen Abundances in Metal-Poor Halo Stars
Authors: Shchukina, N. G.; Trujillo Bueno, J.; Asplund, M.
2005ApJ...618..939S    Altcode: 2004astro.ph.10475S
  This paper presents the results of a detailed theoretical investigation
  of the impact of non-LTE (NLTE) effects and of granulation
  inhomogeneities on the derived iron and oxygen abundances in the
  metal-poor halo subgiant HD 140283. Our analysis is based on both the
  “classical” one-dimensional stellar atmosphere models and on the
  new generation of three-dimensional hydrodynamic models. The NLTE
  calculations presented here have been carried out without inelastic
  collisions with neutral hydrogen atoms. We find that if NLTE effects
  are taken into account when synthesizing the Fe I spectrum in both
  types of atmospheric models, then the derived iron abundance turns out
  to be very similar in both cases. The emergent spectral line profiles
  in both models are very much weaker in NLTE than in LTE because the
  UV overionization mechanism produces a very strong underpopulation
  of the Fe I levels, in particular in the granular regions of the
  three-dimensional model. As a result, the NLTE effects on the derived
  iron abundance are very important, amounting to ~0.9 and to ~0.6 dex in
  the three- and one-dimensional cases, respectively. On the other hand,
  we find that NLTE and three-dimensional effects have to be taken into
  account for a reliable determination of the iron abundance from weak Fe
  II lines, because the significant overexcitation of their upper levels
  in the granular regions tend to produce emission features. As a result,
  such Fe II lines are weaker than in LTE and the abundance correction
  amounts to ~0.4 dex for the three-dimensional case. We also derive
  the oxygen-to-iron abundance ratio in the metal-poor star HD 140283
  by using the O I triplet at 7772-7775 Å and the forbidden [O I] line
  at 6300 Å. Our results for the oxygen abundance confirm the values
  reported in some recent investigations. While the oxygen abundance
  derived from the O I IR triplet is not very sensitive to the presence
  of granulation inhomogeneities, such three-dimensional effects amount to
  ~-0.2 dex for the [O I] line. The NLTE abundance correction for the O I
  IR triplet turns out to be -0.2 dex, approximately. Interestingly, when
  both NLTE and three-dimensional effects are taken into account there
  still remain significant discrepancies in the iron abundances derived
  from Fe I and Fe II lines, as well as in the oxygen abundances inferred
  from the O I and [O I] lines. We conclude that the discrepancies could
  be due to uncertainties in the stellar parameters of this metal-poor
  star. We argue that adopting T<SUB>eff</SUB>~5600 K (instead of
  T<SUB>eff</SUB>~5700 K) and [Fe/H]~-2.0 (instead of [Fe/H]~-2.5)
  substantially reduces the discrepancies in the abundances of iron and
  oxygen inferred from several spectral lines. Under such circumstances,
  we find [O/Fe]~0.5 at [Fe/H]=-2. Obviously, our tentative conclusion
  that the metallicity of this type of metal-poor star is significantly
  larger than previously thought may have far-reaching implications in
  stellar astrophysics.

---------------------------------------------------------
Title: 3D hydrodynamical model stellar atmospheres of metal-poor
    red giants
Authors: Collet, Remo; Asplund, Martin; Trampedach, Regner
2005IAUS..228..247C    Altcode:
  We investigate the main differences between static 1D and 3D
  time-dependent model stellar atmospheres of red giants at very low
  metallicities. We focus in particular on the impact of 3D LTE spectral
  line formation on the derivation of elemental abundances for the
  extremely metal-poor ([Fe/H] ≈-5.3) red giant HE 0107-5240.

---------------------------------------------------------
Title: The New Solar Chemical Composition
Authors: Grevesse, N.; Asplund, M.; Sauval, A. J.
2005EAS....17...21G    Altcode:
  We present our current knowledge of the solar chemical composition based
  on the recent significant downward revision of the solar photospheric
  abundances of the most abundant metals very recently reviewed in detail
  by Asplund et al. (2005a). These new solar abundances result from the
  use of a 3D hydrodynamical model of the solar atmosphere instead of
  the classical 1D hydrostatic models, accounting for departures from
  LTE, and improved atomic and molecular data. With these abundances,
  the new solar metallicity, Z, and Z/X, decrease to Z = 0.012 and Z/X =
  0.0165 respectively, almost a factor of 2 lower than earlier widely
  used values. While resolving a number of longstanding problems, the new
  3D-based solar photospheric composition also poses serious challenges
  for the standard solar model.

---------------------------------------------------------
Title: Chemical abundances in 43 metal-poor stars
Authors: Gustafsson, Bengt; Asplund, Martin; Edvardsson, Bengt;
   Jonsell, Karin; Magain, Pierre; Nissen, Poul Erik
2005IAUS..228..259G    Altcode:
  We have derived abundances of O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe,
  Ni and Ba for 43 metal-poor field stars, mostly stars at the turn-off
  point and on the subgiant branch, in the interval {-}3.0{[Fe/H]{. The
  analysis is differential relative to the Sun. Oxygen abundances,
  with consideration of NLTE effects, were derived from the OI 777.4 nm
  triplet lines. We find [O/Fe] to gradually increase with decreasing
  [Fe/H], though considerably slower than has earlier been obtained from
  OH lines in the UV. A scatter in [O,Mg,Ca,Ti/Fe] at a given [Fe/H] is
  found and we argue that this scatter is partly real. The deviations from
  the mean trends of abundance ratios vs [Fe/H] are found to correlate
  in non-trivial ways for different abundances. Similar trends are found
  from results of accurate studies by other groups. This seems to give
  further evidence for the hypothesis that the stars once formed in
  different subsystems, with different star-formation rates.The paper
  is in press in A&amp;A, may be obtained as astro-ph/0505118.

---------------------------------------------------------
Title: Center-to-limb variation of solar line profiles as a test of
    NLTE line formation calculations
Authors: Allende Prieto, C.; Asplund, M.; Fabiani Bendicho, P.
2004A&A...423.1109A    Altcode: 2004astro.ph..5154A; 2004astro.ph..5154P
  We present new observations of the center-to-limb variation
  of spectral lines in the quiet Sun. Our long-slit spectra are
  corrected for scattered light, which amounts to 4-8% of the continuum
  intensity, by comparison with a Fourier transform spectrum of the disk
  center. Different spectral lines exhibit different behaviors, depending
  on their sensitivity to the physical conditions in the photosphere and
  the range of depths they probe as a function of the observing angle,
  providing a rich database to test models of the solar photosphere and
  line formation. We examine the effect of inelastic collisions with
  neutral hydrogen in NLTE line formation calculations of the oxygen
  infrared triplet, and the Na I λ6160.8 line. Adopting a classical
  one-dimensional theoretical model atmosphere, we find that the sodium
  transition, formed in higher layers, is more effectively thermalized
  by hydrogen collisions than the high-excitation oxygen lines. This
  result appears as a simple consequence of the decrease of the ratio
  N<SUB>H</SUB>/N<SUB>e</SUB> with depth in the solar photosphere. The
  center-to-limb variation of the selected lines is studied both under
  LTE and NLTE conditions. In the NLTE analysis, inelastic collisions
  with hydrogen atoms are considered with a simple approximation or
  neglected, in an attempt to test the validity of such approximation. For
  the sodium line studied, the best agreement between theory and
  observation happens when NLTE is considered and inelastic collisions
  with hydrogen are neglected in the rate equations. The analysis of
  the oxygen triplet benefits from a very detailed calculation using an
  LTE three-dimensional model atmosphere and NLTE line formation. The
  χ<SUP>2</SUP> statistics favors including hydrogen collisions with
  the approximation adopted, but the oxygen abundance derived in that
  case is significantly higher than the value derived from OH infrared
  transitions. <P />GCT spectra are only available in electronic form
  at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)
  or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/423/1109

---------------------------------------------------------
Title: Line formation in solar granulation. V. Missing UV-opacity
    and the photospheric Be abundance
Authors: Asplund, M.
2004A&A...417..769A    Altcode: 2003astro.ph.12291A
  The possibility of unaccounted for opacity sources in the UV for
  late-type stars has often been invoked to explain discrepancies
  between predicted and observed flux distributions and spectral
  line strengths. Such missing UV-opacity could among other things
  have a significant impact on abundance determination for elements
  whose only relevant spectral features are accessible in this
  wavelength region, such as Be. Here, the study by Balachandran
  &amp; Bell (\cite{Balachandran98}) is re-visited in the light of a
  realistic 3D hydrodynamical solar model atmosphere and the recently
  significantly downward revised solar O abundance obtained with the
  same model atmosphere. The amount of missing UV-opacity, if any, is
  quantified by enforcing that the OH A-X electronic lines around 313
  nm produce the same O abundance as the other available diagnostics:
  OH vibration-rotation and pure rotation lines in the IR, the forbidden
  [O I] 630.0 and 636.3 nm lines and high-excitation, permitted O I
  lines. This additional opacity is then applied for the synthesis of the
  Be II line at 313.0 nm to derive a solar photospheric Be abundance in
  excellent agreement with the meteoritic value, thus re-enforcing the
  conclusions of Balachandran &amp; Bell. The about 50% extra opacity
  over accounted for opacity sources can be well explained by recent
  calculations by the Iron Project for photo-ionization of Fe I.

---------------------------------------------------------
Title: Line formation in solar granulation. IV. [O I], O I and OH
    lines and the photospheric O abundance
Authors: Asplund, M.; Grevesse, N.; Sauval, A. J.; Allende Prieto,
   C.; Kiselman, D.
2004A&A...417..751A    Altcode: 2003astro.ph.12290A
  The solar photospheric oxygen abundance has been determined from
  [O I], O I, OH vibration-rotation and OH pure rotation lines by
  means of a realistic time-dependent, 3D, hydrodynamical model of
  the solar atmosphere. In the case of the O I lines, 3D non-LTE
  calculations have been performed, revealing significant departures
  from LTE as a result of photon losses in the lines. We derive a solar
  oxygen abundance of log ɛ<SUB>O</SUB> = 8.66 ± 0.05. All oxygen
  diagnostics yield highly consistent abundances, in sharp contrast
  with the results of classical 1D model atmospheres. This low value
  is in good agreement with measurements of the local interstellar
  medium and nearby B stars. This low abundance is also supported by
  the excellent correspondence between lines of very different line
  formation sensitivities, and between the observed and predicted line
  shapes and center-to-limb variations. Together with the corresponding
  down-ward revisions of the solar carbon, nitrogen and neon abundances,
  the resulting significant decrease in solar metal mass fraction to Z =
  0.0126 can, however, potentially spoil the impressive agreement between
  predicted and observed sound speed in the solar interior determined
  from helioseismology.

---------------------------------------------------------
Title: Sulphur and zinc abundances in Galactic stars  and damped
    Lyα systems
Authors: Nissen, P. E.; Chen, Y. Q.; Asplund, M.; Pettini, M.
2004A&A...415..993N    Altcode: 2003astro.ph.11529N
  High resolution spectra of 34 halo population dwarf and subgiant
  stars have been obtained with VLT/UVES and used to derive sulphur
  abundances from the λ λ 8694.0, 8694.6 and λ λ 9212.9, 9237.5 S
  I lines. In addition, iron abundances have been determined from 19 Fe
  II lines and zinc abundances from the λ λ 4722.2, 4810.5 lines. The
  abundances are based on a classical 1D, LTE model atmosphere analysis,
  but effects of 3D hydrodynamical modelling on the [S/Fe], [Zn/Fe] and
  [S/Zn] ratios are shown to be small. We find that most halo stars
  with metallicities in the range -3.2 &lt; [Fe/H] &lt; -0.8 have a
  near-constant [S/Fe] ≃ +0.3; a least square fit to [S/Fe] vs. [Fe/H]
  shows a slope of only -0.04 ± 0.01. Among halo stars with -1.2 &lt;
  [Fe/H] &lt; -0.8 the majority have [S/Fe] ≃ +0.3, but two stars
  (previously shown to have low α/Fe ratios) have [S/Fe] ≃ 0.0. For
  disk stars with [Fe/H] &gt; -1, [S/Fe] decreases with increasing [Fe/H]
  . Hence, sulphur behaves like other typical α-capture elements, Mg,
  Si and Ca. Zinc, on the other hand, traces iron over three orders
  of magnitude in [Fe/H], although there is some evidence for a small
  systematic Zn overabundance ([Zn/Fe] ≃ +0.1) among metal-poor disk
  stars and for halo stars with [Fe/H] &lt; -2.0. Recent measurements of
  S and Zn in ten damped Lyα systems (DLAs) with redshifts between 1.9
  and 3.4 and zinc abundances in the range -2.1 &lt; [Zn/H] &lt; -0.15
  show an offset relative to the [S/Zn] - [Zn/H] relation in Galactic
  stars. Possible reasons for this offset are discussed, including
  low and intermittent star formation rates in DLAs. <P />Based on
  observations collected at the European Southern Observatory, Chile
  (ESO No. 67.D-0106). <P />Table A1 is only available in electronic
  form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)
  or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/415/993

---------------------------------------------------------
Title: The evolution of the C/O ratio in metal-poor halo stars
Authors: Akerman, C. J.; Carigi, L.; Nissen, P. E.; Pettini, M.;
   Asplund, M.
2004A&A...414..931A    Altcode: 2003astro.ph.10472A
  We report new measurements of carbon and oxygen abundances in 34 F and
  G dwarf and subgiant stars belonging to the halo population and spanning
  a range of metallicity from [Fe/H] = -0.7 to -3.2 . The survey is based
  on observations of four permitted lines of C I near 9100 Å and the O
  I,λ 7774 triplet, all recorded at high signal-to-noise ratios with the
  UVES echelle spectrograph on the ESO VLT. The line equivalent widths
  were analysed with the 1D, LTE, MARCS model atmosphere code to deduce
  C and O abundances; corrections due to non-LTE and 3D effects are
  discussed. When combined with similar published data for disk stars,
  our results confirm the metallicity dependence of the C/O ratio known
  from previous stellar and interstellar studies: C/O drops by a factor
  of ∼3-4 as O/H decreases from solar to ∼1/10 solar. Analysed
  within the context of standard models for the chemical evolution of
  the solar vicinity, this drop results from the metallicity dependence
  of the C yields from massive stars with mass loss, augmented by the
  delayed release of C from stars of low and intermediate mass. The
  former is, however, always the dominant factor. Our survey has also
  uncovered tentative evidence to suggest that, as the oxygen abundance
  decreases below [O/H] = -1, [C/O] may not remain constant at [C/O] =
  -0.5, as previously thought, but increase again, possibly approaching
  near-solar values at the lowest metallicities ([O/H] ≲ -3). With the
  current dataset this is no more than a 3σ effect and it may be due
  to metallicity-dependent non-LTE corrections to the [C/O] ratio which
  have not been taken into account. However, its potential importance
  as a window on the nucleosynthesis by Population III stars is a
  strong incentive for future work, both observational and theoretical,
  to verify its reality. <P />Based on observations collected at the
  European Southern Observatory, Chile (ESO No. 67.D-0106).

---------------------------------------------------------
Title: Globular cluster abundances in the light of 3D hydrodynamical
    model atmospheres
Authors: Asplund, Martin
2004MmSAI..75..300A    Altcode: 2003astro.ph.10444A
  The new generation of 3D hydrodynamical model atmospheres have been
  employed to study the impact of a realistic treatment of stellar
  convection on element abundance determinations of globular cluster stars
  for a range of atomic and molecular lines. Due to the vastly different
  temperature structures in the optically thin atmospheric layers in 3D
  metal-poor models compared with corresponding hydrostatic 1D models,
  some species can be suspected to be hampered by large systematic errors
  in existing analyses. In particular, 1D analyses based on minority
  species and low excitation lines may overestimate the abundances by
  &gt;0.3 dex. Even more misleading may be the use of molecular lines for
  metal-poor globular clusters. However, the prominent observed abundance
  (anti-)correlations and cluster variations are largely immune to the
  choice of model atmospheres.

---------------------------------------------------------
Title: The future of stellar model atmospheres: macroscopic
    nightmares?
Authors: Asplund, M.
2004EAS....11....3A    Altcode:
  Stellar atmospheres represent unique windows for understanding stellar,
  galactic and cosmic evolution by being responsible for the emission of
  stellar spectra. Much progress has been made over the years in modelling
  stellar atmospheres but still the modelling efforts are hampered by
  various, often questionable, assumptions and approximations. This review
  describes promising avenues for improving the realism of stellar model
  atmospheres for hot (spectral types O, B, A), cool (F, G, K) and very
  cool (M and later) stars, respectively, in the coming decade. A common
  theme will be time-dependent 3D hydrodynamical calculations with a
  detailed non-LTE treatment of the radiative transfer. It is argued
  that this is fully within the realm of possibility on this time-scale
  and indeed will be necessary to complement the expected advances on
  the observational side.

---------------------------------------------------------
Title: Infrared Absorption By Carbon Monoxide in R CrB Type Stars
Authors: Tenenbaum, E.; Clayton, G. C.; Englebracht, C.; Asplund, M.
2003AAS...20312701T    Altcode: 2003BAAS...35.1413T
  R Coronae Borealis (RCB) type stars experience massive irregular
  declines caused by circumstellar dust formation. The dust formation
  mechanism remains a mystery, and it has been proposed that CO molecules
  play a cooling role in the dust formation process. The detection
  of the CO first vibrational overtone (Δ v=2) absorption band in
  RCB spectra was first reported by Clayton in 1999. We report on the
  first attempt to analyze the CO Δ v=2 band in a large survey of RCB
  stars. Low-resolution IR spectra of 10 RCB stars, obtained with FSpec
  on the 90" telescope at Steward Observatory, were analyzed for the
  presence and, if applicable, equivalent widths of CO Δ v=2 absorption
  lines. Effective temperatures of the ten stars range from 3500 to
  20000 K. We compared the spectra to line-blanketed model spectra of
  RCB stars. As predicted by the model, the CO bands are strongest in
  the coolest RCB stars. No correlation was found between the presence
  of CO bands and lightcurve declines. This project was supported by the
  NSF/REU grant AST-0097694 and the Nantucket Maria Mitchell Association.

---------------------------------------------------------
Title: VizieR Online Data Catalog: FeII, ZNI and SI abundances on
    halo stars (Nissen+, 2004)
Authors: Nissen, P. E.; Chen, Y. Q.; Asplund, M.; Pettini, M.
2003yCat..34150993N    Altcode:
  The table gives equivalent widths (in m{AA}) for 19 FeII lines, two
  ZnI lines, and four SI lines, as measured in high resolution VLT/UVES
  spectra of 34 metal-poor, main sequence and subgiant, halo stars. <P
  />(2 data files).

---------------------------------------------------------
Title: Inelastic H+Li and H<SUP>-</SUP>+Li<SUP>+</SUP> collisions
    and non-LTE Li I line formation in stellar atmospheres
Authors: Barklem, P. S.; Belyaev, A. K.; Asplund, M.
2003A&A...409L...1B    Altcode: 2003astro.ph..8170B
  Rate coefficients for inelastic collisions between Li and H
  atoms covering all transitions between the asymptotic states
  Li(2s,2p,3s,3p,3d,4s,4p,4d,4f)+H(1s) and Li<SUP>+</SUP>+H<SUP>-</SUP>
  are presented for the temperature range 2000-8000 K based on recent
  cross-section calculations. The data are of sufficient completeness
  for non-LTE modelling of the Li I 670.8 nm and 610.4 nm features in
  late-type stellar atmospheres. Non-LTE radiative transfer calculations
  in both 1D and 3D model atmospheres have been carried out for test
  cases of particular interest. Our detailed calculations show that
  the classical modified Drawin-formula for collisional excitation and
  de-excitation (Li<SUP>*</SUP>+H \rightleftharpoons Li<SUP>*'</SUP>+H)
  over-estimates the cross-sections by typically several orders of
  magnitude and consequently that these reactions are negligible
  for the line formation process. However, the charge transfer
  reactions collisional ion-pair production and mutual neutralization
  (Li<SUP>*</SUP>+H \rightleftharpoons Li<SUP>+</SUP>+H<SUP>-</SUP>) are
  of importance in thermalizing Li. In particular, 3D non-LTE calculations
  of the Li I 670.8 nm line in metal-poor halo stars suggest that 1D
  non-LTE results over-estimate the Li abundance by up to about 0.1 dex,
  aggrevating the discrepancy between the observed Li abundances and
  the primordial Li abundance as inferred by the WMAP analysis of the
  cosmic microwave background.

---------------------------------------------------------
Title: Multi-level 3D non-LTE computations of lithium lines in the
    metal-poor halo stars HD 140283 and HD 84937
Authors: Asplund, M.; Carlsson, M.; Botnen, A. V.
2003A&A...399L..31A    Altcode: 2003astro.ph..2406A
  The lithium abundances in metal-poor halo stars are of importance
  for cosmology, galaxy evolution and stellar structure. In an attempt
  to study possible systematic errors in the derived Li abundances,
  the line formation of Li I lines has been investigated by means of
  realistic 3D hydrodynamical model atmospheres of halo stars and
  3D non-LTE radiative transfer calculations. These are the first
  detailed 3D non-LTE computations reported employing a multi-level
  atomic model showing that such problems are now computationally
  tractable. The detailed computations reveal that the Li I population
  has a strong influence from the radiation field rather than the local
  gas temperature, indicating that the low derived Li abundances found by
  Asplund et al. (\cite{Asplund1999}) are an artifact of their assumption
  of LTE. Relative to 3D LTE, the detailed calculations show pronounced
  over-ionization. In terms of abundances the 3D non-LTE values are
  within 0.05 dex of the 1D non-LTE results for the particular cases of
  HD 140283 and HD 84937, which is a consequence of the dominance of the
  radiation in determining the population density of Li I. Although 3D
  non-LTE can be expected to give results rather close (~+/- 0.1 dex)
  to 1D non-LTE for this reason, there may be systematic trends with
  metallicity and effective temperature.

---------------------------------------------------------
Title: New generations of stellar model atmospheres
Authors: Asplund, Martin
2003astro.ph..2409A    Altcode:
  Stellar model atmospheres form the basis for any element abundance
  determination and hence are crucial ingredients for studies of stellar,
  galactic and cosmic evolution. With recent observational progress with
  the advent of 8m-class telescopes and efficient spectrographs, the
  dominant source of uncertainty today originates with the assumptions
  and approximations in the analyses, emphasizing the great need for
  continuing efforts in improving the realism of stellar atmosphere
  modelling. In the present contribution I will describe recent
  progress in this regard by focussing on three complementary types
  of model atmospheres: line-blanketed non-LTE models of hot stars,
  3D hydrodynamical models of cool stars and semi-empirical models for
  large-scale stellar abundance analyses.

---------------------------------------------------------
Title: Uncertainties in Stellar Abundance Analyses
Authors: Asplund, Martin
2003IAUJD..15E...8A    Altcode: 2003astro.ph.10445A
  Stellar element abundances are never observed. Instead they are
  inferred from observations using models of the stellar atmospheres
  and the line-forming processes. Any shortcomings in this modelling
  will therefore directly affect the conclusions inferred about the
  stellar abundances. For late-type stars the most severe approximations
  normally done is the use of 1D hydrostatic model atmospheres with
  convection treated with the mixing length ""theory"" and adopting local
  thermodynamic equilibrium for the line formation. Recently much progress
  have been achieved in both of these areas which I will briefly describe
  in the present talk emphasing on those aspects affecting the analyses of
  metal-poor halo stars. In addition I will touch upon other uncertainties
  in stellar abundance analysis such as transition probabilities.

---------------------------------------------------------
Title: Globular Cluster Abundances and 3d Model Atmospheres
Authors: Asplund, Martin
2003IAUJD...4E...7A    Altcode:
  Recently realistic time-dependent 3D hydrodynamical simulations of
  stellar surface convection have become feasible. Such 3D hydrodynamical
  model atmospheres often show significant differences in their
  atmospheric structures compared with existing hydrostatic 1D model
  atmospheres which directly propagate to differences in the emergent
  spectrum and the inferred interpretations in terms of for example
  elemental abundances. In this review I will discuss the impact of the
  new generation of 3D model atmospheres on the derived abundances for
  globular clusters concentrating on elements of specific importance for
  the understanding of the formation and evolution of globular clusters.

---------------------------------------------------------
Title: Radiative Transfer with Very Few Wavelengths
Authors: Trampedach, R.; Asplund, M.
2003ASPC..293..209T    Altcode: 2003tdse.conf..209T
  Our aim is to develop an opacity sampling scheme suitable for 3D
  hydrodynamical simulations of convective stellar atmospheres. This
  paper presents a feasibility test for the concept.

---------------------------------------------------------
Title: Radiative Transfer in 3D Model Stellar Atmospheres
Authors: Asplund, M.; Collet, R.
2003ASPC..293..197A    Altcode: 2003astro.ph..2408A; 2003tdse.conf..197A
  Recently 3D hydrodynamical simulations of stellar surface convection
  have become feasible thanks to advances in computer technology and
  efficient numerical algorithms. Available observational diagnostics
  indicate that these models are highly realistic in describing the
  topology of stellar granulation and for spectral line formation
  purposes. The traditional free parameters (mixing length parameters,
  micro- and macroturbulence) always inherent in standard 1D analyses
  have thus finally become obsolete. These 3D models can therefore both
  shed light on the elusive nature of stellar convection as well as be
  employed in element abundance analyses. In the present contribution
  we will describe some aspects of the models and possible applications
  of them in terms of radiative transfer.

---------------------------------------------------------
Title: Sulphur and Iron Abundances in Halo Stars
Authors: Nissen, P. E.; Chen, Y. Q.; Asplund, M.; Pettini, M.
2003IAUS..210P.E51N    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Effects of UV Line Blanketing on the Non-LTE Fe I Line
    Formation
Authors: Collet, R.; García Pérez, A. E.; Asplund, M.; Thévenin, F.
2003IAUS..210P..B3C    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Non-LTE Determination of Iron and Oxygen Abundances Using 3D
Hydrodynamical Models: the Metal-Poor Star HD140283
Authors: Shchukina, N. G.; Vasiljeva, I. E.; Trujillo Bueno, J.;
   Asplund, M.
2003IAUS..210P.B10S    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Stellar Abundance Analyses in the Light of 3D Hydrodynamical
    Model Atmospheres
Authors: Asplund, M.
2003IAUS..210..273A    Altcode: 2003astro.ph..2407A
  I describe recent progress in terms of 3D hydrodynamical model
  atmospheres and 3D line formation and their applications to stellar
  abundance analyses of late-type stars. Such 3D studies remove the free
  parameters inherent in classical 1D investigations (mixing length
  parameters, macro- and microturbulence) yet are highly successful
  in reproducing a large arsenal of observational constraints such as
  detailed line shapes and asymmetries. Their potential for abundance
  analyses is illustrated by discussing the derived oxygen abundances
  in the Sun and in metal-poor stars, where they seem to resolve
  long-standing problems as well as significantly alter the inferred
  conclusions.

---------------------------------------------------------
Title: New Generations of Stellar Model Atmospheres (invited review)
Authors: Asplund, M.
2003ASPC..304..275A    Altcode: 2003cnou.conf..275A
  No abstract at ADS

---------------------------------------------------------
Title: Sulphur and Zinc Abundances in Halo and Disk Stars
Authors: Nissen, Poul Erik; Chen, Yu Qin; Asplund, Martin; Max, Pettini
2003IAUJD..15E..26N    Altcode:
  Sulphur and zinc are key elements in studies of the chemical evolution
  of DLAs because they are undepleted on interstellar dust. It is often
  assumed that S is an ""alpha""-element made by Type II supernovae
  whereas Zn follows iron in its chemical evolution. If correct the S/Zn
  ratio can be used as ""a chemical clock"" to date the star formation
  process in DLAs. Recent studies of S/Fe and Zn/Fe in Galactic stars
  have however questioned these assumptions. <P />In order to advance
  the study of the chemical evolution of S and Zn in our Galaxy we have
  obtained high resolution ESO VLT/UVES spectra for 35 halo stars and
  the Xinglong 2.16m telescope has been used to observe disk stars. From
  a model atmosphere analysis of these spectra including estimates of
  3D effects we have derived the trends of S/Fe and Zn/Fe for Galactic
  stars in the metallicity range -3.2 &lt; [Fe/H] &lt; +0.2. Preliminary
  results suggest that S behaves like an ""alpha""-element whereas Zn
  may show small deviations from the trend of iron.

---------------------------------------------------------
Title: The Granulation Fingerprints of Spectral Lines
Authors: Kiselman, D.; Asplund, M.
2003IAUS..210P.E62K    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Freshly Ionized Matter around the Final Helium Shell Flash
    ObjectV4334 Sagittarii (Sakurai's Object)
Authors: Kerber, F.; Pirzkal, N.; De Marco, Orsola; Asplund, M.;
   Clayton, G. C.; Rosa, M. R.
2002ApJ...581L..39K    Altcode: 2002astro.ph.11275K
  We report on the discovery of recently ionized hydrogen-deficient gas
  in the immediate circumstellar environment of the final helium shell
  flash star V4334 Sgr (Sakurai's object). On spectra obtained with
  FORS2 multiobject spectroscopy, we have found spatially extended (~2")
  emission from [N II], [O I], [O II], and very faint Hα and [S II]. In
  the [N II] (λλ6548, 6583) lines, we have identified two components
  located at velocities -350+/-50 and +200+/-50 km s<SUP>-1</SUP>,
  relative to V4334 Sgr itself. The full width of the [N II] λ6583
  feature at zero intensity corresponds to a velocity spread of ~1500
  km s<SUP>-1</SUP>. On the basis of the available data, it is not
  possible to conclusively determine the mechanism of ionization. Both
  photoionization, from a rapidly evolving central star, and shock
  excitation, resulting from the collision of the fast ouflows with slower
  circumstellar matter, could account for the observed lines. The central
  star is still hidden behind strong dust absorption, since only a faint
  highly reddened continuum is apparent in the spectra. Theory states
  that it will become hotter and will retrace its post-asymptotic giant
  branch evolution toward the planetary nebula domain. Our detection
  of the ionized ejecta from the very late helium shell flash marks the
  beginning of a new phase in this star's amazingly rapid evolution. Based
  on observations collected at the European Southern Observatory, Chile,
  proposal 67.D-0405.

---------------------------------------------------------
Title: O/Fe in metal-poor main sequence and subgiant stars
Authors: Nissen, P. E.; Primas, F.; Asplund, M.; Lambert, D. L.
2002A&A...390..235N    Altcode: 2002astro.ph..5372N
  A study of the O/Fe ratio in metal-poor main sequence and subgiant
  stars is presented using the \ion{Oi},6300 Å line, the O I 7774 Å
  triplet, and a selection of weak Fe Ii lines observed on high-resolution
  spectra acquired with the VLT UVES spectrograph. The \ion{Oi line is
  detected in the spectra of 18 stars with -2.4 &lt; [Fe/H] &lt; -0.5,
  and the triplet is observed for 15 stars with Fe/H ranging from -1.0
  to -2.7. The abundance analysis was made first using standard model
  atmospheres taking into account non-LTE effects on the triplet: the
  \ion{Oi} line and the triplet give consistent results with [O/Fe]
  increasing quasi-linearly with decreasing [Fe/H] reaching [O/Fe] =~
  +0.7 at [Fe/H] = -2.5. This trend is in reasonable agreement with
  other results for [O/Fe] in metal-poor dwarfs obtained using standard
  atmospheres and both ultraviolet and infrared OH lines. There is also
  broad agreement with published results for [O/Fe] for giants obtained
  using standard model atmospheres and the \ion{Oi} line, and the OH
  infrared lines, but the O I lines give higher [O/Fe] values which may,
  however, fall into place when non-LTE effects are considered. When
  hydrodynamical model atmospheres representing stellar granulation in
  dwarf and subgiant stars replace standard models, the [O/Fe] from the
  \ion{Oi} and Fe Ii lines is decreased by an amount which increases
  with decreasing [Fe/H]. These 3D effects on [O/Fe] is compounded by
  the opposite behaviour of the \ion{Oi} (continuous opacity effect)
  and Fe Ii lines (excitation effect). The [O/Fe] vs. [Fe/H] relation
  remains quasi-linear extending to [O/Fe] =~ +0.5 at [Fe/H] = -2.5,
  but with a tendency of a plateau with [O/Fe] =~ +0.3 for -2.0 &lt;
  [Fe/H] &lt; -1.0, and a hint of cosmic scatter in [O/Fe] at [Fe/H] =~
  -1.0. Use of the hydrodynamical models disturbs the broad agreement
  between the oxygen abundances from the \ion{Oi} , O I, and OH lines,
  but 3D non-LTE effects may serve to erase these differences. The [O/Fe]
  values from the \ion{Oi} line and the hydrodynamical model atmospheres
  for dwarfs and subgiant stars are lower than the values for giants
  using standard model atmospheres and the \ion{Oi}, and O I lines. Based
  on observations collected at the European Southern Observatory, Chile
  (ESO Nos. 65.L-0131, 65.L-0507, and 67.D-0439).

---------------------------------------------------------
Title: Sulphur and iron abundances in halo stars
Authors: Nissen, P. E.; Chen, Y. Q.; Asplund, M.; Pettini, M.
2002astro.ph..7163N    Altcode:
  From equivalent widths of the SI lines at 8694 A, Israelian &amp; Rebolo
  (2001) and Takada-Hidai et al. (2002) have derived a surprisingly high
  sulphur-to-iron ratio ([S/Fe] = 0.5 to 0.7) in six halo stars with
  [Fe/H] ~ -2.0 suggesting perhaps that hypernovae made a significant
  contribution to the formation of elements in the early Galaxy. To
  investigate this problem we have used high-resolution spectra obtained
  with the ESO VLT/UVES spectrograph to determine the S/Fe ratio in
  19 main-sequence and subgiant stars ranging in [Fe/H] from -3.2 to
  -0.7. The sulphur abundances are determined from SI lines at 8694 A and
  9212 - 9237 A, and the iron abundances from about 20 FeII lines. S/Fe
  ratios as derived from 1D model atmospheres are presented and possible
  3D effects are discussed. The initial results from our survey do not
  confirm the high values of [S/Fe] quoted above; instead we find that
  the ratio [S/Fe] remains constant at about 0.35 dex for metallicities
  -3 &lt; [Fe/H] -1.

---------------------------------------------------------
Title: Sulphur abundances in disk stars: A correlation with silicon
Authors: Chen, Y. Q.; Nissen, P. E.; Zhao, G.; Asplund, M.
2002A&A...390..225C    Altcode: 2002astro.ph..6075C
  We have performed new determinations of sulphur and silicon
  abundances for a sample of 26 disk stars based on high-resolution,
  high signal-to-noise spectra. The results indicate a solar [S/Fe]
  for [Fe/H] &gt;-0.3, below which [S/Fe] increases to ~ 0.25 dex at
  [Fe/H] =-1.0. We find that there is a good correlation between [S/H]
  and [Si/H], indicating the same nucleosynthetic origin of the two
  elements. It seems that the ratio of sulphur to silicon does not depend
  on metallicity for [Fe/H] &gt; -1.0. The implications of these results
  on models for the nucleosynthesis of alpha -capture elements and the
  chemical evolution of the Galaxy are discussed. Based on observations
  carried out at National Astronomical Observatories (Xinglong, PR China).

---------------------------------------------------------
Title: A Reappraisal of the Solar Photospheric C/O Ratio
Authors: Allende Prieto, Carlos; Lambert, David L.; Asplund, Martin
2002ApJ...573L.137A    Altcode: 2002astro.ph..6089A; 2002astro.ph..6089P
  An accurate determination of photospheric solar abundances requires
  detailed modeling of the solar granulation and accounting for departures
  from local thermodynamical equilibrium (LTE). We argue that the
  forbidden C I line at 8727 Å is largely immune to departures from
  LTE and can be realistically modeled using LTE radiative transfer
  in a time-dependent three-dimensional simulation of solar surface
  convection. We analyze the [C I] line in the solar flux spectrum to
  derive the abundance logɛ(C)=8.39+/-0.04 dex. Combining this result
  with our parallel analysis of [O I] λ6300, we find C/O=0.50+/-0.07,
  in agreement with the ratios measured in the solar corona from gamma-ray
  spectroscopy and solar energetic particles.

---------------------------------------------------------
Title: Signatures of Convection in the Spectrum of Procyon:
    Fundamental Parameters and Iron Abundance
Authors: Allende Prieto, Carlos; Asplund, Martin; García López,
   Ramón J.; Lambert, David L.
2002ApJ...567..544A    Altcode: 2001astro.ph.11055A; 2001astro.ph.11055P
  We have observed the spectrum of Procyon A (F5 IV) from 4559 to 5780
  Å with a signal-to-noise ratio of ~10<SUP>3</SUP> and a resolving
  power of 2×10<SUP>5</SUP>. We have measured the line bisectors
  and relative line shifts of a large number of Fe I and Fe II lines,
  comparing them to those found in the solar spectrum. A three-dimensional
  hydrodynamical model atmosphere has been computed and is tested against
  observations. The model reproduces in detail most of the features
  observed, although we identify some room for improvement. At all levels,
  the comparison of the three-dimensional time-dependent calculations
  with the observed spectral lines shows a much better agreement than for
  classical homogeneous models, making it possible to refine previous
  estimates of the iron abundance, the projected rotational velocity,
  the limb darkening, and the systemic velocity of the Procyon binary
  system. The difference between the iron abundance determined with
  the three-dimensional model and its one-dimensional counterpart is
  &lt;~0.05 dex. We find consistency between the iron abundance derived
  from Fe I and Fe II lines, suggesting that departures from LTE in the
  formation of the studied lines are relatively small. The scatter in
  the iron abundance determined from different lines still exceeds the
  expectations from the uncertainties in the atomic data, pointing out
  that one or more components in the modeling can be refined further.

---------------------------------------------------------
Title: V838 Monocerotis - a Newly Discovered, Very Peculiar, Slow
    Nova-Like Object
Authors: Rauch, Thomas; Hauschildt, Peter; Asplund, Martin; Gredel,
   Roland; Käufl, Hans-Ulrich; Kerber, Florian; Rosa, Michael;
   Starrfield, Sumner G.; Wagner, R. Mark; Williams, Robert E.
2002ASPC..279..345R    Altcode: 2002IAUCo.187..345R; 2002esce.conf..345R
  No abstract at ADS

---------------------------------------------------------
Title: Oxygen line formation in 3D hydrodynamical model atmospheres
Authors: Asplund, Martin
2002HiA....12..432A    Altcode:
  The formation of [O I], O I and OH lines in metal-poor stars has
  been studied by means of 3D hydrodynamical model atmospheres. For
  O I detailed 3D non-LTE calculations have been performed. While the
  influence of 3D model atmospheres is minor for [O I] and O I lines,
  the very low temperatures encountered at low metallicities have a
  drastic impact on OH. As a result, the derived O abundances are found
  to be systematically overestimated in 1D analyses, casting doubts on
  the recent claims for a monotonic increase in [O/Fe] towards lower
  metallicities.

---------------------------------------------------------
Title: The Star Too Tough to Die
Authors: Kerber, Florian; Asplund, Martin
2001S&T...102e..48K    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Chemical Abundances from Inversions of Stellar Spectra:
    Analysis of Solar-Type Stars with Homogeneous and Static Model
    Atmospheres
Authors: Allende Prieto, Carlos; Barklem, Paul S.; Asplund, Martin;
   Ruiz Cobo, Basilio
2001ApJ...558..830A    Altcode: 2001astro.ph..5262P; 2001astro.ph..5262A
  Spectra of late-type stars are usually analyzed with static model
  atmospheres in local thermodynamic equilibrium (LTE) and a homogeneous
  plane-parallel or spherically symmetric geometry. The energy balance
  requires particular attention, as two elements that are particularly
  difficult to model play an important role: line blanketing and
  convection. Inversion techniques are able to bypass the difficulties
  of a detailed description of the energy balance. Assuming that the
  atmosphere is in hydrostatic equilibrium and LTE, it is possible
  to constrain its structure from spectroscopic observations. Among
  the most serious approximations still implicit in the method is a
  static and homogeneous geometry. In this paper, we take advantage of a
  realistic three-dimensional radiative hydrodynamical simulation of the
  solar surface to check the systematic errors incurred by an inversion
  assuming a plane-parallel horizontally-homogeneous atmosphere. The
  thermal structure recovered resembles the spatial and time average
  of the three-dimensional atmosphere. Furthermore, the abundances
  retrieved are typically within 10% (0.04 dex) of the abundances used
  to construct the simulation. The application to a fairly complete data
  set from the solar spectrum provides further confidence in previous
  analyses of the solar composition. There is only a narrow range of
  one-dimensional thermal structures able to fit the absorption lines in
  the spectrum of the Sun. With our carefully selected data set, random
  errors are about a factor of 2 smaller than systematic errors. A small
  number of strong metal lines can provide very reliable results. We
  foresee no major difficulties in applying the technique to other
  similar stars, and obtaining similar accuracies, using spectra with
  λ/δλ~5×10<SUP>4</SUP> and a signal-to-noise ratio as low as 30.

---------------------------------------------------------
Title: Oxygen abundances of halo dwarf and subgiant stars from
    VLT/UVES observations of the [O I] λ 6300 line
Authors: Nissen, Poul E.; Primas, Francesca; Asplund, Martin
2001NewAR..45..545N    Altcode:
  The forbidden oxygen line at 6300 Å has been observed with UVES on
  the ESO VLT for 13 dwarf and subgiant stars ranging in metallicity
  from [Fe/H]≃-0.7 to -1.8. The spectra obtained have a resolution
  of R=55 000 and S/ N≃400. After removal of telluric lines, the
  equivalent width of the [O I] line could be measured with an accuracy of
  0.2 to 0.3 mÅ. Using these data and the equivalent widths of eight weak
  Fe II lines, the trend of [O/Fe] with [Fe/H] has been derived. Below
  [Fe/H]≃-1.0 the oxygen-to-iron ratio is nearly constant at a level of
  [O/Fe]≃0.4 in contradiction to recent results from UV OH lines.

---------------------------------------------------------
Title: Abundance analyses of cool extreme helium stars
Authors: Pandey, Gajendra; Kameswara Rao, N.; Lambert, David L.;
   Jeffery, C. Simon; Asplund, Martin
2001MNRAS.324..937P    Altcode: 2001astro.ph..1518P
  Extreme helium stars (EHes) with effective temperatures from 8000 to
  13000K are among the coolest EHes and overlap the hotter R CrB stars in
  effective temperature. The cool EHes may represent an evolutionary link
  between the hot EHes and the R CrB stars. Abundance analyses of four
  cool EHes, BD+1°4381 (FQ Aqr), LS IV -14°109, BD -1°3438 (NO Ser) and
  LS IV -1°002 (V2244 Oph), are presented. All these stars show evidence
  of H- and He-burning at earlier stages of their evolution. To test for
  an evolutionary connection, the chemical compositions of cool EHes are
  compared with those of hot EHes and R CrB stars. Relative to Fe, the
  N abundance of these stars is intermediate between those of hot EHes
  and R CrB stars. For the R CrB stars, the metallicity M derived from
  the mean of Si and S appears to be more consistent with the kinematics
  than that derived from Fe. When metallicity M derived from Si and S
  replaces Fe, the observed N abundances of EHes and R CrB stars fall at
  or below the upper limit corresponding to thorough conversion of initial
  C and O to N. There is an apparent difference between the composition
  of R CrB stars and EHes, the former having systematically higher [N/M]
  ratios. The material present in the atmospheres of many R CrB stars is
  heavily CN- and ON-cycled. Most of the EHes have only CN-cycled material
  in their atmospheres. There is an indication that the CN- and ON-cycled
  N in EHes was partially converted to Ne by α-captures. If EHes are
  to evolve to R CrB stars, fresh C in EHes has to be converted to N;
  the atmospheres of EHes have just sufficient hydrogen to raise the N
  abundance to the level of R CrB stars. If Ne is found to be normal in
  R CrB stars, the proposal that EHes evolve to R CrB stars fails. The
  idea that R CrB stars evolve to EHes is ruled out; the N abundance in
  R CrB stars has to be reduced to the level of EHes, as the C/He, which
  is observed to be uniform across EHes, has to be maintained. Hence the
  inferred [N/M], C/He and [Ne/M] ratios, and the H-abundances of these
  two groups indicate that the EHes and the R CrB stars may not be on the
  same evolutionary path. The atmospheres of H-deficient stars probably
  consist of three ingredients: a residue of normal H-rich material,
  substantial amounts of H-poor CN(O)-cycled material, and C- (and O-)
  rich material from gas exposed to He-burning. This composition could
  be a result of final He-shell flash in a single post-AGB star (FF
  scenario), or a merger of two white dwarfs (DD scenario). Although
  the FF scenario accounts for Sakurai's object and other stars (e.g.,
  the H-poor central stars of planetary nebulae), present theoretical
  calculations imply higher C/He and O/He ratios than are observed in
  EHes and R CrB stars. Quantitative predictions are lacking for the
  DD scenario.

---------------------------------------------------------
Title: The Forbidden Abundance of Oxygen in the Sun
Authors: Allende Prieto, Carlos; Lambert, David L.; Asplund, Martin
2001ApJ...556L..63A    Altcode: 2001astro.ph..6360P; 2001astro.ph..6360A
  We reexamine closely the solar photospheric line at 6300 Å, which is
  attributed to a forbidden line of neutral oxygen and is widely used
  in analyses of other late-type stars. We use a three-dimensional
  time-dependent hydrodynamical model solar atmosphere that has been
  tested successfully against observed granulation patterns and an array
  of absorption lines. We show that the solar line is a blend with a
  Ni I line, as previously suggested but oftentimes neglected. Thanks
  to accurate atomic data on the [O I] and Ni I lines, we are able to
  derive an accurate oxygen abundance for the Sun: logɛ(O)=8.69+/-0.05
  dex, a value at the lower end of the distribution of previously
  published abundances but in good agreement with estimates for the
  local interstellar medium and hot stars in the solar neighborhood. We
  conclude by discussing the implication of the Ni I blend on oxygen
  abundances derived from [O I] λ6300 in disk and halo stars.

---------------------------------------------------------
Title: On OH line formation and oxygen abundances in metal-poor stars
Authors: Asplund, M.; García Pérez, A. E.
2001A&A...372..601A    Altcode: 2001astro.ph..4071A
  The formation of the UV OH spectral lines has been investigated for a
  range of stellar parameters in the light of 3D hydrodynamical model
  atmospheres. The low atmospheric temperatures encountered at low
  metallicities compared with the radiative equilibrium values enforced
  in classical 1D hydrostatic model atmospheres have a profound impact
  on the OH line strengths. As a consequence, the derived O abundances
  using 3D models are found to be systematically lower by more than 0.6
  dex at [Fe/H] =-3.0 compared with previous 1D analyses, casting doubts
  on the recent claims for a monotonic increase in [O/Fe] towards lower
  metallicities. In fact, taken at face value the resulting 3D LTE trend
  is in rough agreement with the conventional [O/Fe] plateau. Caution
  must, however, be exercised in view of the remaining assumptions in
  the 3D calculations. We have verified that the stellar parameters
  remain essentially unchanged with 3D model atmospheres provided
  that the infrared flux method (Delta T_eff &lt;~ 20 K), Hipparcos
  parallaxes (Delta {log } g &lt;~ 0.05) and Fe ii lines (Delta [Fe/H]
  &lt;~ 0.1 dex) are utilised, leaving the 3D O abundances from OH
  lines largely intact (Delta [O/H] &lt;~ 0.05 dex). Greater concern
  stems from possible departures from LTE in both the line formation
  and the molecular equilibrium, which, if present, would increase the
  derived O abundances again. Non-LTE line formation calculations with
  1D model atmospheres suggest no significant steepening of the [O/Fe]
  trend even if the abundance corrections amount to about 0.2 dex for
  all investigated stellar parameters. We note, however, that the 3D
  case may not necessarily be as metallicity-independent. The apparent
  lack of laboratory or theoretical rate coefficients at the relevant
  temperatures for the involved molecular reactions unfortunately prevents
  a quantitative discussion on the possible effects of non-equilibrium
  chemistry.

---------------------------------------------------------
Title: The lithium isotope ratio in metal-poor stars
Authors: Nissen, P. E.; Asplund, M.
2001NuPhA.688..402N    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Effects of Convection on Line Profiles and Abundances (CD-ROM
Directory: contribs/asplund)
Authors: Asplund, M.
2001ASPC..223..217A    Altcode: 2001csss...11..217A
  No abstract at ADS

---------------------------------------------------------
Title: Spatially Resolved Solar Lines as Diagnostics of NLTE Effects
(CD-ROM Directory: contribs/kiselman)
Authors: Kiselman, D.; Asplund, M.
2001ASPC..223..684K    Altcode: 2001csss...11..684K
  No abstract at ADS

---------------------------------------------------------
Title: Observing beryllium with UVES at the VLT
Authors: Primas, Francesca; Asplund, Martin; Nissen, Poul Erik
2001coev.conf..117P    Altcode:
  We present preliminary results of a new analysis of Be abundances in a
  large sample of stars, spanning the metallicity range -2.4 ≤[Fe/H]≤
  -0.7. The observations were taken with the Ultraviolet and Visible
  Echelle Spectrograph (UVES) at the ESO Very Large Telescope (VLT),
  which made it possible to obtain very high data quality and measurements
  accuracy. The aim of the project is to further investigate the trend
  of Be with metallicity, and the possible presence of dispersion. Our
  recent detections of very high Be abundances in two of the most
  metal-poor stars suggest either a Be plateau or significant scatter
  at the lowest metallicities.

---------------------------------------------------------
Title: Departures from LTE in be Line Formation
Authors: García Perez, A. E.; Asplund, M.; Kiselman, D.
2001coev.conf..131G    Altcode:
  Stellar abundances of Be can be affected by NLTE effects. We have
  calculated the NLTE corrections to the LTE abundances obtained
  from the Bell doublet at 313.0 and 313.1 nm for a range of stellar
  parameters. These lines are not formed in LTE due to over-ionization
  and over-excitation but the NLTE corrections are in general small
  (~0.1 dex).

---------------------------------------------------------
Title: R200,000 Spectroscopic Observations of Procyon. The Surface
Convection and Radial Velocity (CD-ROM Directory: contribs/allende2)
Authors: Allende Prieto, C.; Asplund, M.; García López, R. J.;
   Lambert, D. L.; Nordlund, Å.
2001ASPC..223..760A    Altcode: 2001csss...11..760A
  No abstract at ADS

---------------------------------------------------------
Title: Lithium Isotope Ratios in Metal-Poor Halo Stars
Authors: Asplund, Martin; Lambert, David L.; Nissen, Poul Erik;
   Primas, Francesca; Smith, Verne V.
2001coev.conf...95A    Altcode:
  Equipped with very high quality observations obtained from VLT/UVES
  and the new generation of 3D hydrodynamical model atmospheres, we
  have initiated a survey of <SUP>6</SUP>Li/<SUP>7</SUP>Li ratios in
  metal-poor halo stars. Here we present the first preliminary results of
  this investigation, reporting four new likely detections at a similar
  level (<SUP>6</SUP>Li/<SUP>7</SUP>Li = 2 - 5%) to that previously
  found for HD 84937, BD +26°3578 and G271-162.

---------------------------------------------------------
Title: The beryllium abundance in the very metal-poor halo star G
    64-12 from VLT/UVES observations
Authors: Primas, F.; Asplund, M.; Nissen, P. E.; Hill, V.
2000A&A...364L..42P    Altcode: 2000astro.ph..9482P
  We report on a new spectroscopic analysis of the very metal deficient
  star G 64-12 ([Fe/H]=-3.3), aimed at determining, for the first time,
  its beryllium content. The spectra were observed during the Science
  Verification of UVES, the ESO VLT Ultraviolet and Visible Echelle
  Spectrograph. The high resolution ( ~ 48 000) and high S/N ( ~ 130
  per pixel) achieved at the wavelengths of the Be Ii resonance doublet
  allowed an accurate determination of its abundance: log N(Be/H) = -13.10
  +/- 0.15 dex. The Be abundance is significantly higher than expected
  from previous measurements of Be in stars of similar metallicity
  (3D and NLTE corrections acting to make a slightly higher value than
  an LTE analysis). When compared to iron, the high [Be/Fe] ratio thus
  found may suggest a flattening in the beryllium evolutionary trend
  at the lowest metallicity end or the presence of dispersion at early
  epochs of galactic evolution. Based on observations taken during the
  Science Verification of UVES at the VLT/Kueyen telescope, European
  Southern Observatory, Paranal, Chile

---------------------------------------------------------
Title: FG Sagittae (FG Sge)
Authors: Asplund, M.
2000eaa..bookE2887A    Altcode:
  FG Sge (α=20°11'56”, δ=+20°20'04”, epoch = 2000) is a very
  peculiar giant star undergoing extremely rapid evolutionary changes
  and nucleosynthetic processing. It has evolved at a remarkable pace
  over the last century changing among other properties its appearance
  from a hot (O-type) star to a luminous, cool (K-type) giant today. FG
  Sge is classified as a `born-again giant' currently experiencin...

---------------------------------------------------------
Title: Line formation in solar granulation. II. The photospheric
    Fe abundance
Authors: Asplund, M.; Nordlund, Å.; Trampedach, R.; Stein, R. F.
2000A&A...359..743A    Altcode: 2000astro.ph..5321A
  The solar photospheric Fe abundance has been determined using realistic
  ab initio 3D, time-dependent, hydrodynamical model atmospheres. The
  study is based on the excellent agreement between the predicted
  and observed line profiles directly rather than equivalent widths,
  since the intrinsic Doppler broadening from the convective motions and
  oscillations provide the necessary non-thermal broadening. Thus, three
  of the four hotly debated parameters (equivalent widths, microturbulence
  and damping enhancement factors) in the center of the recent solar Fe
  abundance dispute regarding Fe i lines no longer enter the analysis,
  leaving the transition probabilities as the main uncertainty. Both Fe i
  (using the samples of lines of both the Oxford and Kiel studies) and
  Fe ii lines have been investigated, which give consistent results:
  log epsilon_FeI = 7.44 +/- 0.05 and log epsilon_FeII = 7.45 +/-
  0.10. Also the wings of strong Fe i lines return consistent abundances,
  log epsilon_FeII = 7.42 +/- 0.03, but due to the uncertainties inherent
  in analyses of strong lines we give this determination lower weight
  than the results from weak and intermediate strong lines. In view of
  the recent slight downward revision of the meteoritic Fe abundance
  log epsilon_Fe = 7.46 +/- 0.01, the agreement between the meteoritic
  and photospheric values is very good, thus appearingly settling the
  debate over the photospheric Fe abundance from Fe i lines.

---------------------------------------------------------
Title: The effects of numerical resolution on hydrodynamical surface
    convection simulations and spectral line formation
Authors: Asplund, M.; Ludwig, H. -G.; Nordlund, Å.; Stein, R. F.
2000A&A...359..669A    Altcode: 2000astro.ph..5319A
  The computationally demanding nature of radiative-hydrodynamical
  simulations of stellar surface convection warrants an investigation
  of the sensitivity of the convective structure and spectral synthesis
  to the numerical resolution and dimension of the simulations, which
  is presented here. With too coarse a resolution the predicted spectral
  lines tend to be too narrow, reflecting insufficient Doppler broadening
  from the convective motions, while at the currently highest affordable
  resolution the line shapes have converged essentially perfectly to
  the observed profiles. Similar conclusions are drawn from the line
  asymmetries and shifts. Due to the robustness of the pressure and
  temperature structures with respect to the numerical resolution, strong
  Fe lines with pronounced damping wings and H i lines are essentially
  immune to resolution effects, and can therefore be used for improved
  T_eff and log g determinations even at very modest resolutions. In
  terms of abundances, weak Fe i and Fe ii lines show a very small
  dependence ( =~ 0.02 dex) while for intermediate strong lines with
  significant non-thermal broadening the sensitivity increases (&lt;~ 0.10
  dex). Problems arise when using 2D convection simulations to describe
  an inherent 3D phenomenon, which translates to inaccurate atmospheric
  velocity fields and temperature and pressure structures. In 2D the
  theoretical line profiles tend to be too shallow and broad compared with
  the 3D calculations and observations, in particular for intermediate
  strong lines. In terms of abundances, the 2D results are systematically
  about 0.1 dex lower than for the 3D case for Fe i lines. Furthermore,
  the predicted line asymmetries and shifts are much inferior in 2D
  with discrepancies amounting to ~ 200 m s<SUP>-1</SUP>. Given these
  shortcomings and computing time considerations it is better to use
  3D simulations of even modest resolution than high-resolution 2D
  simulations.

---------------------------------------------------------
Title: Line formation in solar granulation. I. Fe line shapes,
    shifts and asymmetries
Authors: Asplund, M.; Nordlund, Å.; Trampedach, R.; Allende Prieto,
   C.; Stein, R. F.
2000A&A...359..729A    Altcode: 2000astro.ph..5320A
  Realistic ab-initio 3D, radiative-hydrodynamical convection simulations
  of the solar granulation have been applied to Fe i and Fe ii line
  formation. In contrast to classical analyses based on hydrostatic 1D
  model atmospheres the procedure contains no adjustable free parameters
  but the treatment of the numerical viscosity in the construction
  of the 3D, time-dependent, inhomogeneous model atmosphere and the
  elemental abundance in the 3D spectral synthesis. However, the numerical
  viscosity is introduced purely for numerical stability purposes and is
  determined from standard hydrodynamical test cases with no adjustments
  allowed to improve the agreement with the observational constraints
  from the solar granulation. The non-thermal line broadening is mainly
  provided by the Doppler shifts arising from the convective flows in
  the solar photosphere and the solar oscillations. The almost perfect
  agreement between the predicted temporally and spatially averaged
  line profiles for weak Fe lines with the observed profiles and the
  absence of trends in derived abundances with line strengths, seem to
  imply that the micro- and macroturbulence concepts are obsolete in
  these 3D analyses. Furthermore, the theoretical line asymmetries and
  shifts show a very satisfactory agreement with observations with an
  accuracy of typically 50-100 m s<SUP>-1</SUP> on an absolute velocity
  scale. The remaining minor discrepancies point to how the convection
  simulations can be refined further.

---------------------------------------------------------
Title: Line formation in solar granulation. III. The photospheric
    Si and meteoritic Fe abundances
Authors: Asplund, M.
2000A&A...359..755A    Altcode: 2000astro.ph..5322A
  Using realistic hydrodynamical simulations of the solar surface
  convection as 3D, time-dependent, inhomogeneous model atmospheres,
  the solar photospheric Si abundance has been determined to be log
  epsilon_Si = 7.51+/-0.04. This constitutes a difference of 0.04 dex
  compared with previous estimates based on the 1D Holweger-Müller
  (1974) model, of which half is attributable to the adopted model
  atmosphere and the remaining part to the improved quantum mechanical
  broadening treatment. As a consequence, all meteoritic abundances
  should be adjusted downwards by the same amount. In particular the
  meteoritic Fe abundance will be log epsilon_Fe = 7.46+/-0.01, in good
  agreement with the recently determined photospheric Fe abundance
  (Asplund et al. 2000b). The existing uncertainties unfortunately
  prevent an observational confirmation of the postulated effects of
  elemental migration of metals in the Sun.

---------------------------------------------------------
Title: The continuing saga of Sakurai's object (V4334 Sgr): dust
    production and helium line emission
Authors: Tyne, V. H.; Eyres, S. P. S.; Geballe, T. R.; Evans, A.;
   Smalley, B.; Duerbeck, H. W.; Asplund, M.
2000MNRAS.315..595T    Altcode:
  We report further UKIRT spectroscopic observations of Sakurai's
  object (V4334 Sgr) made in 1999 April/May in the 1-4.75μm range,
  and find that the emission is dominated by amorphous carbon at
  T<SUB>d</SUB>~600K. The estimated maximum grain size is 0.6μm, and the
  mass lower limit is 1.7+/-0.2×10<SUP>-8</SUP>M<SUB>solar</SUB>
  to 8.9+/-0.6×10<SUP>-7</SUP>M<SUB>solar</SUB>
  for distances of 1.1-8kpc. For 3.8kpc the mass is
  2.0+/-0.1×10<SUP>-7</SUP>M<SUB>solar</SUB>. We also report strong
  Hei emission at 1.083μm, in contrast to the strong absorption in
  this line in 1998. We conclude that the excitation is collisional,
  and is probably caused by a wind, consistent with the P Cygni profile
  observed by Eyres et al. in 1998.

---------------------------------------------------------
Title: Abundance analysis of extreme helium stars
Authors: Pandey, Gajendra; Kameswara Rao, N.; Lambert, David L.;
   Jeffery, C. Simon; Asplund, Martin
2000BASI...28..303P    Altcode:
  High resolution spectra were obtained for a sample of hydrogen-deficient
  stars which are hotter than the R CrB stars and cooler among the
  extreme helium stars (EHe). We believe that these stars are transition
  objects evolving either to EHe stars or R CrB stars. We aim to explore
  the evolutionary link between our program stars, R CrB stars and EHe
  stars. Distribution of these stars in the log g - log Teff plane shows
  similar L/M ratios (??4.0). These objects have an abundance pattern
  like R CrB stars and EHe stars.

---------------------------------------------------------
Title: The lithium isotope ratio in the metal-poor halo star G271-162
    from VLT/UVES observations
Authors: Nissen, P. E.; Asplund, M.; Hill, V.; D'Odorico, S.
2000A&A...357L..49N    Altcode: 2000astro.ph..4251N
  A high resolution (lambda /Delta lambda =~ 110 000), very high
  S/N (&gt;~ 600) spectrum of the metal-poor turnoff star <ASTROBJ>G
  271-162</ASTROBJ> has been obtained in connection with the commissioning
  of UVES at VLT/Kueyen. Using both 1D hydrostatic and 3D hydrodynamical
  model atmospheres, the lithium isotope ratio has been estimated
  from the Li I,670.8 nm line by means of spectral synthesis. The
  necessary stellar line broadening (1D: macroturbulence + rotation,
  3D: rotation) has been determined from unblended K I, Ca I and Fe
  I lines. The 3D line profiles agree very well with the observed
  profiles, including the characteristic line asymmetries. Both the
  1D and 3D analyses reveal a possible detection of \element[][6]{Li}
  in <ASTROBJ>G 271-162</ASTROBJ>, element [][6]{Li}/element [][7]{Li}
  = 0.02+/-0.01 (1sigma ). It is discussed if the smaller amount of
  \element[][6]{Li} in <ASTROBJ>G 271-162</ASTROBJ> than in the similar
  halo star <ASTROBJ>HD 84937</ASTROBJ> could be due to differences in
  stellar mass and/or metallicity or whether it may reflect an intrinsic
  scatter of \element[][6]{Li}/\element[][7]{Li} in the ISM at a given
  metallicity. Based on public data released from the UVES commissioning
  at the VLT/Kueyen telescope, ESO, Paranal, Chile

---------------------------------------------------------
Title: The Eddington Limit, Radiative Instabilities and the Declines
    of R Coronae Borealis Stars
Authors: Asplund, Martin
2000IAUS..177..521A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: The Light Elements in the Light of 3D Hydrodynamical Model
    Atmospheres
Authors: Asplund, M.
2000IAUS..198..448A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Oxygen abundances of halo stars from UVES observations of
    the λ6300 [OI] line
Authors: Nissen, P. E.; Primas, F.; Asplund, M.
2000IAUJD...8E..21N    Altcode:
  The forbidden oxygen line at 6300 Å has been observed with UVES at
  the ESO VLT for 15 turnoff and subgiant stars ranging in metallicity
  from [Fe/H] = -0.7 to -1.8. The spectra obtained have a resolution
  of R = 55.000 and S/N &gt; 400 with 6 pixels per spectral resolution
  bin. After removal of telluric O<SUB>2</SUB> lines by the aid of B-type
  calibration spectra, the equivalent width of the [OI] line could be
  measured to a precision of 0.2 to 0.3 m Å . Using these data and the
  eqivalent widths of 8 weak FeII lines, the trend of [O/Fe] with [Fe/H]
  has been derived and is compared with recent results from the UV OH
  lines and the OI triplet at 7774 Å .

---------------------------------------------------------
Title: Oxygen Line Formation in 3D Hydrodynamical Model Atmospheres
Authors: Asplund, M.; Carlsson, M.; Garcia Perez, A. E.; Kiselman, D.
2000IAUJD...8E...8A    Altcode: 2000astro.ph.11043A
  The new generation of realistic 3-dimensional, time-dependent,
  hydrodynamical model atmospheres have been applied to the line
  formation of {O}{I}, [{O}{I}] and OH lines. Additionally detailed 3D
  non-LTE calculations have been performed for {O}{I} in order to study
  the influence of temperature inhomogeneities on the line formation
  process. Implications in terms of the evolution of oxygen abundance
  with metallicity will be discussed, partly based on new VLT/UVES
  observations of metal-poor stars.

---------------------------------------------------------
Title: The R Coronae Borealis stars - atmospheres and abundances
Authors: Asplund, M.; Gustafsson, B.; Lambert, D. L.; Rao, N. K.
2000A&A...353..287A    Altcode:
  An abundance analysis of the H-deficient and He- and C-rich R Coronae
  Borealis (R CrB) stars has been undertaken to examine the ancestry of
  the stars. The investigation is based on high-resolution spectra and
  line-blanketed H-deficient model atmospheres. The models successfully
  reproduce the flux distributions and all spectral features, both
  molecular bands and high-excitation transitions, with one important
  exception, the C i lines. Since photoionization of C i dominates
  the continuous opacity, the line strengths of C i are essentially
  independent of the adopted carbon abundance and stellar parameters. All
  predicted C i lines are, however, much too strong compared with
  observations, with a discrepancy in abundance corresponding to 0.6 dex
  with little star-to-star scatter. Various solutions of this “carbon
  problem” have been investigated. A possible solution is that classical
  model atmospheres are far from adequate descriptions of supergiants such
  as the R CrB stars. We can also not exclude completely, however, the
  possibility that the gf-values for the C i lines are in error. This is
  supported by the fact that the C ii, [C i] and C_2 lines are reproduced
  by the models with no apparent complications. In spite of the carbon
  problem, various tests suggest that abundance ratios are little affected
  by the uncertainties. Judging by chemical composition, the R CrB stars
  can be divided into a homogeneous majority group and a diverse minority,
  which is characterized by extreme abundance ratios, in particular as
  regards Si/Fe and S/Fe. All stars show evidence of H- and He-burning in
  different episodes as well as mild s-process enhancements. Four of the
  majority members are Li-rich, while overabundances of Na, Al, Si and
  S are attributes of all stars. An anti-correlation found between the
  H and Fe abundances of H-deficient stars remains unexplained. These
  enigmatic stars are believed to be born-again giants, formed either
  through a final He-shell flash in a post-AGB star or through a merger
  of two white dwarfs. Owing to a lack of theoretical predictions of
  the resulting chemical compositions, identification of the majority
  and minority groups with the two scenarios is unfortunately only
  preliminary. Furthermore, <ASTROBJ>Sakurai's object</ASTROBJ> and
  <ASTROBJ>V854 Cen</ASTROBJ> exhibit aspects of both majority and
  minority groups, which may suggest that the division into two groups
  is too simplistic.

---------------------------------------------------------
Title: VizieR Online Data Catalog: The R CrB stars (Asplund+, 2000)
Authors: Asplund, M.; Gustafsson, B.; Lambert, D. L.; Rao, N. K.
1999yCat..33530287A    Altcode:
  Adopted line data, measured equivalent widths and derived elemental
  abundances for the individual lines observed in R Coronae Borealis
  and Extreme Helium stars. (2 data files).

---------------------------------------------------------
Title: ISO. Monitoring the mass loss of a very late Helium flash star
Authors: Kerber, F.; Blommaert, J. A. D. L.; Groenewegen, M. A. T.;
   Kimeswenger, S.; Käufl, H. U.; Asplund, M.
1999A&A...350L..27K    Altcode:
  We present ISOCAM observations of Sakurai's object (V4334 Sgr) covering
  the wavelength range of 4 to 15 mu m in seven filters. The photometry
  shows that in the period from February 1997 to February 1998 the flux
  over the whole wavelength range has increased by a factor of about
  ten. Combined with ground-based data we conclude that this increase is
  the result of mass loss from Sakurai's object and the formation of hot
  dust around it. Using a spherically symmetric dust radiative transfer
  model we obtain a quantitative result of a variable and increasing mass
  loss rate reaching some 10(-7) M_⊙/yr, a value not uncommon among
  stars during the Asymptotic Giant Branch (AGB) evolution. This is in
  agreement with the notion that Sakurai's object is retracing its own
  evolutionary history as a consequence of a very late Helium flash. We
  conclusively demonstrate that significant mass loss is associated with
  such an event and foster the link to the other few known examples of
  final Helium flashes. ISO is an ESA project with instruments funded
  by ESA Member States (especially the PI countries: France, Germany,
  The Netherlands and the United Kingdom) and with the participation of
  ISAS and NASA.} observations of dust formation in Sakurai's object

---------------------------------------------------------
Title: Strong helium 10830-Å absorption in Sakurai's object
    (V4334 Sgr)
Authors: Eyres, S. P. S.; Smalley, B.; Geballe, T. R.; Evans, A.;
   Asplund, M.; Tyne, V. H.
1999MNRAS.307L..11E    Altcode:
  We report the appearance and evolution during 1998 of strong neutral
  helium ^3S-^3P^o absorption at ~10830Å in Sakurai's Object (V4334 Sgr),
  which is believed to be a planetary nebula nucleus (PNN) undergoing a
  final helium shell-flash. First detected on 1998 March 18, the profile
  of the Hei feature is P Cygni-like. The absorption depth has increased
  in three subsequent spectra in 1998. If this is owing to a wind, the
  profile indicates a wind velocity of ~670+/-50kms^-1. The strong Ci
  10690-Å line seen prior to the appearance of the helium feature has
  disappeared; however Srii and CN absorption features remain present. We
  tentatively identify several new features as Sii. Taken together
  with other observations we suggest that the data are consistent with
  Sakurai's Object entering a phase in which it seems to have become a
  member of the R Coronae Borealis-type class of stars.

---------------------------------------------------------
Title: 3D hydrodynamical model atmospheres of metal-poor
    stars. Evidence for a low primordial Li abundance
Authors: Asplund, Martin; Nordlund, Åke; Trampedach, Regner; Stein,
   Robert F.
1999A&A...346L..17A    Altcode: 1999astro.ph..5059A
  Realistic 3-dimensional (3D), radiative hydrodynamical surface
  convection simulations of the metal-poor halo stars HD 140283 and
  HD 84937 have been performed. Due to the dominance of adiabatic
  cooling over radiative heating very low atmospheric temperatures are
  encountered. The lack of spectral lines in these metal-poor stars
  thus causes much steeper temperature gradients than in classical 1D
  hydrostatic model atmospheres where the temperature of the optically
  thin layers is determined by radiative equilibrium. The modified
  atmospheric structures cause changes in the emergent stellar spectra. In
  particular, the primordial Li abundances may have been overestimated
  by 0.2-0.35 dex with 1D model atmospheres. However, we caution that
  our result assumes local thermodynamic equilibrium (LTE), while the
  steep temperature gradients may be prone to e.g. over-ionization.

---------------------------------------------------------
Title: First Observations of an R Coronae Borealis Star with the
Space Telescope Imaging Spectrograph: RY Sagittarii near Maximum Light
Authors: Clayton, Geoffrey C.; Ayres, T. R.; Lawson, Warrick A.;
   Drilling, John S.; Woitke, P.; Asplund, Martin
1999ApJ...515..351C    Altcode:
  We describe the far-UV (1140-1740 Å) spectrum of the hydrogen-deficient
  R Coronae Borealis (RCB) star RY Sgr, obtained near maximum light
  (pulsational phase ~0.1) by the Space Telescope Imaging Spectrograph
  (STIS) on Hubble Space Telescope. The far-UV spectrum shows a
  photospheric continuum rising steeply toward longer wavelengths and
  two prominent emission features at the shorter wavelengths: C II λ1335
  and Cl I λ1351 (the latter is radiatively fluoresced by the 10 times
  stronger C II multiplet). We also find evidence for CO A-X 4th-positive
  system absorption band heads and possible weak CO fluorescent emissions
  pumped by C II λ1335, but the inferred column densities are low (~few
  times 10<SUP>16</SUP> cm<SUP>-2</SUP>), consistent with formation in
  a warm (~5000 K) atmospheric layer. The detection of CO molecules,
  if confirmed, would be significant, because they are thought to
  play a key role in the dust ejection episodes of RCB stars through
  the initiation of “molecular cooling catastrophes.” <P />Based on
  observations obtained with the NASA/ESA Hubble Space Telescope, which
  is operated by STScI for the Association of Universities for Research
  in Astronomy Inc. under NASA contract NAS 5-26555.

---------------------------------------------------------
Title: The rapid evolution of the born-again giant Sakurai's object
Authors: Asplund, M.; Lambert, D. L.; Kipper, T.; Pollacco, D.;
   Shetrone, M. D.
1999A&A...343..507A    Altcode: 1998astro.ph.11208A
  The extraordinarily rapid evolution of the born-again giant Sakurai's
  object following discovery in 1996 has been investigated. The
  evolution can be traced both in a continued cooling of the stellar
  surface and dramatic changes in chemical composition on a timescale
  of a mere few months. The abundance alterations are the results
  of the mixing and nuclear reactions which have ensued due to the
  final He-shell flash which occurred during the descent along the
  white dwarf cooling track. The observed changes in the H and Li
  abundances can be explained by ingestion and burning of the H-rich
  envelope and Li-production through the Cameron-Fowler mechanism. The
  rapidly increasing abundances of the light s-elements (including Sc)
  are consistent with current s-processing by neutrons released from
  the concomitantly produced (13) C. However, the possibility that the
  s-elements have previously been synthesized during the AGB-phase and
  only mixed to the surface in connection with the final He-shell flash
  in the pre-white dwarf cannot be convincingly ruled out either. Since
  Sakurai's object shows substantial abundance similarities with the R
  CrB stars and has recently undergone R CrB-like visual fading events,
  the “birth” of an R CrB star may have been witnessed for the first
  time ever. Sakurai's object thus lends strong support for the suggestion
  that at least some of the R CrB stars have been formed through a final
  He-shell flash in a post-AGB star.

---------------------------------------------------------
Title: Confrontation of Stellar Surface Convection Simulations with
    Stellar Spectroscopy
Authors: Asplund, M.; Nordlund, Å.; Trampedach, R.
1999ASPC..173..221A    Altcode: 1999sstt.conf..221A
  No abstract at ADS

---------------------------------------------------------
Title: Sakurai's object -- stellar evolution in real time
Authors: Asplund, M.
1999IAUS..191..481A    Altcode:
  The born-again giant Sakurai's object is currently experiencing
  its second stage as an AGB-star. Furthermore, Sakurai's object has
  shown an unprecedented rapid stellar evolution since discovery in
  1996, both in terms of a continued cooling of the photosphere and
  spectacular changes in chemical composition on a time-scale of a
  mere few months. The surface cooling and abundance alterations of H,
  Li and the s-elements are the direct consequences of the expansion,
  mixing and nucleosynthesis which has ensued as a result of a final
  He-shell flash occurring while the star was descending the white dwarf
  cooling track. Sakurai's object shows striking similarities with the
  R CrB stars in both chemical composition and visual variability.

---------------------------------------------------------
Title: Convection in Metal-Poor Stars as Traced from Spectral Line
    Asymmetries
Authors: Allende Prieto, C.; Asplund, M.; García López, R. J.;
   Gustafsson, B.; Lambert, D. L.
1999ASPC..173..205A    Altcode: 1999sstt.conf..205A
  No abstract at ADS

---------------------------------------------------------
Title: EROS variable stars: discovery of a slow nova in the SMC
Authors: de Laverny, P.; Beaulieu, J. P.; Asplund, M.; Kilkenny, D.;
   Renault, C.; Ferlet, R.; Marquette, J. B.; Vidal-Madjar, A.; Maurice,
   E.; Prevot, L.; Aubourg, E.; Bareyre, P.; Bauer, F.; Brehin, S.;
   Coutures, C.; de Kat, J.; Gros, M.; Laurent, B.; Lachieze-Rey, M.;
   Lesquoy, E.; Magneville, C.; Milsztajn, A.; Moscoso, L.; Queinnec,
   F.; Rich, J.; Spiro, M.; Vigroux, L.; Zylberajch, S.; Ansari, R.;
   Cavalier, F.; Moniez, M.
1998A&A...335L..93D    Altcode:
  We report the discovery of a slow nova found in the core of the Small
  Magellanic Cloud by the EROS microlensing survey. Nova SMC 1994 is a
  classical nova with a DQ Her type lightcurve characterized by a deep
  minimum. Low amplitude variations occuring on time-scales of hours and
  days are also detected at maximum light. Spectra collected during the
  nebular phase indicate that Nova SMC 1994 is similar to Galactic novae
  of the same class. Large helium enhancement in the shell is found and
  O and N enrichments are suspected. Based on observations collected at
  the European Southern Observatory, Chile.

---------------------------------------------------------
Title: Abundance similarities between the RCrB star V854Cen and the
    born-again Sakurai's object
Authors: Asplund, Martin; Gustafsson, Bengt; Kameswara Rao, N.;
   Lambert, David L.
1998A&A...332..651A    Altcode: 1998astro.ph..1068A
  The elemental abundances of the mildly hydrogen-deficient R Coronae
  Borealis (RCrB) star V854Cen have been estimated. The RCrB stars
  have been divided into majority and minority classes judging by their
  abundance patterns. Class assignment has previously been unambiguous
  but V854Cen has traits of both the minority and majority class. Neither
  V854Cen nor the three obvious minority members show any clear abundance
  signatures of having been affected by e.g. dust-gas separation as often
  observed in post-AGB stars. By chemical composition, V854Cen closely
  resembles Sakurai's object, which has probably recently experienced
  a final He-shell flash. Therefore V854Cen and Sakurai's object may
  share the same evolutionary background, which would add support for
  the final-flash scenario as a viable origin of the RCrB stars. Most
  of the few differences in abundance ratios between the stars could if
  so be attributed to milder H-ingestion in connection with the final
  He-shell flash of V854Cen. The identification of either the majority or
  the minority group, if any, as final flash objects, remain uncertain,
  however, due to the unclear membership status of V854Cen.

---------------------------------------------------------
Title: The stability of late-type stars close to the Eddington limit
Authors: Asplund, Martin
1998A&A...330..641A    Altcode: 1997astro.ph.10158A
  The opacity-modified Eddington limit has been computed for
  hydrogen-deficient model atmospheres. The R Coronae Borealis (RCrB)
  stars are found to be located strikingly close to the limit, which
  suggests that the unknown trigger mechanism for their visual declines of
  the stars are instabilities in connection with the stars encountering
  the Eddington limit in their evolution. It also points to a similarity
  between the eruptive behaviours of the RCrB stars and the Luminous
  Blue Variables (LBVs). Super-Eddington luminosities in hydrostatic
  model atmospheres manifest themselves by the presence of gas pressure
  inversions. Such inversions are not an artifact of the assumption of
  hydrostatic equilibrium but can also be present in hydrodynamical model
  atmospheres. Only for very large mass loss rates hardly realized in
  supergiants will the inversions be removed. Instabilities may, however,
  still be present in such inversions, which is investigated for both
  H-rich and H-deficient late-type supergiant model atmospheres. Dynamical
  instabilities may occur in surface ionization zones, which might
  lead to ejections of gas. A local, non-adiabatic, linear stability
  analysis reveals that sound waves can be amplified due to the strong
  radiative forces. However, despite the super-Eddington luminosities,
  the efficiency of the radiative instabilities is fairly low compared
  to for early-type stars with growth rates of 10(-5) s(-1) .

---------------------------------------------------------
Title: (Erratum) Line-blanketed model atmospheres for R Coronae
    Borealis stars and hydrogen-deficient carbon stars.
Authors: Asplund, M.; Gustafsson, B.; Kiselman, D.; Eriksson, K.
1997A&A...323..286A    Altcode:
  Erratum to Astron. Astrophys. 318, 521-534 (1997)

---------------------------------------------------------
Title: Evolution and variability of the R Coronae Borealis stars
Authors: Asplund, M.
1997PhDT........20A    Altcode:
  The R Coronae Borealis (RCrB) stars are characterized by their severe
  hydrogen-deficiency and drastic visual variability. This thesis
  is devoted to both these issues using theoretical, numerical and
  observational investigations. A large sample of the stars has been
  analysed to determine their elemental abundances, which trace both
  their ancestry and the history of stellar nucleosynthesis. For the
  purpose, line-blanketed, hydrogen-deficient model atmospheres have
  been constructed. The peculiar compositions of the stars indicate that
  they are in fact born-again giants, for which two explanations have
  been proposed: either a merger of two white dwarfs or a final He-shell
  flash in a post-AGB star, which briefly re-inflates the star back to
  giant dimensions. According to their composition, the stars can be
  divided into a homogeneous majority group and a diverse minority, which
  might reflect two different evolutionary backgrounds or the effect of
  dust-gas separation. The atmospheres bear witness of H- and He-burning
  in different phases as well as s-processing, but the high Si/Fe and S/Fe
  ratios of in particular the minority remain unexplained. The inability
  of the models to reproduce the CI lines suggests that standard model
  atmospheres are far from adequate descriptions of supergiants such
  as the RCrB stars. An analysis of Sakurai's object, which has likely
  recently experienced a final He-shell flash, reveals similarities
  with the RCrB stars as regards chemical composition. More spectacular,
  the star shows evidence of very rapid evolution and nucleosynthesis,
  most notably a decrease in the H abundance and an increase in the Li
  and s-element contents within only five months. The star represents an
  impressively fast case of stellar evolution very rarely encountered. The
  variability of the stars with fadings of up to 8 magnitudes is unique
  and not yet explained. It is probably due to obscuration events of
  the stars by newly formed dust clouds. Possible instabilities due to
  large radiative forces in the stellar atmospheres, which could be the
  unknown trigger mechanism for the variability by ejecting condensible
  material, are searched for. A connection between such instabilities
  and the declines is supported by the proximity of the stars to the
  theoretical opacity-modified Eddington limit.

---------------------------------------------------------
Title: A stellar endgame - the born-again Sakurai's object.
Authors: Asplund, M.; Gustafsson, B.; Lambert, D. L.; Kameswara Rao, N.
1997A&A...321L..17A    Altcode: 1997astro.ph..4005A
  The surface chemical composition of this remarkable star shows that it
  is hydrogen-deficient, carbon-rich and enriched in the light s-process
  elements. Spectra taken in May and October 1996 indicate a decrease in
  the surface hydrogen abundance by 0.7dex in five months along with an
  increase in the abundances of Li, Sr, Y and Zr. The abundance changes
  are in agreement with the hypothesis of the star being a rapidly
  evolving "born-again" AGB star experiencing a final He-shell flash,
  similar to FGSge. The ^12^C/^13^C ratio in October is very low, also
  suggesting hydrogen ingestion. By chemical composition, Sakurai's
  object resembles the R Coronae Borealis (RCrB) stars.

---------------------------------------------------------
Title: Line-blanketed model atmospheres for R Coronae Borealis stars
    and hydrogen-deficient carbon stars.
Authors: Asplund, M.; Gustafsson, B.; Kiselman, D.; Eriksson, K.
1997A&A...318..521A    Altcode:
  We have constructed line-blanketed model atmospheres for the
  hydrogen-deficient and carbon-rich R Coronae Borealis (RCrB) stars,
  as well as for the similar hydrogen-deficient carbon (HdC) stars and
  the cool extreme helium (EHe) stars. Improved continuum opacities have
  been used together with realistic line absorption data for atomic
  and molecular transitions. The observed dereddened fluxes of R CrB
  are compared with the calculated model fluxes and found to agree best
  with a model effective temperature of 6900K, while the infrared flux
  method gives between 6600 and 6900K, depending on the nature of the
  flux excess in the J and H bands compared to the model fluxes. The
  excess may correspond to a recently formed dust cloud close to the
  star, with a typical temperature around 2000K and a dust mass of
  ~10^-11^M<SUB>sun</SUB>_. The agreement for the ultraviolet flux
  distribution is also very satisfactory as seen from IUE spectra of
  RCrB. Theoretical broad band photometry is presented and effective
  temperatures of RCrB and HdC stars estimated. The constructed
  models show a significantly steeper temperature gradient compared
  to previously existing models as a result of the line opacity. Due
  to the cool surface and high abundance of carbon, molecular bands of
  e.g. C_2_ and CO are visible in the spectra even at as high effective
  temperatures as 7000K. Furthermore, the high temperatures encountered
  at depth explain the observed Hei and CII lines for T_eff_ down to
  ~7000K. In the inner layers (τ_Ross_ &gt; 3) the models show density
  inversions related to the ionization zone of helium. For certain low
  gravity models the luminosity exceeds the local Eddington limit and
  hence gas pressure inversions occur as well, which could be related
  to the decline events of RCrB stars.

---------------------------------------------------------
Title: Evolution and variability of the R Coronae Borealis stars
Authors: Asplund, Martin
1997PhDT.......230A    Altcode:
  No abstract at ADS

---------------------------------------------------------
Title: Are the declines of R Coronae Borealis stars caused by super-
    Eddington luminosities?
Authors: Asplund, M.; Gustafsson, B.
1996ASPC...96...39A    Altcode: 1996hds..conf...39A
  No abstract at ADS

---------------------------------------------------------
Title: A non-LTE investigation of carbon in R Coronae Borealis stars
Authors: Asplund, M.; Ryde, N. A. E.
1996ASPC...96...57A    Altcode: 1996hds..conf...57A
  No abstract at ADS

---------------------------------------------------------
Title: Model atmospheres of cool hydrogen-deficient carbon stars
Authors: Gustafsson, B.; Asplund, M.
1996ASPC...96...27G    Altcode: 1996hds..conf...27G
  No abstract at ADS

---------------------------------------------------------
Title: Spectroscopy of RY Sagittarii during the 1993 minimum.
Authors: Asplund, Martin
1995A&A...294..763A    Altcode:
  The R Coronae Borealis (RCB) star RY Sgr underwent a deep minimum
  ({DELTA}V~7.5mag) in 1993. Here medium and low resolution observations
  from approximately 35 days into the decline are presented together with
  photometry from the early phases until some 100 days thereafter. The
  spectra show sharp chromospheric emission lines of Fe, TiII, ScII, BaII
  and YII, as well as broad emission from Na D, HeI, K and MgI. In general
  the broad lines are stationary or slightly blueshifted relative to the
  star. An absorption feature in Na D_2_ corresponds to a radial velocity
  of -200km/s. The helium line at 587.6nm is surprisingly weak, which
  suggests high optical depths and electron densities. Strong emission
  bands due to the Swan bands of C_2_ are found and two extended emission
  "bumps" around 390nm and 590nm still lack definite identification. I
  also present the first identified forbidden lines in RY Sgr and the
  first published detection of [CaII] in a RCB star. Other lines are
  tentatively ascribed to [NII] and [CI]. Comparison of calcium line
  ratios indicates an electron density of ~10^9^cm^-3^, but it seems like
  at least two different regions emit the broad lines: a high density
  chromospheric environment and a much less dense nebula-like region.