Author name code: dreizler ADS astronomy entries on 2022-09-14 author:"Dreizler, Stefan" ------------------------------------------------------------------------ Title: The CARMENES search for exoplanets around M dwarfs: Stable radial-velocity variations at the rotation period of AD~Leonis -- A test case study of current limitations to treating stellar activity Authors: Kossakowski, D.; Kürster, M.; Henning, Th.; Trifonov, T.; Caballero, J. A.; Lafarga, M.; Bauer, F. F.; Stock, S.; Kemmer, J.; Jeffers, S. V.; Amado, P. J.; Pérez-Torres, M.; Béjar, V. J. S.; Cortés-Contreras, M.; Ribas, I.; Reiners, A.; Quirrenbach, A.; Aceituno, J.; Baroch, D.; Cifuentes, C.; Dreizler, S.; Forcada, J. S.; Hatzes, A.; Kaminski, A.; Montes, D.; Morales, J. C.; Pavlov, A.; Peña, L.; Perdelwitz, V.; Reffert, S.; Revilla, D.; Rodríguez López, C.; Rosich, A.; Sadegi, S.; Schöfer, P.; Schweitzer, A.; Zechmeister, M. Bibcode: 2022arXiv220905814K Altcode: Context: A challenge with radial-velocity (RV) data is disentangling the origin of signals either due to a planetary companion or to stellar activity. In fact, the existence of a planetary companion has been proposed, as well as contested, around the relatively bright, nearby M3.0V star AD Leo at the same period as the stellar rotation of 2.23d. Aims: We further investigate the nature of this signal. We introduce new CARMENES optical and near-IR RV data and an analysis in combination with archival data taken by HIRES and HARPS, along with more recent data from HARPS-N, GIANO-B, and HPF. Also, we address the confusion concerning the binarity of AD Leo. Methods: We consider possible correlations between the RVs and various stellar activity indicators accessible with CARMENES. We applied models within a Bayesian framework to determine whether a Keplerian model, a red-noise quasi-periodic model using a Gaussian process, or a mixed model would explain the observed data best. We also exclusively focus on spectral lines potentially associated with stellar activity. Results: The CARMENES RV data agree with the previously reported periodicity of 2.23d, correlate with some activity indicators, and exhibit chromaticity. However, when considering the entire RV data set, we find that a mixed model composed of a stable and a variable component performs best. Moreover, when recomputing the RVs using only spectral lines insensitive to activity, there appears to be some residual power at the period of interest. We therefore conclude that it is not possible to determinedly prove that there is no planet orbiting in synchronization with the stellar rotation given our data, current tools, machinery, and knowledge of how stellar activity affects RVs. We do rule out planets more massive than 27M_E (=0.084M_J). We also exclude any binary companion around AD Leo with Msini > 3-6M_J on orbital periods <14yr. Title: The BlueMUSE data reduction pipeline: lessons learned from MUSE and first design choices Authors: Weilbacher, Peter M.; Martens, Sven; Wendt, Martin; Roth, Martin M.; Dreizler, Stefan; Kelz, Andreas; Bacon, Roland; Richard, Johan Bibcode: 2022arXiv220906022W Altcode: BlueMUSE is an integral field spectrograph in an early development stage for the ESO VLT. For our design of the data reduction software for this instrument, we are first reviewing capabilities and issues of the pipeline of the existing MUSE instrument. MUSE has been in operation at the VLT since 2014 and led to discoveries published in more than 600 refereed scientific papers. While BlueMUSE and MUSE have many common properties we briefly point out a few key differences between both instruments. We outline a first version of the flowchart for the science reduction, and discuss the necessary changes due to the blue wavelength range covered by BlueMUSE. We also detail specific new features, for example, how the pipeline and subsequent analysis will benefit from improved handling of the data covariance, and a more integrated approach to the line-spread function, as well as improvements regarding the wavelength calibration which is of extra importance in the blue optical range. We finally discuss how simulations of BlueMUSE datacubes are being implemented and how they will be used to prepare the science of the instrument. Title: Precise mass determination for the keystone sub-Neptune planet transiting the mid-type M dwarf G 9-40 Authors: Luque, R.; Nowak, G.; Hirano, T.; Kossakowski, D.; Pallé, E.; Nixon, M. C.; Morello, G.; Amado, P. J.; Albrecht, S. H.; Caballero, J. A.; Cifuentes, C.; Cochran, W. D.; Deeg, H. J.; Dreizler, S.; Esparza-Borges, E.; Fukui, A.; Gandolfi, D.; Goffo, E.; Guenther, E. W.; Hatzes, A. P.; Henning, T.; Kabath, P.; Kawauchi, K.; Korth, J.; Kotani, T.; Kudo, T.; Kuzuhara, M.; Lafarga, M.; Lam, K. W. F.; Livingston, J.; Morales, J. C.; Muresan, A.; Murgas, F.; Narita, N.; Osborne, H. L. M.; Parviainen, H.; Passegger, V. M.; Persson, C. M.; Quirrenbach, A.; Redfield, S.; Reffert, S.; Reiners, A.; Ribas, I.; Serrano, L. M.; Tamura, M.; Van Eylen, V.; Watanabe, N.; Zapatero Osorio, M. R. Bibcode: 2022arXiv220807287L Altcode: Context. Despite being a prominent subset of the exoplanet population discovered in the past three decades, the nature and provenance of sub-Neptune-sized planets are still one of the open questions in exoplanet science. Aims. For planets orbiting bright stars, precisely measuring the orbital and planet parameters of the system is the best approach to distinguish between competing theories regarding their formation and evolution. Methods. We obtained 69 new radial velocity observations of the mid-M dwarf G 9-40 with the CARMENES instrument to measure for the first time the mass of its transiting sub-Neptune planet, G 9-40 b, discovered in data from the K2 mission. Results. Combined with new observations from the TESS mission during Sectors 44, 45, and 46, we are able to measure the radius of the planet to an uncertainty of 3.4% (Rb = 1.900 +- 0.065 Re) and determine its mass with a precision of 16% (Mb = 4.00 +- 0.63 Me). The resulting bulk density of the planet is inconsistent with a terrestrial composition and suggests the presence of either a water-rich core or a significant hydrogen-rich envelope. Conclusions. G 9-40 b is referred to as a keystone planet due to its location in period-radius space within the radius valley. Several theories offer explanations for the origin and properties of this population and this planet is a valuable target for testing the dependence of those models on stellar host mass. By virtue of its brightness and small size of the host, it joins L 98-59 d as one of the two best warm (Teq ~ 400 K) sub-Neptunes for atmospheric characterization with JWST, which will probe cloud formation in sub-Neptune-sized planets and break the degeneracies of internal composition models. Title: Detailed stellar activity analysis and modelling of GJ 832. Reassessment of the putative habitable zone planet GJ 832c Authors: Gorrini, P.; Astudillo-Defru, N.; Dreizler, S.; Damasso, M.; Díaz, R. F.; Bonfils, X.; Jeffers, S. V.; Barnes, J. R.; Del Sordo, F.; Almenara, J. -M.; Artigau, E.; Bouchy, F.; Charbonneau, D.; Delfosse, X.; Doyon, R.; Figueira, P.; Forveille, T.; Haswell, C. A.; López-González, M. J.; Melo, C.; Mennickent, R. E.; Gaisné, G.; Morales Morales, N.; Murgas, F.; Pepe, F.; Rodríguez, E.; Santos, N. C.; Tal-Or, L.; Tsapras, Y.; Udry, S. Bibcode: 2022A&A...664A..64G Altcode: 2022arXiv220607552G Context. Gliese-832 (GJ 832) is an M2V star hosting a massive planet on a decade-long orbit, GJ 832b, discovered by radial velocity (RV). Later, a super Earth or mini-Neptune orbiting within the stellar habitable zone was reported (GJ 832c). The recently determined stellar rotation period (45.7 ± 9.3 days) is close to the orbital period of putative planet c (35.68 ± 0.03 days).
Aims: We aim to confirm or dismiss the planetary nature of the RV signature attributed to GJ 832c, by adding 119 new RV data points, new photometric data, and an analysis of the spectroscopic stellar activity indicators. Additionally, we update the orbital parameters of the planetary system and search for additional signals.
Methods: We performed a frequency content analysis of the RVs to search for periodic and stable signals. Radial velocity time series were modelled with Keplerians and Gaussian process (GP) regressions alongside activity indicators to subsequently compare them within a Bayesian framework.
Results: We updated the stellar rotational period of GJ 832 from activity indicators, obtaining 37.5+1.4-1.5 days, improving the precision by a factor of 6. The new photometric data are in agreement with this value. We detected an RV signal near 18 days (FAP < 4.6%), which is half of the stellar rotation period. Two Keplerians alone fail at modelling GJ 832b and a second planet with a 35-day orbital period. Moreover, the Bayesian evidence from the GP analysis of the RV data with simultaneous activity indices prefers a model without a second Keplerian, therefore negating the existence of planet c.

Activity indices, photometric and RV time series are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/664/A64 Title: The HD 260655 system: Two rocky worlds transiting a bright M dwarf at 10 pc Authors: Luque, R.; Fulton, B. J.; Kunimoto, M.; Amado, P. J.; Gorrini, P.; Dreizler, S.; Hellier, C.; Henry, G. W.; Molaverdikhani, K.; Morello, G.; Peña-Moñino, L.; Pérez-Torres, M.; Pozuelos, F. J.; Shan, Y.; Anglada-Escudé, G.; Béjar, V. J. S.; Bergond, G.; Boyle, A. W.; Caballero, J. A.; Charbonneau, D.; Ciardi, D. R.; Dufoer, S.; Espinoza, N.; Everett, M.; Fischer, D.; Hatzes, A. P.; Henning, Th.; Hesse, K.; Howard, A. W.; Howell, S. B.; Isaacson, H.; Jeffers, S. V.; Jenkins, J. M.; Kane, S. R.; Kemmer, J.; Khalafinejad, S.; Kidwell, R. C.; Kossakowski, D.; Latham, D. W.; Lillo-Box, J.; Lissauer, J. J.; Montes, D.; Orell-Miquel, J.; Pallé, E.; Pollacco, D.; Quirrenbach, A.; Reffert, S.; Reiners, A.; Ribas, I.; Ricker, G. R.; Rogers, L. A.; Sanz-Forcada, J.; Schlecker, M.; Schweitzer, A.; Seager, S.; Shporer, A.; Stassun, K. G.; Stock, S.; Tal-Or, L.; Ting, E. B.; Trifonov, T.; Vanaverbeke, S.; Vanderspek, R.; Villaseñor, J.; Winn, J. N.; Winters, J. G.; Zapatero Osorio, M. R. Bibcode: 2022A&A...664A.199L Altcode: 2022arXiv220410261L We report the discovery of a multiplanetary system transiting the M0 V dwarf HD 260655 (GJ 239, TOI-4599). The system consists of at least two transiting planets, namely HD 260655 b, with a period of 2.77 d, a radius of Rb = 1.240 ± 0.023 R, a mass of Mb = 2.14 ± 0.34 M, and a bulk density of ρb = 6.2 ± 1.0 g cm−3, and HD 260655 c, with a period of 5.71 d, a radius of {R_c} = 1.533 - 0.046 + 0.051{R_ \oplus }, a mass of Mc = 3.09 ± 0.48 M, and a bulk density of {ρ _c} = 4.7 - 0.8 + 0.9{{g}} g cm−3. The planets have been detected in transit by the Transiting Exoplanet Survey Satellite (TESS) mission and confirmed independently with archival and new precise radial velocities obtained with the HIRES and CARMENES instruments since 1998 and 2016, respectively. At a distance of 10 pc, HD 260655 has become the fourth closest known multitransiting planet system after HD 219134, LTT 1445 A, and AU Mic. Due to the apparent brightness of the host star (J = 6.7 mag), both planets are among the most suitable rocky worlds known today for atmospheric studies with the James Webb Space Telescope, both in transmission and emission. Title: VizieR Online Data Catalog: GJ 832 stellar activity (Gorrini+, 2022) Authors: Gorrini, P.; Astudillo-Defru, N.; Dreizler, S.; Damasso, M.; Diaz, R. F.; Bonfils, X.; Jeffers, S. V.; Barnes, J. R.; Del Sordo, F.; Almenara, J. -M.; Artigau, E.; Bouchy, F.; Charbonneau, D.; Delfosse, X.; Doyon, R.; Figueira, P.; Forveille, T.; Haswell, C. A.; Lopez-Gonzalez, M. J.; Melo, C.; Mennickent, R. E.; Gaisne, G.; Morales, N.; Murgas, F.; Pepe, F.; Rodriguez, E.; Santos, N. C.; Tal-Or, L.; Tsapras, Y.; Udry, S. Bibcode: 2022yCat..36640064G Altcode: This work makes use of data from HARPS, the University College London Echelle Spectrograph (UCLES) , and the Planet Finding Spectrograph (PFS). HARPS data are available as raw images and reduced spectra, while we accessed UCLES and PFS data only as RV time series. We used a total of 227 RV data points for GJ 832.

(3 data files). Title: The CARMENES search for exoplanets around M dwarfs. Rotational variation in activity indicators of Ross 318, YZ CMi, TYC 3529-1437-1, and EV Lac Authors: Schöfer, P.; Jeffers, S. V.; Reiners, A.; Zechmeister, M.; Fuhrmeister, B.; Lafarga, M.; Ribas, I.; Quirrenbach, A.; Amado, P. J.; Caballero, J. A.; Anglada-Escudé, G.; Bauer, F. F.; Béjar, V. J. S.; Cortés-Contreras, M.; Alonso, E. Díez; Dreizler, S.; Guenther, E. W.; Herbort, O.; Johnson, E. N.; Kaminski, A.; Kürster, M.; Montes, D.; Morales, J. C.; Pedraz, S.; Tal-Or, L. Bibcode: 2022A&A...663A..68S Altcode: 2022arXiv220411685S Context. The Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Échelle Spectrographs (CARMENES) instrument is searching for periodic radial-velocity (RV) variations of M dwarfs, which are induced by orbiting planets. However, there are other potential sources of such variations, including rotational modulation caused by stellar activity.
Aims: We aim to investigate four M dwarfs (Ross 318, YZ CMi, TYC 3529-1437-1, and EV Lac) with different activity levels and spectral sub-types. Our goal is to compare the periodicities seen in 22 activity indicators and the stellar RVs, and to examine their stability over time.
Methods: For each star, we calculated generalised Lomb-Scargle periodograms of pseudo-equivalent widths of chromospheric lines, indices of photospheric bands, the differential line width as a measure of the width of the average photospheric absorption line, the RV, the chromatic index that describes the wavelength dependence of the RV, and parameters of the cross-correlation function. We also calculated periodograms for subsets of the data and compared our results to TESS photometry.
Results: We find the rotation periods of all four stars to manifest themselves in the RV and photospheric indicators, particularly the TiO 7050 index, whereas the chromospheric lines show clear signals only at lower activity levels. For EV Lac and TYC 3529-1437-1, we find episodes during which indicators vary with the rotation period, and episodes during which they vary with half the rotation period, similarly to photometric light curves.
Conclusions: The changing periodicities reflect the evolution of stellar activity features on the stellar surface. We therefore conclude that our results not only emphasise the importance of carefully analysing indicators complementary to the RV in RV surveys, but they also suggest that it is also useful to search for signals in activity indicators in subsets of the dataset, because an activity signal that is present in the RV may not be visible in the activity indicators all the time, in particular for the most active stars. Title: Transit Timing Variations for AU Microscopii b and c Authors: Wittrock, Justin M.; Dreizler, Stefan; Reefe, Michael A.; Morris, Brett M.; Plavchan, Peter P.; Lowrance, Patrick J.; Demory, Brice-Olivier; Ingalls, James G.; Gilbert, Emily A.; Barclay, Thomas; Cale, Bryson L.; Collins, Karen A.; Collins, Kevin I.; Crossfield, Ian J. M.; Dragomir, Diana; Eastman, Jason D.; Mufti, Mohammed El; Feliz, Dax; Gagné, Jonathan; Gaidos, Eric; Gao, Peter; Geneser, Claire S.; Hebb, Leslie; Henze, Christopher E.; Horne, Keith D.; Jenkins, Jon M.; Jensen, Eric L. N.; Kane, Stephen R.; Kaye, Laurel; Martioli, Eder; Monsue, Teresa A.; Pallé, Enric; Quintana, Elisa V.; Radford, Don J.; Roccatagliata, Veronica; Schlieder, Joshua E.; Schwarz, Richard P.; Shporer, Avi; Stassun, Keivan G.; Stockdale, Christopher; Tan, Thiam-Guan; Tanner, Angelle M.; Vanderburg, Andrew; Vega, Laura D.; Wang, Songhu Bibcode: 2022AJ....164...27W Altcode: 2022arXiv220205813W We explore the transit timing variations (TTVs) of the young (22 Myr) nearby AU Mic planetary system. For AU Mic b, we introduce three Spitzer (4.5 μm) transits, five TESS transits, 11 LCO transits, one PEST transit, one Brierfield transit, and two transit timing measurements from Rossiter-McLaughlin observations; for AU Mic c, we introduce three TESS transits. We present two independent TTV analyses. First, we use EXOFASTv2 to jointly model the Spitzer and ground-based transits and obtain the midpoint transit times. We then construct an O - C diagram and model the TTVs with Exo-Striker. Second, we reproduce our results with an independent photodynamical analysis. We recover a TTV mass for AU Mic c of ${10.8}_{-2.2}^{+2.3}$ M . We compare the TTV-derived constraints to a recent radial velocity (RV) mass determination. We also observe excess TTVs that do not appear to be consistent with the dynamical interactions of b and c alone or due to spots or flares. Thus, we present a hypothetical nontransiting "middle-d" candidate exoplanet that is consistent with the observed TTVs and candidate RV signal and would establish the AU Mic system as a compact resonant multiplanet chain in a 4:6:9 period commensurability. These results demonstrate that the AU Mic planetary system is dynamically interacting, producing detectable TTVs, and the implied orbital dynamics may inform the formation mechanisms for this young system. We recommend future RV and TTV observations of AU Mic b and c to further constrain the masses and confirm the existence of possible additional planet(s). Title: A detailed analysis of the Gl 486 planetary system Authors: Caballero, J. A.; Gonzalez-Alvarez, E.; Brady, M.; Trifonov, T.; Ellis, T. G.; Dorn, C.; Cifuentes, C.; Molaverdikhani, K.; Bean, J. L.; Boyajian, T.; Rodriguez, E.; Sanz-Forcada, J.; Zapatero Osorio, M. R.; Abia, C.; Amado, P. J.; Anugu, N.; Bejar, V. J. S.; Davies, C. L.; Dreizler, S.; Dubois, F.; Ennis, J.; Espinoza, N.; Farrington, C. D.; Garcia Lopez, A.; Gardner, T.; Hatzes, A. P.; Henning, Th.; Herrero, E.; Herrero-Cisneros, E.; Kaminski, A.; Kasper, D.; Klement, R.; Kraus, S.; Labdon, A.; Lanthermann, C.; Le Bouquin, J. -B.; Lopez Gonzalez, M. J.; Luque, R.; Mann, A. W.; Marfil, E.; Monnier, J. D.; Montes, D.; Morales, J. C.; Palle, E.; Pedraz, S.; Quirrenbach, A.; Reffert, S.; Reiners, A.; Ribas, I.; Rodriguez-Lopez, C.; Schaefer, G.; Schweitzer, A.; Seifahrt, A.; Setterholm, B. R.; Shan, Y.; Shulyak, D.; Solano, E.; Sreenivas, K. R.; Stefansson, G.; Stuermer, J.; Tabernero, H. M.; Tal-Or, L.; ten Brummelaar, T.; Vanaverbeke, S.; von Braun, K.; Youngblood, A.; Zechmeister, M. Bibcode: 2022arXiv220609990C Altcode: The Gl 486 system consists of a very nearby, relatively bright, weakly active M3.5 V star at just 8 pc with a warm transiting rocky planet of about 1.3 R_Terra and 3.0 M_Terra that is ideal for both transmission and emission spectroscopy and for testing interior models of telluric planets. To prepare for future studies, we collected light curves of seven new transits observed with the CHEOPS space mission and new radial velocities obtained with MAROON-X/Gemini North and CARMENES/Calar Alto telescopes, together with previously published spectroscopic and photometric data from the two spectrographs and TESS. We also performed interferometric observations with the CHARA Array and new photometric monitoring with a suite of smaller telescopes. From interferometry, we measure a limb-darkened disc angular size of the star Gl 486. Together with a corrected Gaia EDR3 parallax, we obtain a stellar radius. We also measure a stellar rotation period at P_rot ~ 49.9 d, an upper limit to its XUV (5-920 AA) flux with new Hubble/STIS data, and, for the first time, a variety of element abundances (Fe, Mg, Si, V, Sr, Zr, Rb) and C/O ratio. Besides, we impose restrictive constraints on the presence of additional components, either stellar or substellar, in the system. With the input stellar parameters and the radial-velocity and transit data, we determine the radius and mass of the planet Gl 486 b at R_p = 1.343+/0.063 R_Terra and M_p = 3.00+/-0.13 M_Terra. From the planet parameters and the stellar element abundances, we infer the most probable models of planet internal structure and composition, which are consistent with a relatively small metallic core with respect to the Earth, a deep silicate mantle, and a thin volatile upper layer. With all these ingredients, we outline prospects for Gl 486 b atmospheric studies, especially with forthcoming James Webb Space Telescope observations (abridged). Title: Transit Timing Variations for AU Microscopii b & c Authors: Wittrock, Justin M.; Dreizler, Stefan; Reefe, Michael; Morris, Brett; Plavchan, Peter; Lowrance, Patrick; Demory, Brice-Olivier; Ingalls, James; Gilbert, Emily; Barclay, Thomas; Cale, Bryson; Collins, Karen; Collins, Kevin; Crossfield, Ian; Dragomir, Diana; Eastman, Jason; El Mufti, Mohammed; Feliz, Dax; Gagné, Jonathan; Gaidos, Eric; Gao, Peter; Geneser, Claire; Hebb, Leslie; Henze, Chris; Horne, Keith; Jenkins, Jon; Jensen, Eric; Kane, Stephen; Kaye, Laurel; Martioli, Eder; Monsue, Teresa; Palle Bago, Enric; Quintana, Elisa; Radford, Don; Roccatagliata, Veronica; Schlieder, Joshua; Schwarz, Richard; Shporer, Avi; Stassun, Keivan; Stockdale, Christopher; Tan, Thiam-Guan; Tanner, Angelle; Vanderburg, Andrew; Vega, Laura; Wang, Songhu Bibcode: 2022BAAS...54e.275W Altcode: We explore the transit timing variations (TTVs) of the young (22 Myr) nearby AU Mic planetary system. For AU Mic b, we introduce three Spitzer (4.5 μm) transits, five TESS transits, 11 LCO transits, one PEST transit, one Brierfield transit, and two transit timing measurements from Rossiter-McLaughlin observations; for AU Mic c, we introduce three TESS transits. We present two independent TTV analyses. First, we use EXOFASTv2 to jointly model the Spitzer and ground-based transits and to obtain the midpoint transit times. We then construct an O-C diagram and model the TTVs with Exo-Striker. Second, we reproduce our results with an independent photodynamical analysis. We recover a TTV mass for AU Mic c of 10.8+2.3-2.2 M. We compare the TTV-derived constraints to a recent radial-velocity (RV) mass determination. We also observe excess TTVs that do not appear to be consistent with the dynamical interactions of b and c alone, and do not appear to be due to spots or flares. Thus, we present a hypothetical non-transiting "middle-d" candidate exoplanet that is consistent with the observed TTVs, the candidate RV signal, and would establish the AU Mic system as a compact resonant multi-planet chain in a 4:6:9 period commensurability. These results demonstrate that the AU Mic planetary system is dynamically interacting producing detectable TTVs, and the implied orbital dynamics may inform the formation mechanisms for this young system. We recommend future RV and TTV observations of AU Mic b and c to further constrain the masses and to confirm the existence of possible additional planet(s). 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. Bibcode: 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.

(3 data files). Title: VizieR Online Data Catalog: VRI photometry and radial velocity of TOI-1759 (Espinoza+, 2022) Authors: Espinoza, N.; Palle, E.; Kemmer, J.; Luque, R.; Caballero, J. A.; Cifuentes, C.; Herrero, E.; Sanchez Bejar, V. J.; Stock, S.; Molaverdikhani, K.; Morello, G.; Kossakowski, D.; Schlecker, M.; Amado, P. J.; Bluhm, P.; Cortes-Contreras, M.; Henning, T.; Kreidberg, L.; Kurster, M.; Lafarga, M.; Lodieu, N.; Morales, J. C.; Oshagh, M.; Passegger, V. M.; Pavlov, A.; Quirrenbach, A.; Reffert, S.; Reiners, A.; Ribas, I.; Rodriguez, E.; Lopez, C. R.; Schweitzer, A.; Trifonov, T.; Chaturvedi, P.; Dreizler, S.; Jeffers, S. V.; Kaminski, A.; Lopez-Gonzalez, M. J.; Lillo-Box, J.; Montes, D.; Nowak, G.; Pedraz, S.; Vanaverbeke, S.; Zapatero Osorio, M. R.; Zechmeister, M.; Collins, K. A.; Girardin, E.; Guerra, P.; Naves, R.; Crossfield, I. J. M.; Matthews, E. C.; Howell, S. B.; Ciardi, D. R.; Gonzales, E.; Matson, R. A.; Beichman, C. A.; Schlieder, J. E.; Barclay, T.; Vezie, M.; Villasenor, J. N.; Daylan, T.; Mireies, I.; Dragomir, D.; Twicken, J. D.; Jenkins, J.; Winn, J. N.; Latham, D.; Ricker, G.; Seager, S. Bibcode: 2022yCat..51630133E Altcode: The 2 minutes cadence data were processed in the TESS Science Processing Operations Center (SPOC) photometry and transit search pipelines at NASA Ames Research Center, in Sectors 16 (2019 September to October), 17 (2019 October to November), and 24 (2020 April to May).

Among the observations, a transit of TOI-1759b in 2020 May 21 was captured by three independent telescopes/observatories: the OAA telescope of the Observatori Astronomic Albanya (Spain; precision of 1140ppm; R-filter observations), the RCO telescope of the Grand-Pra Observatory (Valais Sion, Switzerland; precision of 1080ppm; ip-filter observations), and the OMC telescope of the Montcabrer Observatory (Barcelona, Spain; precision of 1500ppm; Ic-filter observations).

Long-term photometric monitoring was also performed from the ground using the 0.8m Joan Oro telescope (TJO) at the Montsec Observatory in Lleida, Spain and the 90cm telescope at the Sierra Nevada Observatory (SNO) in R and V filter.

We monitored TOI-1759 with the CARMENES 38 instrument located on the 3.5m telescope at the Calar Alto Observatory in Almeria, Spain, from 2020 July 24 to 2021 January 17 (R=94600).

(3 data files). Title: A black hole detected in the young massive LMC cluster NGC 1850 Authors: Saracino, S.; Kamann, S.; Guarcello, M. G.; Usher, C.; Bastian, N.; Cabrera-Ziri, I.; Gieles, M.; Dreizler, S.; Da Costa, G. S.; Husser, T. -O.; Hénault-Brunet, V. Bibcode: 2022MNRAS.511.2914S Altcode: 2021MNRAS.tmp.2924S; 2021arXiv211106506S We report on the detection of a black hole (NGC 1850 BH1) in the ~100-Myr-old massive cluster NGC 1850 in the Large Magellanic Cloud. It is in a binary system with a main-sequence turn-off star (4.9 ± 0.4 M), which is starting to fill its Roche lobe and is becoming distorted. Using 17 epochs of Very Large Telescope/Multi-Unit Spectroscopic Explorer observations, we detected radial velocity variations exceeding 300 km s-1 associated with the target star, linked to the ellipsoidal variations measured by the fourth phase of the Optical Gravitational Lensing Experiment in the optical bands. Under the assumption of a semidetached system, the simultaneous modelling of radial velocity and light curves constrains the orbital inclination of the binary to 38° ± 2°, resulting in a true mass of the unseen companion of $11.1_{-2.4}^{+2.1}\,{\rm M}_{\odot }$. This represents the first direct dynamical detection of a black hole in a young massive cluster, opening up the possibility of studying the initial mass function and the early dynamical evolution of such compact objects in high-density environments. Title: The MAVERIC Survey: The first radio and X-ray limits on the detached black holes in NGC 3201 Authors: Paduano, Alessandro; Bahramian, Arash; Miller-Jones, James C. A.; Kawka, Adela; Göttgens, Fabian; Strader, Jay; Chomiuk, Laura; Kamann, Sebastian; Dreizler, Stefan; Heinke, Craig O.; Husser, Tim-Oliver; Maccarone, Thomas J.; Tremou, Evangelia; Zhao, Yue Bibcode: 2022MNRAS.510.3658P Altcode: 2021MNRAS.tmp.3428P; 2022arXiv220101418P The Galactic globular cluster (GC) NGC 3201 is the first Galactic GC observed to host dynamically confirmed stellar-mass black holes (BHs), containing two confirmed and one candidate BH. This result indicates that GCs can retain BHs, which has important implications for GC evolution. NGC 3201 has been observed as part of the MAVERIC survey of Galactic GCs. We use these data to confirm that there is no radio or X-ray detection of the three BHs, and present the first radio and X-ray limits on these sources. These limits indicate that any accretion present is at an extremely low rate and may be extremely inefficient. In particular, for the system ACS ID #21859, by assuming the system is tidally locked and any accretion is through the capture of the companion's winds, we constrain the radiative efficiency of any accretion to ≲ 1.5 × 10-5. We also combine the radio and X-ray source catalogues from the MAVERIC survey with the existing MUSE spectroscopic surveys and the HUGS catalogue of NGC 3201 to provide a catalogue of 42 multiwavelength sources in this cluster. We identify a new red straggler source with X-ray emission, and investigate the multiwavelength properties of the sub-subgiant population in the cluster. Title: A Transiting, Temperate Mini-Neptune Orbiting the M Dwarf TOI-1759 Unveiled by TESS Authors: Espinoza, Néstor; Pallé, Enric; Kemmer, Jonas; Luque, Rafael; Caballero, José A.; Cifuentes, Carlos; Herrero, Enrique; Sánchez Béjar, Víctor J.; Stock, Stephan; Molaverdikhani, Karan; Morello, Giuseppe; Kossakowski, Diana; Schlecker, Martin; Amado, Pedro J.; Bluhm, Paz; Cortés-Contreras, Miriam; Henning, Thomas; Kreidberg, Laura; Kürster, Martin; Lafarga, Marina; Lodieu, Nicolas; Morales, Juan Carlos; Oshagh, Mahmoudreza; Passegger, Vera M.; Pavlov, Alexey; Quirrenbach, Andreas; Reffert, Sabine; Reiners, Ansgar; Ribas, Ignasi; Rodríguez, Eloy; López, Cristina Rodríguez; Schweitzer, Andreas; Trifonov, Trifon; Chaturvedi, Priyanka; Dreizler, Stefan; Jeffers, Sandra V.; Kaminski, Adrian; López-González, María José; Lillo-Box, Jorge; Montes, David; Nowak, Grzegorz; Pedraz, Santos; Vanaverbeke, Siegfried; Zapatero Osorio, Maria R.; Zechmeister, Mathias; Collins, Karen A.; Girardin, Eric; Guerra, Pere; Naves, Ramon; Crossfield, Ian J. M.; Matthews, Elisabeth C.; Howell, Steve B.; Ciardi, David R.; Gonzales, Erica; Matson, Rachel A.; Beichman, Charles A.; Schlieder, Joshua E.; Barclay, Thomas; Vezie, Michael; Villaseñor, Jesus Noel; Daylan, Tansu; Mireies, Ismael; Dragomir, Diana; Twicken, Joseph D.; Jenkins, Jon; Winn, Joshua N.; Latham, David; Ricker, George; Seager, Sara Bibcode: 2022AJ....163..133E Altcode: 2022arXiv220201240E We report the discovery and characterization of TOI-1759 b, a temperate (400 K) sub-Neptune-sized exoplanet orbiting the M dwarf TOI-1759 (TIC 408636441). TOI-1759 b was observed by TESS to transit in Sectors 16, 17, and 24, with only one transit observed per sector, creating an ambiguity regarding the orbital period of the planet candidate. Ground-based photometric observations, combined with radial-velocity measurements obtained with the CARMENES spectrograph, confirm an actual period of 18.85019 ± 0.00014 days. A joint analysis of all available photometry and radial velocities reveals a radius of 3.17 ± 0.10 R and a mass of 10.8 ± 1.5 M . Combining this with the stellar properties derived for TOI-1759 (R = 0.597 ± 0.015 R ; M = 0.606 ± 0.020 M ; T eff = 4065 ± 51 K), we compute a transmission spectroscopic metric (TSM) value of over 80 for the planet, making it a good target for transmission spectroscopy studies. TOI-1759 b is among the top five temperate, small exoplanets (T eq < 500 K, R p < 4 R ) with the highest TSM discovered to date. Two additional signals with periods of 80 days and >200 days seem to be present in our radial velocities. While our data suggest both could arise from stellar activity, the later signal's source and periodicity are hard to pinpoint given the ~200 days baseline of our radial-velocity campaign with CARMENES. Longer baseline radial-velocity campaigns should be performed in order to unveil the true nature of this long-period signal. Title: Discovery and mass measurement of the hot, transiting, Earth-sized planet, GJ 3929 b Authors: Kemmer, J.; Dreizler, S.; Kossakowski, D.; Stock, S.; Quirrenbach, A.; Caballero, J. A.; Amado, P. J.; Collins, K. A.; Espinoza, N.; Herrero, E.; Jenkins, J. M.; Latham, D. W.; Lillo-Box, J.; Narita, N.; Pallé, E.; Reiners, A.; Ribas, I.; Ricker, G.; Rodríguez, E.; Seager, S.; Vanderspek, R.; Wells, R.; Winn, J.; Aceituno, F. J.; Béjar, V. J. S.; Barclay, T.; Bluhm, P.; Chaturvedi, P.; Cifuentes, C.; Collins, K. I.; Cortés-Contreras, M.; Demory, B. -O.; Fausnaugh, M. M.; Fukui, A.; Gómez Maqueo Chew, Y.; Galadí-Enríquez, D.; Gan, T.; Gillon, M.; Golovin, A.; Hatzes, A. P.; Henning, Th.; Huang, C.; Jeffers, S. V.; Kaminski, A.; Kunimoto, M.; Kürster, M.; López-González, M. J.; Lafarga, M.; Luque, R.; McCormac, J.; Molaverdikhani, K.; Montes, D.; Morales, J. C.; Passegger, V. M.; Reffert, S.; Sabin, L.; Schöfer, P.; Schanche, N.; Schlecker, M.; Schroffenegger, U.; Schwarz, R. P.; Schweitzer, A.; Sota, A.; Tenenbaum, P.; Trifonov, T.; Vanaverbeke, S.; Zechmeister, M. Bibcode: 2022A&A...659A..17K Altcode: 2022arXiv220200970K We report the discovery of GJ 3929 b, a hot Earth-sized planet orbiting the nearby M3.5 V dwarf star, GJ 3929 (G 180-18, TOI-2013). Joint modelling of photometric observations from TESS sectors 24 and 25 together with 73 spectroscopic observations from CARMENES and follow-up transit observations from SAINT-EX, LCOGT, and OSN yields a planet radius of Rb = 1.150 ± 0.040 R, a mass of Mb = 1.21 ± 0.42 M, and an orbital period of Pb = 2.6162745 ± 0.0000030 d. The resulting density of ρb = 4.4 ± 1.6 g cm−3 is compatible with the Earth's mean density of about 5.5 g cm−3. Due to the apparent brightness of the host star (J = 8.7 mag) and its small size, GJ 3929 b is a promising target for atmospheric characterisation with the JWST. Additionally, the radial velocity data show evidence for another planet candidate with P[c] = 14.303 ± 0.035 d, which is likely unrelated to the stellar rotation period, Prot = 122 ± 13 d, which we determined from archival HATNet and ASAS-SN photometry combined with newly obtained TJO data.

RV data and stellar activity indices are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/659/A17 Title: VizieR Online Data Catalog: GJ 3929 b RVs and activity indicators (Kemmer+, 2022) Authors: Kemmer, J.; Dreizler, S.; Kossakowski, D.; Stock, S.; Quirrenbach, A.; Caballero, J. A.; Amado, P. J.; Collins, K. A.; Espinoza, N.; Herrero, E.; Jenkins, J. M.; Latham, D. W.; Lillo-Box, J.; Narita, N.; Palle, E.; Reiners, A.; Ribas, I.; Ricker, G.; Rodriguez, E.; Seager, S.; Vanderspek, R.; Wells, R.; Winn, J.; Aceituno, F. J.; Bejar, V. J. S.; Barclay, T.; Bluhm, P.; Chaturvedi, P.; Cifuentes, C.; Collins, K. I.; Cortes-Contreras, M.; Demory, B. O.; Fausnaugh, M. M.; Fukui, A.; Gomez Maqueo Chew, Y.; Galadi-Enriquez, D.; Gan, T.; Gillon, M.; Golovin, A.; Hatzes, A. P.; Henning, T.; Huang, C.; Jeffers, S. V.; Kaminski, A.; Kunimoto, M.; Kurster, M.; Lopez-Gonzalez, M. J.; Lafarga, M.; Luque, R.; McCormac, J.; Molaverdikhani, K.; Montes, D.; Morales, J. C.; Passegger, V. M.; Reffert, S.; Sabin, L.; Schoefer, P.; Schanche, N.; Schlecker, M.; Schroffenegger, U.; Schwarz, R. P.; Schweitzer, A.; Sota, A.; Tenenbaum, P.; Trifonov, T.; Vanaverbeke, S.; Zechmeister, M. Bibcode: 2022yCat..36590017K Altcode: Radial velocities and activity indices of GJ 3929 acquired with CARMENES (Quirrenbach et al., 2014, in Proc. SPIE, Vol. 9147, Ground-based and Airborne Instrumentation for Astronomy V, 91471F), a high-resolution precise echelle spectrograph mounted at the 3.5m telescope at the Calar Alto Observatory in Spain.

(1 data file). Title: A multi-planetary system orbiting the early-M dwarf TOI-1238 Authors: González-Álvarez, E.; Zapatero Osorio, M. R.; Sanz-Forcada, J.; Caballero, J. A.; Reffert, S.; Béjar, V. J. S.; Hatzes, A. P.; Herrero, E.; Jeffers, S. V.; Kemmer, J.; López-González, M. J.; Luque, R.; Molaverdikhani, K.; Morello, G.; Nagel, E.; Quirrenbach, A.; Rodríguez, E.; Rodríguez-López, C.; Schlecker, M.; Schweitzer, A.; Stock, S.; Passegger, V. M.; Trifonov, T.; Amado, P. J.; Baker, D.; Boyd, P. T.; Cadieux, C.; Charbonneau, D.; Collins, K. A.; Doyon, R.; Dreizler, S.; Espinoza, N.; Fűrész, G.; Furlan, E.; Hesse, K.; Howell, S. B.; Jenkins, J. M.; Kidwell, R. C.; Latham, D. W.; McLeod, K. K.; Montes, D.; Morales, J. C.; O'Dwyer, T.; Pallé, E.; Pedraz, S.; Reiners, A.; Ribas, I.; Quinn, S. N.; Schnaible, C.; Seager, S.; Skinner, B.; Smith, J. C.; Schwarz, R. P.; Shporer, A.; Vanderspek, R.; Winn, J. N. Bibcode: 2022A&A...658A.138G Altcode: 2021arXiv211114602G Context. The number of super-Earth and Earth-mass planet discoveries has increased significantly in the last two decades thanks to the Doppler radial velocity and planetary transit observing techniques. Either technique can detect planet candidates on its own, but the power of a combined photometric and spectroscopic analysis is unique for an insightful characterization of the planets, which in turn has repercussions for our understanding of the architecture of planetary systems and, therefore, their formation and evolution.
Aims: Two transiting planet candidates with super-Earth radii around the nearby (d = 70.64 ± 0.06 pc) K7-M0 dwarf star TOI-1238 were announced by NASA's Transiting Exoplanet Survey Satellite (TESS), which observed the field of TOI-1238 in four different sectors. We aim to validate their planetary nature using precise radial velocities taken with the CARMENES spectrograph.
Methods: We obtained 55 CARMENES radial velocity measurements that span the 11 months between 9 May 2020 and 5 April 2021. For a better characterization of the parent star's activity, we also collected contemporaneous optical photometric observations at the Joan Oró and Sierra Nevada observatories and retrieved archival photometry from the literature. We performed a combined TESS+CARMENES photometric and spectroscopic analysis by including Gaussian processes and Keplerian orbits to account for the stellar activity and planetary signals simultaneously.
Results: We estimate that TOI-1238 has a rotation period of 40 ± 5 d based on photometric and spectroscopic data. The combined analysis confirms the discovery of two transiting planets, TOI-1238 b and c, with orbital periods of 0.764597−0.000011+0.000013 d and 3.294736−0.000036+0.000034 d, masses of 3.76−1.07+1.15 M and 8.32−1.88+1.90 M, and radii of 1.21−0.10+0.11 R and 2.11−0.14+0.14 R. They orbit their parent star at semimajor axes of 0.0137 ± 0.0004 au and 0.036 ± 0.001 au, respectively.The two planets are placed on opposite sides of the radius valley for M dwarfs and lie between the star and the inner border of TOI-1238's habitable zone. The inner super-Earth TOI-1238 b is one of the densest ultra-short-period planets ever discovered (ρ = 11.7−3.4+4.2 g cm−3). The CARMENES data also reveal the presence of an outer, non-transiting, more massive companion with an orbital period and radial velocity amplitude of ≥600 d and ≥70 m s−1, which implies a likely mass of M ≥ 2 √(1− e2) MJup and a separation ≥1.1 au from its parent star. Title: MUSE crowded field 3D spectroscopy in NGC 300. II. Quantitative spectroscopy of BA-type supergiants Authors: González-Torà, G.; Urbaneja, M. A.; Przybilla, N.; Dreizler, S.; Roth, M. M.; Kamann, S.; Castro, N. Bibcode: 2022A&A...658A.117G Altcode: 2022arXiv220101311G
Aims: A quantitative spectral analysis of BA-type supergiants and bright giants in an inner spiral arm region of the nearby spiral galaxy NGC 300 is presented, based on observations with the Multi Unit Spectroscopic Explorer (MUSE) on the European Southern Obsevatory, Very Large Telescope. The flux-weighted gravity-luminosity relationship (FGLR), a stellar spectroscopic distance determination method for galaxies, is extended towards stars at lower luminosities.
Methods: Point spread function fitting 3D spectroscopy was performed with PampelMUSE on the datacube. The 16 stars with the highest signal-to-noise ratios are classified with regard to their spectral type and luminosity class using Galactic templates. They were analysed using hybrid non-local thermodynamic equilibrium model spectra to fit the strongest observed hydrogen, helium, and metal lines in the intermediate-resolution spectra. Supplemented by photometric data, this facilitates fundamental stellar parameters and interstellar reddening which have yet to be determined.
Results: Effective temperatures, surface gravities, reddening E(B−V), bolometric magnitudes and luminosities, as well as radii and masses are presented for the sample stars. The majority of the objects follow the FGLR as established from more luminous BA-type supergiants in NGC 300. An increase in the scatter in the flux-weighted gravity-luminosity plane is observed at these lower luminosities, which is in line with predictions from population synthesis models. Title: TOI-1201 b: A mini-Neptune transiting a bright and moderately young M dwarf Authors: Kossakowski, D.; Kemmer, J.; Bluhm, P.; Stock, S.; Caballero, J. A.; Béjar, V. J. S.; Guillén, C. Cardona; Lodieu, N.; Collins, K. A.; Oshagh, M.; Schlecker, M.; Espinoza, N.; Pallé, E.; Henning, Th.; Kreidberg, L.; Kürster, M.; Amado, P. J.; Anderson, D. R.; Morales, J. C.; Cartwright, S.; Charbonneau, D.; Chaturvedi, P.; Cifuentes, C.; Conti, D. M.; Cortés-Contreras, M.; Dreizler, S.; Galadí-Enríquez, D.; Guerra, P.; Hart, R.; Hellier, C.; Henze, C.; Herrero, E.; Jeffers, S. V.; Jenkins, J. M.; Jensen, E. L. N.; Kaminski, A.; Kielkopf, J. F.; Kunimoto, M.; Lafarga, M.; Latham, D. W.; Lillo-Box, J.; Luque, R.; Molaverdikhani, K.; Montes, D.; Morello, G.; Morgan, E. H.; Nowak, G.; Pavlov, A.; Perger, M.; Quintana, E. V.; Quirrenbach, A.; Reffert, S.; Reiners, A.; Ricker, G.; Ribas, I.; López, C. Rodríguez; Osorio, M. R. Zapatero; Seager, S.; Schöfer, P.; Schweitzer, A.; Trifonov, T.; Vanaverbeke, S.; Vanderspek, R.; West, R.; Winn, J.; Zechmeister, M. Bibcode: 2021A&A...656A.124K Altcode: 2021arXiv210909346K We present the discovery of a transiting mini-Neptune around TOI-1201, a relatively bright and moderately young early M dwarf (J ≈ 9.5 mag, ~600-800 Myr) in an equal-mass ~8 arcsecond-wide binary system, using data from the Transiting Exoplanet Survey Satellite, along with follow-up transit observations. With an orbital period of 2.49 d, TOI-1201 b is a warm mini-Neptune with a radius of Rb = 2.415 ± 0.090 R. This signal is also present in the precise radial velocity measurements from CARMENES, confirming the existence of the planet and providing a planetary mass of Mb = 6.28 ± 0.88 M and, thus, an estimated bulk density of 2.45−0.42+0.48 g cm−3. The spectroscopic observations additionally show evidence of a signal with a period of 19 d and a long periodic variation of undetermined origin. In combination with ground-based photometric monitoring from WASP-South and ASAS-SN, we attribute the 19 d signal to the stellar rotation period (Prot = 19-23 d), although we cannot rule out that the variation seen in photometry belongs to the visually close binary companion. We calculate precise stellar parameters for both TOI-1201 and its companion. The transiting planet is anexcellent target for atmosphere characterization (the transmission spectroscopy metric is 97−16+21) with the upcoming James Webb Space Telescope. It is also feasible to measure its spin-orbit alignment via the Rossiter-McLaughlin effect using current state-of-the-art spectrographs with submeter per second radial velocity precision.

Additional data (i.e., stellar activity indicators) are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/656/A124 Title: The CARMENES search for exoplanets around M dwarfs. Stellar atmospheric parameters of target stars with SteParSyn Authors: Marfil, E.; Tabernero, H. M.; Montes, D.; Caballero, J. A.; Lázaro, F. J.; González Hernández, J. I.; Nagel, E.; Passegger, V. M.; Schweitzer, A.; Ribas, I.; Reiners, A.; Quirrenbach, A.; Amado, P. J.; Cifuentes, C.; Cortés-Contreras, M.; Dreizler, S.; Duque-Arribas, C.; Galadí-Enríquez, D.; Henning, Th.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; López-Gallifa, Á.; Morales, J. C.; Shan, Y.; Zechmeister, M. Bibcode: 2021A&A...656A.162M Altcode: 2021arXiv211007329M We determined effective temperatures, surface gravities, and metallicities for a sample of 343 M dwarfs observed with CARMENES, the double-channel, high-resolution spectrograph installed at the 3.5 m telescope at Calar Alto Observatory. We employed SteParSyn, a Bayesian spectral synthesis implementation particularly designed to infer the stellar atmospheric parameters of late-type stars following a Markov chain Monte Carlo approach. We made use of the BT-Settl model atmospheres and the radiative transfer code turbospectrum to compute a grid of synthetic spectra around 75 magnetically insensitive Fe I and Ti I lines plus the TiO γ and ϵ bands. To avoid any potential degeneracy in the parameter space, we imposed Bayesian priors on Teff and logg based on the comprehensive, multi-band photometric data available for the sample. We find that this methodology is suitable down to M7.0 V, where refractory metals such as Ti are expected to condense in the stellar photospheres. The derived Teff, logg, and [Fe/H] range from 3000 to 4200 K, 4.5 to 5.3 dex, and −0.7 to 0.2 dex, respectively. Although our Teff scale is in good agreement with the literature, we report large discrepancies in the [Fe/H] scales, which might arise from the different methodologies and sets of lines considered. However, our [Fe/H] is in agreement with the metallicity distribution of FGK-type stars in the solar neighbourhood and correlates well with the kinematic membership of the targets in the Galactic populations. Lastly, excellent agreement in Teff is found for M dwarfs with interferometric angular diameter measurements, as well as in the [Fe/H] between the components in the wide physical FGK+M and M+M systems included in our sample.

Full Tables B.1-B.3 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/656/A162 Title: Diving Beneath the Sea of Stellar Activity: Chromatic Radial Velocities of the Young AU Mic Planetary System Authors: Cale, Bryson L.; Reefe, Michael; Plavchan, Peter; Tanner, Angelle; Gaidos, Eric; Gagné, Jonathan; Gao, Peter; Kane, Stephen R.; Béjar, Víctor J. S.; Lodieu, Nicolas; Anglada-Escudé, Guillem; Ribas, Ignasi; Pallé, Enric; Quirrenbach, Andreas; Amado, Pedro J.; Reiners, Ansgar; Caballero, José A.; Rosa Zapatero Osorio, María; Dreizler, Stefan; Howard, Andrew W.; Fulton, Benjamin J.; Xuesong Wang, Sharon; Collins, Kevin I.; El Mufti, Mohammed; Wittrock, Justin; Gilbert, Emily A.; Barclay, Thomas; Klein, Baptiste; Martioli, Eder; Wittenmyer, Robert; Wright, Duncan; Addison, Brett; Hirano, Teruyuki; Tamura, Motohide; Kotani, Takayuki; Narita, Norio; Vermilion, David; Lee, Rena A.; Geneser, Claire; Teske, Johanna; Quinn, Samuel N.; Latham, David W.; Esquerdo, Gilbert A.; Calkins, Michael L.; Berlind, Perry; Zohrabi, Farzaneh; Stibbards, Caitlin; Kotnana, Srihan; Jenkins, Jon; Twicken, Joseph D.; Henze, Christopher; Kidwell, Richard; Burke, Christopher; Villaseñor, Joel; Boyd, Patricia Bibcode: 2021AJ....162..295C Altcode: 2021arXiv210913996C We present updated radial-velocity (RV) analyses of the AU Mic system. AU Mic is a young (22 Myr) early-M dwarf known to host two transiting planets-P b ~ 8.46 days, ${R}_{b}={4.38}_{-0.18}^{+0.18}\ {R}_{\oplus }$ , P c ~ 18.86 days, ${R}_{c}={3.51}_{-0.16}^{+0.16}\ {R}_{\oplus }$ . With visible RVs from Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical echelle Spectrographs (CARMENES)-VIS, CHIRON, HARPS, HIRES, MINERVA-Australis, and Tillinghast Reflector Echelle Spectrograph, as well as near-infrared (NIR) RVs from CARMENES-NIR, CSHELL, IRD, iSHELL, NIRSPEC, and SPIRou, we provide a 5σ upper limit to the mass of AU Mic c of M c ≤ 20.13 M and present a refined mass of AU Mic b of ${M}_{b}={20.12}_{-1.57}^{+1.72}\ {M}_{\oplus }$ . Used in our analyses is a new RV modeling toolkit to exploit the wavelength dependence of stellar activity present in our RVs via wavelength-dependent Gaussian processes. By obtaining near-simultaneous visible and near-infrared RVs, we also compute the temporal evolution of RV "color" and introduce a regressional method to aid in isolating Keplerian from stellar activity signals when modeling RVs in future works. Using a multiwavelength Gaussian process model, we demonstrate the ability to recover injected planets at 5σ significance with semi-amplitudes down to ≍10 m s-1 with a known ephemeris, more than an order of magnitude below the stellar activity amplitude. However, we find that the accuracy of the recovered semi-amplitudes is ~50% for such signals with our model. Title: Central kinematics of the Galactic globular cluster M80 Authors: Göttgens, Fabian; Kamann, Sebastian; Baumgardt, Holger; Dreizler, Stefan; Giesers, Benjamin; Husser, Tim-Oliver; den Brok, Mark; Fétick, Romain; Krajnovic, Davor; Weilbacher, Peter M. Bibcode: 2021MNRAS.507.4788G Altcode: 2021arXiv210811393G; 2021MNRAS.tmp.2212G We use spectra observed with the integral-field spectrograph Multi Unit Spectroscopic Explorer (MUSE) to reveal the central kinematics of the Galactic globular cluster Messier 80 (M80, NGC 6093). Using observations obtained with the recently commissioned narrow-field mode of MUSE, we are able to analyse 932 stars in the central 7.5 arcsec by 7.5 arcsec of the cluster for which no useful spectra previously existed. Mean radial velocities of individual stars derived from the spectra are compared to predictions from axisymmetric Jeans models, resulting in radial profiles of the velocity dispersion, the rotation amplitude, and the mass-to-light ratio. The new data allow us to search for an intermediate-mass black hole (IMBH) in the centre of the cluster. Our Jeans model finds two similarly probable solutions around different dynamical cluster centres. The first solution has a centre close to the photometric estimates available in the literature and does not need an IMBH to fit the observed kinematics. The second solution contains a location of the cluster centre that is offset by about 2.4 arcsec from the first one and it needs an IMBH mass of $4600^{+1700}_{-1400}~\text{M}_\odot {}$. N-body models support the existence of an IMBH in this cluster with a mass of up to 6000 M in this cluster, although models without an IMBH provide a better fit to the observed surface brightness profile. They further indicate that the cluster has lost nearly all stellar-mass black holes. We further discuss the detection of two potential high-velocity stars with radial velocities of 80-90 $\text{km}\, \text{s}^{-1}$ relative to the cluster mean. Title: VizieR Online Data Catalog: CARMENES stellar atmospheric parameters (Marfil+, 2021) Authors: Marfil, E.; Tabernero, H. M.; Montes, D.; Caballero, J. A.; Lazaro, F. J.; Gonzalez Hernandez, J. I.; Nagel, E.; Passegger, V. M.; Schweitzer, A.; Ribas, I.; Reiners, A.; Quirrenbach, A.; Amado, P. J.; Cifuentes, C.; Cortes-Contreras, M.; Dreizler, S.; Duque-Arribas, C.; Galadi-Enriquez, D.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kurster, M.; Lafarga, M.; Lopez-Gallifa, A.; Morales, J. C.; Shan, Y.; Zechmeister, M. Bibcode: 2021yCat..36560162M Altcode: We present basic information of investigated M dwarfs, atomic data of the selected TiI and FeI lines, wavelength ranges synthesised, and the stellar atmospheric parameters (effective temperatures, surface gravities, and metallicities) derived for the sample with SteParSyn.

(3 data files). Title: Mapping magnetic activity indicators across the M dwarf domain Authors: Lafarga, Marina; Ribas, Ignasi; Reiners, Ansgar; Quirrenbach, Andreas; Amado, Pedro J.; Caballero, Jose A.; Azzaro, Marco; Béjar, Víctor J. S.; Cortés-Contreras, Miriam; Dreizler, Stefan; Hatzes, Artie P.; Henning, Thomas; Jeffers, Sandra V.; Kaminski, A.; Kürster, Martin; Montes, David; Morales, Juan Carlos; Oshagh, Mahmoud; Rodríguez-López, Cristina; Schöfer, Patrick; Schweitzer, Andreas; Zechmeister, Mathias Bibcode: 2021spc..confE...7L Altcode: Stellar activity poses one of the main obstacles for the detection and characterisation of exoplanets around cool stars, as it can induce radial velocity (RV) signals that can hide or mimic the presence of companions. Several activity indicators are routinely used to identify activity-related signals in RV measurements, but not all indicators trace exactly the same effects, nor are any of them always effective in all stars. In this work, we evaluate the performance of a set of common spectroscopic activity indicators for 98 M dwarfs observed with CARMENES. We find that different indicators behave differently depending on the mass and activity level of the target star. In addition, we also observe that stars at the low-mass end of the sample show the lowest RV scatter, which could potentially hint at different manifestations of activity compared to higher-mass stars, as well as being better candidates for planet searches. Overall, our results show that when assessing the origin of an RV signal, it is critical to take into account a large set of indicators, or at least the most effective ones considering the characteristics of the star, as failing to do so may lead to false planet claims. Title: The CARMENES search for exoplanets around M dwarfs. Not-so-fine hyperfine-split vanadium lines in cool star spectra Authors: Shan, Y.; Reiners, A.; Fabbian, D.; Marfil, E.; Montes, D.; Tabernero, H. M.; Ribas, I.; Caballero, J. A.; Quirrenbach, A.; Amado, P. J.; Aceituno, J.; Béjar, V. J. S.; Cortés-Contreras, M.; Dreizler, S.; Hatzes, A. P.; Henning, Th.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; Morales, J. C.; Nagel, E.; Pallé, E.; Passegger, V. M.; Rodriguez-López, C.; Schweitzer, A.; Zechmeister, M. Bibcode: 2021A&A...654A.118S Altcode: 2021arXiv210812442S Context. M-dwarf spectra are complex and notoriously difficult to model, posing challenges to understanding their photospheric properties and compositions in depth. Vanadium (V) is an iron-group element whose abundance supposedly closely tracks that of iron, but has origins that are not completely understood.
Aims: Our aim is to characterize a series of neutral vanadium atomic absorption lines in the 800-910 nm wavelength region of high signal-to-noise, high-resolution, telluric-corrected M-dwarf spectra from the CARMENES survey. Many of these lines are prominent and exhibit a distinctive broad and flat-bottom shape, which is a result of hyperfine structure (HFS). We investigate the potential and implications of these HFS split lines for abundance analysis of cool stars.
Methods: With standard spectral synthesis routines, as provided by the spectroscopy software iSpec and the latest atomic data (including HFS) available from the VALD3 database, we modeled these striking line profiles. We used them to measure V abundances of cool dwarfs.
Results: We determined V abundances for 135 early M dwarfs (M0.0 V to M3.5 V) in the CARMENES guaranteed time observations sample. They exhibit a [V/Fe]-[Fe/H] trend consistent with that derived from nearby FG dwarfs. The tight (±0.1 dex) correlation between [V/H] and [Fe/H] suggests the potential application of V as an alternative metallicity indicator in M dwarfs. We also show hints that neglecting to model HFS could partially explain the temperature correlation in V abundance measurements observed in previous studies of samples involving dwarf stars with Teff ≲ 5300 K.
Conclusions: Our work suggests that HFS can impact certain absorption lines in cool photospheres more severely than in Sun-like ones. Therefore, we advocate that HFS should be carefully treated in abundance studies in stars cooler than ~5000 K. On the other hand, strong HFS split lines in high-resolution spectra present an opportunity for precision chemical analyses of large samples of cool stars. The V-to-Fe trends exhibited by the local M dwarfs continue to challenge theoretical models of V production in the Galaxy.

Full Table A.1 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/654/A118 Title: VizieR Online Data Catalog: Metallicities on multiple MSs of Omega Centauri (Latour+, 2021) Authors: Latour, M.; Calamida, A.; Husser, T. -O.; Kamann, S.; Dreizler, S.; Brinchmann, J. Bibcode: 2021yCat..36539008L Altcode: We analyzed the MUSE spectra of selected stars on the MS of Omega Centauri. We include the stars selected by us on the red- and blue-MS as well as additional stars included in the 15 MSs identified by Bellini et al., (2017, Cat. J/ApJ/844/164). We include only the stars that have a spectrum with S/N>15. The effective temperatures and metallicities are derived from a full spectral fit against grids of model atmospheres computed with the PHEONIX code (Husser et al., 2011A&A...533A...6B). We note that the model atmospheres used for the fits are alpha-enhanced ([alpha/Fe]=0.3). Uncertainties on Teff and M/H are calibrated as explained in the paper. Surface gravities are derived from isochrones. Uncertainties on the log g are the standard deviations of the log g values obtained from different isochrones (see text in the paper for more details).

IDs and coordinates are from Bellini (2017, Cat. J/ApJ/844/164) and the populations tags can be retrieved from Bellini et al. (2017, Cat. J/ApJ/844/164).

(1 data file). Title: VizieR Online Data Catalog: TOI-1201 RV and activity index (Kossakowski+, 2021) Authors: Kossakowski, D.; Kemmer, J.; Bluhm, P.; Stock, S.; Caballero, J. A.; Bejar, V. J. S.; Cardona Guillen, C.; Lodieu, N.; Collins, K. A.; Oshagh, M.; Schlecker, M.; Espinoza, N.; Palle, E.; Henning, Th.; Kreidberg, L.; Kuerster, M.; Amado, P. J.; Anderson, D. R.; Morales, J. C.; Cartwright, S.; Charbonneau, D.; Chaturvedi, P.; Cifuentes, C.; Conti, D. M.; Cortes-Contreras, M.; Dreizler, S.; Galadi-Enriquez, D.; Guerra, P.; Hart, R.; Hellier, C.; Henze, C.; Herrero, E.; Jeffers, S. V.; Jenkins, J. M.; Jensen, E. L. N.; Kaminski, A.; Kielkopf, J. F.; Kunimoto, M.; Lafarga, M.; Latham, D. W.; Lillo-Box, J.; Luque, R.; Molvaerdikhani, K.; Montes, D.; Morello, G.; Morgan, E. H.; Nowak, G.; Pavlov, A.; Perger, M.; Quintana, E. V.; Quirrenbach, A.; Reffert, S.; Reiners, A.; Ricker, G.; Ribas, I.; Rodriguez Lopez, C.; Zapatero Osorio, M. R.; Seager, S.; Schoefer, P.; Schweitzer, A.; Trifonov, T.; Vanaverbeke, S.; Vanderspek, R.; West, R.; Winn, J.; Zechmeister, M. Bibcode: 2021yCat..36560124K Altcode: High-resolution spectroscopy taken with the CARMENES VIS instrument for the two M dwarfs in a binary system, TOI-1201 and its companion (PM J02489-1432E). Likewise, the stellar activity indicators are output from the SERVAL pipeline (Zechmeister et al. 2018A&A...609A..12Z), namely, this entails the chromatic index (CRX), the differential line width (dLW), the Halpha index, the Calcium triplet lines (CAIRT). The photospheric TiO absorption band indices (at 7050Å, 8430Å, and 8860Å) following Schoefer et al. (2019A&A...623A..44S, Cat. J/A+A/623/A44) are included. Also, the cross-correlation function parameters, as provided following Lafarga et al. (2020A&A...636A..36L, Cat. J/A+A/636/A36), are included and these are: bisector velocity span (BVS), contrast (CTR), and full width at half maximum (FWHM).

Most observations are simultaneously, however there are 33 data points for TOI-1201 (Nov. 2019 - Feb. 2020) and 23 for PM J02489-1432E (Nov. 2019 - Jan. 2020).

(2 data files). Title: The CARMENES search for exoplanets around M dwarfs. Spectroscopic orbits of nine M-dwarf multiple systems, including two triples, two brown dwarf candidates, and one close M-dwarf-white dwarf binary Authors: Baroch, D.; Morales, J. C.; Ribas, I.; Béjar, V. J. S.; Reffert, S.; Cardona Guillén, C.; Reiners, A.; Caballero, J. A.; Quirrenbach, A.; Amado, P. J.; Anglada-Escudé, G.; Colomé, J.; Cortés-Contreras, M.; Dreizler, S.; Galadí-Enríquez, D.; Hatzes, A. P.; Jeffers, S. V.; Henning, Th.; Herrero, E.; Kaminski, A.; Kürster, M.; Lafarga, M.; Lodieu, N.; López-González, M. J.; Montes, D.; Pallé, E.; Perger, M.; Pollacco, D.; Rodríguez-López, C.; Rodríguez, E.; Rosich, A.; Schöfer, P.; Schweitzer, A.; Shan, Y.; Tal-Or, L.; Zechmeister, M. Bibcode: 2021A&A...653A..49B Altcode: 2021arXiv210514770B Context. M dwarfs are ideal targets for the search of Earth-size planets in the habitable zone using the radial velocity method, and are attracting the attention of many ongoing surveys. One of the expected results of these surveys is that new multiple-star systems have also been found. This is the case also for the CARMENES survey, thanks to which nine new double-line spectroscopic binary systems have already been announced.
Aims: Throughout the five years of the survey the accumulation of new observations has resulted in the detection of several new multiple-stellar systems with long periods and low radial-velocity amplitudes. Here we newly characterise the spectroscopic orbits and constrain the masses of eight systems and update the properties of a system that we had reported earlier.
Methods: We derived the radial velocities of the stars using two-dimensional cross-correlation techniques and template matching. The measurements were modelled to determine the orbital parameters of the systems. We combined CARMENES spectroscopic observations with archival high-resolution spectra from other instruments to increase the time span of the observations and improve our analysis. When available, we also added archival photometric, astrometric, and adaptive optics imaging data to constrain the rotation periods and absolute masses of the components.
Results: We determined the spectroscopic orbits of nine multiple systems, eight of which are presented for the first time. The sample is composed of five single-line binaries, two double-line binaries, and two triple-line spectroscopic triple systems. The companions of two of the single-line binaries, GJ 3626 and GJ 912, have minimum masses below the stellar boundary, and thus could be brown dwarfs. We found a new white dwarf in a close binary orbit around the M star GJ 207.1, located at a distance of 15.79 pc. From a global fit to radial velocities and astrometric measurements, we were able to determine the absolute masses of the components of GJ 282 C, which is one of the youngest systems with measured dynamical masses. Title: A stellar census in globular clusters with MUSE. A new perspective on the multiple main sequences of ω Centauri Authors: Latour, M.; Calamida, A.; Husser, T. -O.; Kamann, S.; Dreizler, S.; Brinchmann, J. Bibcode: 2021A&A...653L...8L Altcode: 2021arXiv210901540L Context. ω Cen is a rare example of a globular cluster where the iron abundance of the stars spans more than one order of magnitude. Many spectroscopic investigations of its red-giant and sub-giant branches have revealed multiple peaks in the iron abundance distribution. The metallicity distribution of main sequence (MS) stars is not well characterized yet due to the faintness of the stars and lack of data. So far, almost all studies of MS stars have been based on photometric measurements.
Aims: Our goal is to investigate the metallicity distribution of a statistically significant sample of MS stars in ω Cen. In particular, we aim to revisit the metallicity difference between the red and blue MS of the cluster.
Methods: We used MUSE spectra obtained for the central region of ω Cen to derive metallicities for ≈4200 MS stars.
Results: We find that blue MS stars are, on average, ≈0.1 dex more metal-rich than their red counterparts. On the basis of this new estimate, we find that the two sequences can be fit on the Hubble Space Telescope color-magnitude diagram with two isochrones having the same global metallicity and age, but a higher helium abundance for the blue MS, that is ΔY ≲ 0.1. Furthermore, we determined the average metallicity of the five main populations along ω Cen MS and these estimates are consistent with expectations from previous photometric studies.

Table B.1 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/653/L8

Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile (Program IDs 094.D-0142(B), 095.D-0629(A), 096.D-0175(A), 097.D-0295(A), 098.D-0148(A), 099.D-0019(A), 0100.D-0161(A), 0101.D-0268(A), 0102.D-0270(A), 0103.D-0204(A), and 0104.D-0257(B)). Title: The CARMENES search for exoplanets around M dwarfs. Planet occurrence rates from a subsample of 71 stars Authors: Sabotta, S.; Schlecker, M.; Chaturvedi, P.; Guenther, E. W.; Muñoz Rodríguez, I.; Muñoz Sánchez, J. C.; Caballero, J. A.; Shan, Y.; Reffert, S.; Ribas, I.; Reiners, A.; Hatzes, A. P.; Amado, P. J.; Klahr, H.; Morales, J. C.; Quirrenbach, A.; Henning, Th.; Dreizler, S.; Pallé, E.; Perger, M.; Azzaro, M.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; Montes, D.; Passegger, V. M.; Zechmeister, M. Bibcode: 2021A&A...653A.114S Altcode: 2021arXiv210703802S Context. The CARMENES exoplanet survey of M dwarfs has obtained more than 18 000 spectra of 329 nearby M dwarfs over the past five years as part of its guaranteed time observations (GTO) program.
Aims: We determine planet occurrence rates with the 71 stars from the GTO program for which we have more than 50 observations.
Methods: We use injection-and-retrieval experiments on the radial-velocity time series to measure detection probabilities. We include 27 planets in 21 planetary systems in our analysis.
Results: We find 0.06−0.03+0.04 giant planets (100 M < Mpl sin i < 1000 M) per star in periods of up to 1000 d, but due to a selection bias this number could be up to a factor of five lower in the whole 329-star sample. The upper limit for hot Jupiters (orbital period of less than 10 d) is 0.03 planets per star, while the occurrence rate of planets with intermediate masses (10 M < Mpl sin i < 100 M) is 0.18−0.05+0.07 planets per star. Less massive planets with 1 M < Mpl sin i < 10 M are very abundant, with an estimated rate of 1.32−0.31+0.33 planets per star for periods of up to 100 d. When considering only late M dwarfs with masses M < 0.34 M, planets more massive than 10 M become rare. Instead, low-mass planets with periods shorter than 10 d are significantly overabundant.
Conclusions: For orbital periods shorter than 100 d, our results confirm the known stellar mass dependences from the Kepler survey: M dwarfs host fewer giant planets and at least two times more planets with Mpl sin i < 10 M than G-type stars. In contrast to previous results, planets around our sample of very low-mass stars have a higher occurrence rate in short-period orbits of less than 10 d. Our results demonstrate the need to take into account host star masses in planet formation models. Title: VizieR Online Data Catalog: Vanadium measurements for 135 M dwarfs (Shan+, 2021) Authors: Shan, Y.; Reiners, A.; Fabbian, D.; Marfil, E.; Montes, D.; Tabernero, H. M.; Ribas, I.; Caballero, J. A.; Quirrenbach, A.; Amado, P. J.; Aceituno, J.; Bejar, V. J. S.; Cortes-Contreras, M.; Dreizler, S.; Hatzes, A. P.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kuerster, M.; Lafarga, M.; Morales, J. C.; Nagel, E.; Palle, E.; Passegger, V. M.; Rodriguez-Lopez, C.; Schweitzer, A.; Zechmeister, M. Bibcode: 2021yCat..36540118S Altcode: Table A1 presents the measured V abundances ([V/H]) for 135 nearby early-M dwarfs from the CARMENES GTO sample. Two sets of measurements are given, which are based on two independently measured sets of fundamental stellar parameters for this sample (Schweitzer et al., 2019A&A...625A..68S, Cat. J/A+A/625/A68 and Marfil et al., submitted). Rotational velocities from Reiners et al. (2018A&A...612A..49R, Cat. J/A+A/612/A49) and disk kinematic membership designations (Cortes-Contreras+ in prep) are also included.

(1 data file). Title: The CARMENES search for exoplanets around M dwarfs. Mapping stellar activity indicators across the M dwarf domain Authors: Lafarga, M.; Ribas, I.; Reiners, A.; Quirrenbach, A.; Amado, P. J.; Caballero, J. A.; Azzaro, M.; Béjar, V. J. S.; Cortés-Contreras, M.; Dreizler, S.; Hatzes, A. P.; Henning, Th.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Montes, D.; Morales, J. C.; Oshagh, M.; Rodríguez-López, C.; Schöfer, P.; Schweitzer, A.; Zechmeister, M. Bibcode: 2021A&A...652A..28L Altcode: 2021arXiv210513467L Context. Stellar activity poses one of the main obstacles for the detection and characterisation of small exoplanets around cool stars, as it can induce radial velocity (RV) signals that can hide or mimic the presence of planetary companions. Several indicators of stellar activity are routinely used to identify activity-related signals in RVs, but not all indicators trace exactly the same activity effects, nor are any of them always effective in all stars.
Aims: We evaluate the performance of a set of spectroscopic activity indicators for M dwarf stars with different masses and activity levels with the aim of finding a relation between the indicators and stellar properties.
Methods: In a sample of 98 M dwarfs observed with CARMENES, we analyse the temporal behaviour of RVs and nine spectroscopic activity indicators: cross-correlation function (CCF) full-width-at-half-maximum (FWHM), CCF contrast, CCF bisector inverse slope (BIS), RV chromatic index (CRX), differential line width (dLW), and indices of the chromospheric lines Hα and calcium infrared triplet.
Results: A total of 56 stars of the initial sample show periodic signals related to activity in at least one of these ten parameters. RV is the parameter for which most of the targets show an activity-related signal. CRX and BIS are effective activity tracers for the most active stars in the sample, especially stars with a relatively high mass, while for less active stars, chromospheric lines perform best. FWHM and dLW show a similar behaviour in all mass and activity regimes, with the highest number of activity detections in the low-mass, high-activity regime. Most of the targets for which we cannot identify any activity-related signals are stars at the low-mass end of the sample (i.e. with the latest spectral types). These low-mass stars also show the lowest RV scatter, which indicates that ultracool M dwarfs could be better candidates for planet searches than earlier types, which show larger RV jitter.
Conclusions: Our results show that the spectroscopic activity indicators analysed behave differently, depending on the mass and activity level of the target star. This underlines the importance of considering different indicators of stellar activity when studying the variability of RV measurements. Therefore, when assessing the origin of an RV signal, it is critical to take into account a large set of indicators, or at least the most effective ones considering the characteristics of the star, as failing to do so may lead to false planet claims.

Full Table A.1 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/652/A28 Title: Transit Timing Variations for AU Microscopii b & c Authors: Wittrock, Justin M.; Dreizler, Stefan; Reefe, Michael; Plavchan, Peter; Gilbert, Emily A.; Barclay, Thomas; Morris, Brett M.; Demory, Brice-Olivier; Dragomir, Diana; Crossfield, Ian J. M.; Ingalls, James; Lowrance, Patrick; Gao, Peter; Kaye, Laurel; Wang, Songhu; Newton, Elisabeth R.; Gaidos, Eric; Cale, Bryson L.; El Mufti, Mohammed; Collins, Kevin I.; Kane, Stephen R.; Tanner, Angelle; Gagné, Jonathan; Quintana, Elisa V.; Vega, Laura D.; Schlieder, Joshua E.; Monsue, Teresa; Hebb, Leslie; Stassun, Keivan G.; Roccatagliata, Veronica; Schwarz, Richard P.; Tan, T. G.; Radford, Don J.; Stockdale, Christopher Bibcode: 2021tsc2.confE...7W Altcode: AU Mic is a relatively bright, nearby (9.7 pc), young (22 Myr) M1V pre-main sequence star hosting two transiting exoplanets AU Mic b and c and a spatially-resolved outer dusty debris disk. This research explores the transit timing variations (TTVs) of AU Mic b and c. For AU Mic b, we present three Spitzer/IRAC (4.5 μm) transits (two new), five TESS Cycle 1 and 3 transits, 11 LCO transits, one PEST-0.30m transit, one Brierfield-0.36m transit, and two transit timing measurements from Rossiter-McLaughlin observations; for AU Mic c, we present three TESS Cycle 1 and 3 transits. We use EXOFASTv2 to jointly model the transits and to obtain the midpoint transit times. We then construct an O-C diagram to map the TTVs. We model the TTVs for AU Mic b and c with Exo-Striker to recover constraints on the mass for AU Mic c. We compare the TTV-derived constraints to a recent radial-velocity mass determination. The results demonstrate that the AU Mic planetary system is dynamically interacting producing detectable TTVs, and the implied orbital dynamics may inform future constraints on the formation mechanisms for this young planetary system. However, stellar activity from flares and rotational spot modulation complicate our analysis of this young system. We recommend future TTV observations of AU Mic b and c to further constrain the dynamical masses and to search for additional planets in the system. Title: Small and rocky worlds orbiting M dwarfs: GJ 3473 b and GJ 3929 b Authors: Kemmer, Jonas; Stock, Stephan; Kossakowski, Diana; Dreizler, Stefan; Kaminski, Adrian; Molaverdikhani, Karan; Schlecker, Martin; Caballero, Jose A. Bibcode: 2021tsc2.confE..67K Altcode: We present two small transiting planets with mass measurements orbiting bright mid M dwarfs (GJ 3473, GJ 3929). GJ 3473 b (Kemmer et al. 2020) is a hot, presumably rocky, planet (P = 1.198 d, Mb = 1.86 ± 0.30 Me, and radius, Rb = 1.264 ± 0.050 Re), which is due to its high temperature a particularly attractive target for thermal emission spectroscopy. Further, it is accompanied by another non-transiting planet (Pc = 15.509 ± 0.033 d) that has a minimum mass of Mc sin i = 7.41 ± 0.91 Me. For GJ 3929 b (in prep.) we present a preliminary analysis that yields a period of P = 2.616 d, mass Mb = 2.03 ± 0.59 Me, and radius, Rb = 1.155 ± 0.043 Re. The radial velocity data show evidence for another signal, whose origin is, however, not yet clarified. Both systems add to the TESS level-one science goal to measure the masses for 50 transiting planets with radii smaller than 4 Re. Title: Simultaneous photometric and CARMENES spectroscopic monitoring of fast-rotating M dwarf GJ 3270. Discovery of a post-flare corotating feature Authors: Johnson, E. N.; Czesla, S.; Fuhrmeister, B.; Schöfer, P.; Shan, Y.; Cardona Guillén, C.; Reiners, A.; Jeffers, S. V.; Lalitha, S.; Luque, R.; Rodríguez, E.; Béjar, V. J. S.; Caballero, J. A.; Tal-Or, L.; Zechmeister, M.; Ribas, I.; Amado, P. J.; Quirrenbach, A.; Cortés-Contreras, M.; Dreizler, S.; Fukui, A.; López-González, M. J.; Hatzes, A. P.; Henning, Th.; Kaminski, A.; Kürster, M.; Lafarga, M.; Montes, D.; Morales, J. C.; Murgas, F.; Narita, N.; Pallé, E.; Parviainen, H.; Pedraz, S.; Pollacco, D.; Sota, A. Bibcode: 2021A&A...651A.105J Altcode: 2021arXiv210407080J Context. Active M dwarfs frequently exhibit large flares, which can pose an existential threat to the habitability of any planet in orbit in addition to making said planets more difficult to detect. M dwarfs do not lose angular momentum as easily as earlier-type stars, which maintain the high levels of stellar activity for far longer. Studying young, fast-rotating M dwarfs is key to understanding their near stellar environment and the evolution of activity.
Aims: We study stellar activity on the fast-rotating M dwarf GJ 3270.
Methods: We analyzed dedicated high cadence, simultaneous, photometric and high-resolution spectroscopic observations obtained with CARMENES of GJ 3270 over 7.7 h, covering a total of eight flares of which two are strong enough to facilitate a detailed analysis. We consult the TESS data, obtained in the month prior to our own observations, to study rotational modulation and to compare the TESS flares to those observed in our campaign.
Results: The TESS data exhibit rotational modulation with a period of 0.37 d. The strongest flare covered by our observing campaign released a total energy of about 3.6 × 1032 erg, putting it close to the superflare regime. This flare is visible in the B,V, r, i, and z photometric bands, which allows us to determine a peak temperature of about 10 000 K. The flare also leaves clear marks in the spectral time series. In particular, we observe an evolving, mainly blue asymmetry in chromospheric lines, which we attribute to a post-flare, corotating feature. To our knowledge this is the first time such a feature has been seen on a star other than our Sun.
Conclusions: Our photometric and spectroscopic time series covers the eruption of a strong flare followed up by a corotating feature analogous to a post-flare arcadal loop on the Sun with a possible failed ejection of material. Title: VizieR Online Data Catalog: Activity indicators across the M dwarf domain (Lafarga+, 2021) Authors: Lafarga, M.; Ribas, I.; Reiners, A.; Quirrenbach, A.; Amado, P. J.; Caballero, J. A.; Azzaro, M.; Bejar, V. J. S.; Cortes-Contreras, M.; Dreizler, S.; Hatzes, A. P.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kuerster, M.; Montes, D.; Morales, J. C.; Oshagh, M.; Rodriguez-Lopez, C.; Schoefer, P.; Schweitzer, A.; Zechmeister, M. Bibcode: 2021yCat..36520028L Altcode: Properties of the 98 sample stars. Values taken from the latest version of the Carmencita database available at the time. We also show the number of CARMENES VIS observations (before performing any sigma-clipping or discarding any observations due to low S/N), the number of different nights covered by the observations, their time span, and their RV scatter, measured as the standard deviation (std) of the corrected serval RVs (instrumental drift and nightly average corrected, averaged same-night observations, and linear trend removed).

(1 data file). Title: An ultra-short-period transiting super-Earth orbiting the M3 dwarf TOI-1685 Authors: Bluhm, P.; Pallé, E.; Molaverdikhani, K.; Kemmer, J.; Hatzes, A. P.; Kossakowski, D.; Stock, S.; Caballero, J. A.; Lillo-Box, J.; Béjar, V. J. S.; Soto, M. G.; Amado, P. J.; Brown, P.; Cadieux, C.; Cloutier, R.; Collins, K. A.; Collins, K. I.; Cortés-Contreras, M.; Doyon, R.; Dreizler, S.; Espinoza, N.; Fukui, A.; González-Álvarez, E.; Henning, Th.; Horne, K.; Jeffers, S. V.; Jenkins, J. M.; Jensen, E. L. N.; Kaminski, A.; Kielkopf, J. F.; Kusakabe, N.; Kürster, M.; Lafrenière, D.; Luque, R.; Murgas, F.; Montes, D.; Morales, J. C.; Narita, N.; Passegger, V. M.; Quirrenbach, A.; Schöfer, P.; Reffert, S.; Reiners, A.; Ribas, I.; Ricker, G. R.; Seager, S.; Schweitzer, A.; Schwarz, R. P.; Tamura, M.; Trifonov, T.; Vanderspek, R.; Winn, J.; Zechmeister, M.; Zapatero Osorio, M. R. Bibcode: 2021A&A...650A..78B Altcode: 2021arXiv210301016B Dynamical histories of planetary systems, as well as the atmospheric evolution of highly irradiated planets, can be studied by characterizing the ultra-short-period planet population, which the TESS mission is particularly well suited to discover. Here, we report on the follow-up of a transit signal detected in the TESS sector 19 photometric time series of the M3.0 V star TOI-1685 (2MASS J04342248+4302148). We confirm the planetary nature of the transit signal, which has a period of Pb = 0.6691403−0.0000021+0.0000023 d, using precise radial velocity measurements taken with the CARMENES spectrograph. From the joint photometry and radial velocity analysis, we estimate the following parameters for TOI-1685 b: a mass of Mb = 3.78−0.63+0.63 M, a radius of Rb = 1.70−0.07+0.07 R, which together result in a bulk density of ρb = 4.21−0.82+0.95 g cm−3, and an equilibrium temperature of Teq = 1069−16+16 K. TOI-1685 b is the least dense ultra-short-period planet around an M dwarf known to date. TOI-1685 b is also one of the hottest transiting super-Earth planets with accurate dynamical mass measurements, which makes it a particularly attractive target for thermal emission spectroscopy. Additionally, we report with moderate evidence an additional non-transiting planet candidate in the system, TOI-1685 [c], which has an orbital period of Pc = 9.02−0.12+0.10 d. Title: Deciphering the Formation History of Omega Cen with a Comprehensive Stellar Kinematic and Population Dataset Authors: Seth, Anil C.; Alfaro Cuello, Mayte; Bellini, Andrea; Dotter, Aaron L.; Dreizler, S.; Haeberle, Maximilian; Hannah, Christian; Husser, Tim-Oliver; Kacharov, Nikolay; Kamann, Sebastian; Milone, Antonino Paolo; Neumayer, Nadine; Nitschai, Maria Selina; Pechetti, Renuka; Voggel, Karina; Weisz, Daniel R.; van de Ven, Glenn Bibcode: 2021hst..prop16777S Altcode: Omega Centauri appears to be the stripped nucleus of one of the largest satellite galaxies that has fallen into the Milky Way. Yet the formation history of Omega Centauri is poorly understood due to the complexity of its stellar populations. We propose to obtain WFC3/UVIS imaging to measure proper motions and use UV photometry to constrain stellar abundances and ages for hundreds of thousands of stars within Omega Centauri's effective radius. In combination with a MUSE spectral mosaic that will provide star-by-star metallicity and radial velocity measurements, we will create and publicly release an unprecedented catalog of 3-D stellar velocities, age estimates, and abundance information. This combination of kinematic and stellar population information will enable us to study the details of both how and when Omega Centauri formed. These results will provide insight on the galaxy in which Omega Centauri formed and its interaction with the Milky Way, and will serve as a template for understanding the formation and tidal stripping of nuclear star clusters. Title: The CARMENES search for exoplanets around M dwarfs. Two terrestrial planets orbiting G 264-012 and one terrestrial planet orbiting Gl 393 Authors: Amado, P. J.; Bauer, F. F.; Rodríguez López, C.; Rodríguez, E.; Cardona Guillén, C.; Perger, M.; Caballero, J. A.; López-González, M. J.; Muñoz Rodríguez, I.; Pozuelos, F. J.; Sánchez-Rivero, A.; Schlecker, M.; Quirrenbach, A.; Ribas, I.; Reiners, A.; Almenara, J.; Astudillo-Defru, N.; Azzaro, M.; Béjar, V. J. S.; Bohemann, R.; Bonfils, X.; Bouchy, F.; Cifuentes, C.; Cortés-Contreras, M.; Delfosse, X.; Dreizler, S.; Forveille, T.; Hatzes, A. P.; Henning, Th.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; Lodieu, N.; Lovis, C.; Mayor, M.; Montes, D.; Morales, J. C.; Morales, N.; Murgas, F.; Ortiz, J. L.; Pallé, E.; Pepe, F.; Perdelwitz, V.; Pollaco, D.; Santos, N. C.; Schöfer, P.; Schweitzer, A.; Ségransan, N. C.; Shan, Y.; Stock, S.; Tal-Or, L.; Udry, S.; Zapatero Osorio, M. R.; Zechmeister, M. Bibcode: 2021A&A...650A.188A Altcode: 2021arXiv210513785A We report the discovery of two planetary systems, namely G 264-012, an M 4.0 dwarf with two terrestrial planets (Mb sin i=2.50−0.30+0.29 M and Mc sin i=3.75−0.47+0.48 M), and Gl 393, a bright M 2.0 dwarf with one terrestrial planet (Mb sini = 1.71 ± 0.24M). Although both stars were proposed to belong to young stellar kinematic groups, we estimate their ages to be older than about 700 Ma. The two planets around G 264-012 were discovered using only radial-velocity (RV) data from the CARMENES exoplanet survey, with estimated orbital periods of 2.30 d and 8.05 d, respectively.Photometric monitoring and analysis of activity indicators reveal a third signal present in the RV measurements, at about 100 d,caused by stellar rotation. The planet Gl 393 b was discovered in the RV data from the HARPS, CARMENES, and HIRES instruments. Its identification was only possible after modelling, with a Gaussian process (GP), the variability produced by the magnetic activity of the star. For the earliest observations, this variability produced a forest of peaks in the periodogram of the RVs at around the 34 d rotation period determined from Kepler data, which disappeared in the latestepochs. After correcting for them with this GP model, a significant signal showed at a period of 7.03 d. No significant signals in any of our spectral activity indicators or contemporaneous photometry were found at any of the planetary periods. Given the orbital and stellar properties, the equilibrium temperatures of the three planets are all higher than that for Earth. Current planet formation theories suggest that these two systems represent a common type of architecture. This is consistent with formation following the core accretion paradigm.

Full Tables B.1 and B.2 are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/650/A188 Title: VizieR Online Data Catalog: G 264-012 and Gl 393 radial velocity curves (Amado+, 2021) Authors: Amado, P. J.; Bauer, F. F.; Rodriguez Lopez, C.; Rodriguez, E.; Cardona Guillen, C.; Perger, M.; Caballero, J. A.; Lopez-Gonzalez, M. J.; Munoz-Rodriguez, I.; Pozuelos, F. J.; Sanchez-Rivero, A.; Schlecker, M.; Quirrenbach, A.; Ribas, I.; Reiners, A.; Almenara, J.; Astudillo-Defru, N.; Azzaro, M.; Bejar, V. J. S.; Bohemann, R.; Bonfils, X.; Bouchy, F.; Cifuentes, C.; Cortes-Contreras, M.; Delfosse, X.; Dreizler, S.; Forveille, T.; Hatzes, A. P.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kuerster, M.; Lafarga, M.; Lodieu, N.; Lovis, C.; Mayor, M.; Montes, D.; Morales, J. C.; Morales, N.; Murgas, F.; Ortiz, J. L.; Palle, E.; Pepe, F.; Perdelwitz, V.; Pollaco, D.; Santos, N. C.; Schoefer, P.; Schweitzer, A.; Segransan, N. C.; Shan, Y.; Stock, S.; Tal-Or, L.; Udry, S.; Zapatero Osorio, M. R.; Zechmeister, M. Bibcode: 2021yCat..36500188A Altcode: We tabulate the radial velocity (RV) time series (BJD) of the stars G 264-012 and Gl 393, the error of each RV measurement and the instrument with which it was acquired.

(2 data files). Title: VizieR Online Data Catalog: GJ 1151 radial velocity curve (Perger+, 2021) Authors: Perger, M.; Ribas, I.; Anglada-Escude, G.; Morales, J. C.; Amado, P. J.; Caballero, J. A.; Quirrenbach, A.; Reiners, A.; Bejar, V. J. S.; Dreizler, S.; Galadi-Enriquez, D.; Hatzes, A. P.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kuerster, M.; Lafarga, M.; Montes, D.; Palle, E.; Rodriguez-Lopez, C.; Schweitzer, A.; Zapatero Osorio, M. R.; Zechmeister, M. Bibcode: 2021yCat..36499012P Altcode: CARMENES serval (CAR) and HARPS-N terra (HAN) radial velocities of GJ 1151.

(1 data file). Title: Mass and density of the transiting hot and rocky super-Earth LHS 1478 b (TOI-1640 b) Authors: Soto, M. G.; Anglada-Escudé, G.; Dreizler, S.; Molaverdikhani, K.; Kemmer, J.; Rodríguez-López, C.; Lillo-Box, J.; Pallé, E.; Espinoza, N.; Caballero, J. A.; Quirrenbach, A.; Ribas, I.; Reiners, A.; Narita, N.; Hirano, T.; Amado, P. J.; Béjar, V. J. S.; Bluhm, P.; Burke, C. J.; Caldwell, D. A.; Charbonneau, D.; Cloutier, R.; Collins, K. A.; Cortés-Contreras, M.; Girardin, E.; Guerra, P.; Harakawa, H.; Hatzes, A. P.; Irwin, J.; Jenkins, J. M.; Jensen, E.; Kawauchi, K.; Kotani, T.; Kudo, T.; Kunimoto, M.; Kuzuhara, M.; Latham, D. W.; Montes, D.; Morales, J. C.; Mori, M.; Nelson, R. P.; Omiya, M.; Pedraz, S.; Passegger, V. M.; Rackham, B. V.; Rudat, A.; Schlieder, J. E.; Schöfer, P.; Schweitzer, A.; Selezneva, A.; Stockdale, C.; Tamura, M.; Trifonov, T.; Vanderspek, R.; Watanabe, D. Bibcode: 2021A&A...649A.144S Altcode: 2021arXiv210211640S One of the main objectives of the Transiting Exoplanet Survey Satellite (TESS) mission is the discovery of small rocky planets around relatively bright nearby stars. Here, we report the discovery and characterization of the transiting super-Earth planet orbiting LHS 1478 (TOI-1640). The star is an inactive red dwarf (J ~ 9.6 mag and spectral type m3 V) with mass and radius estimates of 0.20 ± 0.01M and 0.25 ± 0.01R, respectively, and an effective temperature of 3381 ± 54 K. It was observed by TESS in four sectors. These data revealed a transit-like feature with a period of 1.949 days. We combined the TESS data with three ground-based transit measurements, 57 radial velocity (RV) measurements from CARMENES, and 13 RV measurements from IRD, determining that the signal is produced by a planet with a mass of 2.33−0.20+0.20 M and a radius of 1.24−0.05+0.05 R. The resulting bulk density of this planet is 6.67 g cm−3, which is consistent with a rocky planet with an Fe- and MgSiO3-dominated composition. Although the planet would be too hot to sustain liquid water on its surface (its equilibrium temperature is about ~595 K, suggesting aVenus-like atmosphere), spectroscopic metrics based on the capabilities of the forthcoming James Webb Space Telescope and the fact that the host star is rather inactive indicate that this is one of the most favorable known rocky exoplanets for atmospheric characterization. Title: The CARMENES search for exoplanets around M dwarfs. No evidence for a super-Earth in a 2-day orbit around GJ 1151 Authors: Perger, M.; Ribas, I.; Anglada-Escudé, G.; Morales, J. C.; Amado, P. J.; Caballero, J. A.; Quirrenbach, A.; Reiners, A.; Béjar, V. J. S.; Dreizler, S.; Galadí-Enríquez, D.; Hatzes, A. P.; Henning, Th.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; Montes, D.; Pallé, E.; Rodríguez-López, C.; Schweitzer, A.; Zapatero Osorio, M. R.; Zechmeister, M. Bibcode: 2021A&A...649L..12P Altcode: 2021arXiv210310216P Context. The interaction between Earth-like exoplanets and the magnetic field of low-mass host stars are considered to produce weak emission signals at radio frequencies. A study using LOFAR data announced the detection of radio emission from the mid M-type dwarf GJ 1151 that could potentially arise from a close-in terrestrial planet. Recently, the presence of a 2.5-M planet orbiting GJ 1151 with a 2-day period has been claimed using 69 radial velocities (RVs) from the HARPS-N and HPF instruments.
Aims: We have obtained 70 new high-precision RV measurements in the framework of the CARMENES M-dwarf survey and use these data to confirm the presence of the claimed planet and to place limits on possible planetary companions in the GJ 1151 system.
Methods: We analysed the periodicities present in the combined RV data sets from all three instruments and calculated the detection limits for potential planets in short-period orbits.
Results: We cannot confirm the recently announced candidate planet and conclude that the 2-day signal in the HARPS-N and HPF data sets is most probably produced by a long-term RV variability, possibly arising from an outer planetary companion that has yet to be constrained. We calculate a 99.9% significance detection limit of 1.50 m s−1 in the RV semi-amplitude, which places upper limits of 0.7 M and 1.2 M on the minimum masses of potential exoplanets with orbital periods of 1 and 5 days, respectively.

Table A.1 is only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/649/L12 Title: Stellar atmospheric parameters of CARMENES GTO M dwarfs with spectral synthesis and SteParSyn Authors: Marfil, Emilio; Tabernero, Hugo M.; Montes, David; Caballero, Jose Antonio; Lazaro-Barrasa, Francisco Javier; González Hernández, Jonay I.; Nagel, Evangelos; Passegger, Vera M.; Schweitzer, Andreas; Ribas, Ignasi; Reiners, Ansgar; Quirrenbach, Andreas; Amado, Pedro J.; Cifuentes, Carlos; Cortés-Contreras, Miriam; Dreizler, Stefan; Duque-Arribas, Christian; Galadí-Enríquez, David; Henning, Thomas; Jeffers, Sandra V.; Kaminski, Adrian; Kürster, Martin; Lafarga, Marina; López-Gallifa, Álvaro; Morales, Juan Carlos; Shan, Yutong; Zechmeister, Matthias Bibcode: 2021csss.confE..19M Altcode: 2021csss.confE.298M We aim to review the spectral synthesis technique to derive the stellar atmospheric parameters (Teff, log g, and [Fe/H]) of 348 M dwarfs in light of the optical and near-infrared spectra obtained with CARMENES, the high-resolution, double-channel spectrograph installed at the 3.5 m telescope at the Calar Alto observatory (Spain). The analysis relies on the SteParSyn code as the preferred MCMC implementation of the spectral synthesis technique, along with 75 carefully selected, magnetically insensitive, Fe I and Ti I lines plus the γ- and ϵ-TiO bands synthesised with a grid of BT-Settl model atmospheres and the turbospectrum code. To avoid potential degeneracies in the parameter space, we impose a Bayesian prior on Teff and log g based on comprehensive, multi-band photometric data available for the sample. As a benchmark test in Teff, log g, and [Fe/H] we place special emphasis on three special subsets in our sample, namely 14 M dwarfs with interferometric angular diameter measurements, 15 M+M systems, and 7 wide physical binaries harbouring an FGK-type primary with known metallicity. Title: The Lines are Not Fine: Measuring Vanadium Abundances in M dwarfs from Hyperfine-Split Lines Authors: Shan, Yutong; Reiners, Ansgar; Fabbian, Damian; Marfil, Emilio; Montes, David; Tabernero, Hugo M.; Ribas, Ignasi; Caballero, Jose A.; Quirrenbach, Andreas; Amado, Pedro J.; Aceituno, J.; Bejar, Victor J. S.; Cortes-Contreras, Miriam; Dreizler, Stefan; Hatzes, Artie P.; Henning, Thomas; Jeffers, Sandra V.; Kaminski, Adrian; Kürster, Martin; Lafarga, Marina; Morales, Juan Carlos; Nagel, Evangelos; Rodriguez-Lopez, Cristina; Passegger, Vera M.; Schweitzer, Andreas; Zechmeister, Mathias Bibcode: 2021csss.confE.160S Altcode: Cool star atmospheres present challenges to chemical abundance studies. To date, only a handful of elements have been quantified for a handful of M dwarfs. In high-resolution spectra from the CARMENES survey, we identify a series of dramatically hyperfine-split vanadium features between 800 and 910 nm, which have strong and clean profiles throughout the early M-dwarf range. These 'bucket-shaped' line regions can be well-modeled with standard model atmospheres combined with the latest atomic data from VALD. From these line regions, we measure vanadium abundances for 140 nearby early M dwarfs in the CARMENES GTO sample and confirm that they follow the same trend with metallicity as the FG-type stars in the solar neighborhood, i.e., significantly above predictions from galactic chemical evolution models. Exhibiting a tight correlation with iron, vanadium abundances show promise as a potential metallicity indicator for M dwarfs. We also present evidence that several well-known chemical studies of K dwarfs have systematically overestimated their vanadium abundances largely as a result of neglecting to model hyperfine structure, a bias that worsens with decreasing temperature. Our work highlights opportunities for robust chemical analysis of cool stars afforded by high-quality spectra redward of visible. Title: Mapping stellar activity indicators across the M dwarf domain Authors: Lafarga, Marina; Ribas, Ignasi; Reiners, Ansgar; Quirrenbach, Andreas; Amado, Pedro J.; Caballero, Jose A.; Azzaro, Marco; Béjar, Víctor J. S.; Cortés-Contreras, Miriam; Dreizler, Stefan; Hatzes, Artie P.; Henning, Thomas; Jeffers, Sandra V.; Kaminski, A.; Kürster, Martin; Montes, David; Morales, Juan Carlos; Oshagh, Mahmoud; Rodríguez-López, Cristina; Schöfer, Patrick; Schweitzer, Andreas; Zechmeister, Mathias Bibcode: 2021csss.confE.184L Altcode: Despite stellar magnetic activity being present in most cool stars, its effects on spectroscopic observations are still not well understood. Several activity indicators are routinely used to identify activity-related signals in radial velocity (RV) measurements, but not all indicators trace exactly the same effects, nor are any of them always effective in all stars. This poses one of the main obstacles for the detection and characterisation of small exoplanets, as magnetic activity biases RV signals. In this work, we analyse the temporal behaviour of RVs and a set of spectroscopic indicators for 98 M dwarfs observed with CARMENES, with the aim of finding a relation between indicator performance and stellar properties. We find periodic signals related to activity for 56 sample stars. The activity indicators behave differently depending on the mass and activity level of the target star, e.g., cross-correlation function bisector inverse slope and chromatic index are effective activity tracers for the most active stars in the sample, especially stars with relatively high mass, while for less active stars, chromospheric lines perform best. Most of the targets for which we cannot identify any activity-related signal are stars at the low-mass end of the sample, where stars are fully convective, and also show the lowest RV scatter. This could potentially hint at different manifestations of activity compared to higher-mass stars. Moreover, ultracool M dwarfs could be better candidates for planet searches than earlier types, which display higher levels of RV variability. Our results show that none of the indicators are effective activity tracers for all stars. Therefore, an analysis of a large set of indicators seems necessary to obtain a complete picture of stellar activity variability. This becomes critical when assessing the origin of RV signals, as not using the most effective indicators considering the characteristics of the star may lead to false planet claims. Title: A Deep Learning Approach to photospheric Parameters of CARMENES Target Stars Authors: Passegger, Vera Maria; Ordieres-Meré, Joaquin; Bello-García, Antonio; Caballero, José Antonio; Schweitzer, Andreas; Amado, Pedro J.; González-Marcos, Ana; Ribas, Ignasi; Reiners, Ansgar; Quirrenbach, Andreas; Sarro, Luis M.; Solano, Enrique; Azzaro, Marco; Bauer, Florian F.; Béjar, Victor J. S.; Cortés-Contreras, Miriam; Dreizler, Stefan; Hatzes, Artie P.; Henning, Thomas; Jeffers, Sandra V.; Kaminski, Adrian; Kürster, Martin; Lafarga, Marina; Marfil, Emilio; Montes, David; Morales, Juan Carlos; Nagel, Evangelos; Tabernero, Hugo M.; Zechmeister, Mathias Bibcode: 2021csss.confE..71P Altcode: We construct an individual convolutional neural network architecture for each of the four stellar parameters effective temperature (Teff), surface gravity (log g), metallicity [M/H], and rotational velocity (v sin i). The networks are trained on synthetic PHOENIX-ACES spectra, showing small training and validation errors. We apply the trained networks to the observed spectra of 283 M dwarfs observed with CARMENES. Although the network models do very well on synthetic spectra, we find large deviations from literature values especially for metallicity, due to the synthetic gap. Title: A nearby transiting rocky exoplanet that is suitable for atmospheric investigation Authors: Trifonov, T.; Caballero, J. A.; Morales, J. C.; Seifahrt, A.; Ribas, I.; Reiners, A.; Bean, J. L.; Luque, R.; Parviainen, H.; Pallé, E.; Stock, S.; Zechmeister, M.; Amado, P. J.; Anglada-Escudé, G.; Azzaro, M.; Barclay, T.; Béjar, V. J. S.; Bluhm, P.; Casasayas-Barris, N.; Cifuentes, C.; Collins, K. A.; Collins, K. I.; Cortés-Contreras, M.; de Leon, J.; Dreizler, S.; Dressing, C. D.; Esparza-Borges, E.; Espinoza, N.; Fausnaugh, M.; Fukui, A.; Hatzes, A. P.; Hellier, C.; Henning, Th.; Henze, C. E.; Herrero, E.; Jeffers, S. V.; Jenkins, J. M.; Jensen, E. L. N.; Kaminski, A.; Kasper, D.; Kossakowski, D.; Kürster, M.; Lafarga, M.; Latham, D. W.; Mann, A. W.; Molaverdikhani, K.; Montes, D.; Montet, B. T.; Murgas, F.; Narita, N.; Oshagh, M.; Passegger, V. M.; Pollacco, D.; Quinn, S. N.; Quirrenbach, A.; Ricker, G. R.; Rodríguez López, C.; Sanz-Forcada, J.; Schwarz, R. P.; Schweitzer, A.; Seager, S.; Shporer, A.; Stangret, M.; Stürmer, J.; Tan, T. G.; Tenenbaum, P.; Twicken, J. D.; Vanderspek, R.; Winn, J. N. Bibcode: 2021Sci...371.1038T Altcode: 2021arXiv210304950T Spectroscopy of transiting exoplanets can be used to investigate their atmospheric properties and habitability. Combining radial velocity (RV) and transit data provides additional information on exoplanet physical properties. We detect a transiting rocky planet with an orbital period of 1.467 days around the nearby red dwarf star Gliese 486. The planet Gliese 486 b is 2.81 Earth masses and 1.31 Earth radii, with uncertainties of 5%, as determined from RV data and photometric light curves. The host star is at a distance of ~8.1 parsecs, has a J-band magnitude of ~7.2, and is observable from both hemispheres of Earth. On the basis of these properties and the planet’s short orbital period and high equilibrium temperature, we show that this terrestrial planet is suitable for emission and transit spectroscopy. Title: A deep learning approach to photospheric parameters of CARMENES target stars Authors: Passegger, Vera Maria; Bello-García, Antonio; Ordieres-Meré, Joaquin; Caballero, José Antonio; Schweitzer, Andreas; Amado, Pedro J.; González-Marcos, Ana; Ribas, Ignasi; Reiners, Ansgar; Quirrenbach, Andreas; Sarro, Luis M.; Solano, Enrique; Azzaro, Marco; Bauer, Florian F.; Béjar, Victor J. S.; Cortés-Contreras, Miriam; Dreizler, Stefan; Hatzes, Artie P.; Henning, Thomas; Jeffers, Sandra V.; Kaminski, Adrian; Kürster, Martin; Lafarga, Marina; Marfil, Emilio; Montes, David; Morales, Juan Carlos; Nagel, Evangelos; Tabernero, Hugo M.; Zechmeister, Mathias Bibcode: 2021csss.confE.312P Altcode: In the light of more and more new instrumentation to get a deeper insight into the universe, tons of data are collected. While traditional machine-learning methods have been used in processing stellar spectral data, such large new datasets are better handled with Deep Learning (DL) techniques. In this work, we present a Deep Convolutional Neural Network (CNN) approach to derive fundamental stellar parameters (effective temperature, surface gravity, metallicity and rotational velocity) from high-resolution high signal-to-noise ratio spectra. We construct an individual CNN architecture for each of the four parameters and train them on synthetic PHOENIX-ACES spectra. After that, we apply the trained networks to the observed spectra of 50 M dwarfs observed with CARMENES. The CARMENES spectrograph, installed on the 3.5 m telescope at the Calar Alto Observatory (Spain) has two channels, covering the visible (0.52 to 0.96 µm, R = 96,400) and near-infrared (0.96 to 1.71 µm, R = 80,600) spectral ranges. We compare our results to literature values, and demonstrate that our method can be used for stellar parameter determination without the need of having a huge sample of stellar spectra with known parameters, because our networks can be trained on synthetic spectra. Introducing Deep Transfer Learning (DTL) in our approach allows us to transfer external knowledge about the stellar parameters (e.g., from interferometry) to our training set and therefore improve our results compared to literature. Title: Identification and Mitigation of a Vibrational Telescope Systematic with Application to Spitzer Authors: Challener, Ryan C.; Harrington, Joseph; Jenkins, James; Kurtovic, Nicolás T.; Ramirez, Ricardo; McIntyre, Kathleen J.; Himes, Michael D.; Rodríguez, Eloy; Anglada-Escudé, Guillem; Dreizler, Stefan; Ofir, Aviv; Peña Rojas, Pablo A.; Ribas, Ignasi; Rojo, Patricio; Kipping, David; Butler, R. Paul; Amado, Pedro J.; Rodríguez-López, Cristina; Palle, Enric; Murgas, Felipe Bibcode: 2021PSJ.....2....9C Altcode: 2020arXiv201105270C We observed Proxima Centauri with the Spitzer Space Telescope Infrared Array Camera five times in 2016 and 2017 to search for transits of Proxima Centauri b. Following standard analysis procedures, we found three asymmetric, transit-like events that are now understood to be vibrational systematics. This systematic is correlated with the width of the point-response function (PRF), which we measure with rotated and nonrotated-Gaussian fits with respect to the detector array. We show that the systematic can be removed with a novel application of an adaptive elliptical-aperture photometry technique, and compare the performance of this technique with fixed and variable circular-aperture photometry, using both BiLinearly Interpolated Subpixel Sensitivity (BLISS) maps and nonbinned Pixel-Level Decorrelation (PLD). With BLISS maps, elliptical photometry results in a lower standard deviation of normalized residuals, and reduced or similar correlated noise when compared to circular apertures. PLD prefers variable, circular apertures, but generally results in more correlated noise than BLISS. This vibrational effect is likely present in other telescopes and Spitzer observations, where correction could improve results. Our elliptical apertures can be applied to any photometry observations, and may be even more effective when applied to more circular PRFs than Spitzer's. Title: The CARMENES search for exoplanets around M dwarfs. LP 714-47 b (TOI 442.01): populating the Neptune desert Authors: Dreizler, S.; Crossfield, I. J. M.; Kossakowski, D.; Plavchan, P.; Jeffers, S. V.; Kemmer, J.; Luque, R.; Espinoza, N.; Pallé, E.; Stassun, K.; Matthews, E.; Cale, B.; Caballero, J. A.; Schlecker, M.; Lillo-Box, J.; Zechmeister, M.; Lalitha, S.; Reiners, A.; Soubkiou, A.; Bitsch, B.; Zapatero Osorio, M. R.; Chaturvedi, P.; Hatzes, A. P.; Ricker, G.; Vanderspek, R.; Latham, D. W.; Seager, S.; Winn, J.; Jenkins, J. M.; Aceituno, J.; Amado, P. J.; Barkaoui, K.; Barbieri, M.; Batalha, N. M.; Bauer, F. F.; Benneke, B.; Benkhaldoun, Z.; Beichman, C.; Berberian, J.; Burt, J.; Butler, R. P.; Caldwell, D. A.; Chintada, A.; Chontos, A.; Christiansen, J. L.; Ciardi, D. R.; Cifuentes, C.; Collins, K. A.; Collins, K. I.; Combs, D.; Cortés-Contreras, M.; Crane, J. D.; Daylan, T.; Dragomir, D.; Esparza-Borges, E.; Evans, P.; Feng, F.; Flowers, E. E.; Fukui, A.; Fulton, B.; Furlan, E.; Gaidos, E.; Geneser, C.; Giacalone, S.; Gillon, M.; Gonzales, E.; Gorjian, V.; Hellier, C.; Hidalgo, D.; Howard, A. W.; Howell, S.; Huber, D.; Isaacson, H.; Jehin, E.; Jensen, E. L. N.; Kaminski, A.; Kane, S. R.; Kawauchi, K.; Kielkopf, J. F.; Klahr, H.; Kosiarek, M. R.; Kreidberg, L.; Kürster, M.; Lafarga, M.; Livingston, J.; Louie, D.; Mann, A.; Madrigal-Aguado, A.; Matson, R. A.; Mocnik, T.; Morales, J. C.; Muirhead, P. S.; Murgas, F.; Nandakumar, S.; Narita, N.; Nowak, G.; Oshagh, M.; Parviainen, H.; Passegger, V. M.; Pollacco, D.; Pozuelos, F. J.; Quirrenbach, A.; Reefe, M.; Ribas, I.; Robertson, P.; Rodríguez-López, C.; Rose, M. E.; Roy, A.; Schweitzer, A.; Schlieder, J.; Shectman, S.; Tanner, A.; Şenavcı, H. V.; Teske, J.; Twicken, J. D.; Villasenor, J.; Wang, S. X.; Weiss, L. M.; Wittrock, J.; Yılmaz, M.; Zohrabi, F. Bibcode: 2020A&A...644A.127D Altcode: 2020arXiv201101716D We report the discovery of a Neptune-like planet (LP 714-47 b, P = 4.05204 d, mb = 30.8 ± 1.5M, Rb = 4.7 ± 0.3 R) located in the "hot Neptune desert". Confirmation of the TESS Object of Interest (TOI 442.01) was achieved with radial-velocity follow-up using CARMENES, ESPRESSO, HIRES, iSHELL, and PFS, as well as from photometric data using TESS, Spitzer, and ground-based photometry from MuSCAT2, TRAPPIST-South, MONET-South, the George Mason University telescope, the Las Cumbres Observatory Global Telescope network, the El Sauce telescope, the TÜBİTAK National Observatory, the University of Louisville Manner Telescope, and WASP-South. We also present high-spatial resolution adaptive optics imaging with the Gemini Near-Infrared Imager. The low uncertainties in the mass and radius determination place LP 714-47 b among physically well-characterised planets, allowing for a meaningful comparison with planet structure models. The host star LP 714-47 is a slowly rotating early M dwarf (Teff = 3950 ± 51 K) with a mass of 0.59 ± 0.02M and a radius of 0.58 ± 0.02R. From long-term photometric monitoring and spectroscopic activity indicators, we determine a stellar rotation period of about 33 d. The stellar activity is also manifested as correlated noise in the radial-velocity data. In the power spectrum of the radial-velocity data, we detect a second signal with a period of 16 days in addition to the four-day signal of the planet. This could be shown to be a harmonic of the stellar rotation period or the signal of a second planet. It may be possible to tell the difference once more TESS data and radial-velocity data are obtained.

RV data are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/644/A127

Based on observations carried out at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Junta de Andalucía and the Instituto de Astrofísica de Andalucía (CSIC), on observations carried out at the European Southern Observatory under ESO programme 0103.C-0152(A), and data collected with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile. Title: The CARMENES M-dwarf planet survey Authors: Quirrenbach, Andreas; CARMENES Consortium; Amado, P. J.; Ribas, I.; Reiners, A.; Caballero, J. A.; Aceituno, J.; Alacid, J. M.; Alonso-Floriano, F. J.; Anglada-Escudé, G.; Azzaro, M.; Baroch, D.; Bauer, F. F.; Becerril, S.; Béjar, V. J. S.; Bluhm, P.; Calvo Ortega, R.; Cardona Guillén, C.; Casasayas-Barris, N.; Chaturvedi, P.; Cifuentes, C.; Colomé, J.; Conte, D.; Cortés-Contreras, M.; Czesla, S.; Díez-Alonso, E.; Domínguez Fernández, A. J.; Dreizler, S.; Duque-Arribas, C.; Espinoza, N.; Fuhrmeister, B.; Galadí-Enríquez, D.; Gar´a Quintana, E.; González-Alvare, E.; González Cuesta, z. L.; González Hernández, J. I.; Guenther, E. W.; de Guindos, E.; Hatzes, A. P.; Henning, T.; Herbort, O.; Herrero, E.; Hintz, D.; Iglesias-Pára, J.; Jeffers, S. V.; Johnson, E. N.; de Juan, E.; Kaminski, A.; Kemmer, J.; Khaimova, J.; Khalafinejad, S.; Klahr, H.; Kossakowski, D.; Kreidberg, L.; Kürster, M.; Labarga, F.; Lafarga, M.; Lampón, M.; Lara, L. M.; Lillo-Box, J.; Lodieu, N.; López Gallifa, A.; López González, M. J.; López-Puertas, M.; Luque, R.; Marfil, E.; Martín-Ruiz, S.; Matthé, C.; Molaverdikhani, K.; Montes, D.; Morales, J. C.; Morales-Calderóon, M.; Nagel, E.; Nortmann, L.; Nowak, G.; Ofir, A.; Oshaghi, M.; Pallé, E.; Passegger, V. M.; Pavlov, A.; Pedraz, S.; Perdelwitz, V.; Perger, M.; Reffert, S.; Revilla, D.; Rodríguez, E.; Rodríguez López, C.; Sabotta, S.; Sadegi, S.; Sairam, L.; Salz, M.; Sánchez-López, A.; Sanz-Forcada, J.; Sarkis, P.; Schäfer, S.; Schiller, J.; Schlecker, M.; Schmitt, J. H. M. M.; Schöfer, P.; Schweitzer, A.; Seiferta, W.; Shan, Y.; Shulyak, D.; Skrzypinski, S. L.; Solano, E.; Soto, M. G.; Stahl, O.; Stangret, M.; Stock, S. A.; Strachan, J. B. P.; Stuber, T.; Stürmer, J.; Tabernero, H. M.; Tal-Or, L.; Tala-Pinto, M.; Trifonov, T.; Vanaverbeke, S.; Yan, F.; Zapatero Osorio, M. R.; Zechmeister, M. Bibcode: 2020SPIE11447E..3CQ Altcode: The CARMENES instrument consists of two cross-dispersed Échelle spectrographs, which together cover the wavelength range from 5,200 to 17,100 Å. During its first five years of operation at the 3.5 m telescope on Calar Alto, Spain, it has been used for a radial-velocity survey of 365 M dwarfs, for follow-up radial-velocity observations of transiting exoplanets, and for spectroscopic studies of exoplanet atmospheres during transits. The CARMENES data have also yielded a wealth of information on the fundamental parameters and activity of M dwarfs. We provide an overview of the scientific results from the main CARMENES survey in the years 2016 to 2020. Title: The CARMENES search for exoplanets around M dwarfs. Three temperate-to-warm super-Earths Authors: Stock, S.; Nagel, E.; Kemmer, J.; Passegger, V. M.; Reffert, S.; Quirrenbach, A.; Caballero, J. A.; Czesla, S.; Béjar, V. J. S.; Cardona, C.; Díez-Alonso, E.; Herrero, E.; Lalitha, S.; Schlecker, M.; Tal-Or, L.; Rodríguez, E.; Rodríguez-López, C.; Ribas, I.; Reiners, A.; Amado, P. J.; Bauer, F. F.; Bluhm, P.; Cortés-Contreras, M.; González-Cuesta, L.; Dreizler, S.; Hatzes, A. P.; Henning, Th.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; López-González, M. J.; Montes, D.; Morales, J. C.; Pedraz, S.; Schöfer, P.; Schweitzer, A.; Trifonov, T.; Zapatero Osorio, M. R.; Zechmeister, M. Bibcode: 2020A&A...643A.112S Altcode: 2020arXiv201000474S We announce the discovery of two planets orbiting the M dwarfs GJ 251 (0.360 ± 0.015M) and HD 238090 (0.578 ± 0.021M) based on CARMENES radial velocity (RV) data. In addition, we independently confirm with CARMENES data the existence of Lalande 21185 b, a planet that has recently been discovered with the SOPHIE spectrograph. All three planets belong to the class of warm or temperate super-Earths and share similar properties. The orbital periods are 14.24 d, 13.67 d, and 12.95 d and the minimum masses are 4.0 ± 0.4 M, 6.9 ± 0.9 M, and 2.7 ± 0.3 M for GJ 251 b, HD 238090 b, and Lalande 21185 b, respectively. Based on the orbital and stellar properties, we estimate equilibrium temperatures of 351.0 ± 1.4 K for GJ 251 b, 469.6 ± 2.6 K for HD 238090 b, and 370.1 ± 6.8 K for Lalande 21185 b. For the latter we resolve the daily aliases that were present in the SOPHIE data and that hindered an unambiguous determination of the orbital period. We find no significant signals in any of our spectral activity indicators at the planetary periods. The RV observations were accompanied by contemporaneous photometric observations. We derive stellar rotation periods of 122.1 ± 2.2 d and 96.7 ± 3.7 d for GJ 251 and HD 238090, respectively. The RV data of all three stars exhibit significant signals at the rotational period or its first harmonic. For GJ 251 and Lalande 21185, we also find long-period signals around 600 d, and 2900 d, respectively, which we tentatively attribute to long-term magnetic cycles. We apply a Bayesian approach to carefully model the Keplerian signals simultaneously with the stellar activity using Gaussian process regression models and extensively search for additional significant planetary signals hidden behind the stellar activity. Current planet formation theories suggest that the three systems represent a common architecture, consistent with formation following the core accretion paradigm.

Tables D.1-D.3 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/643/A112 Title: Leveraging HST with MUSE - I. Sodium abundance variations within the 2-Gyr-old cluster NGC 1978 Authors: Saracino, S.; Kamann, S.; Usher, C.; Bastian, N.; Martocchia, S.; Lardo, C.; Latour, M.; Cabrera-Ziri, I.; Dreizler, S.; Giesers, B.; Husser, T. -O.; Kacharov, N.; Salaris, M. Bibcode: 2020MNRAS.498.4472S Altcode: 2020arXiv200903320S Nearly all of the well-studied ancient globular clusters (GCs), in the Milky Way and in nearby galaxies, show star-to-star variations in specific elements (e.g. He, C, N, O, Na, and Al), known as 'multiple populations' (MPs). However, MPs are not restricted to ancient clusters, with massive clusters down to ~2 Gyr showing signs of chemical variations. This suggests that young and old clusters share the same formation mechanism but most of the work to date on younger clusters has focused on N variations. Initial studies even suggested that younger clusters may not host spreads in other elements beyond N (e.g. Na), calling into question whether these abundance variations share the same origin as in the older GCs. In this work, we combine Hubble Space Telescope (HST) photometry with Very Large Telescope (VLT)/Multi-Unit Spectroscopic Explorer (MUSE) spectroscopy of a large sample of red giant branch (RGB) stars (338) in the Large Magellanic Cloud cluster NGC 1978, the youngest globular to date with reported MPs in the form of N spreads. By combining the spectra of individual RGB stars into N-normal and N-enhanced samples, based on the 'chromosome map' derived from HST, we search for mean abundance variations. Based on the NaD line, we find a Na difference of Δ[Na/Fe] = 0.07 ± 0.01 between the populations. While this difference is smaller than typically found in ancient GCs (which may suggest a correlation with age), this result further confirms that the MP phenomenon is the same, regardless of cluster age and host galaxy. As such, these young clusters offer some of the strictest tests for theories on the origin of MPs. Title: Leveraging HST with MUSE: II. Na-abundance variations in intermediate age star clusters Authors: Martocchia, S.; Kamann, S.; Saracino, S.; Usher, C.; Bastian, N.; Rejkuba, M.; Latour, M.; Lardo, C.; Cabrera-Ziri, I.; Dreizler, S.; Kacharov, N.; Kozhurina-Platais, V.; Larsen, S.; Mancino, S.; Platais, I.; Salaris, M. Bibcode: 2020MNRAS.499.1200M Altcode: 2020arXiv200910023M; 2020MNRAS.tmp.2740M Ancient (>10 Gyr) globular clusters (GCs) show chemical abundance variations in the form of patterns among certain elements, e.g. N correlates with Na and anticorrelates with O. Recently, N abundance spreads have also been observed in massive star clusters that are significantly younger than old GCs, down to an age of ~2 Gyr. However, so far N has been the only element found to vary in such young objects. We report here the presence of Na abundance variations in the intermediate age massive star clusters NGC 416 (~6.5 Gyr old) and Lindsay 1 (~7.5 Gyr old) in the Small Magellanic Cloud, by combining Hubble Space Telescope (HST) and European Southern Observatory Very Large Telescope MUSE observations. Using HST photometry, we were able to construct 'chromosome maps' and separate subpopulations with different N content, in the red giant branch of each cluster. MUSE spectra of individual stars belonging to each population were combined, resulting in high signal-to-noise spectra representative of each population, which were compared to search for mean differences in Na. We find a mean abundance variation of Δ[Na/Fe] = 0.18 ± 0.04 dex for NGC 416 and Δ[Na/Fe] = 0.24 ± 0.05 dex for Lindsay 1. In both clusters, we find that the population that is enhanced in N is also enhanced in Na, which is the same pattern to the one observed in ancient GCs. Furthermore, we detect a bimodal distribution of core-helium-burning red clump (RC) giants in the UV colour-magnitude diagram of NGC 416. A comparison of the stacked MUSE spectra of the two RCs shows the same mean Na abundance difference between the two populations. The results reported in this work are a crucial hint that star clusters of a large age range share the same origin: they are the same types of objects, but only separated in age. Title: VizieR Online Data Catalog: LP714-47 (TOI 442) radial velocity curve (Dreizler+, 2020) Authors: Dreizler, S.; Crossfield, I. J. M.; Kossakowski, D.; Plavchan, P.; Jeffers, S. V.; Kemmer, J.; Luque, R.; Espinoza, N.; Palle, E.; Stassun, K.; Matthews, E.; Cale, B.; Caballero, J. A.; Schlecker, M.; Lillo-Box, J.; Zechmeister, M.; Lalitha, S.; Reiners, A.; Soubkiou, A.; Bitsch, B.; Zapatero Osorio, M. R.; Chaturvedi, P.; Hatzes, A. P.; Ricker, G.; Vanderspek, R.; Latham, D. W.; Seager, S.; Winn, J.; Jenkins, J. M.; Aceituno, J.; Amado, P. J.; Barkaoui, K.; Barbieri, M.; Batalha, N. M.; Bauer, F. F.; Benneke, B.; Benkhaldoun, Z.; Beichman, C.; Berberian, J.; Burt, J.; Butler, R. P.; Caldwell, D. A.; Chintada, A.; Chontos, A.; Christiansen, J. L.; Ciardi, D. R.; Cifuentes, C.; Collins, K. A.; Collins, K. I.; Combs, D.; Cortes-Contreras, M.; Crane, J. D.; Daylan, T.; Dragomir, D.; Esparza-Borges, E.; Evans, P.; Feng, F.; Flowers, E. E.; Fukui, A.; Fulton, B.; Furlan, E.; Gaidos, E.; Geneser, C.; Giacalone, S.; Gillon, M.; Gonzales, E.; Gorjian, V.; Hellier, C.; Hidalgo, D.; Howard, A. W.; Howell, S.; Huber, D.; Isaacson, H.; Jehin, E.; Jensen, E. L. N.; Kaminski, A.; Kane, S. R.; Kawauchi, K.; Kielkopf, J. F.; Klahr, H.; Kosiarek, M. R.; Kreidberg, L.; Kuerster, M.; Lafarga, M.; Livingston, J.; Louie, D.; Mann, A.; Madrigal-Aguado, A.; Matson, R. A.; Mocnik, T.; Morales, J. C.; Muirhead, P. S.; Murgas, F.; Nandakumar, S.; Narita, N.; Nowak, G.; Oshagh, M.; Parviainen, H.; Passegger, V. M.; Pollacco, D.; Pozuelos, F. J.; Quirrenbach, A.; Reefe, M.; Ribas, I.; Robertson, P.; Rodriguez-Lopez, C.; Rose, M. E.; Roy, A.; Schweitzer, A.; Schlieder, J.; Shectman, S.; Tanner, A.; Senavci, H. V.; Teske, J.; Twicken, J. D.; Villasenor, J.; Wang, S. X.; Weiss, L. M.; Wittrock, J.; Yilmaz, M.; Zohrabi, F. Bibcode: 2020yCat..36440127D Altcode: High-resolution follow-up spectroscopy of the TESS planet candidates is arranged by the TESS follow-up programme (TFOP), "Precise Radial Velocities" SG4 subgroup.

We obtained High-resolution follow-up spectroscopy for LP714-47 with CARMENES-VIS, CARMENES-NIR, ESPRESSO, HIRES, iSHELL, and PFS. The observations began at mid February 2019, just after the announcement of the transiting planet candidate, and ended in January 2020. In this period, we collected 102 spectra. The spectral resolution and the number of spectra obtained by the individual instruments are listed in Table 1 of the paper.

The table contains the time of observation as Barycentric Julian Date in units of days, the measure radial velocities in unites of m/s, the measurement uncertainties measured in m/s, and the instrument name.

(1 data file). Title: Discovery of a hot, transiting, Earth-sized planet and a second temperate, non-transiting planet around the M4 dwarf GJ 3473 (TOI-488) Authors: Kemmer, J.; Stock, S.; Kossakowski, D.; Kaminski, A.; Molaverdikhani, K.; Schlecker, M.; Caballero, J. A.; Amado, P. J.; Astudillo-Defru, N.; Bonfils, X.; Ciardi, D.; Collins, K. A.; Espinoza, N.; Fukui, A.; Hirano, T.; Jenkins, J. M.; Latham, D. W.; Matthews, E. C.; Narita, N.; Pallé, E.; Parviainen, H.; Quirrenbach, A.; Reiners, A.; Ribas, I.; Ricker, G.; Schlieder, J. E.; Seager, S.; Vanderspek, R.; Winn, J. N.; Almenara, J. M.; Béjar, V. J. S.; Bluhm, P.; Bouchy, F.; Boyd, P.; Christiansen, J. L.; Cifuentes, C.; Cloutier, R.; Collins, K. I.; Cortés-Contreras, M.; Crossfield, I. J. M.; Crouzet, N.; de Leon, J. P.; Della-Rose, D. D.; Delfosse, X.; Dreizler, S.; Esparza-Borges, E.; Essack, Z.; Forveille, Th.; Figueira, P.; Galadí-Enríquez, D.; Gan, T.; Glidden, A.; Gonzales, E. J.; Guerra, P.; Harakawa, H.; Hatzes, A. P.; Henning, Th.; Herrero, E.; Hodapp, K.; Hori, Y.; Howell, S. B.; Ikoma, M.; Isogai, K.; Jeffers, S. V.; Kürster, M.; Kawauchi, K.; Kimura, T.; Klagyivik, P.; Kotani, T.; Kurokawa, T.; Kusakabe, N.; Kuzuhara, M.; Lafarga, M.; Livingston, J. H.; Luque, R.; Matson, R.; Morales, J. C.; Mori, M.; Muirhead, P. S.; Murgas, F.; Nishikawa, J.; Nishiumi, T.; Omiya, M.; Reffert, S.; Rodríguez López, C.; Santos, N. C.; Schöfer, P.; Schwarz, R. P.; Shiao, B.; Tamura, M.; Terada, Y.; Twicken, J. D.; Ueda, A.; Vievard, S.; Watanabe, N.; Zechmeister, M. Bibcode: 2020A&A...642A.236K Altcode: 2020arXiv200910432K We present the confirmation and characterisation of GJ 3473 b (G 50-16, TOI-488.01), a hot Earth-sized planet orbiting an M4 dwarf star, whose transiting signal (P = 1.1980035 ± 0.0000018 d) was first detected by the Transiting Exoplanet Survey Satellite (TESS). Through a joint modelling of follow-up radial velocity observations with CARMENES, IRD, and HARPS together with extensive ground-based photometric follow-up observations with LCOGT, MuSCAT, and MuSCAT2, we determined a precise planetary mass, Mb = 1.86 ± 0.30 M, and radius, Rb = 1.264 ± 0.050 R. Additionally, we report the discovery of a second, temperate, non-transiting planet in the system, GJ 3473 c, which has a minimum mass, Mc sin i = 7.41 ± 0.91 M, and orbital period, Pc = 15.509 ± 0.033 d. The inner planet of the system, GJ 3473 b, is one of the hottest transiting Earth-sized planets known thus far, accompanied by a dynamical mass measurement, which makes it a particularly attractive target for thermal emission spectroscopy.

RV data are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/642/A236 Title: The CARMENES search for exoplanets around M dwarfs. Two planets on opposite sides of the radius gap transiting the nearby M dwarf LTT 3780 Authors: Nowak, G.; Luque, R.; Parviainen, H.; Pallé, E.; Molaverdikhani, K.; Béjar, V. J. S.; Lillo-Box, J.; Rodríguez-López, C.; Caballero, J. A.; Zechmeister, M.; Passegger, V. M.; Cifuentes, C.; Schweitzer, A.; Narita, N.; Cale, B.; Espinoza, N.; Murgas, F.; Hidalgo, D.; Zapatero Osorio, M. R.; Pozuelos, F. J.; Aceituno, F. J.; Amado, P. J.; Barkaoui, K.; Barrado, D.; Bauer, F. F.; Benkhaldoun, Z.; Caldwell, D. A.; Casasayas Barris, N.; Chaturvedi, P.; Chen, G.; Collins, K. A.; Collins, K. I.; Cortés-Contreras, M.; Crossfield, I. J. M.; de León, J. P.; Díez Alonso, E.; Dreizler, S.; El Mufti, M.; Esparza-Borges, E.; Essack, Z.; Fukui, A.; Gaidos, E.; Gillon, M.; Gonzales, E. J.; Guerra, P.; Hatzes, A.; Henning, Th.; Herrero, E.; Hesse, K.; Hirano, T.; Howell, S. B.; Jeffers, S. V.; Jehin, E.; Jenkins, J. M.; Kaminski, A.; Kemmer, J.; Kielkopf, J. F.; Kossakowski, D.; Kotani, T.; Kürster, M.; Lafarga, M.; Latham, D. W.; Law, N.; Lissauer, J. J.; Lodieu, N.; Madrigal-Aguado, A.; Mann, A. W.; Massey, B.; Matson, R. A.; Matthews, E.; Montañés-Rodríguez, P.; Montes, D.; Morales, J. C.; Mori, M.; Nagel, E.; Oshagh, M.; Pedraz, S.; Plavchan, P.; Pollacco, D.; Quirrenbach, A.; Reffert, S.; Reiners, A.; Ribas, I.; Ricker, G. R.; Rose, M. E.; Schlecker, M.; Schlieder, J. E.; Seager, S.; Stangret, M.; Stock, S.; Tamura, M.; Tanner, A.; Teske, J.; Trifonov, T.; Twicken, J. D.; Vanderspek, R.; Watanabe, D.; Wittrock, J.; Ziegler, C.; Zohrabi, F. Bibcode: 2020A&A...642A.173N Altcode: 2020arXiv200301140N We present the discovery and characterisation of two transiting planets observed by the Transiting Exoplanet Survey Satellite (TESS) orbiting the nearby (d ≈ 22 pc), bright (J ≈ 9 mag) M3.5 dwarf LTT 3780 (TOI-732). We confirm both planets and their association with LTT 3780 via ground-based photometry and determine their masses using precise radial velocities measured with the CARMENES spectrograph. Precise stellar parameters determined from CARMENES high-resolution spectra confirm that LTT 3780 is a mid-M dwarf with an effective temperature of Teff = 3360 ± 51 K, a surface gravity of log g = 4.81 ± 0.04 (cgs), and an iron abundance of [Fe/H] = 0.09 ± 0.16 dex, with an inferred mass of M = 0.379 ± 0.016M and a radius of R = 0.382 ± 0.012R. The ultra-short-period planet LTT 3780 b (Pb = 0.77 d) with a radius of 1.35-0.06+0.06 R, a mass of 2.34-0.23+0.24 M, and a bulk density of 5.24-0.81+0.94 g cm-3 joins the population of Earth-size planets with rocky, terrestrial composition. The outer planet, LTT 3780 c, with an orbital period of 12.25 d, radius of 2.42-0.10+0.10 R, mass of 6.29-0.61+0.63 M, and mean density of 2.45-0.37+0.44 g cm-3 belongs to the population of dense sub-Neptunes. With the two planets located on opposite sides of the radius gap, this planetary system is anexcellent target for testing planetary formation, evolution, and atmospheric models. In particular, LTT 3780 c is an ideal object for atmospheric studies with the James Webb Space Telescope (JWST). Title: The CARMENES search for exoplanets around M dwarfs. Rubidium abundances in nearby cool stars Authors: Abia, C.; Tabernero, H. M.; Korotin, S. A.; Montes, D.; Marfil, E.; Caballero, J. A.; Straniero, O.; Prantzos, N.; Ribas, I.; Reiners, A.; Quirrenbach, A.; Amado, P. J.; Béjar, V. J. S.; Cortés-Contreras, M.; Dreizler, S.; Henning, Th.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; López-Gallifa, Á.; Morales, J. C.; Nagel, E.; Passegger, V. M.; Pedraz, S.; Rodríguez López, C.; Schweitzer, A.; Zechmeister, M. Bibcode: 2020A&A...642A.227A Altcode: 2020arXiv200900876A Due to their ubiquity and very long main-sequence lifetimes, abundance determinations in M dwarfs provide a powerful and alternative tool to GK dwarfs to study the formation and chemical enrichment history of our Galaxy. In this study, abundances of the neutron-capture elements Rb, Sr, and Zr are derived, for the first time, in a sample of nearby M dwarfs. We focus on stars in the metallicity range - 0.5 ≲ [Fe/H] ≲ +0.3, an interval poorly explored for Rb abundances in previous analyses. To do this we use high-resolution, high-signal-to-noise-ratio, optical and near-infrared spectra of 57 M dwarfs observed with CARMENES. The resulting [Sr/Fe] and [Zr/Fe] ratios for most M dwarfs are almost constant at about the solar value, and are identical to those found in GK dwarfs of the same metallicity. However, for Rb we find systematic underabundances ([Rb/Fe] < 0.0) by a factor two on average. Furthermore, a tendency is found for Rb - but not for other heavy elements (Sr, Zr) - to increase with increasing metallicity such that [Rb/Fe] ≳ 0.0 is attained at metallicities higher than solar. These are surprising results, never seen for any other heavy element, and are difficult to understand within the formulation of the s- and r-processes, both contributing sources to the Galactic Rb abundance. We discuss the reliability of these findings for Rb in terms of non-LTE (local thermodynamic equilibrium) effects, stellar activity, or an anomalous Rb abundance in the Solar System, but no explanation is found. We then interpret the full observed [Rb/Fe] versus [Fe/H] trend within the framework of theoretical predictions from state-of-the-art chemical evolution models for heavy elements, but a simple interpretation is not found either. In particular, the possible secondary behaviour of the [Rb/Fe] ratio at super-solar metallicities would require a much larger production of Rb than currently predicted in AGB stars through the s-process without overproducing Sr and Zr. Title: The CARMENES search for exoplanets around M dwarfs. A deep learning approach to determine fundamental parameters of target stars Authors: Passegger, V. M.; Bello-García, A.; Ordieres-Meré, J.; Caballero, J. A.; Schweitzer, A.; González-Marcos, A.; Ribas, I.; Reiners, A.; Quirrenbach, A.; Amado, P. J.; Azzaro, M.; Bauer, F. F.; Béjar, V. J. S.; Cortés-Contreras, M.; Dreizler, S.; Hatzes, A. P.; Henning, Th.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; Marfil, E.; Montes, D.; Morales, J. C.; Nagel, E.; Sarro, L. M.; Solano, E.; Tabernero, H. M.; Zechmeister, M. Bibcode: 2020A&A...642A..22P Altcode: 2020arXiv200801186P Existing and upcoming instrumentation is collecting large amounts of astrophysical data, which require efficient and fast analysis techniques. We present a deep neural network architecture to analyze high-resolution stellar spectra and predict stellar parameters such as effective temperature, surface gravity, metallicity, and rotational velocity. With this study, we firstly demonstrate the capability of deep neural networks to precisely recover stellar parameters from a synthetic training set. Secondly, we analyze the application of this method to observed spectra and the impact of the synthetic gap (i.e., the difference between observed and synthetic spectra) on the estimation of stellar parameters, their errors, and their precision. Our convolutional network is trained on synthetic PHOENIX-ACES spectra in different optical and near-infrared wavelength regions. For each of the four stellar parameters, Teff, log g, [M/H], and v sin i, we constructed a neural network model to estimate each parameter independently. We then applied this method to 50 M dwarfs with high-resolution spectra taken with CARMENES (Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Échelle Spectrographs), which operates in the visible (520-960 nm) and near-infrared wavelength range (960-1710 nm) simultaneously. Our results are compared with literature values for these stars. They show mostly good agreement within the errors, but also exhibit large deviations in some cases, especially for [M/H], pointing out the importance of a better understanding of the synthetic gap. Title: VizieR Online Data Catalog: CARMENES VIS RVs of 3 M dwarfs (Stock+, 2020) Authors: Stock, S.; Nagel, E.; Kemmer, J.; Passegger, V. M.; Reffert, S.; Quirrenbach, A.; Caballero, J. A.; Czesla, S.; Bejar, V. J. S.; Cardona, C.; Diez-Alonso, E.; Herrero, E.; Lalitha, S.; Schlecker, M.; Tal-Or, L.; Rodriguez, E.; Rodriguez-Lopez, C.; Ribas, I.; Reiners, A.; Amado, P. J.; Bauer, F. F.; Bluhm, P.; Cortes-Contreras, M.; Gonzalez-Cuesta, L.; Dreizler, S.; Hatzes, A. P.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kuerster, M.; Lafarga, M.; Lopez-Gonzalez, M. J.; Montes, D.; Morales, J. C.; Pedraz, S.; Schoefer, P.; Schweitzer, A.; Trifonov, T.; Zapatero Osorio, M. R.; Zechmeister, M. Bibcode: 2020yCat..36430112S Altcode: We acquired spectra with CARMENES (Quirrenbach et al., 2014, in Proc. SPIE, Vol. 9147, Ground-based and Airborne Instrumentation for Astronomy V, 91471F), a high-resolution precise echelle spectrograph mounted at the 3.5m telescope at the Calar Alto Observatory in Spain.

(3 data files). Title: VizieR Online Data Catalog: GJ 3473 (TOI-488) radial velocity curve (Kemmer+, 2020) Authors: Kemmer, J.; Stock, S.; Kossakowski, D.; Kaminski, A.; Molaverdikhani, K.; Schlecker, M.; Caballero, J. A.; Amado, P. J.; Astudillo-Defru, N.; Bonfils, X.; Ciardi, D.; Collins, K. A.; Espinoza, N.; Fukui, A.; Hirano, T.; Jenkins, J. M.; Latham, D. W.; Matthews, E. C.; Narita, N.; Palle, E.; Parviainen, H.; Quirrenbach, A.; Reiners, A.; Ribas, I.; Ricker, G.; Schlieder, J. E.; Seager, S.; Vanderspek, R.; Winn, J. N.; Almenara, J. M.; Bejar, V. J. S.; Bluhm, P.; Bouchy, F.; Boyd, P.; Christiansen, J. L.; Cifuentes, C.; Cloutier, R.; Collins, K. I.; Cortes-Contreras, M.; I. J. M., Crossfield; Crouzet, N.; de, Leon J. P.; Della-Rose, D. D.; Delfosse, X.; Dreizler, S.; Esparza-Borges, E.; Essack, Z.; Forveille, T.; Figueira, P.; Galadi-Enriquez, D.; Gan, T.; Glidden, A.; Gonzales, E. J.; Guerra, P.; Harakawa, H.; Hatzes, A. P.; Henning, T.; Herrero, E.; Hodapp, K.; Hori, Y.; Howell, S. B.; Ikoma, M.; Isogai, K.; Jeffers, S. V.; Kuerster, M.; Kawauchi, K.; Kimura, T.; Klagyivik, P.; Kotani, T.; Kurokawa, T.; Kusakabe, N.; Kuzuhara, M.; Lafarga, M.; Livingston, J. H.; Luqu!, E. R.; Mat Son, R.; Morales, J. C.; Mori, M.; Muirhead, P. S.; Murgas, F.; Nishikawa, J.; Nishiumi, T.; Omiya, M.; Reffert, S.; Rodriguez Lopez, C.; Santos, N. C.; Schoefer, P.; Schwarz, R. P.; Shiao, B.; Tamura, M.; Terada, Y.; Twicken, J. D.; Ueda, A.; Vievard, S.; Watanabe, N.; Zechmeister, M. Bibcode: 2020yCat..36420236K Altcode: High-resolution follow-up spectroscopy of the TESS planet candidates is arranged by the TESS follow-up programme (TFOP), "Precise Radial Velocities" SG4 subgroup.

We observed GJ 3473 with CARMENES. The observations began at the end of March 2019, just after the announcement of the transiting planet candidate, and ended in January 2020. In this period, we collected 67 pairs of VIS and NIR spectra with exposure times of about 30 min each.

In the course of the Subaru IRD TESS Intensive Follow-up Project (proposal S19A-069I), we observed GJ 3473 with the InfraRed Doppler spectrograph (IRD). A total of 56 frames were acquired for GJ 3473 by IRD on 12 different nights between April 2019 and December 2019.

GJ 3473 was also observed by the High Accuracy Radial velocity Planet Searcher (HARPS). The 32 observations presented here were taken between May 2019 and March 2020.

(1 data file). Title: The CARMENES search for exoplanets around M dwarfs. Convective shift and starspot constraints from chromatic radial velocities Authors: Baroch, D.; Morales, J. C.; Ribas, I.; Herrero, E.; Rosich, A.; Perger, M.; Anglada-Escudé, G.; Reiners, A.; Caballero, J. A.; Quirrenbach, A.; Amado, P. J.; Jeffers, S. V.; Cifuentes, C.; Passegger, V. M.; Schweitzer, A.; Lafarga, M.; Bauer, F. F.; Béjar, V. J. S.; Colomé, J.; Cortés-Contreras, M.; Dreizler, S.; Galadí-Enríquez, D.; Hatzes, A. P.; Henning, Th.; Kaminski, A.; Kürster, M.; Montes, D.; Rodríguez-López, C.; Zechmeister, M. Bibcode: 2020A&A...641A..69B Altcode: 2020arXiv200616608B Context. Variability caused by stellar activity represents a challenge to the discovery and characterization of terrestrial exoplanets and complicates the interpretation of atmospheric planetary signals.
Aims: We aim to use a detailed modeling tool to reproduce the effect of active regions on radial velocity measurements, which aids the identification of the key parameters that have an impact on the induced variability.
Methods: We analyzed the effect of stellar activity on radial velocities as a function of wavelength by simulating the impact of the properties of spots, shifts induced by convective motions, and rotation. We focused our modeling effort on the active star YZ CMi (GJ 285), which was photometrically and spectroscopically monitored with CARMENES and the Telescopi Joan Oró.
Results: We demonstrate that radial velocity curves at different wavelengths yield determinations of key properties of active regions, including spot-filling factor, temperature contrast, and location, thus solving the degeneracy between them. Most notably, our model is also sensitive to convective motions. Results indicate a reduced convective shift for M dwarfs when compared to solar-type stars (in agreement with theoretical extrapolations) and points to a small global convective redshift instead of blueshift.
Conclusions: Using a novel approach based on simultaneous chromatic radial velocities and light curves, we can set strong constraints on stellar activity, including an elusive parameter such as the net convective motion effect. Title: The CARMENES search for exoplanets around M dwarfs. Variability of the He I line at 10 830 Å Authors: Fuhrmeister, B.; Czesla, S.; Hildebrandt, L.; Nagel, E.; Schmitt, J. H. M. M.; Jeffers, S. V.; Caballero, J. A.; Hintz, D.; Johnson, E. N.; Schöfer, P.; Zechmeister, M.; Reiners, A.; Ribas, I.; Amado, P. J.; Quirrenbach, A.; Nortmann, L.; Bauer, F. F.; Béjar, V. J. S.; Cortés-Contreras, M.; Dreizler, S.; Galadí-Enríquez, D.; Hatzes, A. P.; Kaminski, A.; Kürster, M.; Lafarga, M.; Montes, D. Bibcode: 2020A&A...640A..52F Altcode: 2020arXiv200609372F The He I infrared (IR) triplet at 10 830 Å is known as an activity indicator in solar-type stars and has become a primary diagnostic in exoplanetary transmission spectroscopy. He I IR lines are a tracer of the stellar extreme-ultraviolet irradiation from the transition region and corona. We study the variability of the He I triplet lines in a spectral time series of 319 M dwarf stars that was obtained with the CARMENES high-resolution optical and near-infrared spectrograph at Calar Alto. We detect He I IR line variability in 18% of our sample stars, all of which show Hα in emission. Therefore, we find detectable He I variability in 78% of the sub-sample of stars with Hα emission. Detectable variability is strongly concentrated in the latest spectral sub-types, where the He I lines during quiescence are typically weak. The fraction of stars with detectable He I variation remains lower than 10% for stars earlier than M3.0 V, while it exceeds 30% for the later spectral sub-types. Flares are accompanied by particularly pronounced line variations, including strongly broadened lines with red and blue asymmetries. However, we also find evidence for enhanced He I absorption, which is potentially associated with increased high-energy irradiation levels at flare onset. Generally, He I and Hα line variations tend to be correlated, with Hα being the most sensitive indicator in terms of pseudo-equivalent width variation. This makes the He I triplet a favourable target for planetary transmission spectroscopy.

Full Table 2 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/640/A52 Title: The CARMENES search for exoplanets around M dwarfs. Measuring precise radial velocities in the near infrared: The example of the super-Earth CD Cet b Authors: Bauer, F. F.; Zechmeister, M.; Kaminski, A.; Rodríguez López, C.; Caballero, J. A.; Azzaro, M.; Stahl, O.; Kossakowski, D.; Quirrenbach, A.; Becerril Jarque, S.; Rodríguez, E.; Amado, P. J.; Seifert, W.; Reiners, A.; Schäfer, S.; Ribas, I.; Béjar, V. J. S.; Cortés-Contreras, M.; Dreizler, S.; Hatzes, A.; Henning, T.; Jeffers, S. V.; Kürster, M.; Lafarga, M.; Montes, D.; Morales, J. C.; Schmitt, J. H. M. M.; Schweitzer, A.; Solano, E. Bibcode: 2020A&A...640A..50B Altcode: 2020arXiv200601684B The high-resolution, dual channel, visible and near-infrared spectrograph CARMENES offers exciting opportunities for stellar and exoplanetary research on M dwarfs. In this work we address the challenge of reaching the highest radial velocity precision possible with a complex, actively cooled, cryogenic instrument, such as the near-infrared channel. We describe the performance of the instrument and the work flow used to derive precise Doppler measurements from the spectra. The capability of both CARMENES channels to detect small exoplanets is demonstrated with the example of the nearby M5.0 V star CD Cet (GJ 1057), around which we announce a super-Earth (4.0 ± 0.4 M) companion on a 2.29 d orbit.

Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, Almería, Spain, operated jointly by the Junta de Andalucía and the Instituto de Astrofísica de Andalucía (CSIC).

Based on observations collected at the European Southern Observatory, Paranal, Chile, under program 0103.C-0152(A), and La Silla, Chile, under programs 072.C-0488(E) and 183.C-0437(A). Title: Stellar atmospheric parameters of FGK-type stars (EW method) and M-type stars (spectral synthesis) from high-resolution optical and near-infrared CARMENES spectra Authors: Marfil, E.; Tabernero, H. M.; Montes, D.; Caballero, J. A.; Lázaro-Barrasa, F. J.; González Hernández, J. I.; Soto, M. G.; Nagel, E.; Kaminski, A.; Reiners, A.; Ribas, I.; Quirrenbach, A.; Amado, P. J.; Bauer, F. F.; Cortés-Contreras, M.; Dreizler, S.; Jeffers, S. V.; Kürster, M.; Lafarga, M.; Morales, J. C.; Passegger, V. M.; Schweitzer, A.; Zechmeister, M. Bibcode: 2020sea..confE.156M Altcode: We aim to review the equivalent width (EW) method and the spectral synthesis technique to derive stellar atmospheric parameters of FGKM-type stars in light of the optical and near-infrared spectra obtained with CARMENES, the high-resolution, double-channel spectrograph installed at the 3.5 m telescope at the Calar Alto Observatory (Almería, Spain). On the one hand, we show the results for 65 FGK-type stars observed with CARMENES and analysed with the S TE P AR code, a Python implementation of the EW method, placing special emphasis on the impact of the near-infrared wavelength region on the parameter computations. On the other hand, we also highlight the stellar atmospheric parameters obtained for the target M dwarfs in the CARMENES Guaranteed Time Observations (GTO) programme by means of the spectral synthesis technique as implemented in the SteParSyn code. Title: Precise mass and radius of a transiting super-Earth planet orbiting the M dwarf TOI-1235: a planet in the radius gap? Authors: Bluhm, P.; Luque, R.; Espinoza, N.; Pallé, E.; Caballero, J. A.; Dreizler, S.; Livingston, J. H.; Mathur, S.; Quirrenbach, A.; Stock, S.; Van Eylen, V.; Nowak, G.; López, E. D.; Csizmadia, Sz.; Zapatero Osorio, M. R.; Schöfer, P.; Lillo-Box, J.; Oshagh, M.; González-Álvarez, E.; Amado, P. J.; Barrado, D.; Béjar, V. J. S.; Cale, B.; Chaturvedi, P.; Cifuentes, C.; Cochran, W. D.; Collins, K. A.; Collins, K. I.; Cortés-Contreras, M.; Díez Alonso, E.; El Mufti, M.; Ercolino, A.; Fridlund, M.; Gaidos, E.; García, R. A.; Georgieva, I.; González-Cuesta, L.; Guerra, P.; Hatzes, A. P.; Henning, Th.; Herrero, E.; Hidalgo, D.; Isopi, G.; Jeffers, S. V.; Jenkins, J. M.; Jensen, E. L. N.; Kábath, P.; Kaminski, A.; Kemmer, J.; Korth, J.; Kossakowski, D.; Kürster, M.; Lafarga, M.; Mallia, F.; Montes, D.; Morales, J. C.; Morales-Calderón, M.; Murgas, F.; Narita, N.; Passegger, V. M.; Pedraz, S.; Persson, C. M.; Plavchan, P.; Rauer, H.; Redfield, S.; Reffert, S.; Reiners, A.; Ribas, I.; Ricker, G. R.; Rodríguez-López, C.; Santos, A. R. G.; Seager, S.; Schlecker, M.; Schweitzer, A.; Shan, Y.; Soto, M. G.; Subjak, J.; Tal-Or, L.; Trifonov, T.; Vanaverbeke, S.; Vanderspek, R.; Wittrock, J.; Zechmeister, M.; Zohrabi, F. Bibcode: 2020A&A...639A.132B Altcode: 2020arXiv200406218B We report the confirmation of a transiting planet around the bright weakly active M0.5 V star TOI-1235 (TYC 4384-1735-1, V ≈ 11.5 mag), whose transit signal was detected in the photometric time series of sectors 14, 20, and 21 of the TESS space mission. We confirm the planetary nature of the transit signal, which has a period of 3.44 d, by using precise RV measurements with the CARMENES, HARPS-N, and iSHELL spectrographs, supplemented by high-resolution imaging and ground-based photometry. A comparison of the properties derived for TOI-1235 b with theoretical models reveals that the planet has a rocky composition, with a bulk density slightly higher than that of Earth. In particular, we measure a mass of Mp = 5.9 ± 0.6 M and a radius of Rp = 1.69 ± 0.08 R, which together result in a density of ρp = 6.7- 1.1+ 1.3 g cm-3. When compared with other well-characterized exoplanetary systems, the particular combination of planetary radius and mass places our discovery in the radius gap, which is a transition region between rocky planets and planets with significant atmospheric envelopes. A few examples of planets occupying the radius gap are known to date. While the exact location of the radius gap for M dwarfs is still a matter of debate, our results constrain it to be located at around 1.7 R or larger at the insolation levels received by TOI-1235 b (~60 S). This makes it an extremely interesting object for further studies of planet formation and atmospheric evolution. Title: The CARMENES search for exoplanets around M dwarfs. Dynamical characterization of the multiple planet system GJ 1148 and prospects of habitable exomoons around GJ 1148 b Authors: Trifonov, T.; Lee, M. H.; Kürster, M.; Henning, Th.; Grishin, E.; Stock, S.; Tjoa, J.; Caballero, J. A.; Wong, K. H.; Bauer, F. F.; Quirrenbach, A.; Zechmeister, M.; Ribas, I.; Reffert, S.; Reiners, A.; Amado, P. J.; Kossakowski, D.; Azzaro, M.; Béjar, V. J. S.; Cortés-Contreras, M.; Dreizler, S.; Hatzes, A. P.; Jeffers, S. V.; Kaminski, A.; Lafarga, M.; Montes, D.; Morales, J. C.; Pavlov, A.; Rodríguez-López, C.; Schmitt, J. H. M. M.; Solano, E.; Barnes, R. Bibcode: 2020A&A...638A..16T Altcode: 2020arXiv200200906T Context. GJ 1148 is an M-dwarf star hosting a planetary system composed of two Saturn-mass planets in eccentric orbits with periods of 41.38 and 532.02 days.
Aims: We reanalyze the orbital configuration and dynamics of the GJ 1148 multi-planetary system based on new precise radial velocity measurements taken with CARMENES.
Methods: We combined new and archival precise Doppler measurements from CARMENES with those available from HIRES for GJ 1148 and modeled these data with a self-consistent dynamical model. We studied the orbital dynamics of the system using the secular theory and direct N-body integrations. The prospects of potentially habitable moons around GJ 1148 b were examined.
Results: The refined dynamical analyses show that the GJ 1148 system is long-term stable in a large phase-space of orbital parameters with an orbital configuration suggesting apsidal alignment, but not in any particular high-order mean-motion resonant commensurability. GJ 1148 b orbits inside the optimistic habitable zone (HZ). We find only a narrow stability region around the planet where exomoons can exist. However, in this stable region exomoons exhibit quick orbital decay due to tidal interaction with the planet.
Conclusions: The GJ 1148 planetary system is a very rare M-dwarf planetary system consisting of a pair of gas giants, the inner of which resides in the HZ. We conclude that habitable exomoons around GJ 1148 b are very unlikely to exist. Title: VizieR Online Data Catalog: M dwarfs HeI infrared triplet variability (Fuhrmeister+, 2020) Authors: Fuhrmeister, B.; Czesla, S.; Hildebrandt, L.; Nagel, E.; Schmitt, J. H. M. M.; Jeffers, S. V.; Caballero, J. A.; Hintz, D.; Johnson, E. N.; Schoefer, P.; Zechmeister, M.; Reiners, A.; Ribas, I.; Amado, P. J.; Quirrenbach, A.; Nortmann, L.; Bauer, F. F.; Bejar, V. J. S.; Cortes-Contreras, M.; Dreizler, S.; Galadi-Enriquez, D.; Hatzes, A. P.; Kaminski, A.; Kuerster, M.; Lafarga, M.; Montes, D. Bibcode: 2020yCat..36400052F Altcode: The HeI infrared (IR) triplet at 10830Å is known as an activity indicator and has become a primary diagnostic in exoplanetary transmission spectroscopy. The HeI IR lines are a tracer of the stellar extreme-ultraviolet irradiation from the transition region and corona. We study the variability of the HeI IR triplet lines in spectral time series of 319 M dwarf stars, obtained with the CARMENES spectrograph.

We measure the pseudo-equivalent width (pEW) in each stellar spectrum. The integration ranges for the line and the reference bands are found in Table 1 of the paper. For comparison purposes we also measure pEW values of Hα, the bluest CaII IR triplet line, and the HeI D3 line. From these measurements we compute the mean pEW, the median absolute deviation (MAD) and Pearson's correlation coefficients for the lines.

(1 data file). Title: A multiplanet system of super-Earths orbiting the brightest red dwarf star GJ 887 Authors: Jeffers, S. V.; Dreizler, S.; Barnes, J. R.; Haswell, C. A.; Nelson, R. P.; Rodríguez, E.; López-Gonz‧lez, M. J.; Morales, N.; Luque, R.; Zechmeister, M.; Vogt, S. S.; Jenkins, J. S.; Palle, E.; Berdi ñas, Z. M.; Coleman, G. A. L.; Díaz, M. R.; Ribas, I.; Jones, H. R. A.; Butler, R. P.; Tinney, C. G.; Bailey, J.; Carter, B. D.; O'Toole, S.; Wittenmyer, R. A.; Crane, J. D.; Feng, F.; Shectman, S. A.; Teske, J.; Reiners, A.; Amado, P. J.; Anglada-Escudé, G. Bibcode: 2020Sci...368.1477J Altcode: 2020arXiv200616372J The closet exoplanets to the Sun provide opportunities for detailed characterization of planets outside the Solar System. We report the discovery, using radial velocity measurements, of a compact multiplanet system of super-Earth exoplanets orbiting the nearby red dwarf star GJ 887. The two planets have orbital periods of 9.3 and 21.8 days. Assuming an Earth-like albedo, the equilibrium temperature of the 21.8-day planet is ~350 kelvin. The planets are interior to, but close to the inner edge of, the liquid-water habitable zone. We also detect an unconfirmed signal with a period of ~50 days, which could correspond to a third super-Earth in a more temperate orbit. Our observations show that GJ 887 has photometric variability below 500 parts per million, which is unusually quiet for a red dwarf. Title: The CARMENES search for exoplanets around M dwarfs. The He I infrared triplet lines in PHOENIX models of M 2-3 V stars Authors: Hintz, D.; Fuhrmeister, B.; Czesla, S.; Schmitt, J. H. M. M.; Schweitzer, A.; Nagel, E.; Johnson, E. N.; Caballero, J. A.; Zechmeister, M.; Jeffers, S. V.; Reiners, A.; Ribas, I.; Amado, P. J.; Quirrenbach, A.; Anglada-Escudé, G.; Bauer, F. F.; Béjar, V. J. S.; Cortés-Contreras, M.; Dreizler, S.; Galadí-Enríquez, D.; Guenther, E. W.; Hauschildt, P. H.; Kaminski, A.; Kürster, M.; Lafarga, M.; López del Fresno, M.; Montes, D.; Morales, J. C. Bibcode: 2020A&A...638A.115H Altcode: 2020arXiv200506246H The He I infrared (IR) line at a vacuum wavelength of 10 833 Å is a diagnostic for the investigation of atmospheres of stars and planets orbiting them. For the first time, we study the behavior of the He I IR line in a set of chromospheric models for M-dwarf stars, whose much denser chromospheres may favor collisions for the level population over photoionization and recombination, which are believed to be dominant in solar-type stars. For this purpose, we use published PHOENIX models for stars of spectral types M2 V and M3 V and also compute new series of models with different levels of activity following an ansatz developed for the case of the Sun. We perform a detailed analysis of the behavior of the He I IR line within these models. We evaluate the line in relation to other chromospheric lines and also the influence of the extreme ultraviolet (EUV) radiation field. The analysis of the He I IR line strengths as a function of the respective EUV radiation field strengths suggests that the mechanism of photoionization and recombination is necessary to form the line for inactive models, while collisions start to play a role in our most active models. Moreover, the published model set, which is optimized in the ranges of the Na I D2, Hα, and the bluest Ca II IR triplet line, gives an adequate prediction of the He I IR line for most stars of the stellar sample. Because especially the most inactive stars with weak He I IR lines are fit worst by our models, it seems that our assumption of a 100% filling factor of a single inactive component no longer holds for these stars. Title: The CARMENES search for exoplanets around M dwarfs. A super-Earth planet orbiting HD 79211 (GJ 338 B) Authors: González-Álvarez, E.; Zapatero Osorio, M. R.; Caballero, J. A.; Sanz-Forcada, J.; Béjar, V. J. S.; González-Cuesta, L.; Dreizler, S.; Bauer, F. F.; Rodríguez, E.; Tal-Or, L.; Zechmeister, M.; Montes, D.; López-González, M. J.; Ribas, I.; Reiners, A.; Quirrenbach, A.; Amado, P. J.; Anglada-Escudé, G.; Azzaro, M.; Cortés-Contreras, M.; Hatzes, A. P.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; Morales, J. C.; Pallé, E.; Perger, M.; Schmitt, J. H. M. M. Bibcode: 2020A&A...637A..93G Altcode: 2020arXiv200313052G
Aims: We report on radial velocity time series for two M0.0 V stars, GJ 338 B and GJ 338 A, using the CARMENES spectrograph, complemented by ground-telescope photometry from Las Cumbres and Sierra Nevada observatories. We aim to explore the presence of small planets in tight orbits using the spectroscopic radial velocity technique.
Methods: We obtained 159 and 70 radial velocity measurements of GJ 338 B and A, respectively, with the CARMENES visible channel between 2016 January and 2018 October. We also compiled additional relative radial velocity measurements from the literature and a collection of astrometric data that cover 200 a of observations to solve for the binary orbit.
Results: We found dynamical masses of 0.64 ± 0.07 M for GJ 338 B and 0.69 ± 0.07 M for GJ 338 A. The CARMENES radial velocity periodograms show significant peaks at 16.61 ± 0.04 d (GJ 338 B) and 16.3-1.3+3.5 d (GJ 338 A), which have counterparts at the same frequencies in CARMENES activity indicators and photometric light curves. We attribute these to stellar rotation. GJ 338 B shows two additional, significant signals at 8.27 ± 0.01 and 24.45 ± 0.02 d, with no obvious counterparts in the stellar activity indices. The former is likely the first harmonic of the star's rotation, while we ascribe the latter to the existence of a super-Earth planet with a minimum mass of 10.27-1.38+1.47 M orbiting GJ 338 B. We have not detected signals of likely planetary origin around GJ 338 A.
Conclusions: GJ 338 Bb lies inside the inner boundary of the habitable zone around its parent star. It is one of the least massive planets ever found around any member of stellar binaries. The masses, spectral types, brightnesses, and even the rotational periods are very similar for both stars, which are likely coeval and formed from the same molecular cloud, yet they differ in the architecture of their planetary systems.

Full Tables B.1-B.6 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/637/A93 Title: The CARMENES search for exoplanets around M dwarfs. Characterization of the nearby ultra-compact multiplanetary system YZ Ceti Authors: Stock, S.; Kemmer, J.; Reffert, S.; Trifonov, T.; Kaminski, A.; Dreizler, S.; Quirrenbach, A.; Caballero, J. A.; Reiners, A.; Jeffers, S. V.; Anglada-Escudé, G.; Ribas, I.; Amado, P. J.; Barrado, D.; Barnes, J. R.; Bauer, F. F.; Berdiñas, Z. M.; Béjar, V. J. S.; Coleman, G. A. L.; Cortés-Contreras, M.; Díez-Alonso, E.; Domínguez-Fernández, A. J.; Espinoza, N.; Haswell, C. A.; Hatzes, A.; Henning, T.; Jenkins, J. S.; Jones, H. R. A.; Kossakowski, D.; Kürster, M.; Lafarga, M.; Lee, M. H.; López González, M. J.; Montes, D.; Morales, J. C.; Morales, N.; Pallé, E.; Pedraz, S.; Rodríguez, E.; Rodríguez-López, C.; Zechmeister, M. Bibcode: 2020A&A...636A.119S Altcode: 2020arXiv200201772S Context. The nearby ultra-compact multiplanetary system YZ Ceti consists of at least three planets, and a fourth tentative signal. The orbital period of each planet is the subject of discussion in the literature due to strong aliasing in the radial velocity data. The stellar activity of this M dwarf also hampers significantly the derivation of the planetary parameters.
Aims: With an additional 229 radial velocity measurements obtained since the discovery publication, we reanalyze the YZ Ceti system and resolve the alias issues.
Methods: We use model comparison in the framework of Bayesian statistics and periodogram simulations based on a method by Dawson and Fabrycky to resolve the aliases. We discuss additional signals in the RV data, and derive the planetary parameters by simultaneously modeling the stellar activity with a Gaussian process regression model. To constrain the planetary parameters further we apply a stability analysis on our ensemble of Keplerian fits.
Results: We find no evidence for a fourth possible companion. We resolve the aliases: the three planets orbit the star with periods of 2.02 d, 3.06 d, and 4.66 d. We also investigate an effect of the stellar rotational signal on the derivation of the planetary parameters, in particular the eccentricity of the innermost planet. Using photometry we determine the stellar rotational period to be close to 68 d and we also detect this signal in the residuals of a three-planet fit to the RV data and the spectral activity indicators. From our stability analysis we derive a lower limit on the inclination of the system with the assumption of coplanar orbits which is imin = 0.9 deg. From the absence of a transit event with TESS, we derive an upper limit of the inclination of imax = 87.43 deg.
Conclusions: YZ Ceti is a prime example of a system where strong aliasing hindered the determination of the orbital periods of exoplanets. Additionally, stellar activity influences the derivation of planetary parameters and modeling them correctly is important for the reliable estimation of the orbital parameters in this specific compact system. Stability considerations then allow additional constraints to be placed on the planetary parameters.

Table B.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/636/A119. Title: The CARMENES search for exoplanets around M dwarfs. Radial velocities and activity indicators from cross-correlation functions with weighted binary masks Authors: Lafarga, M.; Ribas, I.; Lovis, C.; Perger, M.; Zechmeister, M.; Bauer, F. F.; Kürster, M.; Cortés-Contreras, M.; Morales, J. C.; Herrero, E.; Rosich, A.; Baroch, D.; Reiners, A.; Caballero, J. A.; Quirrenbach, A.; Amado, P. J.; Alacid, J. M.; Béjar, V. J. S.; Dreizler, S.; Hatzes, A. P.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Montes, D.; Pedraz, S.; Rodríguez-López, C.; Schmitt, J. H. M. M. Bibcode: 2020A&A...636A..36L Altcode: 2020arXiv200307471L Context. For years, the standard procedure to measure radial velocities (RVs) of spectral observations consisted in cross-correlating the spectra with a binary mask, that is, a simple stellar template that contains information on the position and strength of stellar absorption lines. The cross-correlation function (CCF) profiles also provide several indicators of stellar activity.
Aims: We present a methodology to first build weighted binary masks and, second, to compute the CCF of spectral observations with these masks from which we derive radial velocities and activity indicators. These methods are implemented in a python code that is publicly available.
Methods: To build the masks, we selected a large number of sharp absorption lines based on the profile of the minima present in high signal-to-noise ratio (S/N) spectrum templates built from observations of reference stars. We computed the CCFs of observed spectra and derived RVs and the following three standard activity indicators: full-width-at-half-maximum as well as contrast and bisector inverse slope.
Results: We applied our methodology to CARMENES high-resolution spectra and obtain RV and activity indicator time series of more than 300 M dwarf stars observed for the main CARMENES survey. Compared with the standard CARMENES template matching pipeline, in general we obtain more precise RVs in the cases where the template used in the standard pipeline did not have enough S/N. We also show the behaviour of the three activity indicators for the active star YZ CMi and estimate the absolute RV of the M dwarfs analysed using the CCF RVs.

Table A.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/636/A36 Title: Power spectra of solar brightness variations at various inclinations Authors: Nèmec, N. -E.; Shapiro, A. I.; Krivova, N. A.; Solanki, S. K.; Tagirov, R. V.; Cameron, R. H.; Dreizler, S. Bibcode: 2020A&A...636A..43N Altcode: 2020arXiv200210895N Context. Magnetic features on the surfaces of cool stars lead to variations in their brightness. Such variations on the surface of the Sun have been studied extensively. Recent planet-hunting space telescopes have made it possible to measure brightness variations in hundred thousands of other stars. The new data may undermine the validity of setting the sun as a typical example of a variable star. Putting solar variability into the stellar context suffers, however, from a bias resulting from solar observations being carried out from its near-equatorial plane, whereas stars are generally observed at all possible inclinations.
Aims: We model solar brightness variations at timescales from days to years as they would be observed at different inclinations. In particular, we consider the effect of the inclination on the power spectrum of solar brightness variations. The variations are calculated in several passbands that are routinely used for stellar measurements.
Methods: We employ the surface flux transport model to simulate the time-dependent spatial distribution of magnetic features on both the near and far sides of the Sun. This distribution is then used to calculate solar brightness variations following the Spectral And Total Irradiance REconstruction approach.
Results: We have quantified the effect of the inclination on solar brightness variability at timescales down to a single day. Thus, our results allow for solar brightness records to be made directly comparable to those obtained by planet-hunting space telescopes. Furthermore, we decompose solar brightness variations into components originating from the solar rotation and from the evolution of magnetic features. Title: VizieR Online Data Catalog: Absolute radial velocities of CARMENES M dwarfs (Lafarga+, 2020) Authors: Lafarga, M.; Ribas, I.; Lovis, C.; Perger, M.; Zechmeister, M.; Bauer, F. F.; Kuerster, M.; Cortes-Contreras, M.; Morales, J. C.; Herrero, E.; Rosich, A.; Baroch, D.; Reiners, A.; Caballero, J. A.; Quirrenbach, A.; Amado, P. J.; Alacid, J. M.; Bejar, V. J. S.; Dreizler, S.; Hatzes, A. P.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Montes, D.; Pedraz, S.; Rodriguez-Lopez, C.; Schmitt, J. H. M. M. Bibcode: 2020yCat..36360036L Altcode: Absolute radial velocities (RVs) of 323 M dwarf stars observed with CARMENES. The RVs were computed using the cross-correlation function (CCF) method with binary masks on CARMENES visual observations. The RV values and uncertainties also take into account the gravitational redshift and the convective blueshift of the stars. The gravitational redshift is computed using mass and radius values from Schweitzer et al., 2019A&A...625A..68S, Cat. J/A+A/625/A68. We consider the convective blueshift to be 0+/-100m/s for all stars.

(1 data file). Title: VizieR Online Data Catalog: HD 79211 CARMENES radial velocities (Gonzalez-Alvarez+, 2020) Authors: Gonzalez-Alvarez, E.; Zapatero Osorio, M. R.; Caballero, J. A.; Sanz-Forcada, J.; Bejar, V. J. S.; Gonzalez-Cuesta, L.; Dreizler, S.; Bauer, F. F.; Rodriguez, E.; Tal-Or, L.; Zechmeister, M.; Montes, D.; Lopez-Gonzalez, M. J.; Ribas, I.; Reiners, A.; Quirrenbach, A.; Amado, P. J.; Anglada-Escude, G.; Azzaro, M.; Cortes-Contreras, M.; Hatzes, A. P.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kuerster, M.; Lafarga, M.; Morales, J. C.; Palle, E.; Perger, M.; Schmitt, J. H. M. M. Bibcode: 2020yCat..36370093G Altcode: Detailed CARMENES RV analysis of the M0.0 V stars GJ 338 A (HD 79210) and GJ 338 B (HD 79211), a wide binary system with similar mass stellar components.

New RVs were obtained for each member of the stellar binary using the CARMENES fibre-fed, echelle spectrograph. CARMENES is installed at the 3.5m telescope of the Calar Alto Observatory in Almeria (Spain).

(6 data files). Title: Stellar activity consequence on the retrieved transmission spectra through chromatic Rossiter-McLaughlin observations Authors: Boldt, S.; Oshagh, M.; Dreizler, S.; Mallonn, M.; Santos, N. C.; Claret, A.; Reiners, A.; Sedaghati, E. Bibcode: 2020A&A...635A.123B Altcode: 2020arXiv200206373B Mostly multiband photometric transit observations have been used so far to retrieve broadband transmission spectra of transiting exoplanets in order to study their atmosphere. An alternative method has been proposed and has only been used once to recover transmission spectra using chromatic Rossiter-McLaughlin observations. Stellar activity has been shown to potentially imitate narrow and broadband features in the transmission spectra retrieved from multiband photometric observations; however, there has been no study regarding the influence of stellar activity on the retrieved transmission spectra through chromatic Rossiter-McLaughlin. In this study with the modified SOAP3.0 tool, we consider different types of stellar activity features (spots and plages), and we generated a large number of realistic chromatic Rossiter-McLaughlin curves for different types of planets and stars. We were then able to retrieve their transmission spectra to evaluate the impact of stellar activity on them. We find that chromatic Rossiter-McLaughlin observations are also not immune to stellar activity, which can mimic broadband features, such as Rayleigh scattering slope, in their retrieved transmission spectra. We also find that the influence is independent of the planet radius, orbital orientations, orbital period, and stellar rotation rate. However, more general simulations demonstrate that the probability of mimicking strong broadband features is lower than 25% and that can be mitigated by combining several Rossiter-McLaughlin observations obtained during several transits. Title: The binary content of multiple populations in NGC 3201 Authors: Kamann, S.; Giesers, B.; Bastian, N.; Brinchmann, J.; Dreizler, S.; Göttgens, F.; Husser, T. -O.; Latour, M.; Weilbacher, P. M.; Wisotzki, L. Bibcode: 2020A&A...635A..65K Altcode: 2019arXiv191201627K We investigate the binary content of the two stellar populations that coexist in the globular cluster NGC 3201. Previous studies of binary stars in globular clusters have reported higher binary fractions in their first populations (P1, having field-like abundances) compared to their second populations (P2, having anomalous abundances). This is interpreted as evidence for the latter forming more centrally concentrated. In contrast to previous studies, our analysis focusses on the cluster centre, where comparable binary fractions between the populations are predicted because of short relaxation times. However, we find that even in the centre of NGC 3201, the observed binary fraction of P1 is higher (23.1 ± 6.2)% compared to (8.2 ± 3.5)% in P2. Our results are difficult to reconcile with a scenario in which the populations only differ in their initial concentrations, but instead suggests that the populations also formed with different fractions of binary stars. Title: The MUSE-Faint survey. I. Spectroscopic evidence for a star cluster in Eridanus 2 and constraints on MACHOs as a constituent of dark matter Authors: Zoutendijk, Sebastiaan L.; Brinchmann, Jarle; Boogaard, Leindert A.; Gunawardhana, Madusha L. P.; Husser, Tim-Oliver; Kamann, Sebastian; Ramos Padilla, Andrés Felipe; Roth, Martin M.; Bacon, Roland; den Brok, Mark; Dreizler, Stefan; Krajnović, Davor Bibcode: 2020A&A...635A.107Z Altcode: 2020arXiv200108790Z
Aims: It has been shown that the ultra-faint dwarf galaxy Eridanus 2 may host a stellar cluster in its centre. If this cluster is shown to exist, it can be used to set constraints on the mass and abundance of massive astrophysical compact halo objects (MACHOs) as a form of dark matter. Previous research has shown promising expectations in the mass range of 10-100 M, but lacked spectroscopic measurements of the cluster. We aim to provide spectroscopic evidence regarding the nature of the putative star cluster in Eridanus 2 and to place constraints on MACHOs as a constituent of dark matter.
Methods: We present spectroscopic observations of the central square arcminute of Eridanus 2 from MUSE-Faint, a survey of ultra-faint dwarf galaxies with the Multi Unit Spectroscopic Explorer on the Very Large Telescope. We derived line-of-sight velocities for possible member stars of the putative cluster and for stars in the centre of Eridanus 2. We discuss the existence of the cluster and determine new constraints for MACHOs using the Fokker-Planck diffusion approximation.
Results: Out of 182 extracted spectra, we identify 26 member stars of Eridanus 2, seven of which are possible cluster members. We find intrinsic mean line-of-sight velocities of 79.7+3.1-3.8 km s-1 and 76.0+3.2-3.7 km s-1 for the cluster and the bulk of Eridanus 2, respectively, as well as intrinsic velocity dispersions of < 7.6 km s-1 (68% upper limit) and 10.3+3.9-3.2 km s-1, respectively. This indicates that the cluster most likely exists as a distinct dynamical population hosted by Eridanus 2 and that it does not have a surplus of dark matter over the background distribution. Among the member stars in the bulk of Eridanus 2, we find possible carbon stars, alluding to the existence of an intermediate-age population. We derived constraints on the fraction of dark matter that can consist of MACHOs with a given mass between 1 and 105 M. For dark matter consisting purely of MACHOs, the mass of the MACHOs must be less than ∼7.6 M and ∼44 M at a 68- and 95% confidence level, respectively.

Table 2 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/635/A107

Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under programme ID 0100.D-0807. Title: A stellar census in globular clusters with MUSE. Extending the CaT-metallicity relation below the horizontal branch and applying it to multiple populations Authors: Husser, Tim-Oliver; Latour, Marilyn; Brinchmann, Jarle; Dreizler, Stefan; Giesers, Benjamin; Göttgens, Fabian; Kamann, Sebastian; Roth, Martin M.; Weilbacher, Peter M.; Wendt, Martin Bibcode: 2020A&A...635A.114H Altcode: 2020arXiv200107725H
Aims: We use the spectra of more than 30 000 red giant branch (RGB) stars in 25 globular clusters (GC), obtained within the MUSE survey of Galactic globular clusters, to calibrate the Ca II triplet metallicity relation and derive metallicities for all individual stars. We investigate the overall metallicity distributions as well as those of the different populations within each cluster.
Methods: The Ca II triplet in the near-infrared at 8498, 8542, and 8662 Å is visible in stars with spectral types between F and M and can be used to determine their metallicities. In this work, we calibrate the relation using average cluster metallicities from literature and MUSE spectra, and extend it below the horizontal branch - a cutoff that has traditionally been made to avoid a non-linear relation - using a quadratic function. In addition to the classic relation based on V - VHB, we also present calibrations based on absolute magnitude and luminosity. The obtained relations were used to calculate metallicities for all the stars in the sample and to derive metallicity distributions for different populations within a cluster, which have been separated using so-called "chromosome maps" based on HST photometry.
Results: We show that despite the relatively low spectral resolution of MUSE (R = 1900 - 3700) we can derive single star metallicities with a mean statistical intra-cluster uncertainty of ∼0.12 dex. We present metallicity distributions for the RGB stars in 25 GCs and investigate the different metallicities of the populations P3 (and higher) in so-called metal-complex or Type II clusters, finding metallicity variations in all of them. We also detected unexpected metallicity variations in the Type I cluster NGC 2808 and confirm the Type II status of NGC 7078.

Table 8 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/635/A114 Title: VizieR Online Data Catalog: GJ 3512 radial velocity and light curves (Morales+, 2019) Authors: Morales, J. C.; Mustill, A. J.; Ribas, I.; Davies, M. B.; Reiners, A.; Bauer, F. F.; Kossakowski, D.; Herrero, E.; Rodriguez, E.; Lopez-Gonzalez, M. J.; Rodriguez-Lopez, C.; Bejar, V. J. S.; Gonzalez-Cuesta, L.; Luque, R.; Palle, E.; Perger, M.; Baroch, D.; Johansen, A.; Klahr, H.; Mordasini, C.; Anglada-Escude, G.; Caballero, J. A.; Cortes-Contreras, M.; Dreizler, S.; Lafarga, M.; Nagel, E.; Passegger, V. M.; Reffert, S.; Rosich, A.; Schweitzer, A.; Tal-Or, L.; Trifonov, T.; Zechmeister, M.; Quirrenbach, A.; Amado, P. J.; Guenther, E. W.; Hagen, H. -J.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kurster, M.; Montes, D.; Seifert, W.; Abellan, F. J.; Abril, M.; Aceituno, J.; Aceituno, F. J.; Alonso-Floriano, F. J.; Ammler-von Eiff, M.; Antona, R.; Arroyo-Torres, B.; Azzaro, M.; Barrado, D.; Becerril-Jarque, S.; Benitez, D.; Berdinas, Z. M.; Bergond, G.; Brinkmoller, M.; Del Burgo, C.; Burn, R.; Calvo-Ortega, R.; Cano, J.; Cardenas, M. C.; Cardona Guillen, C.; Carro, J.; Casal, E.; Casanova, V.; Casasayas-Barris, N.; Chaturvedi, P.; Cifuentes, C.; Claret, A.; Colome, J.; Czesla, S.; Diez-Alonso, E.; Dorda, R.; Emsenhuber, A.; Fernandez, M.; Fernandez-Martin, A.; Ferro, I. M.; Fuhrmeister, B.; Galadi-Enriquez, D.; Gallardo Cava, I.; Garcia Vargas, M. L.; Garcia-Piquer, A.; Gesa, L.; Gonzalez-Alvarez, E.; Gonzalez Hernandez, J. I.; Gonzalez-Peinado, R.; Guardia, J.; Guijarro, A.; de Guindos, E.; Hatzes, A. P.; Hauschildt, P. H.; Hedrosa, R. P.; Hermelo, I.; Hernandez Arabi, R.; Hernandez, Otero F.; Hintz, D.; Holgado, G.; Huber, A.; Huke, P.; Johnson, E. N.; de Juan, E.; Kehr, M.; Kemmer, J.; Kim, M.; Kluter, J.; Klutsch, A.; Labarga, F.; Labiche, N.; Lalitha, S.; Lampon, M.; Lara, L. M.; Launhardt, R.; Lazaro, F. J.; Lizon, J. -L.; Llamas, M.; Lodieu, N.; Lopez Del Fresno, M.; Lopez Salas, J. F.; Lopez-Santiago, J.; Magan Madinabeitia, H.; Mall, U.; Mancini, L.; Mandel, H.; Marfil, E.; Marin Molina, J. A.; Martin, E. L.; Martin-Fernandez, P.; Martin-Ruiz, S.; Martinez-Rodriguez, H.; Marvin, C. J.; Mirabet, E.; Moya, A.; Naranjo, V.; Nelson, R. P.; Nortmann, L.; Nowak, G.; Ofir, A.; Pascual, J.; Pavlov, A.; Pedraz, S.; Perez Medialde, A. D.; Perez-Calpena, A.; Perryman, M. A. C.; Rabaza, O.; Ramon Ballesta, A.; Rebolo, R.; Redondo, P.; Rix, H. -W.; Rodler, F.; Rodriguez Trinidad, A.; Sabotta, S.; Sadegi, S.; Salz, M.; Sanchez-Blanco, E.; Sanchez Carrasco, M. A.; Sanchez-Lopez, A.; Sanz-Forcada, J.; Sarkis, P.; Sarmiento, L. F.; Schafer, S.; Schlecker, M.; Schmitt, J. H. M. M.; Schofer, P.; Solano, E.; Sota, A.; Stahl, O.; Stock, S.; Stuber, T.; Sturmer, J.; Suarez, J. C.; Tabernero, H. M.; Tulloch, S. M.; Veredas, G.; Vico-Linares, J. I.; Vilardell, F.; Wagner, K.; Winkler, J.; Wolthoff, V.; Yan, F.; Zapatero Osorio, M. R. Bibcode: 2020yCatp021036502M Altcode: These tables list the radial velocities measured with the visual (VIS) and near-infrared (NIR) channels of the CARMENES spectrograph (Quirrenbach et al. 2018SPIE10702E..0WQ), and the stellar activity indices computed with SERVAL (Zechmeister et al. 2018A&A...609A..12Z). Photometry obtained from the Montsec, Sierra Nevada, and las Cumbres observatories is also listed here as used in the paper.

(4 data files). Title: RedDots: a temperate 1.5 Earth-mass planet candidate in a compact multiterrestrial planet system around GJ 1061 Authors: Dreizler, S.; Jeffers, S. V.; Rodríguez, E.; Zechmeister, M.; Barnes, J. R.; Haswell, C. A.; Coleman, G. A. L.; Lalitha, S.; Hidalgo Soto, D.; Strachan, J. B. P.; Hambsch, F. -J.; López-González, M. J.; Morales, N.; Rodríguez López, C.; Berdiñas, Z. M.; Ribas, I.; Pallé, E.; Reiners, A.; Anglada-Escudé, G. Bibcode: 2020MNRAS.493..536D Altcode: 2019arXiv190804717D; 2020MNRAS.tmp..235D Small low-mass stars are favourable targets for the detection of rocky habitable planets. In particular, planetary systems in the solar neighbourhood are interesting and suitable for precise characterization. The RedDots campaigns seek to discover rocky planets orbiting nearby low-mass stars. The 2018 campaign targeted GJ 1061, which is the 20th nearest star to the Sun. For three consecutive months we obtained nightly, high-precision radial velocity measurements with the HARPS spectrograph. We analysed these data together with archival HARPS data. We report the detection of three planet candidates with periods of 3.204 ± 0.001, 6.689 ± 0.005, and 13.03 ± 0.03 d, which are close to 1:2:4 period commensurability. After several considerations related to the properties of the noise and sampling, we conclude that a fourth signal is most likely explained by stellar rotation, although it may be due to a planet. The proposed three-planet system (and the potential four-planet solution) is long-term dynamically stable. Planet-planet gravitational interactions are below our current detection threshold. The minimum masses of the three planets range from 1.4 ± 0.2 to 1.8 ± 0.3 M. Planet d, with msin I = 1.64 ± 0.24 M, receives a similar amount of energy as Earth receives from the Sun. Consequently it lies within the liquid-water habitable zone of the star and has a similar equilibrium temperature to Earth. GJ 1061 has very similar properties to Proxima Centauri but activity indices point to lower levels of stellar activity. Title: The peculiar kinematics of the multiple populations in the globular cluster Messier 80 (NGC 6093) Authors: Kamann, S.; Dalessandro, E.; Bastian, N.; Brinchmann, J.; den Brok, M.; Dreizler, S.; Giesers, B.; Göttgens, F.; Husser, T. -O.; Krajnović, D.; van de Ven, G.; Watkins, L. L.; Wisotzki, L. Bibcode: 2020MNRAS.492..966K Altcode: 2019arXiv191206158K; 2019MNRAS.tmp.3140K We combine MUSE spectroscopy and Hubble Space Telescope ultraviolet (UV) photometry to perform a study of the chemistry and dynamics of the Galactic globular cluster Messier 80 (M80, NGC 6093). Previous studies have revealed three stellar populations that vary not only in their light-element abundances, but also in their radial distributions, with the concentration decreasing with increasing nitrogen enrichment. This remarkable trend, which sets M80 apart from other Galactic globular clusters, points towards a complex formation and evolutionary history. To better understand how M80 formed and evolved, revealing its internal kinematics is key. We find that the most N-enriched population rotates faster than the other two populations at a 2σ confidence level. While our data further suggest that the intermediate population shows the least amount of rotation, this trend is rather marginal (1-2σ). Using axisymmetric Jeans models, we show that these findings can be explained from the radial distributions of the populations if they possess different angular momenta. Our findings suggest that the populations formed with primordial kinematical differences. Title: The CARMENES search for exoplanets around M dwarfs. Photospheric parameters of target stars from high-resolution spectroscopy. II. Simultaneous multi-wavelength range modeling of activity insensitive lines (Corrigendum) Authors: Passegger, V. M.; Schweitzer, A.; Shulyak, D.; Nagel, E.; Hauschildt, P. H.; Reiners, A.; Amado, P. J.; Caballero, J. A.; Cortés-Contreras, M.; Domínguez-Fernández, A. J.; Quirrenbach, A.; Ribas, I.; Azzaro, M.; Anglada-Escudé, G.; Bauer, F. F.; Béjar, V. J. S.; Dreizler, S.; Guenther, E. W.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; Martín, E. L.; Montes, D.; Morales, J. C.; Schmitt, J. H. M. M.; Zechmeister, M. Bibcode: 2020A&A...634C...2P Altcode: No abstract at ADS Title: VizieR Online Data Catalog: EW and [Fe/H] for 30000 globular cluster RGB stars (Husser+ 2020) Authors: Husser, T. -O.; Latour, M.; Brinchmann, J.; Dreizler, S.; Giesers, B.; Goettgens, F.; Kamann, S.; Roth, M. M.; Weilbacher, P. M.; Wendt, M. Bibcode: 2020yCat..36350114H Altcode: We measured equivalent widths of >30000 red giant branch stars in 25 globular clusters from our large MUSE survey and used mean cluster metallicities to calibrate the CaT-metallicity relation, from which reduced equivalent widths and metallicities were calculated for all stars. Metallicities are given for four different calibrations, based on the classical linear relation with only stars brighter than the HB (1), all RGB stars and a quadratic relation (2), and two calibrations based on absolute magnitude (3) and luminosity (4). All metallicities are derived on the scale defined by Dias et al. (2016A&A...590A...9D). The star IDs are taken from the ACS Survey of Galactic Globular Clusters (Anderson et al., 2008AJ....135.2055A), if they exist in that catalog.

(1 data file). Title: VizieR Online Data Catalog: Spectroscopy of the Eri 2 cluster (Zoutendijk+, 2020) Authors: Zoutendijk, S. L.; Brinchmann, J.; Boogaard, L. A.; Gunawardhana, M. L. P.; Husser, T. -O.; Kamann, S.; Ramos Padilla, A. F.; Roth, M. M.; Bacon, R.; den Brok, M.; Dreizler, S.; Krajnovic, K. Bibcode: 2020yCat..36350107Z Altcode: This table contains sources observed with the Multi Unit Spectroscopic Explorer on the Very Large Telescope towards the centre of the ultra-faint dwarf galaxy Eridanus 2 and its possible stellar cluster. These measurements were used to determine the velocity distributions of the putative cluster and the bulk of Eridanus 2, to assess the nature of the cluster, and to derive constraints on massive astrophysical compact halo objects. The sources in this table were limited to those with a spectral signal to noise of at least 5, a spectrum not showing galactic emission lines, and a measurement of radial velocity; or those that we identified as potential carbon stars. The positions have been calibrated against GAIA DR2.

(1 data file). Title: VizieR Online Data Catalog: YZ Ceti CARMENES and HARPS radial velocity curve (Stock+, 2020) Authors: Stock, S.; Kemmer, J.; Reffert, S.; Trifonov, T.; Kaminski, A.; Dreizler, S.; Quirrenbach, A.; Caballero, J. A.; Reiners, A.; Jeffers, S. V.; Anglada-Escude, G.; Ribas, I.; Amado, P. J.; Barrado, D.; Barnes, J. R.; Bauer, F. F.; Berdinas, Z. M.; Bejar, V. J. S.; Coleman, G. A. L.; Cortes-Contreras, M.; Diez-Alonso, E.; Dominguez-Fernandez, A. J.; Espinoza, N.; Haswell, C. A.; Hatzes, A.; Henning, T.; Jenkins, J. S.; Jones, H. R. A.; Kossakowski, D.; Kuerster, M.; Lafarga, M.; Lee, M. H.; Lopez Gonzalez, M. J.; Montes, D.; Morales, J. C.; Morales, N.; Palle, E.; Pedraz, S.; Rodriguez, E.; Rodriguez-Lopez, C.; Zechmeister, M. Bibcode: 2020yCat..36360119S Altcode: We acquired spectra with CARMENES (Quirrenbach et al., 2014, in Proc. SPIE, Vol. 9147, Ground-based and Airborne Instrumentation for Astronomy V, 91471F), a high-resolution precise echelle spectrograph mounted at the 3.5m telescope at the Calar Alto Observatory in Spain. We combined this data with 334 high-resolution spectra from HARPS, of which 59 were collected by the Red Dots program (Dreizler et al., 2019, arXiv e-prints, arXiv:1908.04717) and the remaining by Astudillo-Defru et al. (2017A&A...605L..11A, Cat. J/A+A/605/L11).

(1 data file). Title: A stellar census in globular clusters with MUSE: Binaries in NGC 3201 Authors: Giesers, Benjamin; Kamann, Sebastian; Dreizler, Stefan; Husser, Tim-Oliver; Askar, Abbas; Göttgens, Fabian; Brinchmann, Jarle; Latour, Marilyn; Weilbacher, Peter M.; Wendt, Martin; Roth, Martin M. Bibcode: 2019A&A...632A...3G Altcode: 2019arXiv190904050G We utilise multi-epoch MUSE spectroscopy to study binary stars in the core of the Galactic globular cluster NGC 3201. Our sample consists of 3553 stars with 54 883 spectra in total comprising 3200 main-sequence stars up to 4 magnitudes below the turn-off. Each star in our sample has between 3 and 63 (with a median of 14) reliable radial velocity measurements within five years of observations. We introduce a statistical method to determine the probability of a star showing radial velocity variations based on the whole inhomogeneous radial velocity sample. Using HST photometry and an advanced dynamical MOCCA simulation of this specific cluster we overcome observational biases that previous spectroscopic studies had to deal with. This allows us to infer a binary frequency in the MUSE field of view and enables us to deduce the underlying true binary frequency of (6.75 ± 0.72)% in NGC 3201. The comparison of the MUSE observations with the MOCCA simulation suggests a large portion of primordial binaries. We can also confirm a radial increase in the binary fraction towards the cluster centre due to mass segregation. We discovered that in the core of NGC 3201 at least (57.5 ± 7.9)% of blue straggler stars are in a binary system. For the first time in a study of globular clusters, we were able to fit Keplerian orbits to a significant sample of 95 binaries. We present the binary system properties of eleven blue straggler stars and the connection to SX Phoenicis-type stars. We show evidence that two blue straggler formation scenarios, the mass transfer in binary (or triple) star systems and the coalescence due to binary-binary interactions, are present in our data. We also describe the binary and spectroscopic properties of four sub-subgiant (or red straggler) stars. Furthermore, we discovered two new black hole candidates with minimum masses (M sin i) of (7.68 ± 0.50) M, (4.4 ± 2.8) M, and refine the minimum mass estimate on the already published black hole to (4.53 ± 0.21) M. These black holes are consistent with an extensive black hole subsystem hosted by NGC 3201.

The full radial velocity sample (Table A.1) is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/632/A3 Title: The CARMENES search for exoplanets around M dwarfs. The He I triplet at 10830 Å across the M dwarf sequence Authors: Fuhrmeister, B.; Czesla, S.; Hildebrandt, L.; Nagel, E.; Schmitt, J. H. M. M.; Hintz, D.; Johnson, E. N.; Sanz-Forcada, J.; Schöfer, P.; Jeffers, S. V.; Caballero, J. A.; Zechmeister, M.; Reiners, A.; Ribas, I.; Amado, P. J.; Quirrenbach, A.; Bauer, F. F.; Béjar, V. J. S.; Cortés-Contreras, M.; Díez-Alonso, E.; Dreizler, S.; Galadí-Enríquez, D.; Guenther, E. W.; Kaminski, A.; Kürster, M.; Lafarga, M.; Montes, D. Bibcode: 2019A&A...632A..24F Altcode: 2019arXiv191100246F The He I infrared (IR) triplet at 10 830 Å is an important activity indicator for the Sun and in solar-type stars, however, it has rarely been studied in relation to M dwarfs to date. In this study, we use the time-averaged spectra of 319 single stars with spectral types ranging from M0.0 V to M9.0 V obtained with the CARMENES high resolution optical and near-infrared spectrograph at Calar Alto to study the properties of the He I IR triplet lines. In quiescence, we find the triplet in absorption with a decrease of the measured pseudo equivalent width (pEW) towards later sub-types. For stars later than M5.0 V, the He I triplet becomes undetectable in our study. This dependence on effective temperature may be related to a change in chromospheric conditions along the M dwarf sequence. When an emission in the triplet is observed, we attribute it to flaring. The absence of emission during quiescence is consistent with line formation by photo-ionisation and recombination, while flare emission may be caused by collisions within dense material. The He I triplet tends to increase in depth according to increasing activity levels, ultimately becoming filled in; however, we do not find a correlation between the pEW(He IR) and X-ray properties. This behaviour may be attributed to the absence of very inactive stars (LX/Lbol < -5.5) in our sample or to the complex behaviour with regard to increasing depth and filling in.

Full Table 2 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/632/A24 Title: VizieR Online Data Catalog: EREBOS project. I. (Schaffenroth+, 2019) Authors: Schaffenroth, V.; Barlow, B. N.; Geier, S.; Vuckovic, M.; Kilkenny, D.; Wolz, M.; Kupfer, T.; Heber, U.; Drechsel, H.; Kimeswenger, S.; Marsh, T.; Wolf, M.; Pelisoli, I.; Freudenthal, J.; Dreizler, S.; Kreuzer, S.; Ziegerer, E. Bibcode: 2019yCat..36300080S Altcode: The EREBOS (Eclipsing Reflection Effect Binaries from Optical Surveys) project aims to study a large sample of homogeneously selected HW Vir systems (eclipsing binaries with cool stellar or substellar companions), and in particular their orbital, atmospheric, and fundamental parameters.

Two different photometric surveys are used to search such systems: OGLE (a long-term, large-scale photometric sky survey focused on variability, see Udalski et al., 2015AcA....65....1U) and ATLAS (a high-cadence all-sky survey system designed to find dangerous near-Earth asteroids, see Tonry et al., 2018PASP..130f4505T). The number of known HW Vir systems results increased by a factor of almost ten.

(6 data files). Title: A stellar census in globular clusters with MUSE: multiple populations chemistry in NGC 2808 Authors: Latour, M.; Husser, T. -O.; Giesers, B.; Kamann, S.; Göttgens, F.; Dreizler, S.; Brinchmann, J.; Bastian, N.; Wendt, M.; Weilbacher, P. M.; Molinski, N. S. Bibcode: 2019A&A...631A..14L Altcode: 2019arXiv190904959L Context. Galactic globular clusters (GCs) are now known to host multiple populations displaying particular abundance variations. The different populations within a GC can be well distinguished following their position in the pseudo two-colors diagrams, also referred to as "chromosome maps". These maps are constructed using optical and near-UV photometry available from the Hubble Space Telescope (HST) UV survey of GCs. However, the chemical tagging of the various populations in the chromosome maps is hampered by the fact that HST photometry and elemental abundances are both only available for a limited number of stars.
Aims: The spectra collected as part of the MUSE survey of globular clusters provide a spectroscopic counterpart to the HST photometric catalogs covering the central regions of GCs. In this paper, we use the MUSE spectra of 1115 red giant branch (RGB) stars in NGC 2808 to characterize the abundance variations seen in the multiple populations of this cluster.
Methods: We used the chromosome map of NGC 2808 to divide the RGB stars into their respective populations. We then combined the spectra of all stars belonging to a given population, resulting in one high signal-to-noise ratio spectrum representative of each population.
Results: Variations in the spectral lines of O, Na, Mg, and Al are clearly detected among four of the populations. In order to quantify these variations, we measured equivalent width differences and created synthetic populations spectra that were used to determine abundance variations with respect to the primordial population of the cluster. Our results are in good agreement with the values expected from previous studies based on high-resolution spectroscopy. We do not see any significant variations in the spectral lines of Ca, K, and Ba. We also do not detect abundance variations among the stars belonging to the primordial population of NGC 2808.
Conclusions: We demonstrate that in spite of their low resolution, the MUSE spectra can be used to investigate abundance variations in the context of multiple populations.

The populations spectra and the list of stars included in these spectra are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/631/A14Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile (proposal IDs 094.D-0142(B), 096.D-0175(A)). Title: A stellar census in globular clusters with MUSE: A spectral catalogue of emission-line sources Authors: Göttgens, Fabian; Husser, Tim-Oliver; Kamann, Sebastian; Dreizler, Stefan; Giesers, Benjamin; Kollatschny, Wolfram; Weilbacher, Peter M.; Roth, Martin M.; Wendt, Martin Bibcode: 2019A&A...631A.118G Altcode: 2019arXiv190905872G
Aims: Globular clusters produce many exotic stars due to a much higher frequency of dynamical interactions in their dense stellar environments. Some of these objects were observed together with several hundred thousand other stars in our MUSE survey of 26 Galactic globular clusters. Assuming that at least a few exotic stars have exotic spectra (i.e. spectra that contain emission lines), we can use this large spectroscopic data set of over a million stellar spectra as a blind survey to detect stellar exotica in globular clusters.
Methods: To detect emission lines in each spectrum, we modelled the expected shape of an emission line as a Gaussian curve. This template was used for matched filtering on the differences between each observed 1D spectrum and its fitted spectral model. The spectra with the most significant detections of Hα emission are checked visually and cross-matched with published catalogues.
Results: We find 156 stars with Hα emission, including several known cataclysmic variables (CV) and two new CVs, pulsating variable stars, eclipsing binary stars, the optical counterpart of a known black hole, several probable sub-subgiants and red stragglers, and 21 background emission-line galaxies. We find possible optical counterparts to 39 X-ray sources, as we detected Hα emission in several spectra of stars that are close to known positions of Chandra X-ray sources. This spectral catalogue can be used to supplement existing or future X-ray or radio observations with spectra of potential optical counterparts to classify the sources.

Table A.2 and spectra (FITS) are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/631/A118 Title: VizieR Online Data Catalog: NGC 6397 stars MUSE spectra (Husser+, 2016) Authors: Husser, T. -O.; Kamann, S.; Dreizler, S.; Wendt, M.; Wulff, N.; Bacon, R.; Wisotzki, L.; Brinchmann, J.; Weilbacher, P. M.; Roth, M. M.; Monreal-Ibero, A. Bibcode: 2019yCat..35880148H Altcode: We observed the globular cluster NGC 6397 during MUSE commissioning, lasting from July 26nd to August 3rd, 2014, to explore the capabilities of MUSE in crowded stellar fields.

To obtain clean spectra in a crowded region such as a globular cluster, sophisticated analysis techniques are required.

Provided are all the obtained spectra with a signal-to-noise ratio of five or larger, i.e. 14271 spectra in total.

(3 data files). Title: VizieR Online Data Catalog: NGC 2808 stellar population spectra (Latour+, 2019) Authors: Latour, M.; Husser, T. -O.; Giesers, B.; Kamann, S.; Goettgens, F.; Dreizler, S.; Brinchmann, J.; Bastian, N.; Wendt, M.; Weilbacher, P. M.; Molinski, N. S. Bibcode: 2019yCat..36310014L Altcode: We provide the summed spectra of population 1 to 4. The radial velocities are corrected so that the spectrum are at rest wavelength. The table includes the list of stars whose spectrum are included in the combined spectra along with their population number.

(3 data files). Title: No evidence for intermediate-mass black holes in the globular clusters ω Cen and NGC 6624 Authors: Baumgardt, H.; He, C.; Sweet, S. M.; Drinkwater, M.; Sollima, A.; Hurley, J.; Usher, C.; Kamann, S.; Dalgleish, H.; Dreizler, S.; Husser, T. -O. Bibcode: 2019MNRAS.488.5340B Altcode: 2019arXiv190710845B; 2019MNRAS.tmp.1999B We compare the results of a large grid of N-body simulations with the surface brightness and velocity dispersion profiles of the globular clusters ω Cen and NGC 6624. Our models include clusters with varying stellar-mass black hole retention fractions and varying masses of a central intermediate-mass black hole (IMBH). We find that an ∼ 45 000 M IMBH, whose presence has been suggested based on the measured velocity dispersion profile of ω Cen, predicts the existence of about 20 fast-moving, m > 0.5 M, main-sequence stars with a (1D) velocity v > 60 km s-1 in the central 20 arcsec of ω Cen. However, no such star is present in the HST/ACS proper motion catalogue of Bellini et al. (2017), strongly ruling out the presence of a massive IMBH in the core of ω Cen. Instead, we find that all available data can be fitted by a model that contains 4.6 per cent of the mass of ω Cen in a centrally concentrated cluster of stellar-mass black holes. We show that this mass fraction in stellar-mass BHs is compatible with the predictions of stellar evolution models of massive stars. We also compare our grid of N-body simulations with NGC 6624, a cluster recently claimed to harbour a 20 000 M black hole based on timing observations of millisecond pulsars. However, we find that models with MIMBH > 1000 M IMBHs are incompatible with the observed velocity dispersion and surface brightness profile of NGC 6624, ruling out the presence of a massive IMBH in this cluster. Models without an IMBH provide again an excellent fit to NGC 6624. Title: The EREBOS project: Investigating the effect of substellar and low-mass stellar companions on late stellar evolution. Survey, target selection, and atmospheric parameters Authors: Schaffenroth, V.; Barlow, B. N.; Geier, S.; Vučković, M.; Kilkenny, D.; Wolz, M.; Kupfer, T.; Heber, U.; Drechsel, H.; Kimeswenger, S.; Marsh, T.; Wolf, M.; Pelisoli, I.; Freudenthal, J.; Dreizler, S.; Kreuzer, S.; Ziegerer, E. Bibcode: 2019A&A...630A..80S Altcode: 2019arXiv190709892S Eclipsing post-common-envelope binaries are highly important for resolving the poorly understood, very short-lived common-envelope phase of stellar evolution. Most hot subdwarfs (sdO/Bs) are the bare helium-burning cores of red giants that have lost almost all of their hydrogen envelope. This mass loss is often triggered by common-envelope interactions with close stellar or even substellar companions. Cool companions to hot subdwarf stars such as late-type stars and brown dwarfs are detectable from characteristic light-curve variations - reflection effects and often eclipses. In the recently published catalog of eclipsing binaries in the Galactic Bulge and in the Asteroid Terrestrial-impact Last Alert System (ATLAS) survey, we discovered 125 new eclipsing systems showing a reflection effect seen by visual inspection of the light curves and using a machine-learning algorithm, in addition to the 36 systems previously discovered by the Optical Gravitational Lesing Experiment (OGLE) team. The Eclipsing Reflection Effect Binaries from Optical Surveys (EREBOS) project aims at analyzing all newly discovered eclipsing binaries of the HW Vir type (hot subdwarf + close, cool companion) based on a spectroscopic and photometric follow up to derive the mass distribution of the companions, constrain the fraction of substellar companions, and determine the minimum mass needed to strip off the red-giant envelope. To constrain the nature of the primary we derived the absolute magnitude and the reduced proper motion of all our targets with the help of the parallaxes and proper motions measured by the Gaia mission and compared those to the Gaia white-dwarf candidate catalog. It was possible to derive the nature of a subset of our targets, for which observed spectra are available, by measuring the atmospheric parameter of the primary, confirming that less than 10% of our systems are not sdO/Bs with cool companions but are white dwarfs or central stars of planetary nebula. This large sample of eclipsing hot subdwarfs with cool companions allowed us to derive a significant period distribution for hot subdwarfs with cool companions for the first time showing that the period distribution is much broader than previously thought and is ideally suited to finding the lowest-mass companions to hot subdwarf stars. The comparison with related binary populations shows that the period distribution of HW Vir systems is very similar to WD+dM systems and central stars of planetary nebula with cool companions. In the future, several new photometric surveys will be carried out, which will further increase the sample of this project, providing the potential to test many aspects of common-envelope theory and binary evolution. Title: VizieR Online Data Catalog: HeI IR triplet measurements for M dwarfs (Fuhrmeister+, 2019) Authors: Fuhrmeister, B.; Czesla, S.; Hildebrandt, L.; Nagel, E.; Schmitt, J. H. M. M.; Hintz, D.; Johnson, E. N.; Sanz-Forcada, J.; Schoefer, P.; Jeffers, S. V.; Caballero, J. A.; Zechmeister, M.; Reiners, A.; Ribas, I.; Amado, P. J.; Quirrenbach, A.; Bauer, F. F.; Bejar, V. J. S.; Cortes-Contreras, M.; Diez-Alonso, E.; Dreizler, S.; Galadi-Enriquez, D.; Guenther, E. W.; Kaminski, A.; Kuerster, M.; Lafarga, M.; Montes, D. Bibcode: 2019yCat..36320024F Altcode: We measure the pseudo-equivalent width (pEW) in the averaged stellar spectra using a Voigt fit with four Voigt components to account for neighbouring lines. The fit does not account for the bluest HeI triplet component and treats the two redder components as one component as they are totally blended for the used resolution of 80400. For comparison purposes we give also pEW values of Hα, the bluest CaII IR triplet line, and the HeI D3 line which were obtained by integration over the line from the same spectra. As a further comparison for the activity level of the star we give LX/Lbol values mostly taken from the ROSAT all-sky survey.

(1 data file). Title: A giant exoplanet orbiting a very-low-mass star challenges planet formation models Authors: Morales, J. C.; Mustill, A. J.; Ribas, I.; Davies, M. B.; Reiners, A.; Bauer, F. F.; Kossakowski, D.; Herrero, E.; Rodríguez, E.; López-González, M. J.; Rodríguez-López, C.; Béjar, V. J. S.; González-Cuesta, L.; Luque, R.; Pallé, E.; Perger, M.; Baroch, D.; Johansen, A.; Klahr, H.; Mordasini, C.; Anglada-Escudé, G.; Caballero, J. A.; Cortés-Contreras, M.; Dreizler, S.; Lafarga, M.; Nagel, E.; Passegger, V. M.; Reffert, S.; Rosich, A.; Schweitzer, A.; Tal-Or, L.; Trifonov, T.; Zechmeister, M.; Quirrenbach, A.; Amado, P. J.; Guenther, E. W.; Hagen, H. -J.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Montes, D.; Seifert, W.; Abellán, F. J.; Abril, M.; Aceituno, J.; Aceituno, F. J.; Alonso-Floriano, F. J.; Ammler-von Eiff, M.; Antona, R.; Arroyo-Torres, B.; Azzaro, M.; Barrado, D.; Becerril-Jarque, S.; Benítez, D.; Berdiñas, Z. M.; Bergond, G.; Brinkmöller, M.; del Burgo, C.; Burn, R.; Calvo-Ortega, R.; Cano, J.; Cárdenas, M. C.; Cardona Guillén, C.; Carro, J.; Casal, E.; Casanova, V.; Casasayas-Barris, N.; Chaturvedi, P.; Cifuentes, C.; Claret, A.; Colomé, J.; Czesla, S.; Díez-Alonso, E.; Dorda, R.; Emsenhuber, A.; Fernández, M.; Fernández-Martín, A.; Ferro, I. M.; Fuhrmeister, B.; Galadí-Enríquez, D.; Gallardo Cava, I.; García Vargas, M. L.; Garcia-Piquer, A.; Gesa, L.; González-Álvarez, E.; González Hernández, J. I.; González-Peinado, R.; Guàrdia, J.; Guijarro, A.; de Guindos, E.; Hatzes, A. P.; Hauschildt, P. H.; Hedrosa, R. P.; Hermelo, I.; Hernández Arabi, R.; Hernández Otero, F.; Hintz, D.; Holgado, G.; Huber, A.; Huke, P.; Johnson, E. N.; de Juan, E.; Kehr, M.; Kemmer, J.; Kim, M.; Klüter, J.; Klutsch, A.; Labarga, F.; Labiche, N.; Lalitha, S.; Lampón, M.; Lara, L. M.; Launhardt, R.; Lázaro, F. J.; Lizon, J. -L.; Llamas, M.; Lodieu, N.; López del Fresno, M.; López Salas, J. F.; López-Santiago, J.; Magán Madinabeitia, H.; Mall, U.; Mancini, L.; Mandel, H.; Marfil, E.; Marín Molina, J. A.; Martín, E. L.; Martín-Fernández, P.; Martín-Ruiz, S.; Martínez-Rodríguez, H.; Marvin, C. J.; Mirabet, E.; Moya, A.; Naranjo, V.; Nelson, R. P.; Nortmann, L.; Nowak, G.; Ofir, A.; Pascual, J.; Pavlov, A.; Pedraz, S.; Pérez Medialdea, D.; Pérez-Calpena, A.; Perryman, M. A. C.; Rabaza, O.; Ramón Ballesta, A.; Rebolo, R.; Redondo, P.; Rix, H. -W.; Rodler, F.; Rodríguez Trinidad, A.; Sabotta, S.; Sadegi, S.; Salz, M.; Sánchez-Blanco, E.; Sánchez Carrasco, M. A.; Sánchez-López, A.; Sanz-Forcada, J.; Sarkis, P.; Sarmiento, L. F.; Schäfer, S.; Schlecker, M.; Schmitt, J. H. M. M.; Schöfer, P.; Solano, E.; Sota, A.; Stahl, O.; Stock, S.; Stuber, T.; Stürmer, J.; Suárez, J. C.; Tabernero, H. M.; Tulloch, S. M.; Veredas, G.; Vico-Linares, J. I.; Vilardell, F.; Wagner, K.; Winkler, J.; Wolthoff, V.; Yan, F.; Zapatero Osorio, M. R. Bibcode: 2019Sci...365.1441M Altcode: 2019arXiv190912174M Surveys have shown that super-Earth and Neptune-mass exoplanets are more frequent than gas giants around low-mass stars, as predicted by the core accretion theory of planet formation. We report the discovery of a giant planet around the very-low-mass star GJ 3512, as determined by optical and near-infrared radial-velocity observations. The planet has a minimum mass of 0.46 Jupiter masses, very high for such a small host star, and an eccentric 204-day orbit. Dynamical models show that the high eccentricity is most likely due to planet-planet interactions. We use simulations to demonstrate that the GJ 3512 planetary system challenges generally accepted formation theories, and that it puts constraints on the planet accretion and migration rates. Disk instabilities may be more efficient in forming planets than previously thought. Title: VizieR Online Data Catalog: Emission-line sources MUSE spectral catalogue (Goettgens+, 2019) Authors: Goettgens, F.; Husser, T. -O.; Kamann, S.; Dreizler, S.; Giesers, B.; Kollatschny, W.; Weilbacher, P. M.; Roth, M. M.; Wendt, M. Bibcode: 2019yCat..36310118G Altcode: The spectra were extracted from datacubes taken with MUSE at the VLT. We used matched filtering to search for emission-line objects (ELOs) in globular clusters. The tables contain the properties of the detected ELOs, including references to the literature. Please see the paper for details about which filter was used for the reported V magnitude, and which conventions are used for the cluster membership indicator and the indicator for radial velocity variations.

(3 data files). Title: VizieR Online Data Catalog: MUSE binaries in NGC 3201 (Giesers+, 2019) Authors: Giesers, B.; Kamann, S.; Dreizler, S.; Husser, T. -O.; Askar, A.; Goettgens, F.; Brinchmann, J.; Latour, M.; Weilbacher, P. M.; Wendt, M.; Roth, M. M. Bibcode: 2019yCat..36320003G Altcode: Since 2014, 27 Galactic globular clusters were observed (PI: S. Kamann, formerly S. Dreizler) with the integral field spectrograph Multi Unit Spectroscopic Explorer (MUSE) at the Very Large Telescope (VLT; Kamann et al. 2018MNRAS.473.5591K). In the wide field mode, MUSE covers a 1'x1' field of view (FoV) with a spatial sampling of 0.2" and a spectral sampling of 1.25Å (resolving power of 1770<R<3590) in the wavelength range from 4750 to 9350Å. MUSE allows to extract spectra of some thousand stars per exposure. For this paper, all observations of NGC 3201 obtained before May 2019 were used. In addition to the pointings listed in Kamann et al. (2018MNRAS.473.5591K), a deep field was also implemented. Table 1 lists the number of visits and total integration times for the different pointings. The data include adaptive optics (AO) observations, the standard observing mode since the AO system was commissioned in October 2017. The AO observations are treated in the same way as our previous observations.The only difference is that a wavelength window of each spectrum around the sodium lines (5805Å-5965Å) has to be masked due to the AO laser emission. The catalogue includes the full radial velocity sample obtained from 63 MUSE observations done for different pointings in NGC 3201 and the orbital parameters of the 95 well constrained binaries in NGC 3201.

(5 data files). Title: First light of engineered diffusers at the Nordic Optical Telescope reveal time variability of the optical eclipse depth of WASP-12b Authors: von Essen, C.; Stefansson, G.; Mallonn, M.; Pursimo, T.; Djupvik, A. A.; Mahadevan, S.; Kjeldsen, H.; Freudenthal, J.; Dreizler, S. Bibcode: 2019A&A...628A.115V Altcode: 2019arXiv190405362V We present the characterization of two engineered diffusers mounted on the 2.5-meter Nordic Optical Telescope, located at Roque de Los Muchachos, Spain. To assess the reliability and the efficiency of the diffusers, we carried out several test observations of two photometric standard stars, along with observations of one primary transit observation of TrES-3b in the red (R band), one of CoRoT-1b in the blue (B band), and three secondary eclipses of WASP-12b (V band). The achieved photometric precision is in all cases within the submillimagnitude level for exposures between 25 and 180 s. Along with a detailed analysis of the functionality of the diffusers, we add a new transit depth measurement in the blue (B band) to the already observed transmission spectrum of CoRoT-1b, disfavoring a Rayleigh slope. We also report variability of the eclipse depth of WASP-12b in the V band. For the WASP-12b secondary eclipses, we observe a secondary depth deviation of about 5σ, and a difference of 6σ and 2.5σ when compared to the values reported by other authors in a similar wavelength range determined from Hubble Space Telescope data. We further speculate about the potential physical processes or causes responsible for this observed variability.

The data of the light curves are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/628/A115 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. Bibcode: 2019yCat..18650068B Altcode: To achieve sufficient signal-to-noise for high-precision abundance work, we stacked >=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.

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.

Spectra previously obtained with the MIKE spectrograph and analyzed in Ramirez+ (2014A&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.

(2 data files). Title: Planetary system around the nearby M dwarf GJ 357 including a transiting, hot, Earth-sized planet optimal for atmospheric characterization Authors: Luque, R.; Pallé, E.; Kossakowski, D.; Dreizler, S.; Kemmer, J.; Espinoza, N.; Burt, J.; Anglada-Escudé, G.; Béjar, V. J. S.; Caballero, J. A.; Collins, K. A.; Collins, K. I.; Cortés-Contreras, M.; Díez-Alonso, E.; Feng, F.; Hatzes, A.; Hellier, C.; Henning, T.; Jeffers, S. V.; Kaltenegger, L.; Kürster, M.; Madden, J.; Molaverdikhani, K.; Montes, D.; Narita, N.; Nowak, G.; Ofir, A.; Oshagh, M.; Parviainen, H.; Quirrenbach, A.; Reffert, S.; Reiners, A.; Rodríguez-López, C.; Schlecker, M.; Stock, S.; Trifonov, T.; Winn, J. N.; Zapatero Osorio, M. R.; Zechmeister, M.; Amado, P. J.; Anderson, D. R.; Batalha, N. E.; Bauer, F. F.; Bluhm, P.; Burke, C. J.; Butler, R. P.; Caldwell, D. A.; Chen, G.; Crane, J. D.; Dragomir, D.; Dressing, C. D.; Dynes, S.; Jenkins, J. M.; Kaminski, A.; Klahr, H.; Kotani, T.; Lafarga, M.; Latham, D. W.; Lewin, P.; McDermott, S.; Montañés-Rodríguez, P.; Morales, J. C.; Murgas, F.; Nagel, E.; Pedraz, S.; Ribas, I.; Ricker, G. R.; Rowden, P.; Seager, S.; Shectman, S. A.; Tamura, M.; Teske, J.; Twicken, J. D.; Vanderspeck, R.; Wang, S. X.; Wohler, B. Bibcode: 2019A&A...628A..39L Altcode: 2019arXiv190412818L We report the detection of a transiting Earth-size planet around GJ 357, a nearby M2.5 V star, using data from the Transiting Exoplanet Survey Satellite (TESS). GJ 357 b (TOI-562.01) is a transiting, hot, Earth-sized planet (Teq = 525 ± 11 K) with a radius of Rb = 1.217 ± 0.084 R and an orbital period of Pb = 3.93 d. Precise stellar radial velocities from CARMENES and PFS, as well as archival data from HIRES, UVES, and HARPS also display a 3.93-day periodicity, confirming the planetary nature and leading to a planetary mass of Mb = 1.84 ± 0.31 M. In addition to the radial velocity signal for GJ 357 b, more periodicities are present in the data indicating the presence of two further planets in the system: GJ 357 c, with a minimum mass of Mc = 3.40 ± 0.46 M in a 9.12 d orbit, and GJ 357 d, with a minimum mass of Md = 6.1 ± 1.0 M in a 55.7 d orbit inside the habitable zone. The host is relatively inactive and exhibits a photometric rotation period of Prot = 78 ± 2 d. GJ 357 b isto date the second closest transiting planet to the Sun, making it a prime target for further investigations such as transmission spectroscopy. Therefore, GJ 357 b represents one of the best terrestrial planets suitable for atmospheric characterization with the upcoming JWST and ground-based ELTs.

RV data are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/628/A39 Title: Rocky planets from the CARMENES Survey Authors: Dreizler, Stefan Bibcode: 2019ESS.....410202D Altcode: Since the first discovery, more than 800 exoplanets have been detected through the radial velocity method, the majority orbiting solar-like stars. Although M-stars are the most frequent stars, very few planets have yet been found around M-stars of late spectral type.

CARMENES, operated since 2016, is a high-resolution visible-near-IR spectrograph dedicated to search for such low-mass planets around low-mass stars and already doubled the number of known planets with host stars below 0.2 MSun. Not surprisingly, also this stellar parameter range has its surprises in terms of planetary system architectures. We will give an overview of exoplanet detections (published and unpublished) from the CARMENES survey and then concentrate on the low-mass planets, including the very recent detection of two Earth-mass planets around Teegarden's star highlighting the capability of CARMENES. The planetary system is special since Teegarden's star is only one out of three planet host stars with an effective temperature below 3000K. Its two planets are within the optimistic and conservative habitable zone, respectively. Notably, the Earth, as well as other Solar System planets are currently or in near future in the transit visibility zone see from Teegarden's star. Title: VizieR Online Data Catalog: WASP-12, CoRoT-1 and TrES-3 light curves (von Essen+, 2019) Authors: von Essen, C.; Stefansson, G.; Mallonn, M.; Pursimo, T.; Djupvik, A. A.; Mahadevan, S.; Kjeldsen, H.; Freudenthal, J.; Dreizler, S. Bibcode: 2019yCat..36280115V Altcode: 5 differential photometry time series of primary transit events (first two) and secondary transit events (last three) of three different extrasolar planets.

(1 data file). Title: Kepler Object of Interest Network. III. Kepler-82f: a new non-transiting 21 M planet from photodynamical modelling Authors: Freudenthal, J.; von Essen, C.; Ofir, A.; Dreizler, S.; Agol, E.; Wedemeyer, S.; Morris, B. M.; Becker, A. C.; Deeg, H. J.; Hoyer, S.; Mallonn, M.; Poppenhaeger, K.; Herrero, E.; Ribas, I.; Boumis, P.; Liakos, A. Bibcode: 2019A&A...628A.108F Altcode: 2019arXiv190706534F Context. The Kepler Object of Interest Network (KOINet) is a multi-site network of telescopes around the globe organised for follow-up observations of transiting planet candidate Kepler objects of interest with large transit timing variations (TTVs). The main goal of KOINet is the completion of their TTV curves as the Kepler telescope stopped observing the original Kepler field in 2013.
Aims: We ensure a comprehensive characterisation of the investigated systems by analysing Kepler data combined with new ground-based transit data using a photodynamical model. This method is applied to the Kepler-82 system leading to its first dynamic analysis.
Methods: In order to provide a coherent description of all observations simultaneously, we combine the numerical integration of the gravitational dynamics of a system over the time span of observations with a transit light curve model. To explore the model parameter space, this photodynamical model is coupled with a Markov chain Monte Carlo algorithm.
Results: The Kepler-82b/c system shows sinusoidal TTVs due to their near 2:1 resonance dynamical interaction. An additional chopping effect in the TTVs of Kepler-82c hints to a further planet near the 3:2 or 3:1 resonance. We photodynamically analysed Kepler long- and short-cadence data and three new transit observations obtained by KOINet between 2014 and 2018. Our result reveals a non-transiting outer planet with a mass of mf = 20.9 ± 1.0 M near the 3:2 resonance to the outermost known planet, Kepler-82c. Furthermore, we determined the densities of planets b and c to the significantly more precise values ρb = 0.98-0.14+0.10 g cm-3 and ρc = 0.494-0.077+0.066 g cm-3.

Ground-based photometry is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/628/A108 Title: The CARMENES search for exoplanets around M dwarfs. Photospheric parameters of target stars from high-resolution spectroscopy. II. Simultaneous multiwavelength range modeling of activity insensitive lines Authors: Passegger, V. M.; Schweitzer, A.; Shulyak, D.; Nagel, E.; Hauschildt, P. H.; Reiners, A.; Amado, P. J.; Caballero, J. A.; Cortés-Contreras, M.; Domínguez-Fernández, A. J.; Quirrenbach, A.; Ribas, I.; Azzaro, M.; Anglada-Escudé, G.; Bauer, F. F.; Béjar, V. J. S.; Dreizler, S.; Guenther, E. W.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; Martín, E. L.; Montes, D.; Morales, J. C.; Schmitt, J. H. M. M.; Zechmeister, M. Bibcode: 2019A&A...627A.161P Altcode: 2019arXiv190700807P We present precise photospheric parameters of 282 M dwarfs determined from fitting the most recent version of PHOENIX models to high-resolution CARMENES spectra in the visible (0.52-0.96 μm) and NIR wavelength range (0.96-1.71 μm). With its aim to search for habitable planets around M dwarfs, several planets of different masses have been detected. The characterization of the target sample is important for the ability to derive and constrain the physical properties of any planetary systems that are detected. As a continuation of previous work in this context, we derived the fundamental stellar parameters effective temperature, surface gravity, and metallicity of the CARMENES M-dwarf targets from PHOENIX model fits using a χ2 method. We calculated updated PHOENIX stellar atmosphere models that include a new equation of state to especially account for spectral features of low-temperature stellar atmospheres as well as new atomic and molecular line lists. We show the importance of selecting magnetically insensitive lines for fitting to avoid effects of stellar activity in the line profiles. For the first time, we directly compare stellar parameters derived from multiwavelength range spectra, simultaneously observed for the same star. In comparison with literature values we show that fundamental parameters derived from visible spectra and visible and NIR spectra combined are in better agreement than those derived from the same spectra in the NIR alone.

Full Tables B.1 and B.2 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/627/A161 Title: VizieR Online Data Catalog: Radial velocities of GJ 357 (Luque+, 2019) Authors: Luque, R.; Palle, E.; Kossakowski, D.; Dreizler, S.; Kemmer, J.; Espinoza, N.; Burt, J.; Anglada-Escude, G.; Bejar, V. J. S.; Caballero, J. A.; Collins, K. A.; Collins, K. I.; Cortes-Contreras, M.; Diez-Alonso, E.; Feng, F.; Hatzes, A.; Hellier, C.; Henning, T.; Jeffers, S. V.; Kaltenegger, L.; Kuerster, M.; Madden, J.; Molaverdikhani, K.; Montes, D.; Narita, N.; Nowak, G.; Ofir, A.; Oshagh, M.; Parviainen, H.; Quirrenbach, A.; Reffert, S.; Reiners, A.; Rodriguez-Lopez, C.; Schlecker, M.; Stock, S.; Trifonov, T.; Winn, J. N.; Zapatero Osorio, M. R.; Zechmeister, M.; Amado, P. J.; Anderson, D. R.; Batalha, N. E.; Bauer, F. F.; Bluhm, P.; Burke, C. J.; Butler, R. P.; Caldwell, D. A.; Chen, G.; Crane, J. D.; Dragomir, D.; Dressing, C. D.; Dynes, S.; Jenkins, J. M.; Kaminski, A.; Klahr, H.; Kotani, T.; Lafarga, M.; Latham, D. W.; Lewin, P.; McDermott, S.; Montanes-Rodriguez, P.; Morales, J. C.; Murgas, F.; Nagel, E.; Pedraz, S.; Ribas, I.; Ricker, G. R.; Rowden, P.; Seager, S.; Shectman, S. A.; Tamura, M.; Teske, J.; Twicken, J. D.; Vanderspeck, R.; Wang, S. X.; Wohler, B. Bibcode: 2019yCat..36280039L Altcode: Radial velocities of GJ 357 from HIRES (Vogt et al., 1994, in Proc. SPIE, Vol. 2198, 362), UVES (programs 072.C-0495, 078.C-0829, and 173.C-0606), HARPS (Mayor et al., 2003Msngr.114...20M; programs 072.C-0488, 183.C-0437), CARMENES (Quirrenbach et al., 2016, in Proc. SPIE, Vol. 9147,91471F; 2018, in Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, Vol. 10702, 107020W), and PFS (Crane et al., 2010aepr.confE..19C).

(1 data file). Title: Proxima Centauri b is not a transiting exoplanet Authors: Jenkins, James S.; Harrington, Joseph; Challener, Ryan C.; Kurtovic, Nicolás T.; Ramirez, Ricardo; Peña, Jose; McIntyre, Kathleen J.; Himes, Michael D.; Rodríguez, Eloy; Anglada-Escudé, Guillem; Dreizler, Stefan; Ofir, Aviv; Peña Rojas, Pablo A.; Ribas, Ignasi; Rojo, Patricio; Kipping, David; Butler, R. Paul; Amado, Pedro J.; Rodríguez-López, Cristina; Kempton, Eliza M. -R.; Palle, Enric; Murgas, Felipe Bibcode: 2019MNRAS.487..268J Altcode: 2019MNRAS.tmp.1236J; 2019arXiv190501336J We report Spitzer Space Telescope observations during predicted transits of the exoplanet Proxima Centauri b. As the nearest terrestrial habitable-zone planet we will ever discover, any potential transit of Proxima b would place strong constraints on its radius, bulk density, and atmosphere. Subsequent transmission spectroscopy and secondary-eclipse measurements could then probe the atmospheric chemistry, physical processes, and orbit, including a search for biosignatures. However, our photometric results rule out planetary transits at the 200 ppm level at 4.5 μm, yielding a 3σ upper radius limit of 0.4 R (Earth radii). Previous claims of possible transits from optical ground- and space-based photometry were likely correlated noise in the data from Proxima Centauri's frequent flaring. Our study indicates dramatically reduced stellar activity at near-to-mid infrared wavelengths, compared to the optical. Proxima b is an ideal target for space-based infrared telescopes, if their instruments can be configured to handle Proxima's brightness. Title: The CARMENES search for exoplanets around M dwarfs. Detection of a mini-Neptune around LSPM J2116+0234 and refinement of orbital parameters of a super-Earth around GJ 686 (BD+18 3421) Authors: Lalitha, S.; Baroch, D.; Morales, J. C.; Passegger, V. M.; Bauer, F. F.; Cardona Guillén, C.; Dreizler, S.; Oshagh, M.; Reiners, A.; Ribas, I.; Caballero, J. A.; Quirrenbach, A.; Amado, P. J.; Béjar, V. J. S.; Colomé, J.; Cortés-Contreras, M.; Galadí-Enríquez, D.; González-Cuesta, L.; Guenther, E. W.; Hagen, H. -J.; Henning, T.; Herrero, E.; Husser, T. -O.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; Lodieu, N.; López-González, M. J.; Montes, D.; Perger, M.; Rosich, A.; Rodríguez, E.; Rodríguez-López, C.; Schmitt, J. H. M. M.; Tal-Or, L.; Zechmeister, M. Bibcode: 2019A&A...627A.116L Altcode: 2019arXiv190509075L Although M dwarfs are known for high levels of stellar activity, they are ideal targets for the search of low-mass exoplanets with the radial velocity (RV) method. We report the discovery of a planetary-mass companion around LSPM J2116+0234 (M3.0 V) and confirm the existence of a planet orbiting GJ 686 (BD+18 3421; M1.0 V). The discovery of the planet around LSPM J2116+0234 is based on CARMENES RV observations in the visual and near-infrared channels. We confirm the planet orbiting around GJ 686 by analyzing the RV data spanning over two decades of observationsfrom CARMENES VIS, HARPS-N, HARPS, and HIRES. We find planetary signals at 14.44 and 15.53 d in the RV data for LSPM J2116+0234 and GJ 686, respectively. Additionally, the RV, photometric time series, and various spectroscopic indicators show hints of variations of 42 d for LSPM J2116+0234 and 37 d for GJ 686, which we attribute to the stellar rotation periods. The orbital parameters of the planets are modeled with Keplerian fits together with correlated noise from the stellar activity. A mini-Neptune with a minimum mass of 11.8 M orbits LSPM J2116+0234 producing a RV semi-amplitude of 6.19 m s-1, while a super-Earth of mass 6.6 M orbits GJ 686 and produces a RV semi-amplitude of 3.0 m s-1. Both LSPM J2116+0234 and GJ 686 have planetary companions populating the regime of exoplanets with masses lower than 15 M and orbital periods <20 d.

Table A.1 and A.2 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/627/A116 Title: VizieR Online Data Catalog: Photometry of Kepler-82b and c transits (Freudenthal+, 2019) Authors: Freudenthal, J.; von Essen, C.; Ofir, A.; Dreizler, S.; Agol, E.; Wedemeyer, S.; Morris, B. M.; Becker, A. C.; Deeg, H. J.; Hoyer, S.; Mallonn, M.; Poppenhaeger, K.; Herrero, E.; Ribas, I.; Boumis, P.; Liakos, A. Bibcode: 2019yCat..36280108F Altcode: All our observations were carried out using R-band filter. We provide the differential photometry with varying reference stars for each observation together with the used detrending components. We measured one Kepler-82b and two Kepler-82c transits in three observations between 2014 and 2018.

(4 data files). Title: The CARMENES search for exoplanets around M dwarfs. Two temperate Earth-mass planet candidates around Teegarden's Star Authors: Zechmeister, M.; Dreizler, S.; Ribas, I.; Reiners, A.; Caballero, J. A.; Bauer, F. F.; Béjar, V. J. S.; González-Cuesta, L.; Herrero, E.; Lalitha, S.; López-González, M. J.; Luque, R.; Morales, J. C.; Pallé, E.; Rodríguez, E.; Rodríguez López, C.; Tal-Or, L.; Anglada-Escudé, G.; Quirrenbach, A.; Amado, P. J.; Abril, M.; Aceituno, F. J.; Aceituno, J.; Alonso-Floriano, F. J.; Ammler-von Eiff, M.; Antona Jiménez, R.; Anwand-Heerwart, H.; Arroyo-Torres, B.; Azzaro, M.; Baroch, D.; Barrado, D.; Becerril, S.; Benítez, D.; Berdiñas, Z. M.; Bergond, G.; Bluhm, P.; Brinkmöller, M.; del Burgo, C.; Calvo Ortega, R.; Cano, J.; Cardona Guillén, C.; Carro, J.; Cárdenas Vázquez, M. C.; Casal, E.; Casasayas-Barris, N.; Casanova, V.; Chaturvedi, P.; Cifuentes, C.; Claret, A.; Colomé, J.; Cortés-Contreras, M.; Czesla, S.; Díez-Alonso, E.; Dorda, R.; Fernández, M.; Fernández-Martín, A.; Fuhrmeister, B.; Fukui, A.; Galadí-Enríquez, D.; Gallardo Cava, I.; Garcia de la Fuente, J.; Garcia-Piquer, A.; García Vargas, M. L.; Gesa, L.; Góngora Rueda, J.; González-Álvarez, E.; González Hernández, J. I.; González-Peinado, R.; Grözinger, U.; Guàrdia, J.; Guijarro, A.; de Guindos, E.; Hatzes, A. P.; Hauschildt, P. H.; Hedrosa, R. P.; Helmling, J.; Henning, T.; Hermelo, I.; Hernández Arabi, R.; Hernández Castaño, L.; Hernández Otero, F.; Hintz, D.; Huke, P.; Huber, A.; Jeffers, S. V.; Johnson, E. N.; de Juan, E.; Kaminski, A.; Kemmer, J.; Kim, M.; Klahr, H.; Klein, R.; Klüter, J.; Klutsch, A.; Kossakowski, D.; Kürster, M.; Labarga, F.; Lafarga, M.; Llamas, M.; Lampón, M.; Lara, L. M.; Launhardt, R.; Lázaro, F. J.; Lodieu, N.; López del Fresno, M.; López-Puertas, M.; López Salas, J. F.; López-Santiago, J.; Magán Madinabeitia, H.; Mall, U.; Mancini, L.; Mandel, H.; Marfil, E.; Marín Molina, J. A.; Maroto Fernández, D.; Martín, E. L.; Martín-Fernández, P.; Martín-Ruiz, S.; Marvin, C. J.; Mirabet, E.; Montañés-Rodríguez, P.; Montes, D.; Moreno-Raya, M. E.; Nagel, E.; Naranjo, V.; Narita, N.; Nortmann, L.; Nowak, G.; Ofir, A.; Oshagh, M.; Panduro, J.; Parviainen, H.; Pascual, J.; Passegger, V. M.; Pavlov, A.; Pedraz, S.; Pérez-Calpena, A.; Pérez Medialdea, D.; Perger, M.; Perryman, M. A. C.; Rabaza, O.; Ramón Ballesta, A.; Rebolo, R.; Redondo, P.; Reffert, S.; Reinhardt, S.; Rhode, P.; Rix, H. -W.; Rodler, F.; Rodríguez Trinidad, A.; Rosich, A.; Sadegi, S.; Sánchez-Blanco, E.; Sánchez Carrasco, M. A.; Sánchez-López, A.; Sanz-Forcada, J.; Sarkis, P.; Sarmiento, L. F.; Schäfer, S.; Schmitt, J. H. M. M.; Schöfer, P.; Schweitzer, A.; Seifert, W.; Shulyak, D.; Solano, E.; Sota, A.; Stahl, O.; Stock, S.; Strachan, J. B. P.; Stuber, T.; Stürmer, J.; Suárez, J. C.; Tabernero, H. M.; Tala Pinto, M.; Trifonov, T.; Veredas, G.; Vico Linares, J. I.; Vilardell, F.; Wagner, K.; Wolthoff, V.; Xu, W.; Yan, F.; Zapatero Osorio, M. R. Bibcode: 2019A&A...627A..49Z Altcode: 2019arXiv190607196Z Context. Teegarden's Star is the brightest and one of the nearest ultra-cool dwarfs in the solar neighbourhood. For its late spectral type (M7.0 V), the star shows relatively little activity and is a prime target for near-infrared radial velocity surveys such as CARMENES.
Aims: As part of the CARMENES search for exoplanets around M dwarfs, we obtained more than 200 radial-velocity measurements of Teegarden's Star and analysed them for planetary signals.
Methods: We find periodic variability in the radial velocities of Teegarden's Star. We also studied photometric measurements to rule out stellar brightness variations mimicking planetary signals.
Results: We find evidence for two planet candidates, each with 1.1 M minimum mass, orbiting at periods of 4.91 and 11.4 d, respectively. No evidence for planetary transits could be found in archival and follow-up photometry. Small photometric variability is suggestive of slow rotation and old age.
Conclusions: The two planets are among the lowest-mass planets discovered so far, and they are the first Earth-mass planets around an ultra-cool dwarf for which the masses have been determined using radial velocities.

Tables D.1 and D.2 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/627/A49 Title: Magnetic fields in M dwarfs from the CARMENES survey Authors: Shulyak, D.; Reiners, A.; Nagel, E.; Tal-Or, L.; Caballero, J. A.; Zechmeister, M.; Béjar, V. J. S.; Cortés-Contreras, M.; Martin, E. L.; Kaminski, A.; Ribas, I.; Quirrenbach, A.; Amado, P. J.; Anglada-Escudé, G.; Bauer, F. F.; Dreizler, S.; Guenther, E. W.; Henning, T.; Jeffers, S. V.; Kürster, M.; Lafarga, M.; Montes, D.; Morales, J. C.; Pedraz, S. Bibcode: 2019A&A...626A..86S Altcode: 2019arXiv190412762S Context. M dwarfs are known to generate the strongest magnetic fields among main-sequence stars with convective envelopes, but we are still lacking a consistent picture of the link between the magnetic fields and underlying dynamo mechanisms, rotation, and activity.
Aims: In this work we aim to measure magnetic fields from the high-resolution near-infrared spectra taken with the CARMENES radial-velocity planet survey in a sample of 29 active M dwarfs and compare our results against stellar parameters.
Methods: We used the state-of-the-art radiative transfer code to measure total magnetic flux densities from the Zeeman broadening of spectral lines and filling factors.
Results: We detect strong kG magnetic fields in all our targets. In 16 stars the magnetic fields were measured for the first time. Our measurements are consistent with the magnetic field saturation in stars with rotation periods P < 4 d. The analysis of the magnetic filling factors reveal two different patterns of either very smooth distribution or a more patchy one, which can be connected to the dynamo state of the stars and/or stellar mass.
Conclusions: Our measurements extend the list of M dwarfs with strong surface magnetic fields. They also allow us to better constrain the interplay between the magnetic energy, stellar rotation, and underlying dynamo action. The high spectral resolution and observations at near-infrared wavelengths are the beneficial capabilities of the CARMENES instrument that allow us to address important questions about the stellar magnetism. Title: VizieR Online Data Catalog: CARMENES stars multi wavelength measurements (Passegger+, 2019) Authors: Passegger, V. M.; Schweitzer, A.; Shulyak, D.; Nagel, E.; Hauschildt, P. H.; Reiners, A.; Amado, P. J.; Caballero, J. A.; Cortes-Contreras, M.; Dominguez-Fernandez, A. J.; Quirrenbach, A.; Ribas, I.; Azarro, M.; Anglada-Escude, G.; Bauer, F. F.; Bejar, V. J. S.; Dreizler, S.; Guenther, E. W.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kuerster, M.; Lafarga, M.; Martin, E. L.; Montes, D.; Morales, J. C.; Schmidt, J. H. M. M.; Zechmeister, M. Bibcode: 2019yCat..36270161P Altcode: We present basic photospheric parameters of 282 M dwarfs within the CARMENES survey in the visible and near-infrared wavelength ranges. In table_b1 we provide Carmencita identifier (Karmn), Simbad name, equatorial coordinates, spectral type, rotational velocity, assumed age, and an activity flag for each star in our sample. In table_b2 we give effective temperature, surface gravity and [Fe/H] for each star in different wavelength ranges (VIS+NIR, NIR, and VIS), together with their errors.

(2 data files). Title: BlueMUSE: Project Overview and Science Cases Authors: Richard, Johan; Bacon, Roland; Blaizot, Jérémy; Boissier, Samuel; Boselli, Alessandro; NicolasBouché; Brinchmann, Jarle; Castro, Norberto; Ciesla, Laure; Crowther, Paul; Daddi, Emanuele; Dreizler, Stefan; Duc, Pierre-Alain; Elbaz, David; Epinat, Benoit; Evans, Chris; Fossati, Matteo; Fumagalli, Michele; Garcia, Miriam; Garel, Thibault; Hayes, Matthew; Adamo, Angela; Herrero, Artemio; Hugot, Emmanuel; Humphrey, Andrew; Jablonka, Pascale; Kamann, Sebastian; Kaper, Lex; Kelz, Andreas; Kneib, Jean-Paul; de Koter, Alex; Krajnović, Davor; Kudritzki, Rolf-Peter; Langer, Norbert; Lardo, Carmela; Leclercq, Floriane; Lennon, Danny; Mahler, Guillaume; Martins, Fabrice; Massey, Richard; Mitchell, Peter; Monreal-Ibero, Ana; Najarro, Paco; Opitom, Cyrielle; Papaderos, Polychronis; Péroux, Céline; Revaz, Yves; Roth, Martin M.; Rousselot, Philippe; Sander, Andreas; Simmonds Wagemann, Charlotte; Smail, Ian; Swinbank, Anthony Mark; Tramper, Frank; Urrutia, Tanya; Verhamme, Anne; Vink, Jorick; Walsh, Jeremy; Weilbacher, Peter; Wendt, Martin; Wisotzki, Lutz; Yang, Bin Bibcode: 2019arXiv190601657R Altcode: We present the concept of BlueMUSE, a blue-optimised, medium spectral resolution, panoramic integral field spectrograph based on the MUSE concept and proposed for the Very Large Telescope. With an optimised transmission down to 350 nm, a larger FoV (1.4 x 1.4 arcmin$^2$) and a higher spectral resolution compared to MUSE, BlueMUSE will open up a new range of galactic and extragalactic science cases allowed by its specific capabilities, beyond those possible with MUSE. For example a survey of massive stars in our galaxy and the Local Group will increase the known population of massive stars by a factor $>$100, to answer key questions about their evolution. Deep field observations with BlueMUSE will also significantly increase samples of Lyman-alpha emitters, spanning the era of Cosmic Noon. This will revolutionise the study of the distant Universe: allowing the intergalactic medium to be detected unambiguously in emission, enabling the study of the exchange of baryons between galaxies and their surroundings. By 2030, at a time when the focus of most of the new large facilities (ELT, JWST) will be on the infra-red, BlueMUSE will be a unique facility, outperforming any ELT instrument in the Blue/UV. It will have a strong synergy with ELT, JWST as well as ALMA, SKA, Euclid and Athena. Title: VizieR Online Data Catalog: LSPM J2116+0234 and GJ 686 radial velocities (Lalitha+, 2019) Authors: Lalitha, S.; Baroch, D.; Morales, J. C.; Passegger, V. M.; Bauer, F. F.; Cardona Guillen, C.; Dreizler, S.; Oshagh, M.; Reiners, A.; Ribas, I.; Caballero, J. A.; Quirrenbach, A.; Amado, P. J.; Bejar, V. J. S.; Colome, J.; Cortes-Contreras, M.; Galadi-Enriquez, D.; Gonzalez-Cuesta, L.; Guenther, E. W.; Hagen, H. -J.; Henning, T.; Herrero, E.; Husser, T. -O.; Jeffers, S. V.; Kaminski, A.; Kuerster, M.; Lafarga, M.; Lodieu, N.; Lopez-Gonzalez, M. J.; Montes, D.; Perger, M.; Rosich, A.; Rodriguez, E.; Rodriguez-Lopez, C.; Schmitt, J. H. M. M.; Tal-Or, L.; Zechmeister, M. Bibcode: 2019yCat..36270116L Altcode: We analysed radial velocity data from the CARMENES NIR and VIS channels for LSPM J2116+0234, and from CARMENES VIS channel, HARPS and HIRES for GJ 686. All the RVs are corrected for barycentric motion and secular acceleration. The CARMENES measurements were taken in the context of the CARMENES search for exoplanets around M dwarfs. The CARMENES instrument consists of two channels: the VIS channel obtains spectra at a resolution of R=94600 in the wavelength range 520-960nm, while the NIR channel yields spectra of R=80400 covering 960-1710nm. Both channels are calibrated in wavelength with hollow-cathode lamps and use temperature- and pressure-stabilized Fabry-Perot etalons to interpolate the wavelength solution and simultaneously monitor the spectrograph drift during nightly operations (Bauer et al., 2015A&A...581A.117B).

(2 data files). Title: Discovery of an old nova remnant in the Galactic globular cluster M 22 Authors: Göttgens, Fabian; Weilbacher, Peter M.; Roth, Martin M.; Dreizler, Stefan; Giesers, Benjamin; Husser, Tim-Oliver; Kamann, Sebastian; Brinchmann, Jarle; Kollatschny, Wolfram; Monreal-Ibero, Ana; Schmidt, Kasper B.; Wendt, Martin; Wisotzki, Lutz; Bacon, Roland Bibcode: 2019A&A...626A..69G Altcode: 2019arXiv190411515G A nova is a cataclysmic event on the surface of a white dwarf in a binary system that increases the overall brightness by several orders of magnitude. Although binary systems with a white dwarf are expected to be overabundant in globular clusters compared with in the Galaxy, only two novae from Galactic globular clusters have been observed. We present the discovery of an emission nebula in the Galactic globular cluster M 22 (NGC 6656) in observations made with the integral-field spectrograph MUSE. We extracted the spectrum of the nebula and used the radial velocity determined from the emission lines to confirm that the nebula is part of NGC 6656. Emission-line ratios were used to determine the electron temperature and density. It is estimated to have a mass of 1-17 × 10-5M. This mass and the emission-line ratios indicate that the nebula is a nova remnant. Its position coincides with the reported location of a "guest star", an ancient Chinese term for transients, observed in May 48 BCE. With this discovery, this nova may be one of the oldest confirmed extra-solar events recorded in human history.

Datacubes are also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/626/A69 Title: The CARMENES search for exoplanets around M dwarfs. Different roads to radii and masses of the target stars Authors: Schweitzer, A.; Passegger, V. M.; Cifuentes, C.; Béjar, V. J. S.; Cortés-Contreras, M.; Caballero, J. A.; del Burgo, C.; Czesla, S.; Kürster, M.; Montes, D.; Zapatero Osorio, M. R.; Ribas, I.; Reiners, A.; Quirrenbach, A.; Amado, P. J.; Aceituno, J.; Anglada-Escudé, G.; Bauer, F. F.; Dreizler, S.; Jeffers, S. V.; Guenther, E. W.; Henning, T.; Kaminski, A.; Lafarga, M.; Marfil, E.; Morales, J. C.; Schmitt, J. H. M. M.; Seifert, W.; Solano, E.; Tabernero, H. M.; Zechmeister, M. Bibcode: 2019A&A...625A..68S Altcode: 2019arXiv190403231S
Aims: We determine the radii and masses of 293 nearby, bright M dwarfs of the CARMENES survey. This is the first time that such a large and homogeneous high-resolution (R > 80 000) spectroscopic survey has been used to derive these fundamental stellar parameters.
Methods: We derived the radii using Stefan-Boltzmann's law. We obtained the required effective temperatures Teff from a spectral analysis and we obtained the required luminosities L from integrated broadband photometry together with the Gaia DR2 parallaxes. The mass was then determined using a mass-radius relation that we derived from eclipsing binaries known in the literature. We compared this method with three other methods: (1) We calculated the mass from the radius and the surface gravity log g, which was obtained from the same spectral analysis as Teff. (2) We used a widely used infrared mass-magnitude relation. (3) We used a Bayesian approach to infer stellar parameters from the comparison of the absolute magnitudes and colors of our targets with evolutionary models.
Results: Between spectral types M0 V and M7 V our radii cover the range 0.1 R < R < 0.6 R with an error of 2-3% and our masses cover 0.09 ℳ < ℳ< 0.6ℳ with an error of 3-5%. We find good agreement between the masses determined with these different methods for most of our targets. Only the masses of very young objects show discrepancies. This can be well explained with the assumptions that we used for our methods.

Table B.1 (stellar parameters) is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/625/A68 Title: VizieR Online Data Catalog: Radii and masses of the CARMENES targets (Schweitzer+, 2019) Authors: Schweitzer, A.; Passegger, V. M.; Cifuentes, C.; Bejar, V. J. S.; Cortes-Contreras, M.; Caballero, J. A.; Del Burgo, C.; Czesla, S.; Kuerster, M.; Montes, D.; Zapatero Osorio, M. R.; Ribas, I.; Reiners, A.; Quirrenbach, A.; Amado, P. J.; Aceituno, J.; Anglada-Escude, G.; Bauer, F. F.; Dreizler, S.; Jeffers, S. V.; Guenther, E. W.; Henning, T.; Kaminski, A.; Lafarga, M.; Marfil, E.; Morales, J. C.; Schmitt, J. H. M. M.; Seifert, W.; Solano, E.; Tabernero, H. M.; Zechmeister, M. Bibcode: 2019yCat..36250068S Altcode: Table B1 contains the stellar parameters of our sample. The sample consists of 293 nearby, bright M dwarfs with no known close companions. Their metallicities spread around solar metallicity. Most stars are inactive or mildly active and older than a few hundred million years. However, known active or young stars are also included although most of the analyses assume inactive main sequence stars. All parameters are determined by us except where noted otherwise.

(1 data file). Title: VizieR Online Data Catalog: An old nova remnant in M22 (Goettgens+, 2019) Authors: Goettgens, F.; Weilbacher, P. M.; Roth, M. M.; Dreizler, S.; Giesers, B.; Husser, T. -O.; Kamann, S.; Brinchmann, J.; Kollatschny, W.; Monreal-Ibero, A.; Schmidt, K. B.; Wendt, M.; Wisotzki, L.; Bacon, R. Bibcode: 2019yCat..36260069G Altcode: We release the 3D datacube of the nova remnant in M22. It was combined from data of seven MUSE observations without adaptive optics (see Table 1 in the paper for details).

We also release the spectrum extracted from this datacube as displayed in Fig. 2 in the paper (labelled 'observed' in this figure).

(2 data files). Title: Gliese 49: activity evolution and detection of a super-Earth. A HADES and CARMENES collaboration Authors: Perger, M.; Scandariato, G.; Ribas, I.; Morales, J. C.; Affer, L.; Azzaro, M.; Amado, P. J.; Anglada-Escudé, G.; Baroch, D.; Barrado, D.; Bauer, F. F.; Béjar, V. J. S.; Caballero, J. A.; Cortés-Contreras, M.; Damasso, M.; Dreizler, S.; González-Cuesta, L.; González Hernández, J. I.; Guenther, E. W.; Henning, T.; Herrero, E.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; Leto, G.; López-González, M. J.; Maldonado, J.; Micela, G.; Montes, D.; Pinamonti, M.; Quirrenbach, A.; Rebolo, R.; Reiners, A.; Rodríguez, E.; Rodríguez-López, C.; Schmitt, J. H. M. M.; Sozzetti, A.; Suárez Mascareño, A.; Toledo-Padrón, B.; Zanmar Sánchez, R.; Zapatero Osorio, M. R.; Zechmeister, M. Bibcode: 2019A&A...624A.123P Altcode: 2019arXiv190304808P Context. Small planets around low-mass stars often show orbital periods in a range that corresponds to the temperate zones of their host stars which are therefore of prime interest for planet searches. Surface phenomena such as spots and faculae create periodic signals in radial velocities and in observational activity tracers in the same range, so they can mimic or hide true planetary signals.
Aims: We aim to detect Doppler signals corresponding to planetary companions, determine their most probable orbital configurations, and understand the stellar activity and its impact on different datasets.
Methods: We analyzed 22 yr of data of the M1.5 V-type star Gl 49 (BD+61 195) including HARPS-N and CARMENES spectrographs, complemented by APT2 and SNO photometry. Activity indices are calculated from the observed spectra, and all datasets are analyzed with periodograms and noise models. We investigated how the variation of stellar activity imprints on our datasets. We further tested the origin of the signals and investigate phase shifts between the different sets. To search for the best-fit model we maximize the likelihood function in a Markov chain Monte Carlo approach.
Results: As a result of this study, we are able to detect the super-Earth Gl 49b with a minimum mass of 5.6 M. It orbits its host star with a period of 13.85 d at a semi-major axis of 0.090 au and we calculate an equilibrium temperature of 350 K and a transit probability of 2.0%. The contribution from the spot-dominated host star to the different datasets is complex, and includes signals from the stellar rotation at 18.86 d, evolutionary timescales of activity phenomena at 40-80 d, and a long-term variation of at least four years.

Based on observations made with the Italian TNG, operated on the island of La Palma, Spain; the CARMENES instrument installed at the 3.5 m telescope of the Calar Alto Observatory, Spain; the robotic APT2 located at Serra La Nave on Mt. Etna, Italy; and the T90 telescope at Sierra Nevada Observatory, Spain.Full Table A.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/624/A123 Title: VizieR Online Data Catalog: Gl 49 radial velocities and activity indicators (Perger+, 2019) Authors: Perger, M.; Scandariato, G.; Ribas, I.; Morales, J. C.; Affer, L.; Azzaro, M.; Amado, P. J.; Anglada-Escude, G.; Baroch, D.; Barrado, D.; Bauer, F. F.; Bejar, V. J. S.; Caballero, J. A.; Cortes-Contreras, M.; Damasso, M.; Dreizler, S.; Gonzalez-Cuesta, L.; Gonzalez Hernandez, J. I.; Guenther, E. W.; Henning, T.; Herrero, E.; Jeffers, S. V.; Kaminski, A.; Kuerster, M.; Lafarga, M.; Leto, G.; Lopez-Gonzalez, M. J.; Maldonado, J.; Micela, G.; Montes, D.; Pinamonti, M.; Quirrenbach, A.; Rebolo, R.; Reiners, A.; Rodriguez, E.; Rodriguez-Lopez, C.; Schmitt, J. H. M. M.; Sozzetti, A.; Suarezmascareno, A.; Toledo-Padron, B.; Zanmar Sanchez, R.; Zapatero Osorio, M. R.; Zechmeister, M. Bibcode: 2019yCat..36240123P Altcode: Radial velocity and activity indicator time-series data of Gl 49 from HIRES, HARPS-N, and CARMENES instruments.

We obtained 137 RVs from optical spectra of the HADES program. They were observed over six seasons (S1 to S6) between 3 Sep 2012 and 11 Oct 2017 with HARPS-N.

We obtained spectroscopic observations with the CARMENES instrument, installed since 2015 at the 3.51m telescope of the Calar Alto Observatory in Spain.

Gl 49 was also observed with the HIRES instrument, installed since the late 1990s at the Keck I telescope located in Hawaii, USA.

(1 data file). Title: The CARMENES search for exoplanets around M dwarfs. Period search in Hα, Na I D, and Ca II IRT lines Authors: Fuhrmeister, B.; Czesla, S.; Schmitt, J. H. M. M.; Johnson, E. N.; Schöfer, P.; Jeffers, S. V.; Caballero, J. A.; Zechmeister, M.; Reiners, A.; Ribas, I.; Amado, P. J.; Quirrenbach, A.; Bauer, F.; Béjar, V. J. S.; Cortés-Contreras, M.; Díez Alonso, E.; Dreizler, S.; Galadí-Enríquez, D.; Guenther, E. W.; Kaminski, A.; Kürster, M.; Lafarga, M.; Montes, D. Bibcode: 2019A&A...623A..24F Altcode: 2019arXiv190105173F We use spectra from CARMENES, the Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs, to search for periods in chromospheric indices in 16 M0-M2 dwarfs. We measure spectral indices in the Hα, the Ca II infrared triplet (IRT), and the Na I D lines to study which of these indices are best-suited to finding rotation periods in these stars. Moreover, we test a number of different period-search algorithms, namely the string length method, the phase dispersion minimisation, the generalized Lomb-Scargle periodogram, and the Gaussian process regression with quasi-periodic kernel. We find periods in four stars using Hα and in five stars using the Ca II IRT, two of which have not been found before. Our results show that both Hα and the Ca II IRT lines are well suited for period searches, with the Ca II IRT index performing slightly better than Hα. Unfortunately, the Na I D lines are strongly affected by telluric airglow, and we could not find any rotation period using this index. Further, different definitions of the line indices have no major impact on the results. Comparing the different search methods, the string length method and the phase dispersion minimisation perform worst, while Gaussian process models produce the smallest numbers of false positives and non-detections. Title: The CARMENES search for exoplanets around M dwarfs. Chromospheric modeling of M 2-3 V stars with PHOENIX Authors: Hintz, D.; Fuhrmeister, B.; Czesla, S.; Schmitt, J. H. M. M.; Johnson, E. N.; Schweitzer, A.; Caballero, J. A.; Zechmeister, M.; Jeffers, S. V.; Reiners, A.; Ribas, I.; Amado, P. J.; Quirrenbach, A.; Anglada-Escudé, G.; Bauer, F. F.; Béjar, V. J. S.; Cortés-Contreras, M.; Dreizler, S.; Galadí-Enríquez, D.; Guenther, E. W.; Hauschildt, P. H.; Kaminski, A.; Kürster, M.; Lafarga, M.; López del Fresno, M.; Montes, D.; Morales, J. C.; Passegger, V. M.; Seifert, W. Bibcode: 2019A&A...623A.136H Altcode: 2019arXiv190203992H Chromospheric modeling of observed differences in stellar activity lines is imperative to fully understand the upper atmospheres of late-type stars. We present one-dimensional parametrized chromosphere models computed with the atmosphere code PHOENIX using an underlying photosphere of 3500 K. The aim of this work is to model chromospheric lines of a sample of 50 M2-3 dwarfs observed in the framework of the CARMENES, the Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs, exoplanet survey. The spectral comparison between observed data and models is performed in the chromospheric lines of Na I D2, Hα, and the bluest Ca II infrared triplet line to obtain best-fit models for each star in the sample. We find that for inactive stars a single model with a VAL C-like temperature structure is sufficient to describe simultaneously all three lines adequately. Active stars are rather modeled by a combination of an inactive and an active model, also giving the filling factors of inactive and active regions. Moreover, the fitting of linear combinations on variable stars yields relationships between filling factors and activity states, indicating that more active phases are coupled to a larger portion of active regions on the surface of the star. Title: The CARMENES search for exoplanets around M dwarfs. Activity indicators at visible and near-infrared wavelengths Authors: Schöfer, P.; Jeffers, S. V.; Reiners, A.; Shulyak, D.; Fuhrmeister, B.; Johnson, E. N.; Zechmeister, M.; Ribas, I.; Quirrenbach, A.; Amado, P. J.; Caballero, J. A.; Anglada-Escudé, G.; Bauer, F. F.; Béjar, V. J. S.; Cortés-Contreras, M.; Dreizler, S.; Guenther, E. W.; Kaminski, A.; Kürster, M.; Lafarga, M.; Montes, D.; Morales, J. C.; Pedraz, S.; Tal-Or, L. Bibcode: 2019A&A...623A..44S Altcode: 2019arXiv190108861S Context. The Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs (CARMENES) survey is searching for Earth-like planets orbiting M dwarfs using the radial velocity method. Studying the stellar activity of the target stars is important to avoid false planet detections and to improve our understanding of the atmospheres of late-type stars.
Aims: In this work we present measurements of activity indicators at visible and near-infrared wavelengths for 331 M dwarfs observed with CARMENES. Our aim is to identify the activity indicators that are most sensitive and easiest to measure, and the correlations among these indicators. We also wish to characterise their variability.
Methods: Using a spectral subtraction technique, we measured pseudo-equivalent widths of the He I D3, Hα, He I λ10833 Å, and Pa β lines, the Na I D doublet, and the Ca II infrared triplet, which have a chromospheric component in active M dwarfs. In addition, we measured an index of the strength of two TiO and two VO bands, which are formed in the photosphere. We also searched for periodicities in these activity indicators for all sample stars using generalised Lomb-Scargle periodograms.
Results: We find that the most slowly rotating stars of each spectral subtype have the strongest Hα absorption. Hα is correlated most strongly with He I D3, whereas Na I D and the Ca II infrared triplet are also correlated with Hα. He I λ10833 Å and Paβ show no clear correlations with the other indicators. The TiO bands show an activity effect that does not appear in the VO bands. We find that the relative variations of Hα and He I D3 are smaller for stars with higher activity levels, while this anti-correlation is weaker for Na I D and the Ca II infrared triplet, and is absent for He I λ10833 Å and Paβ. Periodic variation with the rotation period most commonly appears in the TiO bands, Hα, and in the Ca II infrared triplet.

The full version of Table A.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/623/A44 Title: The CARMENES search for exoplanets around M dwarfs. The enigmatic planetary system GJ 4276: one eccentric planet or two planets in a 2:1 resonance? Authors: Nagel, E.; Czesla, S.; Schmitt, J. H. M. M.; Dreizler, S.; Anglada-Escudé, G.; Rodríguez, E.; Ribas, I.; Reiners, A.; Quirrenbach, A.; Amado, P. J.; Caballero, J. A.; Aceituno, J.; Béjar, V. J. S.; Cortés-Contreras, M.; González-Cuesta, L.; Guenther, E. W.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; López-González, M. J.; Montes, D.; Morales, J. C.; Passegger, V. M.; Rodríguez-López, C.; Schweitzer, A.; Zechmeister, M. Bibcode: 2019A&A...622A.153N Altcode: 2019arXiv190102367N We report the detection of a Neptune-mass exoplanet around the M4.0 dwarf GJ 4276 (G 232-070) based on radial velocity (RV) observations obtained with the CARMENES spectrograph. The RV variations of GJ 4276 are best explained by the presence of a planetary companion that has a minimum mass of mb sin i ≈ 16 M on a Pb = 13.35 day orbit. The analysis of the activity indicators and spectral diagnostics exclude stellar induced RV perturbations and prove the planetary interpretation of the RV signal. We show that a circular single-planet solution can be excluded by means of a likelihood ratio test. Instead, we find that the RV variations can be explained either by an eccentric orbit or interpreted as a pair of planets on circular orbits near a period ratio of 2:1. Although the eccentric single-planet solution is slightly preferred, our statistical analysis indicates that none of these two scenarios can be rejected with high confidence using the RV time series obtained so far. Based on the eccentric interpretation, we find that GJ 4276 b is the most eccentric (eb = 0.37) exoplanet around an M dwarf with such a short orbital period known today.

Photometric measurements and Table C.1 are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/622/A153 Title: VizieR Online Data Catalog: Barnard's star radial velocity curve (Ribas+, 2018) Authors: Ribas, I.; Tuomi, M.; Reiners, A.; Butler, R. P.; Morales, J. C.; Perger, M.; Dreizler, S.; Rodriguez-Lopez, C.; Gonzalez Hernandez, J. I.; Rosich, A.; Feng, F.; Trifonov, T.; Vogt, S. S.; Caballero, J. A.; Hatzes, A.; Herrero, E.; Jeffers, S. V.; Lafarga, M.; Murgas, F.; Nelson, R. P.; Rodriguez, E.; Strachan, J. B. P.; Tal-Or, L.; Teske, J.; Toledo-Padron, B.; Zechmeister, M.; Quirrenbach, A.; Amado, P. J.; Azzaro, M.; Bejar, V. J. S.; Barnes, J. R.; Berdinas, Z. M.; Burt, J.; Coleman, G.; Cortes-Contreras, M.; Crane, J.; Engle, S. G.; Guinan, E. F.; Haswell, C. A.; Henning, T.; Holden, B.; Jenkins, J.; Jones, H. R. A.; Kaminski, A.; Kiraga, M.; Kurster, M.; Lee, M. H.; Lopez-Gonzalez, M. J.; Montes, D.; Morin, J.; Ofir, A.; Palle, E.; Rebolo, R.; Reffert, S.; Schweitzer, A.; Seifert, W.; Shectman, S. A.; Staab, D.; Street, R. A.; Suarez Mascareno, A.; Tsapras, Y.; Wang, S. X.; Anglada-Escude, G. Bibcode: 2019yCatp038056301R Altcode: An early analysis of archival radial-velocity datasets of Barnard's star up to 2015 indicated the presence of at least one significant signal, which had a period of about 230 days, but with rather poor sampling. To elucidate its presence and nature we undertook an intensive monitoring campaign with the CARMENES spectrometer, collecting precise radial-velocity measurements on every possible night during 2016 and 2017. We also obtained overlapping observations with the European Southern Observatory (ESO) HARPS and the HARPS-N instruments. The combined Doppler monitoring of Barnard's star, including archival and newly acquired observations, resulted in 771 radial-velocity epochs (nightly averages), with typical individual precisions of 0.9-1.8m/s, obtained over a timespan of more than 20 years from seven different facilities, and yielded eight independent datasets.

(4 data files). Title: Outliers in globular clusters: the case of 47 Tucanae Authors: Campos, Fabiola; Pelisoli, Ingrid; Kamann, Sebastian; Husser, Tim-Oliver; Dreizler, Stefan; Bellini, Andrea; Robinson, Edward L.; Nardiello, Domenico; Piotto, Giampaolo; Oliveira, Kepler; Istrate, Alina; Winget, Don; Montgomery, Michael H.; Dotter, Aaron Bibcode: 2019AAS...23341408C Altcode: We constructed multicolor photometric color-magnitude diagrams of the globular cluster 47 Tucanae using photometry obtained with the Hubble Space Telescope. We identify 24 previously-unremarked objects that are outliers from the single-star model tracks in the color-magnitude diagram.Based on their proper motions, all the objects are members of the cluster with high probability. We show that the majority of the sources are likely to be binary systems. Since only two of those objects are possible counterparts to X-ray sources, we conclude that most of the binaries consist of a white dwarf and a main-sequence star. While three may be double-degenerate binaries. This is the first time multicolor photometry is employed to search for binaries in clusters. Extension of this work can help shed light in late stages of binary stellar evolution in different environments. 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. Bibcode: 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]ZAMS 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: Photometry & RV follow-up observations of K2-18 (Sarkis+, 2018) Authors: Sarkis, P.; Henning, T.; Kurster, M.; Trifonov, T.; Zechmeister, M.; Tal-Or, L.; Anglada-Escude, G.; Hatzes, A. P.; Lafarga, M.; Dreizler, S.; Ribas, I.; Caballero, J. A.; Reiners, A.; Mallonn, M.; Morales, J. C.; Kaminski, A.; Aceituno, J.; Amado, P. J.; Bejar, V. J. S.; Hagen, H. -J.; Jeffers, S.; Quirrenbach, A.; Launhardt, R.; Marvin, C.; Montes, D. Bibcode: 2019yCat..51550257S Altcode: We monitored the host star K2-18 for photometric variability with the robotic 1.2 m twin-telescope STELLA on Tenerife (Strassmeier et al. 2004AN....325..527S) and its wide-field imager WiFSIP. From 2017 February until 2017 June, we obtained blocks of four exposures in Johnson B and four exposures in Cousins R over 33 nights. The exposure time was 120 s in B and 60 s in R. We monitored K2-18 between 2016 December and 2017 June with CARMENES. CARMENES (Calar Alto search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs) is a pair of high-resolution echelle spectrographs (Quirrenbach et al. 2014SPIE.9147E..1FQ) mounted on the 3.5 m telescope of the Calar Alto Observatory (CAHA) in Spain. The VIS channel covers the wavelength range from 0.52 to 0.96 μm and has a spectral resolution R=94600 (Quirrenbach et al. 2016SPIE.9908E..12Q), with a demonstrated precision similar to HARPS and better than Keck/HIRES (Trifonov et al. 2018, J/A+A/609/A117).

(3 data files). Title: CARMENES input catalogue of M dwarfs. IV. New rotation periods from photometric time series Authors: Díez Alonso, E.; Caballero, J. A.; Montes, D.; de Cos Juez, F. J.; Dreizler, S.; Dubois, F.; Jeffers, S. V.; Lalitha, S.; Naves, R.; Reiners, A.; Ribas, I.; Vanaverbeke, S.; Amado, P. J.; Béjar, V. J. S.; Cortés-Contreras, M.; Herrero, E.; Hidalgo, D.; Kürster, M.; Logie, L.; Quirrenbach, A.; Rau, S.; Seifert, W.; Schöfer, P.; Tal-Or, L. Bibcode: 2019A&A...621A.126D Altcode: 2018arXiv181003338D
Aims: The main goal of this work is to measure rotation periods of the M-type dwarf stars being observed by the CARMENES exoplanet survey to help distinguish radial-velocity signals produced by magnetic activity from those produced by exoplanets. Rotation periods are also fundamental for a detailed study of the relation between activity and rotation in late-type stars.
Methods: We look for significant periodic signals in 622 photometric time series of 337 bright, nearby M dwarfs obtained by long-time baseline, automated surveys (MEarth, ASAS, SuperWASP, NSVS, Catalina, ASAS-SN, K2, and HATNet) and for 20 stars which we obtained with four 0.2-0.8 m telescopes at high geographical latitudes.
Results: We present 142 rotation periods (73 new) from 0.12 d to 133 d and ten long-term activity cycles (six new) from 3.0 a to 11.5 a. We compare our determinations with those in the existing literature; we investigate the distribution of Prot in the CARMENES input catalogue, the amplitude of photometric variability, and their relation to v sini and pEW(Hα); and we identify three very active stars with new rotation periods between 0.34 d and 23.6 d.

Tables A.1 and A.2, and tables of the photometric measurements are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/621/A126 Title: Outliers: multicolour photometry guiding the search for evolved binary systems in the globular cluster 47 Tucanae Authors: Campos, Fabíola; Pelisoli, I.; Kamann, S.; Husser, T. -O.; Dreizler, S.; Bellini, A.; Robinson, E. L.; Nardiello, D.; Piotto, G.; Kepler, S. O.; Istrate, A. G.; Winget, D. E.; Montgomery, M. H.; Dotter, A. Bibcode: 2018MNRAS.481.4397C Altcode: 2018MNRAS.tmp.2465C; 2018arXiv180907746C We use Hubble Space Telescope multicolour photometry of the globular cluster 47 Tucanae to uncover a population of 24 objects with no previous classification that are outliers from the single-star model tracks in the colour-magnitude diagram and yet are likely cluster members. By comparing those sources with evolutionary models and X-ray source catalogues, we were able to show that the majority of those sources are likely binary systems that do not have any X-ray source detected nearby, most possibly formed by a white dwarf and a main-sequence star and a small number of possible double-degenerate systems. Title: Ground-based detection of an extended helium atmosphere in the Saturn-mass exoplanet WASP-69b Authors: Nortmann, Lisa; Pallé, Enric; Salz, Michael; Sanz-Forcada, Jorge; Nagel, Evangelos; Alonso-Floriano, F. Javier; Czesla, Stefan; Yan, Fei; Chen, Guo; Snellen, Ignas A. G.; Zechmeister, Mathias; Schmitt, Jürgen H. M. M.; López-Puertas, Manuel; Casasayas-Barris, Núria; Bauer, Florian F.; Amado, Pedro J.; Caballero, José A.; Dreizler, Stefan; Henning, Thomas; Lampón, Manuel; Montes, David; Molaverdikhani, Karan; Quirrenbach, Andreas; Reiners, Ansgar; Ribas, Ignasi; Sánchez-López, Alejandro; Schneider, P. Christian; Zapatero Osorio, María R. Bibcode: 2018Sci...362.1388N Altcode: 2018arXiv181203119N Hot gas giant exoplanets can lose part of their atmosphere due to strong stellar irradiation, and these losses can affect their physical and chemical evolution. Studies of atmospheric escape from exoplanets have mostly relied on space-based observations of the hydrogen Lyman-α line in the far ultraviolet region, which is strongly affected by interstellar absorption. Using ground-based high-resolution spectroscopy, we detected excess absorption in the helium triplet at 1083 nanometers during the transit of the Saturn-mass exoplanet WASP-69b, at a signal-to-noise ratio of 18. We measured line blueshifts of several kilometers per second and posttransit absorption, which we interpret as the escape of part of the atmosphere trailing behind the planet in comet-like form. Title: Detection of He I λ10830 Å absorption on HD 189733 b with CARMENES high-resolution transmission spectroscopy Authors: Salz, M.; Czesla, S.; Schneider, P. C.; Nagel, E.; Schmitt, J. H. M. M.; Nortmann, L.; Alonso-Floriano, F. J.; López-Puertas, M.; Lampón, M.; Bauer, F. F.; Snellen, I. A. G.; Pallé, E.; Caballero, J. A.; Yan, F.; Chen, G.; Sanz-Forcada, J.; Amado, P. J.; Quirrenbach, A.; Ribas, I.; Reiners, A.; Béjar, V. J. S.; Casasayas-Barris, N.; Cortés-Contreras, M.; Dreizler, S.; Guenther, E. W.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; Lara, L. M.; Molaverdikhani, K.; Montes, D.; Morales, J. C.; Sánchez-López, A.; Seifert, W.; Zapatero Osorio, M. R.; Zechmeister, M. Bibcode: 2018A&A...620A..97S Altcode: 2018arXiv181202453S We present three transit observations of HD 189733 b obtained with the high-resolution spectrograph CARMENES at Calar Alto. A strong absorption signal is detected in the near-infrared He I triplet at 10830 Å in all three transits. During mid-transit, the mean absorption level is 0.88 ± 0.04% measured in a ±10 km s-1 range at a net blueshift of - 3.5 ± 0.4 km s-1 (10829.84-10830.57 Å). The absorption signal exhibits radial velocities of + 6.5 ± 3.1 km s-1 and - 12.6 ± 1.0 km s-1 during ingress and egress, respectively; all radial velocities are measured in the planetary rest frame. We show that stellar activity related pseudo-signals interfere with the planetary atmospheric absorption signal. They could contribute as much as 80% of the observed signal and might also affect the observed radial velocity signature, but pseudo-signals are very unlikely to explain the entire signal. The observed line ratio between the two unresolved and the third line of the He I triplet is 2.8 ± 0.2, which strongly deviates from the value expected for an optically thin atmospheres. When interpreted in terms of absorption in the planetary atmosphere, this favors a compact helium atmosphere with an extent of only 0.2 planetary radii and a substantial column density on the order of 4 × 1012 cm-2. The observed radial velocities can be understood either in terms of atmospheric circulation with equatorial superrotation or as a sign of an asymmetric atmospheric component of evaporating material. We detect no clear signature of ongoing evaporation, like pre- or post-transit absorption, which could indicate material beyond the planetary Roche lobe, or radial velocities in excess of the escape velocity. These findings do not contradict planetary evaporation, but only show that the detected helium absorption in HD 189733 b does not trace the atmospheric layers that show pronounced escape signatures. Title: The CARMENES search for exoplanets around M dwarfs. The warm super-Earths in twin orbits around the mid-type M dwarfs Ross 1020 (GJ 3779) and LP 819-052 (GJ 1265) Authors: Luque, R.; Nowak, G.; Pallé, E.; Kossakowski, D.; Trifonov, T.; Zechmeister, M.; Béjar, V. J. S.; Cardona Guillén, C.; Tal-Or, L.; Hidalgo, D.; Ribas, I.; Reiners, A.; Caballero, J. A.; Amado, P. J.; Quirrenbach, A.; Aceituno, J.; Cortés-Contreras, M.; Díez-Alonso, E.; Dreizler, S.; Guenther, E. W.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kürster, M.; Lafarga, M.; Montes, D.; Morales, J. C.; Passegger, V. M.; Schmitt, J. H. M. M.; Schweitzer, A. Bibcode: 2018A&A...620A.171L Altcode: 2018arXiv181007572L We announce the discovery of two planetary companions orbiting around the low-mass stars Ross 1020 (GJ 3779, M4.0V) and LP 819-052 (GJ 1265, M4.5V). The discovery is based on the analysis of CARMENES radial velocity (RV) observations in the visual channel as part of its survey for exoplanets around M dwarfs. In the case of GJ 1265, CARMENES observations were complemented with publicly available Doppler measurements from HARPS. The datasets reveal two planetary companions, one for each star, that share very similar properties: minimum masses of 8.0 ± 0.5 M and 7.4 ± 0.5 M in low-eccentricity orbits with periods of 3.023 ± 0.001 d and 3.651 ± 0.001 d for GJ 3779 b and GJ 1265 b, respectively. The periodic signals around 3 d found in the RV data have no counterpart in any spectral activity indicator. Furthermore, we collected available photometric data for the two host stars, which confirm that the additional Doppler variations found at periods of approximately 95 d can be attributed to the rotation of the stars. The addition of these planets to a mass-period diagram of known planets around M dwarfs suggests a bimodal distribution with a lack of short-period low-mass planets in the range of 2-5 M. It also indicates that super-Earths (>5 M) currently detected by RV and transit techniques around M stars are usually found in systems dominated by a single planet.

The RV and formal uncertainties of GJ 3779 and GJ 1265 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/620/A171 Title: VizieR Online Data Catalog: GJ 4276 radial velocity curve (Nagel+, 2019) Authors: Nagel, E.; Czesla, S.; Schmitt, J. H. M. M.; Dreizler, S.; Anglada-Escude, G.; Rodriguez, E.; Ribas, I.; Reiners, A.; Quirrenbach, A.; Amado, P. J.; Caballero, J. A.; Aceituno, J.; Bejar, V. J. S.; Cortes-Contreras, M.; Gonzalez-Cuesta, L.; Guenther, E. W.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kuerster, M.; Lafarga, M.; Lopez-Gonzalez, M. J.; Montes, D.; Morales, J. C. Passegger V. M.; Rodriguez-Lopez, C.; Schweitzer, A.; Zechmeister, M. Bibcode: 2018yCat..36220153N Altcode: We analyzed radial velocity data from the CARMENES VIS channel. The RVs are corrected for barycentric motion and secular acceleration. The CARMENES measurements were taken in the context of the CARMENES search for exoplanets around M dwarfs. The CARMENES instrument consists of two channels: the VIS channel obtains spectra at a resolution of R=94600 in the wavelength range 520-960nm, while the NIR channel yields spectra of R=80400 covering 960-1710nm. Both channels are calibrated in wavelength with hollow-cathode lamps and use temperature- and pressure-stabilized Fabry-Perot etalons to interpolate the wavelength solution and simultaneously monitor the spectrograph drift during nightly operations (Bauer et al., 2015A&A...581A.117B).

To determine the stellar rotation period, we obtained V band photometry with the T150 telescope located at the Sierra Nevada Observatory (SNO) in Spain.

(2 data files). Title: The CARMENES search for exoplanets around M dwarfs. Nine new double-line spectroscopic binary stars Authors: Baroch, D.; Morales, J. C.; Ribas, I.; Tal-Or, L.; Zechmeister, M.; Reiners, A.; Caballero, J. A.; Quirrenbach, A.; Amado, P. J.; Dreizler, S.; Lalitha, S.; Jeffers, S. V.; Lafarga, M.; Béjar, V. J. S.; Colomé, J.; Cortés-Contreras, M.; Díez-Alonso, E.; Galadí-Enríquez, D.; Guenther, E. W.; Hagen, H. -J.; Henning, T.; Herrero, E.; Kürster, M.; Montes, D.; Nagel, E.; Passegger, V. M.; Perger, M.; Rosich, A.; Schweitzer, A.; Seifert, W. Bibcode: 2018A&A...619A..32B Altcode: 2018arXiv180806895B Context. The CARMENES spectrograph is surveying ∼300 M dwarf stars in search for exoplanets. Among the target stars, spectroscopic binary systems have been discovered, which can be used to measure fundamental properties of stars.
Aims: Using spectroscopic observations, we determine the orbital and physical properties of nine new double-line spectroscopic binary systems by analysing their radial velocity curves.
Methods: We use two-dimensional cross-correlation techniques to derive the radial velocities of the targets, which are then employed to determine the orbital properties. Photometric data from the literature are also analysed to search for possible eclipses and to measure stellar variability, which can yield rotation periods.
Results: Out of the 342 stars selected for the CARMENES survey, 9 have been found to be double-line spectroscopic binaries, with periods ranging from 1.13 to ∼8000 days and orbits with eccentricities up to 0.54. We provide empirical orbital properties and minimum masses for the sample of spectroscopic binaries. Absolute masses are also estimated from mass-luminosity calibrations, ranging between ∼0.1 and ∼0.6 M.
Conclusions: These new binary systems increase the number of double-line M dwarf binary systems with known orbital parameters by 15%, and they have lower mass ratios on average. Title: A candidate super-Earth planet orbiting near the snow line of Barnard's star Authors: Ribas, I.; Tuomi, M.; Reiners, A.; Butler, R. P.; Morales, J. C.; Perger, M.; Dreizler, S.; Rodríguez-López, C.; González Hernández, J. I.; Rosich, A.; Feng, F.; Trifonov, T.; Vogt, S. S.; Caballero, J. A.; Hatzes, A.; Herrero, E.; Jeffers, S. V.; Lafarga, M.; Murgas, F.; Nelson, R. P.; Rodríguez, E.; Strachan, J. B. P.; Tal-Or, L.; Teske, J.; Toledo-Padrón, B.; Zechmeister, M.; Quirrenbach, A.; Amado, P. J.; Azzaro, M.; Béjar, V. J. S.; Barnes, J. R.; Berdiñas, Z. M.; Burt, J.; Coleman, G.; Cortés-Contreras, M.; Crane, J.; Engle, S. G.; Guinan, E. F.; Haswell, C. A.; Henning, Th.; Holden, B.; Jenkins, J.; Jones, H. R. A.; Kaminski, A.; Kiraga, M.; Kürster, M.; Lee, M. H.; López-González, M. J.; Montes, D.; Morin, J.; Ofir, A.; Pallé, E.; Rebolo, R.; Reffert, S.; Schweitzer, A.; Seifert, W.; Shectman, S. A.; Staab, D.; Street, R. A.; Suárez Mascareño, A.; Tsapras, Y.; Wang, S. X.; Anglada-Escudé, G. Bibcode: 2018Natur.563..365R Altcode: 2018arXiv181105955R Barnard's star is a red dwarf, and has the largest proper motion (apparent motion across the sky) of all known stars. At a distance of 1.8 parsecs1, it is the closest single star to the Sun; only the three stars in the α Centauri system are closer. Barnard's star is also among the least magnetically active red dwarfs known2,3 and has an estimated age older than the Solar System. Its properties make it a prime target for planetary searches; various techniques with different sensitivity limits have been used previously, including radial-velocity imaging4-6, astrometry7,8 and direct imaging9, but all ultimately led to negative or null results. Here we combine numerous measurements from high-precision radial-velocity instruments, revealing the presence of a low-amplitude periodic signal with a period of 233 days. Independent photometric and spectroscopic monitoring, as well as an analysis of instrumental systematic effects, suggest that this signal is best explained as arising from a planetary companion. The candidate planet around Barnard's star is a cold super-Earth, with a minimum mass of 3.2 times that of Earth, orbiting near its snow line (the minimum distance from the star at which volatile compounds could condense). The combination of all radial-velocity datasets spanning 20 years of measurements additionally reveals a long-term modulation that could arise from a stellar magnetic-activity cycle or from a more distant planetary object. Because of its proximity to the Sun, the candidate planet has a maximum angular separation of 220 milliarcseconds from Barnard's star, making it an excellent target for direct imaging and astrometric observations in the future. Title: VizieR Online Data Catalog: RV variability of the K-giant γ Draconis (Hatzes+, 2018) Authors: Hatzes, A. P.; Endl, M.; Cochran, W. D.; MacQueen, P. J.; Han, I.; Lee, B. -C.; Kim, K. -M.; Mkrtichian, D.; Dollinger, M.; Hartmann, M.; Karjalainen, M.; Dreizler, S. Bibcode: 2018yCat..51550120H Altcode: A total of four RV data sets were used in the analysis. The earliest observations were made with the coude spectrograph of the 2.1 m Otto Struve Telescope at McDonald Observatory. A 1200 grooves/mm grating was used in second order in combination with a Tektronix 512x512 CCD. Blocking filters were used to isolate the desired order. This instrumental setup resulted in a spectral dispersion of 0.046 Å/pixel at the central wavelength of 5520 Å. An 85 μm slit provided a spectral resolution of 0.11 Å (resolving power R=λ/Δλ=50000). The "McD-2.7" data set used the Tull Spectrograph (Tull et al. 1995PASP..107..251T) at the Harlan J. Smith 2.7 m telescope. This instrument provided a nominal wavelength coverage of 3600-10000 Å at a resolving power of R=60000. RV measurements were also made with the Bohyunsan Observatory Echelle Spectrograph or BOES (Kim et al. 2006A&A...454..839K) of the 1.8 m telescope at the BOAO in South Korea. An 80 μm fiber resulted in a resolving power of R=90000 with a wavelength coverage of 3600-10500 Å. The TLS observations of γ Dra were made as part of the Tautenburg Observatory Planet Search (TOPS) program using the high-resolution coude echelle spectrometer of the Alfred Jensch 2 m telescope and an iodine absorption cell placed in the optical path. The spectrometer is grism cross-dispersed and it has a resolving power R=67000 and wavelength coverage 4630-7370 Å.

(1 data file). 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. Bibcode: 2018yCat..36190073L Altcode: Our sample was selected from the 88 solar twins presented in Ramirez et al. (2014A&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&A...581A..34B; Melendez et al., 2015Msngr.161...28M, 2017A&A...597A..34M). Additional data for 12 stars were found in the ESO archive.

(2 data files). Title: Activity induced variation in spin-orbit angles as derived from Rossiter-McLaughlin measurements Authors: Oshagh, M.; Triaud, A. H. M. J.; Burdanov, A.; Figueira, P.; Reiners, A.; Santos, N. C.; Faria, J.; Boue, G.; Díaz, R. F.; Dreizler, S.; Boldt, S.; Delrez, L.; Ducrot, E.; Gillon, M.; Guzman Mesa, A.; Jehin, E.; Khalafinejad, S.; Kohl, S.; Serrano, L.; Udry, S. Bibcode: 2018A&A...619A.150O Altcode: 2018arXiv180901027O One of the most powerful methods used to estimate sky-projected spin-orbit angles of exoplanetary systems is through a spectroscopic transit observation known as the RossiterMcLaughlin (RM) effect. So far mostly single RM observations have been used to estimate the spin-orbit angle, and thus there have been no studies regarding the variation of estimated spin-orbit angle from transit to transit. Stellar activity can alter the shape of photometric transit light curves and in a similar way they can deform the RM signal. In this paper we present several RM observations, obtained using the HARPS spectrograph, of known transiting planets that all transit extremely active stars, and by analyzing them individually we assess the variation in the estimated spin-orbit angle. Our results reveal that the estimated spin-orbit angle can vary significantly (up to 42°) from transit to transit, due to variation in the configuration of stellar active regions over different nights. This finding is almost two times larger than the expected variation predicted from simulations. We could not identify any meaningful correlation between the variation of estimated spin-orbit angles and the stellar magnetic activity indicators. We also investigated two possible approaches to mitigate the stellar activity influence on RM observations. The first strategy was based on obtaining several RM observations and folding them to reduce the stellar activity noise. Our results demonstrated that this is a feasible and robust way to overcome this issue. The second approach is based on acquiring simultaneous high-precision short-cadence photometric transit light curves using TRAPPIST/SPECULOOS telescopes, which provide more information about the stellar active region's properties and allow a better RM modeling. 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 Bibcode: 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.
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.
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 (SMW), recalibrated the Mount Wilson absolute flux and photospheric correction equations as a function of Teff, and then computed an improved bolometric flux normalized activity index log R'HK (Teff) for the entire sample.
Results: New relations between activity and the age of solar twins were derived by assessing the chromospheric age-dating limits using log R'HK (Teff). We measured an average solar activity of SMW = 0.1712 ± 0.0017 during solar magnetic cycles 23-24 covered by HARPS observations, and we also inferred an average of SMW = 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.
Conclusions: Our research confirms that Ca II H & 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.

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 http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/619/A73 Title: VizieR Online Data Catalog: Radial velocities of GJ 3779 and GJ 1265 (Luque+, 2018) Authors: Luque, R.; Nowak, G.; Palle, E.; Kossakowski, D.; Trifonov, T.; Zechmeister, M.; Bejar, V. J. S.; Cardona Guillen, C.; Tal-Or, L.; Hidalgo, D.; Ribas, I.; Reiners, A.; Caballero, J. A.; Amado, P. J.; Quirrenbach, A.; Aceituno, J.; Cortes-Contreras, M.; Diez-Alonso, E.; Dreizler, S.; Guenther, E. W.; Henning, T.; Jeffers, S. V.; Kaminski, A.; Kuerster, M.; Lafarga, M.; Montes, D.; Morales, J. C.; Passegger, V. M.; Schmitt, J. H. M. M.; Schweitzer, A. Bibcode: 2018yCat..36200171L Altcode: We analyzed radial velocity data from the CARMENES VIS channel for GJ 3779, and from the CARMENES VIS channel and HARPS for GJ 1265. All the RVs are corrected for barycentric motion and secular acceleration. The CARMENES measurements were taken in the context of the CARMENES search for exoplanets around M dwarfs. The CARMENES instrument consists of two channels: the VIS channel obtains spectra at a resolution of R=94600 in the wavelength range 520-960nm, while the NIR channel yields spectra of R=80400 covering 960-1710nm. Both channels are calibrated in wavelength with hollow-cathode lamps and use temperature- and pressure-stabilized Fabry-Perot etalons to interpolate the wavelength solution and simultaneously monitor the spectrograph drift during nightly operations (Bauer et al., 2015A&A...581A.117B).

(2 data files). Title: Spitzer's Search for Proxima Centauri b Transits Authors: Harrington, Joseph; Jenkins, James; Challener, Ryan C.; Kurtovic, Nicolás T.; Ramirez, Ricardo; Peña Zamudio, José; McIntyre, Kathleen J.; Himes, Michael D.; Rodríguez, Eloy; Anglada-Escudé, Guillem; Dreizler, Stefan; Ofir, Aviv; Ribas, Ignasi; Rojo, Patricio; Kipping, David; Butler, R. Paul; Amado, Pedro J.; Rodríguez-López, Cristina; Kempton, Eliza M.; Palle, Enric; Murgas, Felipe Bibcode: 2018DPS....5040509H Altcode: Proxima Centauri, the nearest star to the sun, hosts a habitable-zone planet (Anglada-Escude' et al. 2016 Nature 536, 437). Several teams have sought Proxima b's transits using ground-based photometry, and have reported tentative transit detections (Liu et al. 2018 AJ 155, 12; Blank et al. 2018 AJ 155, 228; others). Proxima, a modest-sized M-dwarf star, flares at the 0.5% level (the predicted Proxima b transit depth) 63 times per day, according to our team's prior analysis of optical photometry from the Microvariability and Oscillations of STars spacecraft (Davenport et al. 2016 ApJL 829, L31). This dramatically limits optical precision. However, the effect of flares is much reduced in the infrared. We observed the system with the Spitzer Space Telescope's Infrared Array Camera in November 2016. Our first observation was a 48-hour stare at 4.5 um. It was centered on the predicted transit and covered the 99% credible region for the transit time, based on the discovery radial-velocity (RV) data. Despite a transit-depth precision of 0.01% for a 1 hour transit, we did not detect the predicted 0.5% transit. There was structure in the light curve, including some asymmetric transit-like features, that led us to conduct follow-up observations in May, June, July, and November 2017. None of these observations contained detections, once we accounted for a new manifestation of systematics due to spacecraft vibration. Our improved methods for identifying and partly removing this effect is the topic of the next presentation. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. We acknowledge support from: NASA Planetary Atmospheres Program grant NNX12AI69G, NASA Astrophysics Data Analysis Program grant NNX13AF38G. CATA-Basal/Chile PB06 Conicyt and Fondecyt/Chile project #1161218 (JSJ). Spanish MINECO programs AYA2016-79245-C03-03-P (PJA, CRL, and ER) and ESP2017-87676-C05-02-R (ER). Title: The CARMENES search for exoplanets around M dwarfs. A Neptune-mass planet traversing the habitable zone around HD 180617 Authors: Kaminski, A.; Trifonov, T.; Caballero, J. A.; Quirrenbach, A.; Ribas, I.; Reiners, A.; Amado, P. J.; Zechmeister, M.; Dreizler, S.; Perger, M.; Tal-Or, L.; Bonfils, X.; Mayor, M.; Astudillo-Defru, N.; Bauer, F. F.; Béjar, V. J. S.; Cifuentes, C.; Colomé, J.; Cortés-Contreras, M.; Delfosse, X.; Díez-Alonso, E.; Forveille, T.; Guenther, E. W.; Hatzes, A. P.; Henning, Th.; Jeffers, S. V.; Kürster, M.; Lafarga, M.; Luque, R.; Mandel, H.; Montes, D.; Morales, J. C.; Passegger, V. M.; Pedraz, S.; Reffert, S.; Sadegi, S.; Schweitzer, A.; Seifert, W.; Stahl, O.; Udry, S. Bibcode: 2018A&A...618A.115K Altcode: 2018arXiv180801183K Despite their activity, low-mass stars are of particular importance for the search of exoplanets by the means of Doppler spectroscopy, as planets with lower masses become detectable. We report on the discovery of a planetary companion around HD 180617, a bright (J = 5.58 mag), low-mass (M = 0.45M) star of spectral type M2.5 V. The star, located at a distance of 5.9 pc, is the primary of the high proper motion binary system containing vB 10, a star with one of the lowest masses known in most of the twentieth century. Our analysis is based on new radial velocity (RV) measurements made at red-optical wavelengths provided by the high-precision spectrograph CARMENES, which was designed to carry out a survey for Earth-like planets around M dwarfs. The available CARMENES data are augmented by archival Doppler measurements from HIRES and HARPS. Altogether, the RVs span more than 16 yr. The modeling of the RV variations, with a semi-amplitude of K = 2.85-0.25+0.16 m s-1, yields a Neptune-like planet with a minimum mass of 12.2-1.4+1.0 M on a 105.90-0.10+0.09 d circumprimary orbit, which is partly located in the host star's habitable zone. The analysis of time series of common activity indicators does not show any dependence on the detected RV signal. The discovery of HD 180617 b not only adds information to a currently hardly filled region of the mass-period diagram of exoplanets around M dwarfs, but the investigated system becomes the third known binary consisting of M dwarfs and hosting an exoplanet in an S-type configuration. Its proximity makes it an attractive candidate for future studies.

The RV data (Table C.1) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/618/A115 Title: Cluster kinematics and stellar rotation in NGC 419 with MUSE and adaptive optics Authors: Kamann, S.; Bastian, N.; Husser, T. -O.; Martocchia, S.; Usher, C.; den Brok, M.; Dreizler, S.; Kelz, A.; Krajnović, D.; Richard, J.; Steinmetz, M.; Weilbacher, P. M. Bibcode: 2018MNRAS.480.1689K Altcode: 2018MNRAS.tmp.1865K; 2018arXiv180710612K We present adaptive optics (AO)-assisted integral-field spectroscopy of the intermediate-age star cluster NGC 419 in the Small Magellanic Cloud. By investigating the cluster dynamics and the rotation properties of main-sequence turn-off (MSTO) stars, we demonstrate the power of AO-fed MUSE observations for this class of objects. Based on 1 049 radial velocity measurements, we determine a dynamical cluster mass of 1.4± 0.2× 10^5 M_⊙ and a dynamical mass-to-light ratio of 0.67 ± 0.08, marginally higher than simple stellar population predictions for a Kroupa initial mass function. A stacking analysis of spectra at both sides of the extended MSTO reveals significant rotational broadening. Our analysis further provides tentative evidence that red MSTO stars rotate faster than their blue counterparts. We find average Vsin i values of 87± 16 and 130± 22 {km s^{-1}} for blue and red MSTO stars, respectively. Potential systematic effects due to the low-spectral resolution of MUSE can reach 30 {km s^{-1}} but the difference in Vsin i between the populations is unlikely to be affected. Title: Kepler Object of Interest Network. II. Photodynamical modelling of Kepler-9 over 8 years of transit observations Authors: Freudenthal, J.; von Essen, C.; Dreizler, S.; Wedemeyer, S.; Agol, E.; Morris, B. M.; Becker, A. C.; Mallonn, M.; Hoyer, S.; Ofir, A.; Tal-Or, L.; Deeg, H. J.; Herrero, E.; Ribas, I.; Khalafinejad, S.; Hernández, J.; Rodríguez S., M. M. Bibcode: 2018A&A...618A..41F Altcode: 2018arXiv180700007F Context. The Kepler Object of Interest Network (KOINet) is a multi-site network of telescopes around the globe organised to follow up transiting planet-candidate Kepler objects of interest (KOIs) with large transit timing variations (TTVs). Its main goal is to complete their TTV curves, as the Kepler telescope no longer observes the original Kepler field.
Aims: Combining Kepler and new ground-based transit data we improve the modelling of these systems. To this end, we have developed a photodynamical model, and we demonstrate its performance using the Kepler-9 system as an example.
Methods: Our comprehensive analysis combines the numerical integration of the system's dynamics over the time span of the observations along with the transit light curve model. This provides a coherent description of all observations simultaneously. This model is coupled with a Markov chain Monte Carlo algorithm, allowing for the exploration of the model parameter space.
Results: Applied to the Kepler-9 long cadence data, short cadence data, and 13 new transit observations collected by KOINet between the years 2014 and 2017, our modelling provides well constrained predictions for the next transits and the system's parameters. We have determined the densities of the planets Kepler-9b and 9c to the very precise values of ρb = 0.439 ± 0.023 g cm-3 and ρc = 0.322 ± 0.017 g cm-3. Our analysis reveals that Kepler-9c will stop transiting in about 30 yr due to strong dynamical interactions between Kepler-9b and 9c, near 2:1 resonance, leading to a periodic change in inclination.
Conclusions: Over the next 30 years, the inclination of Kepler-9c (-9b) will decrease (increase) slowly. This should be measurable by a substantial decrease (increase) in the transit duration, in as soon as a few years' time. Observations that contradict this prediction might indicate the presence of additional objects in this system. If this prediction turns out to be accurate, this behaviour opens up a unique chance to scan the different latitudes of a star: high latitudes with planet c and low latitudes with planet b.

Ground-based photometry is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/618/A41 Title: MUSE crowded field 3D spectroscopy in NGC 300. I. First results from central fields Authors: Roth, Martin M.; Sandin, Christer; Kamann, Sebastian; Husser, Tim-Oliver; Weilbacher, Peter M.; Monreal-Ibero, Ana; Bacon, Roland; den Brok, Mark; Dreizler, Stefan; Kelz, Andreas; Marino, Raffaella Anna; Steinmetz, Matthias Bibcode: 2018A&A...618A...3R Altcode: 2018arXiv180604280R
Aims: As a new approach to the study of resolved stellar populations in nearby galaxies, our goal is to demonstrate with a pilot study in NGC 300 that integral field spectroscopy with high spatial resolution and excellent seeing conditions reaches an unprecedented depth in severely crowded fields.
Methods: Observations by MUSE with seven pointings in NGC 300 have resulted in data cubes that are analyzed in four ways: (1) Point spread function-fitting 3D spectroscopy with PampelMUSE, as already successfully pioneered in globular clusters, yields de-blended spectra of individually distinguishable stars, thus providing a complete inventory of blue and red supergiants, and asymptotic giant branch (AGB) stars of type M and C. The technique is also applicable to emission line point sources and provides samples of planetary nebulae (PNe) that are complete down to m5007 = 28. (2) Pseudo-monochromatic images, created at the wavelengths of the most important emission lines and corrected for continuum light with the P3D visualization tool, provide maps of H II regions, supernova remnants (SNR), and the diffuse interstellar medium (ISM) at a high level of sensitivity, where also faint point sources stand out and allow for the discovery of PNe, Wolf-Rayet (WR) stars, etc. (3) The use of the P3D line-fitting tool yields emission line fluxes, surface brightness, and kinematic information for gaseous objects, corrected for absorption line profiles of the underlying stellar population in the case of Hα. (4) Visual inspection of the data cubes by browsing through the row-stacked spectra image in P3D is demonstrated to be efficient for data mining and the discovery of background galaxies and unusual objects.
Results: We present a catalog of luminous stars, rare stars such as WR, and other emission line stars, carbon stars, symbiotic star candidates, PNe, H II regions, SNR, giant shells, peculiar diffuse and filamentary emission line objects, and background galaxies, along with their spectra.
Conclusions: The technique of crowded-field 3D spectroscopy, using the PampelMUSE code, is capable of deblending individual bright stars, the unresolved background of faint stars, gaseous nebulae, and the diffuse component of the ISM, resulting in unprecedented legacy value for observations of nearby galaxies with MUSE.

Based on observations obtained at the Very Large Telescope (VLT) of the European Southern Observatory, Paranal, Chile (ESO Programme ID 094.D-0116(A), 094.D-0116(B), 095.D-0173(A)).The full version of Tables 6, 9 and the reduced dat-acube (FITS file) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/618/A3 Title: VizieR Online Data Catalog: NGC 300 MUSE spectroscopy for central fields (Roth+, 2018) Authors: Roth, M. M.; Sandin, C.; Kamann, S.; Husser, T. -O., Weilbacher, P. M.; Monreal-Ibero, A.; Bacon, R.; den Brok, M.; Dreizler, S.; Kelz, A.; Marino, R. A.; Steinmetz, M. Bibcode: 2018yCat..36180003R Altcode: Observations were made with the multi unit spectroscopic explorer instrument (MUSE), which is placed at the Nasmyth focus of the UT4 8.2m telescope at the Very Large Telescope observatory (VLT) of the European Southern Observatory (ESO) in Chile. NGC 300 was observed as part of guaranteed time observations of the MUSE instrument-building consortium during the three periods P93, P94, and P95.

We present a catalog of luminous stars, rare stars such as WR, and other emission line stars, carbon stars, symbiotic star candidates, PNe, HII regions, SNR, giant shells, peculiar diffuse and filamentary emission line objects, and background galaxies, along with their spectra.

(4 data files). Title: The atmosphere of WASP-17b: Optical high-resolution transmission spectroscopy Authors: Khalafinejad, Sara; Salz, Michael; Cubillos, Patricio E.; Zhou, George; von Essen, Carolina; Husser, Tim-Oliver; Bayliss, Daniel D. R.; López-Morales, Mercedes; Dreizler, Stefan; Schmitt, Jürgen H. M. M.; Lüftinger, Theresa Bibcode: 2018A&A...618A..98K Altcode: 2018arXiv180710621K High-resolution transmission spectroscopy is a method for understanding the chemical and physical properties of upper exoplanetary atmospheres. Due to large absorption cross-sections, resonance lines of atomic sodium D-lines (at 5889.95 and 5895.92 Å) produce large transmission signals. Our aim is to unveil the physical properties of WASP-17b through an accurate measurement of the sodium absorption in the transmission spectrum. We analyze 37 high-resolution spectra observed during a single transit of WASP-17b with the MIKE instrument on the 6.5 m Magellan Telescopes. We exclude stellar flaring activity during the observations by analyzing the temporal variations of Hα and Ca II infrared triplet (IRT) lines. We then obtain the excess absorption light curves in wavelength bands of 0.75, 1, 1.5, and 3 Å around the center of each sodium line (i.e., the light curve approach). We model the effects of differential limb-darkening, and the changing planetary radial velocity on the light curves. We also analyze the sodium absorption directly in the transmission spectrum, which is obtained by dividing in-transit by out-of-transit spectra (i.e., the division approach). We then compare our measurements with a radiative transfer atmospheric model. Our analysis results in a tentative detection of exoplanetary sodium: we measure the width and amplitude of the exoplanetary sodium feature to be σNa = (0.128 ± 0.078) Å and ANa = (1.7 ± 0.9)% in the excess light curve approach and σNa = (0.850 ± 0.034) Å and ANa = (1.3 ± 0.6)% in the division approach. By comparing our measurements with a simple atmospheric model, we retrieve an atmospheric temperature of 15501550 -200+700 K and radius (at 0.1 bar) of 1.81 ± 0.02 RJup for WASP-17b. Title: Improved Methods for Spitzer Systematic Identification and Removal Authors: Challener, Ryan C.; Harrington, Joseph; Jenkins, James; Kurtovic, Nicolás T.; Ramirez, Ricardo; Peña Zamudio, José; McIntyre, Kathleen J.; Himes, Michael D.; Rodríguez, Eloy; Anglada-Escudé, Guillem; Dreizler, Stefan; Ofir, Aviv; Ribas, Ignasi; Rojo, Patricio; Kipping, David; Butler, R. Paul; Amado, Pedro J.; Rodríguez-López, Cristina; Kempton, Eliza M.; Palle, Enric; Murgas, Felipe Bibcode: 2018DPS....5040510C Altcode: After the discovery of Proxima Centauri b in 2016, we observed the system with the Spitzer Space Telescope to look for transits. We confirmed that the planet does not transit. However, we observed three asymmetric, periodic, comet-like events. Unfortunately, we now understand these events to be systematic effects due to telescope vibration, which is occasionally temporally resolved with our 0.02 second frame time. This systematic has been previously identified as a spike in the number of pixels significantly contributing to photometry, but that metric can be misleading. We show that coherent, high-frequency activity in the point-spread function area, measured several ways, is more indicative of this systematic, and that the effect can be partially removed by a quadratic model dependent on point-spread function width. This systematic occurs at an exoplanet-signal level three times in our 80 hours, and more frequently at a lower level, which has implications for transits and eclipses of small and cool planets, respectively. Spitzer is operated by the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA. This work was supported by NASA Planetary Atmospheres grant NNX12AI69G and NASA Astrophysics Data Analysis Program grant NNX13AF38G. Title: VizieR Online Data Catalog: KOINet. Study of exoplanet systems via TTVs (von Essen+, 2018) Authors: von Essen, C.; Ofir, A.; Dreizler, S.; Agol, E.; Freudenthal, J.; Hernandez, J.; Wedemeyer, S.; Parkash, V.; Deeg, H. J.; Hoyer, S.; Morris, B. M.; Becker, A. C.; Sun, L.; Gu, S. H.; Herrero, E.; Tal-Or, L.; Poppenhaeger, K.; Mallonn, M.; Albrecht, S.; Khalafinejad, S.; Boumis, P.; Delgado-Correal, C.; Fabrycky, D. C.; Janulis, R.; Lalitha, S.; Liakos, A.; Mikolaitis, S.; Moyano D'Angelo, M. L.; Sokov, E.; Pakstiene, E.; Popov, A.; Krushinsky, V.; Ribas, I.; Rodriguez, M. M. S.; Rusov, S.; Sokova, I.; Tautvaisiene, G.; Wang, X. Bibcode: 2018yCat..36150079V Altcode: All our observations were carried out using R-band filter. We provide the differential photometry with varying reference stars for each observation together with the used detrending components. We provide four transits of KOI-0410.01, and one transit of KOI-0902.01, KOI-0525.01, and KOI-0760.01, respectively. The telescope nomenclature, in agreement with the names of the files, is the following:

IAC0.8: IAC80 telescope (0.8m), Instituto de Astrofisica de Canarias, Spain. ARC3.5: Apache Point Observatory (3.5 m), USA. NOT2.5: Nordic Optical Telescope (2.5 m), Spain. YO2.4: Yunnan Observatories (2.4 m), PR China.

(8 data files). 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 Bibcode: 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 10-3 dex Gyr-1 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 >80% of solar twins (at 2σ confidence), suggesting a possible signpost for planetary systems like our own. Title: VizieR Online Data Catalog: CARMENES input catalogue of M dwarfs. IV. (Diez Alonso+ 2019) Authors: Diez Alonso, E.; Caballero, J. A.; Montes, D.; de Cos Juez, F. J.; Dreizler, S.; Dubois, F.; Jeffers, S. V.; Lalitha, S.; Naves, R.; Reiners, A.; Ribas, I.; Vanaverbeke, S.; Amado, P. J.; Bejar, V. J. S.; Cortes-Contreras, M.; Herrero, E.; Hidalgo, D.; Kuerster, M.; Logie, L.; Quirrenbach, A.; Rau, S.; Seifert, W.; Schoefer, P.; Tal-Or, L. Bibcode: 2018yCat..36210126D Altcode: During guaranteed time observations (GTOs), the double-channel CARMENES spectrograph has so far observed a sample of 336 bright, nearby M dwarfs with the goal of detecting low-mass planets in their habitable zone with the radial-velocity method (Quirrenbach et al., 2015, in 18th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun, Proceedings of the conference held at Lowell Observatory, 8-14 June 2014. Edited by G. van Belle and H.C. Harris., pp. 897-906; Reiners et al., 2018, Cat. J/A+A/612/A49). Of these, 324 were presented by Reiners et al. (2018, Cat. J/A+A/612/A49), three did not have enough CARMENES observations at the time of preparing the spectral templates for the study, and nine are new spectroscopic binaries (Baroch et al., 2018, A&A, in prep, arXiv:1808.06895). Here, we investigate the photometric variability of these 336 M dwarfs and of G 34-23 AB (J01221+221AB), which Cortes-Contreras et al. (2017, Cat. J/A+A/597/A47) found to be a close physical binary just before GTO start. This results in a final sample size of 337 stars.

(2 data files). Title: VizieR Online Data Catalog: A Neptune-mass planet traversing the habitable zone around HD 180617 (Kaminski+, 2018) Authors: Kaminski, A.; Trifonov, T.; Caballero, J. A.; Quirrenbach, A.; Ribas, I.; Reiners, A.; Amado, P. J.; Zechmeister, M.; Dreizler, S.; Perger, M.; Tal-Or, L.; Bonfils, X.; Mayor, M.; Astudillo-Defru, N.; Bauer, F. F.; Bejar, V. J. S.; Cifuentes, C.; Colome, J.; Cortes-Contreras, M.; Delfosse, X.; Diez-Alonso, E.; Forveille, T.; Guenther, E. W.; Hatzes, A. P.; Henning, Th.; Jeffers, S. V.; Kuerster, M.; Lafarga, M.; Luque, R.; Mandel, H.; Montes, D.; Morales, J. C.; Passegger, V. M.; Pedraz, S.; Reffert, S.; Sadegi, S.; Schweitzer, A.; Seifert, W.; Stahl, O.; Udry, S. Bibcode: 2018yCat..36180115K Altcode: We analyzed radial velocity data from the CARMENES VIS channel, HIRES/Keck, and HARPS. All the RVs are corrected for barycentric motion and secular acceleration. The CARMENES measurements were taken in the context of the CARMENES search for exoplanets around M dwarfs. The CARMENES instrument consists of two channels: the VIS channel obtains spectra at a resolution of R=94600 in the wavelength range 520-960nm, while the NIR channel yields spectra of R=80400 covering 960-1710nm. Both channels are calibrated in wavelength with hollow-cathode lamps and use temperature- and pressure-stabilized Fabry-Perot etalons to interpolate the wavelength solution and simultaneously monitor the spectrograph drift during nightly operations (Bauer et al., 2015A&A...581A.117B).

(1 data file). Title: VizieR Online Data Catalog: Photometry of Kepler-9b and c transits (Freudenthal+, 2018) Authors: Freudenthal, J.; von Essen, C.; Dreizler, S.; Wedemeyer, S.; Agol, E.; Morris, B. M.; Becker, A. C.; Mallonn, M.; Hoyer, S.; Ofir, A.; Tal-Or, L.; Deeg, H. J.; Herrero, E.; Ribas, I.; Khalafinejad, S.; Hernandez, J.; Rodriguez, S. M. M. Bibcode: 2018yCat..36180041F Altcode: All our observations were carried out using R-band filter. We provide the differential photometry with varying reference stars for each observation together with the used detrending components. We measured five Kepler-9b and four Kepler-9c transits in thirteen observations between 2014 and 2017.

(14 data files). Title: VizieR Online Data Catalog: CARMENES SB2 orbital parameters (Baroch+, 2018) Authors: Baroch, D.; Morales, J. C.; Ribas, I.; Tal-Or, L.; Zechmeister, M.; Reiners, A.; Caballero, J. A.; Quirrenbach, A.; Amado, P. J.; Dreizler, S.; Lalitha, S.; Jeers, S. V.; Lafarga, M.; Bejar, V. J. S.; Colome, J.; Cortes-Contreras, M.; Diez-Alonso, E.; Galadi-Enriquez, D.; Guenther, E. W.; Hagen, H. -J.; Henning, T.; Herrero, E.; Kuerster, M.; Montes, D.; Nagel, E.; Passegger, V. M.; Perger, M.; Rosich, A.; Schweitzer, A.; Seifert, W. Bibcode: 2018yCat..36190032B Altcode: These tables list the radial velocities of the SB2 binary systems detected with CARMENES which are used to compute their orbital and physical properties. Besides, Table D1 is an effort to compile all known M-dwarf SB2s with published orbital parameters. A total of 67 systems, 29 of which are eclipsing, have been found. Most of the systems are taken from the SB9 catalogue of spectroscopic binaries (Pourbaix et al., 2004, Cat. B/sb9), while additional systems have been found in a bibliographic search. CARMENES spectroscopic binaries are included in this table.

(2 data files). Title: The MICADO first light imager for the ELT: overview, operation, simulation Authors: Davies, R.; Alves, J.; Clénet, Y.; Lang-Bardl, F.; Nicklas, H.; Pott, J. -U.; Ragazzoni, R.; Tolstoy, E.; Amico, P.; Anwand-Heerwart, H.; Barboza, S.; Barl, L.; Baudoz, P.; Bender, R.; Bezawada, N.; Bizenberger, P.; Boland, W.; Bonifacio, P.; Borgo, B.; Buey, T.; Chapron, F.; Chemla, F.; Cohen, M.; Czoske, O.; Déo, V.; Disseau, K.; Dreizler, S.; Dupuis, O.; Fabricius, M.; Falomo, R.; Fedou, P.; Förster Schreiber, N.; Garrel, V.; Geis, N.; Gemperlein, H.; Gendron, E.; Genzel, R.; Gillessen, S.; Glück, M.; Grupp, F.; Hartl, M.; Häuser, M.; Hess, H. -J.; Hofferbert, R.; Hopp, U.; Hörmann, V.; Hubert, Z.; Huby, E.; Huet, J. -M.; Hutterer, V.; Ives, D.; Janssen, A.; Jellema, W.; Kausch, W.; Kerber, F.; Kravcar, H.; Le Ruyet, B.; Leschinski, K.; Mandla, C.; Manhart, M.; Massari, D.; Mei, S.; Merlin, F.; Mohr, L.; Monna, A.; Muench, N.; Müller, F.; Musters, G.; Navarro, R.; Neumann, U.; Neumayer, N.; Niebsch, J.; Plattner, M.; Przybilla, N.; Rabien, S.; Ramlau, R.; Ramos, J.; Ramsay, S.; Rhode, P.; Richter, A.; Richter, J.; Rix, H. -W.; Rodeghiero, G.; Rohloff, R. -R.; Rosensteiner, M.; Rousset, G.; Schlichter, J.; Schubert, J.; Sevin, A.; Stuik, R.; Sturm, E.; Thomas, J.; Tromp, N.; Verdoes-Kleijn, G.; Vidal, F.; Wagner, R.; Wegner, M.; Zeilinger, W.; Ziegleder, J.; Ziegler, B.; Zins, G. Bibcode: 2018SPIE10702E..1SD Altcode: 2018arXiv180710003D MICADO will enable the ELT to perform diffraction limited near-infrared observations at first light. The instrument's capabilities focus on imaging (including astrometric and high contrast) as well as single object spectroscopy. This contribution looks at how requirements from the observing modes have driven the instrument design and functionality. Using examples from specific science cases, and making use of the data simulation tool, an outline is presented of what we can expect the instrument to achieve. Title: CARMENES: high-resolution spectra and precise radial velocities in the red and infrared Authors: Quirrenbach, A.; Amado, P. J.; Ribas, I.; Reiners, A.; Caballero, J. A.; Seifert, W.; Aceituno, J.; Azzaro, M.; Baroch, D.; Barrado, D.; Bauer, F.; Becerril, S.; Bèjar, V. J. S.; Benítez, D.; Brinkmöller, M.; Cardona Guillén, C.; Cifuentes, C.; Colomé, J.; Cortés-Contreras, M.; Czesla, S.; Dreizler, S.; Frölich, K.; Fuhrmeister, B.; Galadí-Enríquez, D.; González Hernández, J. I.; González Peinado, R.; Guenther, E. W.; de Guindos, E.; Hagen, H. -J.; Hatzes, A. P.; Hauschildt, P. H.; Helmling, J.; Henning, Th.; Herbort, O.; Hernández Castaño, L.; Herrero, E.; Hintz, D.; Jeffers, S. V.; Johnson, E. N.; de Juan, E.; Kaminski, A.; Klahr, H.; Kürster, M.; Lafarga, M.; Sairam, L.; Lampón, M.; Lara, L. M.; Launhardt, R.; López del Fresno, M.; López-Puertas, M.; Luque, R.; Mandel, H.; Marfil, E. G.; Martín, E. L.; Martín-Ruiz, S.; Mathar, R. J.; Montes, D.; Morales, J. C.; Nagel, E.; Nortmann, L.; Nowak, G.; Pallé, E.; Passegger, V. -M.; Pavlov, A.; Pedraz, S.; Pérez-Medialdea, D.; Perger, M.; Rebolo, R.; Reffert, S.; Rodríguez, E.; Rodríguez López, C.; Rosich, A.; Sabotta, S.; Sadegi, S.; Salz, M.; Sánchez-López, A.; Sanz-Forcada, J.; Sarkis, P.; Schäfer, S.; Schiller, J.; Schmitt, J. H. M. M.; Schöfer, P.; Schweitzer, A.; Shulyak, D.; Solano, E.; Stahl, O.; Tala Pinto, M.; Trifonov, T.; Zapatero Osorio, M. R.; Yan, F.; Zechmeister, M.; Abellán, F. J.; Abril, M.; Alonso-Floriano, F. J.; Ammler-von Eiff, M.; Anglada-Escudé, G.; Anwand-Heerwart, H.; Arroyo-Torres, B.; Berdiñas, Z. M.; Bergondy, G.; Blümcke, M.; del Burgo, C.; Cano, J.; Carro, J.; Cárdenas, M. C.; Casal, E.; Claret, A.; Díez-Alonso, E.; Doellinger, M.; Dorda, R.; Feiz, C.; Fernández, M.; Ferro, I. M.; Gaisné, G.; Gallardo, I.; Gálvez-Ortiz, M. C.; García-Piquer, A.; García-Vargas, M. L.; Garrido, R.; Gesa, L.; Gómez Galera, V.; González-Álvarez, E.; González-Cuesta, L.; Grohnert, S.; Grözinger, U.; Guàrdia, J.; Guijarro, A.; Hedrosa, R. P.; Hermann, D.; Hermelo, I.; Hernández Arabí, R.; Hernández Hernando, F.; Hidalgo, D.; Holgado, G.; Huber, A.; Huber, K.; Huke, P.; Kehr, M.; Kim, M.; Klein, R.; Klüter, J.; Klutsch, A.; Labarga, F.; Labiche, N.; Lamert, A.; Laun, W.; Lázaro, F. J.; Lemke, U.; Lenzen, R.; Llamas, M.; Lizon, J. -L.; Lodieu, N.; López González, M. J.; López-Morales, M.; López Salas, J. F.; López-Santiago, J.; Magán Madinabeitia, H.; Mall, U.; Mancini, L.; Marín Molina, J. A.; Martínez-Rodríguez, H.; Maroto Fernández, D.; Marvin, C. J.; Mirabet, E.; Moreno-Raya, M. E.; Moya, A.; Mundt, R.; Naranjo, V.; Panduro, J.; Pascual, J.; Pérez-Calpena, A.; Perryman, M. A. C.; Pluto, M.; Ramón, A.; Redondo, P.; Reinhart, S.; Rhode, P.; Rix, H. -W.; Rodler, F.; Rohloff, R. -R.; Sánchez-Blanco, E.; Sánchez Carrasco, M. A.; Sarmiento, L. F.; Schmidt, C.; Storz, C.; Strachan, J. B. P.; Stürmer, J.; Suárez, J. C.; Tabernero, H. M.; Tal-Or, L.; Tulloch, S. M.; Ulbrich, R. -G.; Veredas, G.; Vico Linares, J. L.; Vidal-Dasilva, M.; Vilardell, F.; Wagner, K.; Winkler, J.; Wolthoff, V.; Xu, W.; Zhao, Z. Bibcode: 2018SPIE10702E..0WQ Altcode: The design and construction of CARMENES has been presented at previous SPIE conferences. It is a next-generation radial-velocity instrument at the 3.5m telescope of the Calar Alto Observatory, which was built by a consortium of eleven Spanish and German institutions. CARMENES consists of two separate échelle spectrographs covering the wavelength range from 0.52 to 1.71μm at a spec-tral resolution of R < 80,000, fed by fibers from the Cassegrain focus of the telescope. CARMENES saw "First Light" on Nov 9, 2015. During the commissioning and initial operation phases, we established basic performance data such as throughput and spectral resolution. We found that our hollow-cathode lamps are suitable for precise wavelength calibration, but their spectra contain a number of lines of neon or argon that are so bright that the lamps cannot be used in simultaneous exposures with stars. We have therefore adopted a calibration procedure that uses simultaneous star / Fabry Pérot etalon exposures in combination with a cross-calibration between the etalons and hollow-cathode lamps during daytime. With this strategy it has been possible to achieve 1-2 m/s precision in the visible and 5-10 m/s precision in the near-IR; further improvements are expected from ongoing work on temperature control, calibration procedures and data reduction. Comparing the RV precision achieved in different wavelength bands, we find a "sweet spot" between 0.7 and 0.8μm, where deep TiO bands provide rich RV information in mid-M dwarfs. This is in contrast to our pre-survey models, which predicted comparatively better performance in the near-IR around 1μm, and explains in part why our near-IR RVs do not reach the same precision level as those taken with the visible spectrograph. We are now conducting a large survey of 340 nearby M dwarfs (with an average distance of only 12pc), with the goal of finding terrestrial planets in their habitable zones. We have detected the signatures of several previously known or suspected planets and also discovered several new planets. We find that the radial velocity periodograms of many M dwarfs show several significant peaks. The development of robust methods to distinguish planet signatures from activity-induced radial velocity jitter is therefore among our priorities. Due to its large wavelength coverage, the CARMENES survey is generating a unique data set for studies of M star atmospheres, rotation, and activity. The spectra cover important diagnostic lines for activity (H alpha, Na I D1 and D2, and the Ca II infrared triplet), as well as FeH lines, from which the magnetic field can be inferred. Correlating the time series of these features with each other, and with wavelength-dependent radial velocities, provides excellent handles for the discrimination between planetary companions and stellar radial velocity jitter. These data are also generating new insight into the physical properties of M dwarf atmospheres, and the impact of activity and flares on the habitability of M star planets. Title: Kepler Object of Interest Network. I. First results combining ground- and space-based observations of Kepler systems with transit timing variations Authors: von Essen, C.; Ofir, A.; Dreizler, S.; Agol, E.; Freudenthal, J.; Hernández, J.; Wedemeyer, S.; Parkash, V.; Deeg, H. J.; Hoyer, S.; Morris, B. M.; Becker, A. C.; Sun, L.; Gu, S. H.; Herrero, E.; Tal-Or, L.; Poppenhaeger, K.; Mallonn, M.; Albrecht, S.; Khalafinejad, S.; Boumis, P.; Delgado-Correal, C.; Fabrycky, D. C.; Janulis, R.; Lalitha, S.; Liakos, A.; Mikolaitis, Š.; Moyano D'Angelo, M. L.; Sokov, E.; Pakštienė, E.; Popov, A.; Krushinsky, V.; Ribas, I.; Rodríguez S., M. M.; Rusov, S.; Sokova, I.; Tautvaišienė, G.; Wang, X. Bibcode: 2018A&A...615A..79V Altcode: 2018arXiv180106191V During its four years of photometric observations, the Kepler space telescope detected thousands of exoplanets and exoplanet candidates. One of Kepler's greatest heritages has been the confirmation and characterization of hundreds of multi-planet systems via transit timing variations (TTVs). However, there are many interesting candidate systems displaying TTVs on such long timescales that the existing Kepler observations are of insufficient length to confirm and characterize them by means of this technique. To continue with Kepler's unique work, we have organized the "Kepler Object of Interest Network" (KOINet), a multi-site network formed of several telescopes located throughout America, Europe, and Asia. The goals of KOINet are to complete the TTV curves of systems where Kepler did not cover the interaction timescales well, to dynamically prove that some candidates are true planets (or not), to dynamically measure the masses and bulk densities of some planets, to find evidence for non-transiting planets in some of the systems, to extend Kepler's baseline adding new data with the main purpose of improving current models of TTVs, and to build a platform that can observe almost anywhere on the northern hemisphere, at almost any time. KOINet has been operational since March 2014. Here we show some promising first results obtained from analyzing seven primary transits of KOI-0410.01, KOI-0525.01, KOI-0760.01, and KOI-0902.01, in addition to the Kepler data acquired during the first and second observing seasons of KOINet. While carefully choosing the targets we set demanding constraints on timing precision (at least 1 min) and photometric precision (as good as one part per thousand) that were achieved by means of our observing strategies and data analysis techniques. For KOI-0410.01, new transit data revealed a turnover of its TTVs. We carried out an in-depth study of the system, which is identified in the NASA Data Validation Report as a false positive. Among others, we investigated a gravitationally bound hierarchical triple star system and a planet-star system. While the simultaneous transit fitting of ground- andspace-based data allowed for a planet solution, we could not fully reject the three-star scenario. New data, already scheduled in the upcoming 2018 observing season, will set tighter constraints on the nature of the system.

Ground-based photometry is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/615/A79 Title: VizieR Online Data Catalog: 324 CARMENES M dwarfs velocities (Reiners+, 2018) Authors: Reiners, A.; Zechmeister, M.; Caballero, J. A.; Ribas, I.; Morales, J. C.; Jeffers, S. V.; Schofer, P.; Tal-Or, L.; Quirrenbach, A.; Amado, P. J.; Kaminski, A.; Seifert, W.; Abril, M.; Aceituno, J.; Alonso-Floriano, F. J.; Ammler-von Eiff, M.; Antona, R.; Anglada-Escude, G.; Anwand-Heerwart, H.; Arroyo-Torres, B.; Azzaro, M.; Baroch, D.; Barrado, D.; Bauer, F. F.; Becerril, S.; Bejar, V. J. S.; Benitez, D.; Berdinas, Z. M.; Bergond, G.; Blumcke, M.; Brinkmoller, M.; Del Burgo, C.; Cano, J.; Cardenas Vazquez, M. C.; Casal, E.; Cifuentes, C.; Claret, A.; Colome, J.; Cortes-Contreras, M.; Czesla, S.; Diez-Alonso, E.; Dreizler, S.; Feiz, C.; Fernandez, M.; Ferro, I. M.; Fuhrmeister, B.; Galadi-Enriquez, D.; Garcia-Piquer, A.; Garcia Vargas, M. L.; Gesa, L.; Gomez Galera, V.; Gonzalez Hernandez, J. I.; Gonzalez-Peinado, R.; Grozinger, U.; Grohnert, S.; Guardia, J.; Guenther, E. W.; Guijarro, A.; de Guindos, E.; Gutierrez-Soto, J.; Hagen, H. -J.; Hatzes, A. P.; Hauschildt, P. H.; Hedrosa, R. P.; Helmling, J.; Henning, T.; Hermelo, I.; Hernandez Arabi, R.; Hernandez Castano, L.; Hernandez Hernando, F.; Herrero, E.; Huber, A.; Huke, P.; Johnson, E. N.; de Juan, E.; Kim, M.; Klein, R.; Kluter, J.; Klutsch, A.; Kurster, M.; Lafarga, M.; Lamert, A.; Lampon, M.; Lara, L. M.; Laun, W.; Lemke, U.; Lenzen, R.; Launhardt, R.; Lopez Del Fresno, M.; Lopez-Gonzalez, J.; Lopez-Puertas, M.; Lopez Salas, J. F.; Lopez-Santiago, J.; Luque, R.; Magan Madinabeitia, H.; Mall, U.; Mancini, L.; Mandel, H.; Marfil, E.; Marin Molina, J. A.; Maroto Fernandez, D.; Martin, E. L.; Martin-Ruiz, S.; Marvin, C. J.; Mathar, R. J.; Mirabet, E.; Montes, D.; Moreno-Raya, M. E.; Moya, A.; Mundt, R.; Nagel, E.; Naranjo, V.; Nortmann, L.; Nowak, G.; Ofir, A.; Oreiro, R.; Palle, E.; Panduro, J.; Pascual, J.; Passegger, V. M.; Pavlov, A.; Pedraz, S.; Perez-Calpena, A.; Perez Medialdea, D.; Perger, M.; Perryman, M. A. C.; Pluto, M.; Rabaza, O.; Ramon, A.; Rebolo, R.; Redondo, P.; Reffert, S.; Reinhart, S.; Rhode, P.; Rix, H. -W.; Rodler, F.; Rodriguez, E.; Rodriguez-Lopez, C.; Rodriguez Trinidad, A.; Rohloff, R. -R.; Rosich, A.; Sadegi, S.; Sanchez-Blanco, E.; Sanchez Carrasco, M. A.; Sanchez-Lopez, A.; Sanz-Forcada, J.; Sarkis, P.; Sarmiento, L. F.; Schafer, S.; Schmitt, J. H. M. M.; Schiller, J.; Schweitzer, A.; Solano, E.; Stahl, O.; Strachan, J. B. P.; Sturmer, J.; Suarez, J. C.; Tabernero, H. M.; Tala, M.; Trifonov, T.; Tulloch, S. M.; Ulbrich, R. G.; Veredas, G.; Vico Linares, J. I.; Vilardell, F.; Wagner, K.; Winkler, J.; Wolthoff, V.; Xu, W.; Yan, F.; Zapatero Osorio, M. R. Bibcode: 2018yCat..36120049R Altcode: As part of the GTO agreement, we provide early access to one CARMENES spectrum for each of our sample targets (Table B.1). They can be downloaded from the CARMENES GTO Data Archive (Caballero et al., 2016, in Observatory Operations: Strategies, Processes, and Systems VI, Proc. SPIE, 9910, 99100E) (http://carmenes.cab.inta-csic.es)

(1 data file). Title: The CARMENES Search for Exoplanets around M Dwarfs: A Low-mass Planet in the Temperate Zone of the Nearby K2-18 Authors: Sarkis, Paula; Henning, Thomas; Kürster, Martin; Trifonov, Trifon; Zechmeister, Mathias; Tal-Or, Lev; Anglada-Escudé, Guillem; Hatzes, Artie P.; Lafarga, Marina; Dreizler, Stefan; Ribas, Ignasi; Caballero, José A.; Reiners, Ansgar; Mallonn, Matthias; Morales, Juan C.; Kaminski, Adrian; Aceituno, Jesús; Amado, Pedro J.; Béjar, Victor J. S.; Hagen, Hans-Jürgen; Jeffers, Sandra; Quirrenbach, Andreas; Launhardt, Ralf; Marvin, Christopher; Montes, David Bibcode: 2018AJ....155..257S Altcode: 2018arXiv180500830S; 2018arXiv180500830P K2-18 is a nearby M2.5 dwarf, located at 34 pc and hosting a transiting planet that was first discovered by the K2 mission and later confirmed with Spitzer Space Telescope observations. With a radius of ∼2 R and an orbital period of ∼33 days, the planet lies in the temperate zone of its host star and receives stellar irradiation similar to that of Earth. Here we perform radial velocity follow-up observations with the visual channel of CARMENES with the goal of determining the mass and density of the planet. We measure a planetary semi-amplitude of K b ∼ 3.5 {{m}} {{{s}}}-1 and a mass of M b ∼ 9 M , yielding a bulk density around {ρ }b∼ 4 {{g}} {cm}}-3. This indicates a low-mass planet with a composition consistent with a solid core and a volatile-rich envelope. A signal at 9 days was recently reported using radial velocity measurements taken with the HARPS spectrograph. This was interpreted as being due to a second planet. We see a weaker, time- and wavelength-dependent signal in the CARMENES data set and thus favor stellar activity for its origin. K2-18 b joins the growing group of low-mass planets detected in the temperate zone of M dwarfs. The brightness of the host star in the near-infrared makes the system a good target for detailed atmospheric studies with the James Webb Space Telescope. Title: The CARMENES search for exoplanets around M dwarfs. Radial-velocity variations of active stars in visual-channel spectra Authors: Tal-Or, L.; Zechmeister, M.; Reiners, A.; Jeffers, S. V.; Schöfer, P.; Quirrenbach, A.; Amado, P. J.; Ribas, I.; Caballero, J. A.; Aceituno, J.; Bauer, F. F.; Béjar, V. J. S.; Czesla, S.; Dreizler, S.; Fuhrmeister, B.; Hatzes, A. P.; Johnson, E. N.; Kürster, M.; Lafarga, M.; Montes, D.; Morales, J. C.; Reffert, S.; Sadegi, S.; Seifert, W.; Shulyak, D. Bibcode: 2018A&A...614A.122T Altcode: 2018arXiv180302338T Context. Previous simulations predicted the activity-induced radial-velocity (RV) variations of M dwarfs to range from 1 cm s-1 to 1 km s-1, depending on various stellar and activity parameters.
Aims: We investigate the observed relations between RVs, stellar activity, and stellar parameters of M dwarfs by analyzing CARMENES high-resolution visual-channel spectra (0.5-1μm), which were taken within the CARMENES RV planet survey during its first 20 months of operation.
Methods: During this time, 287 of the CARMENES-sample stars were observed at least five times. From each spectrum we derived a relative RV and a measure of chromospheric Hα emission. In addition, we estimated the chromatic index (CRX) of each spectrum, which is a measure of the RV wavelength dependence.
Results: Despite having a median number of only 11 measurements per star, we show that the RV variations of the stars with RV scatter of >10 m s-1 and a projected rotation velocity v sin i > 2 km s-1 are caused mainly by activity. We name these stars "active RV-loud stars" and find their occurrence to increase with spectral type: from 3% for early-type M dwarfs (M0.0-2.5 V) through 30% for mid-type M dwarfs (M3.0-5.5 V) to >50% for late-type M dwarfs (M6.0-9.0 V). Their RV-scatter amplitude is found to be correlated mainly with v sin i. For about half of the stars, we also find a linear RV-CRX anticorrelation, which indicates that their activity-induced RV scatter is lower at longer wavelengths. For most of them we can exclude a linear correlation between RV and Hα emission.
Conclusions: Our results are in agreement with simulated activity-induced RV variations in M dwarfs. The RV variations of most active RV-loud M dwarfs are likely to be caused by dark spots on their surfaces, which move in and out of view as the stars rotate.

The data presented in Figs. 5 and A.1 are only available in electronic form at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz- bin/qcat?J/A+A/614/A122 Title: The CARMENES search for exoplanets around M dwarfs. High-resolution optical and near-infrared spectroscopy of 324 survey stars Authors: Reiners, A.; Zechmeister, M.; Caballero, J. A.; Ribas, I.; Morales, J. C.; Jeffers, S. V.; Schöfer, P.; Tal-Or, L.; Quirrenbach, A.; Amado, P. J.; Kaminski, A.; Seifert, W.; Abril, M.; Aceituno, J.; Alonso-Floriano, F. J.; Ammler-von Eiff, M.; Antona, R.; Anglada-Escudé, G.; Anwand-Heerwart, H.; Arroyo-Torres, B.; Azzaro, M.; Baroch, D.; Barrado, D.; Bauer, F. F.; Becerril, S.; Béjar, V. J. S.; Benítez, D.; Berdinas, Z. M.; Bergond, G.; Blümcke, M.; Brinkmöller, M.; del Burgo, C.; Cano, J.; Cárdenas Vázquez, M. C.; Casal, E.; Cifuentes, C.; Claret, A.; Colomé, J.; Cortés-Contreras, M.; Czesla, S.; Díez-Alonso, E.; Dreizler, S.; Feiz, C.; Fernández, M.; Ferro, I. M.; Fuhrmeister, B.; Galadí-Enríquez, D.; Garcia-Piquer, A.; García Vargas, M. L.; Gesa, L.; Gómez Galera, V.; González Hernández, J. I.; González-Peinado, R.; Grözinger, U.; Grohnert, S.; Guàrdia, J.; Guenther, E. W.; Guijarro, A.; de Guindos, E.; Gutiérrez-Soto, J.; Hagen, H. -J.; Hatzes, A. P.; Hauschildt, P. H.; Hedrosa, R. P.; Helmling, J.; Henning, Th.; Hermelo, I.; Hernández Arabí, R.; Hernández Castaño, L.; Hernández Hernando, F.; Herrero, E.; Huber, A.; Huke, P.; Johnson, E. N.; de Juan, E.; Kim, M.; Klein, R.; Klüter, J.; Klutsch, A.; Kürster, M.; Lafarga, M.; Lamert, A.; Lampón, M.; Lara, L. M.; Laun, W.; Lemke, U.; Lenzen, R.; Launhardt, R.; López del Fresno, M.; López-González, J.; López-Puertas, M.; López Salas, J. F.; López-Santiago, J.; Luque, R.; Magán Madinabeitia, H.; Mall, U.; Mancini, L.; Mandel, H.; Marfil, E.; Marín Molina, J. A.; Maroto Fernández, D.; Martín, E. L.; Martín-Ruiz, S.; Marvin, C. J.; Mathar, R. J.; Mirabet, E.; Montes, D.; Moreno-Raya, M. E.; Moya, A.; Mundt, R.; Nagel, E.; Naranjo, V.; Nortmann, L.; Nowak, G.; Ofir, A.; Oreiro, R.; Pallé, E.; Panduro, J.; Pascual, J.; Passegger, V. M.; Pavlov, A.; Pedraz, S.; Pérez-Calpena, A.; Pérez Medialdea, D.; Perger, M.; Perryman, M. A. C.; Pluto, M.; Rabaza, O.; Ramón, A.; Rebolo, R.; Redondo, P.; Reffert, S.; Reinhart, S.; Rhode, P.; Rix, H. -W.; Rodler, F.; Rodríguez, E.; Rodríguez-López, C.; Rodríguez Trinidad, A.; Rohloff, R. -R.; Rosich, A.; Sadegi, S.; Sánchez-Blanco, E.; Sánchez Carrasco, M. A.; Sánchez-López, A.; Sanz-Forcada, J.; Sarkis, P.; Sarmiento, L. F.; Schäfer, S.; Schmitt, J. H. M. M.; Schiller, J.; Schweitzer, A.; Solano, E.; Stahl, O.; Strachan, J. B. P.; Stürmer, J.; Suárez, J. C.; Tabernero, H. M.; Tala, M.; Trifonov, T.; Tulloch, S. M.; Ulbrich, R. G.; Veredas, G.; Vico Linares, J. I.; Vilardell, F.; Wagner, K.; Winkler, J.; Wolthoff, V.; Xu, W.; Yan, F.; Zapatero Osorio, M. R. Bibcode: 2018A&A...612A..49R Altcode: 2017arXiv171106576R The CARMENES radial velocity (RV) survey is observing 324 M dwarfs to search for any orbiting planets. In this paper, we present the survey sample by publishing one CARMENES spectrum for each M dwarf. These spectra cover the wavelength range 520-1710 nm at a resolution of at least R >80 000, and we measure its RV, Hα emission, and projected rotation velocity. We present an atlas of high-resolution M-dwarf spectra and compare the spectra to atmospheric models. To quantify the RV precision that can be achieved in low-mass stars over the CARMENES wavelength range, we analyze our empirical information on the RV precision from more than 6500 observations. We compare our high-resolution M-dwarf spectra to atmospheric models where we determine the spectroscopic RV information content, Q, and signal-to-noise ratio. We find that for all M-type dwarfs, the highest RV precision can be reached in the wavelength range 700-900 nm. Observations at longer wavelengths are equally precise only at the very latest spectral types (M8 and M9). We demonstrate that in this spectroscopic range, the large amount of absorption features compensates for the intrinsic faintness of an M7 star. To reach an RV precision of 1 m s-1 in very low mass M dwarfs at longer wavelengths likely requires the use of a 10 m class telescope. For spectral types M6 and earlier, the combination of a red visual and a near-infrared spectrograph is ideal to search for low-mass planets and to distinguish between planets and stellar variability. At a 4 m class telescope, an instrument like CARMENES has the potential to push the RV precision well below the typical jitter level of 3-4 m s-1. Title: Lyman-continuum leakage as dominant source of diffuse ionized gas in the Antennae galaxy Authors: Weilbacher, Peter M.; Monreal-Ibero, Ana; Verhamme, Anne; Sandin, Christer; Steinmetz, Matthias; Kollatschny, Wolfram; Krajnović, Davor; Kamann, Sebastian; Roth, Martin M.; Erroz-Ferrer, Santiago; Marino, Raffaella Anna; Maseda, Michael V.; Wendt, Martin; Bacon, Roland; Dreizler, Stefan; Richard, Johan; Wisotzki, Lutz Bibcode: 2018A&A...611A..95W Altcode: 2017arXiv171204450W The Antennae galaxy (NGC 4038/39) is the closest major interacting galaxy system and is therefore often studied as a merger prototype. We present the first comprehensive integral field spectroscopic dataset of this system, observed with the MUSE instrument at the ESO VLT. We cover the two regions in this system which exhibit recent star formation: the central galaxy interaction and a region near the tip of the southern tidal tail. In these fields, we detect HII regions and diffuse ionized gas to unprecedented depth. About 15% of the ionized gas was undetected by previous observing campaigns. This newly detected faint ionized gas is visible everywhere around the central merger, and shows filamentary structure. We estimate diffuse gas fractions of about 60% in the central field and 10% in the southern region. We are able to show that the southern region contains a significantly different population of HII regions, showing fainter luminosities. By comparing HII region luminosities with the HST catalog of young star clusters in the central field, we estimate that there is enough Lyman-continuum leakage in the merger to explain the amount of diffuse ionized gas that we detect. We compare the Lyman-continuum escape fraction of each HII region against emission line ratios that are sensitive to the ionization parameter. While we find no systematic trend between these properties, the most extreme line ratios seem to be strong indicators of density bounded ionization. Extrapolating the Lyman-continuum escape fractions to the southern region, we conclude that simply from the comparison of the young stellar populations to the ionized gas there is no need to invoke other ionization mechanisms than Lyman-continuum leaking HII regions for the diffuse ionized gas in the Antennae.

FITS images and Table of HII regions are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/611/A95 and at http://muse-vlt.eu/science/antennae/ Title: VizieR Online Data Catalog: Radial-velocity of CARMENES M dwarfs (Tal-Or+, 2018) Authors: Tal-Or, L.; Zechmeister, M.; Reiners, A.; Jeffers, S. V.; Schoefer, P.; Quirrenbach, A.; Amado, P. J.; Ribas, I.; Caballero, J. A.; Aceituno, J.; Bauer, F. F.; Bejar, V. J. S.; Czesla, S.; Dreizler, S.; Fuhrmeister, B.; Hatzes, A. P.; Johnson, E. N.; Kurster, M.; Lafarga, M.; Montes, D.; Morales, J. C.; Reffert, S.; Sadegi, S.; Seifert, W.; Shulyak, D. Bibcode: 2018yCat..36140122T Altcode: The catalogue contains the data presented in Figures 5 and A.1 of the source paper.

(2 data files). Title: The Radial Velocity Variability of the K-giant γ Draconis: Stellar Variability Masquerading as a Planet Authors: Hatzes, A. P.; Endl, M.; Cochran, W. D.; MacQueen, P. J.; Han, I.; Lee, B. -C.; Kim, K. -M.; Mkrtichian, D.; Döllinger, M.; Hartmann, M.; Karjalainen, M.; Dreizler, S. Bibcode: 2018AJ....155..120H Altcode: 2018arXiv180105239H We present precise stellar radial velocity (RV) measurements of γ Dra taken from 2003 to 2017. The data from 2003 to 2011 show coherent, long-lived variations with a period of 702 days. These variations are consistent with the presence of a planetary companion having m sin i = 10.7 M Jup whose orbital properties are typical for giant planets found around evolved stars. An analysis of the Hipparcos photometry, Ca II S-index measurements, and measurements of the spectral line shapes during this time show no variations with the RV of the planet, which seems to “confirm” the presence of the planet. However, RV measurements taken from 2011-2017 seem to refute this. From 2011-2013, the RV variations virtually disappear, only to return in 2014 but with a noticeable phase shift. The total RV variations are consistent either with amplitude variations on timescales of ≈10.6 year, or the beating effect between two periods of 666 and 801 days. It seems unlikely that both these signals stem from a two-planet system. A simple dynamical analysis indicates that there is only a 1%-2% chance that the two-planet system is stable. Rather, we suggest that this multi-periodic behavior may represent a new form of stellar variability, possibly related to oscillatory convective modes. If such intrinsic stellar variability is common around K giant stars and is attributed to planetary companions, then the planet occurrence rate among these stars may be significantly lower than thought. Title: A detached stellar-mass black hole candidate in the globular cluster NGC 3201 Authors: Giesers, Benjamin; Dreizler, Stefan; Husser, Tim-Oliver; Kamann, Sebastian; Anglada Escudé, Guillem; Brinchmann, Jarle; Carollo, C. Marcella; Roth, Martin M.; Weilbacher, Peter M.; Wisotzki, Lutz Bibcode: 2018MNRAS.475L..15G Altcode: 2018arXiv180105642G As part of our massive spectroscopic survey of 25 Galactic globular clusters with MUSE, we performed multiple epoch observations of NGC 3201 with the aim of constraining the binary fraction. In this cluster, we found one curious star at the main-sequence turn-off with radial velocity variations of the order of 100 km s- 1, indicating the membership to a binary system with an unseen component since no other variations appear in the spectra. Using an adapted variant of the generalized Lomb-Scargle periodogram, we could calculate the orbital parameters and found the companion to be a detached stellar-mass black hole with a minimum mass of 4.36 ± 0.41 M. The result is an important constraint for binary and black hole evolution models in globular clusters as well as in the context of gravitational wave sources. 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. Bibcode: 2018yCat..74742580S Altcode: Spectroscopic parameters and abundances for the 79 solar twin stars analysed in this paper.

(4 data files). Title: The CARMENES search for exoplanets around M dwarfs . First visual-channel radial-velocity measurements and orbital parameter updates of seven M-dwarf planetary systems Authors: Trifonov, T.; Kürster, M.; Zechmeister, M.; Tal-Or, L.; Caballero, J. A.; Quirrenbach, A.; Amado, P. J.; Ribas, I.; Reiners, A.; Reffert, S.; Dreizler, S.; Hatzes, A. P.; Kaminski, A.; Launhardt, R.; Henning, Th.; Montes, D.; Béjar, V. J. S.; Mundt, R.; Pavlov, A.; Schmitt, J. H. M. M.; Seifert, W.; Morales, J. C.; Nowak, G.; Jeffers, S. V.; Rodríguez-López, C.; del Burgo, C.; Anglada-Escudé, G.; López-Santiago, J.; Mathar, R. J.; Ammler-von Eiff, M.; Guenther, E. W.; Barrado, D.; González Hernández, J. I.; Mancini, L.; Stürmer, J.; Abril, M.; Aceituno, J.; Alonso-Floriano, F. J.; Antona, R.; Anwand-Heerwart, H.; Arroyo-Torres, B.; Azzaro, M.; Baroch, D.; Bauer, F. F.; Becerril, S.; Benítez, D.; Berdiñas, Z. M.; Bergond, G.; Blümcke, M.; Brinkmöller, M.; Cano, J.; Cárdenas Vázquez, M. C.; Casal, E.; Cifuentes, C.; Claret, A.; Colomé, J.; Cortés-Contreras, M.; Czesla, S.; Díez-Alonso, E.; Feiz, C.; Fernández, M.; Ferro, I. M.; Fuhrmeister, B.; Galadí-Enríquez, D.; Garcia-Piquer, A.; García Vargas, M. L.; Gesa, L.; Gómez Galera, V.; González-Peinado, R.; Grözinger, U.; Grohnert, S.; Guàrdia, J.; Guijarro, A.; de Guindos, E.; Gutiérrez-Soto, J.; Hagen, H. -J.; Hauschildt, P. H.; Hedrosa, R. P.; Helmling, J.; Hermelo, I.; Hernández Arabí, R.; Hernández Castaño, L.; Hernández Hernando, F.; Herrero, E.; Huber, A.; Huke, P.; Johnson, E.; de Juan, E.; Kim, M.; Klein, R.; Klüter, J.; Klutsch, A.; Lafarga, M.; Lampón, M.; Lara, L. M.; Laun, W.; Lemke, U.; Lenzen, R.; López del Fresno, M.; López-González, M. J.; López-Puertas, M.; López Salas, J. F.; Luque, R.; Magán Madinabeitia, H.; Mall, U.; Mandel, H.; Marfil, E.; Marín Molina, J. A.; Maroto Fernández, D.; Martín, E. L.; Martín-Ruiz, S.; Marvin, C. J.; Mirabet, E.; Moya, A.; Moreno-Raya, M. E.; Nagel, E.; Naranjo, V.; Nortmann, L.; Ofir, A.; Oreiro, R.; Pallé, E.; Panduro, J.; Pascual, J.; Passegger, V. M.; Pedraz, S.; Pérez-Calpena, A.; Pérez Medialdea, D.; Perger, M.; Perryman, M. A. C.; Pluto, M.; Rabaza, O.; Ramón, A.; Rebolo, R.; Redondo, P.; Reinhardt, S.; Rhode, P.; Rix, H. -W.; Rodler, F.; Rodríguez, E.; Rodríguez Trinidad, A.; Rohloff, R. -R.; Rosich, A.; Sadegi, S.; Sánchez-Blanco, E.; Sánchez Carrasco, M. A.; Sánchez-López, A.; Sanz-Forcada, J.; Sarkis, P.; Sarmiento, L. F.; Schäfer, S.; Schiller, J.; Schöfer, P.; Schweitzer, A.; Solano, E.; Stahl, O.; Strachan, J. B. P.; Suárez, J. C.; Tabernero, H. M.; Tala, M.; Tulloch, S. M.; Veredas, G.; Vico Linares, J. I.; Vilardell, F.; Wagner, K.; Winkler, J.; Wolthoff, V.; Xu, W.; Yan, F.; Zapatero Osorio, M. R. Bibcode: 2018A&A...609A.117T Altcode: 2017arXiv171001595T Context. The main goal of the CARMENES survey is to find Earth-mass planets around nearby M-dwarf stars. Seven M dwarfs included in the CARMENES sample had been observed before with HIRES and HARPS and either were reported to have one short period planetary companion (GJ 15 A, GJ 176, GJ 436, GJ 536 and GJ 1148) or are multiple planetary systems (GJ 581 and GJ 876).
Aims: We aim to report new precise optical radial velocity measurements for these planet hosts and test the overall capabilities of CARMENES.
Methods: We combined our CARMENES precise Doppler measurements with those available from HIRES and HARPS and derived new orbital parameters for the systems. Bona-fide single planet systems were fitted with a Keplerian model. The multiple planet systems were analyzed using a self-consistent dynamical model and their best fit orbits were tested for long-term stability.
Results: We confirm or provide supportive arguments for planets around all the investigated stars except for GJ 15 A, for which we find that the post-discovery HIRES data and our CARMENES data do not show a signal at 11.4 days. Although we cannot confirm the super-Earth planet GJ 15 Ab, we show evidence for a possible long-period (Pc = 7030-630+970 d) Saturn-mass (mcsini = 51.8M) planet around GJ 15 A. In addition, based on our CARMENES and HIRES data we discover a second planet around GJ 1148, for which we estimate a period Pc = 532.6 days, eccentricity ec = 0.342 and minimum mass mcsini = 68.1M.
Conclusions: The CARMENES optical radial velocities have similar precision and overall scatter when compared to the Doppler measurements conducted with HARPS and HIRES. We conclude that CARMENES is an instrument that is up to the challenge of discovering rocky planets around low-mass stars.

Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programmes 072.C-0488, 072.C-0513, 074.C-0012, 074.C-0364, 075.D-0614, 076.C-0878, 077.C-0364, 077.C-0530, 078.C-0044, 078.C-0833, 079.C-0681, 183.C-0437, 60.A-9036, 082.C-0718, 183.C-0972, 085.C-0019, 087.C-0831, 191.C-0873. The appendix tables are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/609/A117 Title: A stellar census in globular clusters with MUSE: The contribution of rotation to cluster dynamics studied with 200 000 stars Authors: Kamann, S.; Husser, T. -O.; Dreizler, S.; Emsellem, E.; Weilbacher, P. M.; Martens, S.; Bacon, R.; den Brok, M.; Giesers, B.; Krajnović, D.; Roth, M. M.; Wendt, M.; Wisotzki, L. Bibcode: 2018MNRAS.473.5591K Altcode: 2017arXiv171007257K This is the first of a series of papers presenting the results from our survey of 25 Galactic globular clusters with the MUSE integral-field spectrograph. In combination with our dedicated algorithm for source deblending, MUSE provides unique multiplex capabilities in crowded stellar fields and allows us to acquire samples of up to 20 000 stars within the half-light radius of each cluster. The present paper focuses on the analysis of the internal dynamics of 22 out of the 25 clusters, using about 500 000 spectra of 200 000 individual stars. Thanks to the large stellar samples per cluster, we are able to perform a detailed analysis of the central rotation and dispersion fields using both radial profiles and two-dimensional maps. The velocity dispersion profiles we derive show a good general agreement with existing radial velocity studies but typically reach closer to the cluster centres. By comparison with proper motion data, we derive or update the dynamical distance estimates to 14 clusters. Compared to previous dynamical distance estimates for 47 Tuc, our value is in much better agreement with other methods. We further find significant (>3σ) rotation in the majority (13/22) of our clusters. Our analysis seems to confirm earlier findings of a link between rotation and the ellipticities of globular clusters. In addition, we find a correlation between the strengths of internal rotation and the relaxation times of the clusters, suggesting that the central rotation fields are relics of the cluster formation that are gradually dissipated via two-body relaxation. 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 Bibcode: 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 <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 CARMENES search for exoplanets around M dwarfs. HD147379 b: A nearby Neptune in the temperate zone of an early-M dwarf Authors: Reiners, A.; Ribas, I.; Zechmeister, M.; Caballero, J. A.; Trifonov, T.; Dreizler, S.; Morales, J. C.; Tal-Or, L.; Lafarga, M.; Quirrenbach, A.; Amado, P. J.; Kaminski, A.; Jeffers, S. V.; Aceituno, J.; Béjar, V. J. S.; Guàrdia, J.; Guenther, E. W.; Hagen, H. -J.; Montes, D.; Passegger, V. M.; Seifert, W.; Schweitzer, A.; Cortés-Contreras, M.; Abril, M.; Alonso-Floriano, F. J.; Ammler-von Eiff, M.; Antona, R.; Anglada-Escudé, G.; Anwand-Heerwart, H.; Arroyo-Torres, B.; Azzaro, M.; Baroch, D.; Barrado, D.; Bauer, F. F.; Becerril, S.; Benítez, D.; Berdiñas, Z. M.; Bergond, G.; Blümcke, M.; Brinkmöller, M.; del Burgo, C.; Cano, J.; Cárdenas Vázquez, M. C.; Casal, E.; Cifuentes, C.; Claret, A.; Colomé, J.; Czesla, S.; Díez-Alonso, E.; Feiz, C.; Fernández, M.; Ferro, I. M.; Fuhrmeister, B.; Galadí-Enríquez, D.; Garcia-Piquer, A.; García Vargas, M. L.; Gesa, L.; Gómez Galera, V.; González Hernández, J. I.; González-Peinado, R.; Grözinger, U.; Grohnert, S.; Guijarro, A.; de Guindos, E.; Gutiérrez-Soto, J.; Hatzes, A. P.; Hauschildt, P. H.; Hedrosa, R. P.; Helmling, J.; Henning, Th.; Hermelo, I.; Hernández Arabí, R.; Hernández Castaño, L.; Hernández Hernando, F.; Herrero, E.; Huber, A.; Huke, P.; Johnson, E. N.; de Juan, E.; Kim, M.; Klein, R.; Klüter, J.; Klutsch, A.; Kürster, M.; Labarga, F.; Lamert, A.; Lampón, M.; Lara, L. M.; Laun, W.; Lemke, U.; Lenzen, R.; Launhardt, R.; López del Fresno, M.; López-González, M. J.; López-Puertas, M.; López Salas, J. F.; López-Santiago, J.; Luque, R.; Magán Madinabeitia, H.; Mall, U.; Mancini, L.; Mandel, H.; Marfil, E.; Marín Molina, J. A.; Maroto Fernández, D.; Martín, E. L.; Martín-Ruiz, S.; Marvin, C. J.; Mathar, R. J.; Mirabet, E.; Moreno-Raya, M. E.; Moya, A.; Mundt, R.; Nagel, E.; Naranjo, V.; Nortmann, L.; Nowak, G.; Ofir, A.; Oreiro, R.; Pallé, E.; Panduro, J.; Pascual, J.; Pavlov, A.; Pedraz, S.; Pérez-Calpena, A.; Pérez Medialdea, D.; Perger, M.; Perryman, M. A. C.; Pluto, M.; Rabaza, O.; Ramón, A.; Rebolo, R.; Redondo, P.; Reffert, S.; Reinhart, S.; Rhode, P.; Rix, H. -W.; Rodler, F.; Rodríguez, E.; Rodríguez-López, C.; Rodríguez Trinidad, A.; Rohloff, R. -R.; Rosich, A.; Sadegi, S.; Sánchez-Blanco, E.; Sánchez Carrasco, M. A.; Sánchez-López, A.; Sanz-Forcada, J.; Sarkis, P.; Sarmiento, L. F.; Schäfer, S.; Schmitt, J. H. M. M.; Schiller, J.; Schöfer, P.; Solano, E.; Stahl, O.; Strachan, J. B. P.; Stürmer, J.; Suárez, J. C.; Tabernero, H. M.; Tala, M.; Tulloch, S. M.; Ulbrich, R. -G.; Veredas, G.; Vico Linares, J. I.; Vilardell, F.; Wagner, K.; Winkler, J.; Wolthoff, V.; Xu, W.; Yan, F.; Zapatero Osorio, M. R. Bibcode: 2018A&A...609L...5R Altcode: 2017arXiv171205797R We report on the first star discovered to host a planet detected by radial velocity (RV) observations obtained within the CARMENES survey for exoplanets around M dwarfs. HD 147379 (V = 8.9 mag, M = 0.58 ± 0.08 M), a bright M0.0 V star at a distance of 10.7 pc, is found to undergo periodic RV variations with a semi-amplitude of K = 5.1 ± 0.4 m s-1 and a period of P = 86.54 ± 0.06 d. The RV signal is found in our CARMENES data, which were taken between 2016 and 2017, and is supported by HIRES/Keck observations that were obtained since 2000. The RV variations are interpreted as resulting from a planet of minimum mass mP sin i = 25 ± 2 M, 1.5 times the mass of Neptune, with an orbital semi-major axis a = 0.32 au and low eccentricity (e < 0.13). HD 147379 b is orbiting inside the temperate zone around the star, where water could exist in liquid form. The RV time-series and various spectroscopic indicators show additional hints of variations at an approximate period of 21.1 d (and its first harmonic), which we attribute to the rotation period of the star.

RV data (Table A.1) are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/609/L5 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 Bibcode: 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 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: Mapping diffuse interstellar bands in the local ISM on small scales via MUSE 3D spectroscopy. A pilot study based on globular cluster NGC 6397 Authors: Wendt, Martin; Husser, Tim-Oliver; Kamann, Sebastian; Monreal-Ibero, Ana; Richter, Philipp; Brinchmann, Jarle; Dreizler, Stefan; Weilbacher, Peter M.; Wisotzki, Lutz Bibcode: 2017A&A...607A.133W Altcode: 2017arXiv170903982W Context. We map the interstellar medium (ISM) including the diffuse interstellar bands (DIBs) in absorption toward the globular cluster NGC 6397 using VLT/MUSE. Assuming the absorbers are located at the rim of the Local Bubble we trace structures on the order of mpc (milliparsec, a few thousand AU).
Aims: We aimed to demonstrate the feasibility to map variations of DIBs on small scales with MUSE. The sightlines defined by binned stellar spectra are separated by only a few arcseconds and we probe the absorption within a physically connected region.
Methods: This analysis utilized the fitting residuals of individual stellar spectra of NGC 6397 member stars and analyzed lines from neutral species and several DIBs in Voronoi-binned composite spectra with high signal-to-noise ratio (S/N).
Results: This pilot study demonstrates the power of MUSE for mapping the local ISM on very small scales which provides a new window for ISM observations. We detect small scale variations in Na I and K I as well as in several DIBs within few arcseconds, or mpc with regard to the Local Bubble. We verify the suitability of the MUSE 3D spectrograph for such measurements and gain new insights by probing a single physical absorber with multiple sight lines. Title: VizieR Online Data Catalog: Diffuse ionized gas in the Antennae galaxy (Weilbacher+, 2018) Authors: Weilbacher, P. M.; Monreal-Ibero, A.; Verhamme, A.; Sandin, C.; Steinmetz, M.; Kollatschny, W.; Krajnovic, D.; Kamann, S.; Roth, M. M.; Erroz-Ferrer, S.; Marino, R. A.; Maseda, M. V.; Wendt, M.; Bacon, R.; Dreizler, S.; Richard, J.; Wisotzki, L. Bibcode: 2017yCat..36110095W Altcode: We provide two-dimensional maps of two different ways to measure the diffuse ionized gas as traced by the Halpha emission line in the Antennae Galaxy, both for the central field and the field at the end of the southern tidal tail. We provide a velocity map derived from the Halpha emission line, binned to a S/N~30. Finally, we provide line measurements and derived properties for all HII regions discussed in the paper.

(4 data files). Title: VizieR Online Data Catalog: HD147379 b velocity curve (Reiners+, 2018) Authors: Reiners, A.; Ribas, I.; Zechmeister, M.; Caballero, J. A.; Trifonov, T.; Dreizler, S.; Morales, J. C.; Tal-Or, L.; Lafarga, M.; Quirrenbach, A.; Amado, P. J.; Kaminski, A.; Jeffers, S. V.; Aceituno, J.; Bejar, V. J. S.; Guardia, J.; Guenther, E. W.; Hagen, H. -J.; Montes, D.; Passegger, V. M.; Seifert, W.; Schweitzer, A.; Cortes-Contreras, M.; Abril, M.; Alonso-Floriano, F. J.; Ammler-von Eiff, M.; Antona, R.; Anglada-Escude, G.; Anwand-Heerwart, H.; Arroyo-Torres, B.; Azzaro, M.; Baroch, D.; Barrado, D.; Bauer, F. F.; Becerril, S.; Benitez, D.; Berdinas, Z. M.; Bergond, G.; Bluemcke, M.; Brinkmoeller, M.; Del Burgo, C.; Cano, J.; Cardenas Vazquez, M. C.; Casal, E.; Cifuentes, C.; Claret, A.; Colome, J.; Czesla, S.; Diez-Alonso, E.; Feiz, C.; Fernandez, M.; Ferro, I. M.; Fuhrmeister, B.; Galadi-Enriquez, D.; Garcia-Piquer, A.; Garcia Vargas, M. L.; Gesa, L.; Gomez Galera, V.; Gonzalez Hernandez, J. I.; Gonzalez-Peinado, R.; Groezinger, U.; Grohnert, S.; Guijarro, A.; de Guindos, E.; Gutierrez-Soto, J.; Hatzes, A. P.; Hauschildt, P. H.; Hedrosa, R. P.; Helml!, Ing J.; H Enning, Th.; Hermelo, I.; Hernandez Arabi, R.; Hernandez Castano, L.; Hernandez Hernando, F.; Herrero, E.; Huber, A.; Huke, P.; Johnson, E. N.; de Juan, E.; Kim, M.; Klein, R.; Klueter, J.; Klutsch, A.; Kuerster, M.; Labarga, F.; Lamert, A.; Lampon, M.; Lara, L. M.; Laun, W.; Lemke, U.; Lenzen, R.; Launhardt, R.; Lopez Del Fresno, M.; Lopez-Gonzalez, M. J.; Lopez-Puertas, M.; Lopez Salas, J. F.; Lopez-Santiago, J.; Luque, R.; Magan Madinabeitia, H.; Mall, U.; Mancini, L.; Mandel, H.; Marfil, E.; Marin Molina, J. A.; Maroto Fernandez, D.; Martin, E. L.; Martin-Ruiz, S.; Marvin, C. J.; Mathar, R. J.; Mirabet, E.; Moreno-Raya, M. E.; Moya, A.; Mundt, R.; Nagel, E.; Naranjo, V.; Nortmann, L.; Nowak, G.; Ofir, A.; Oreiro, R.; Palle, E.; Panduro, J.; Pascual, J.; Pavlov, A.; Pedraz, S.; Perez-Calpena, A.; Perez Medialdea, D.; Perger, M.; Perryman, M. A. C.; Pluto, M.; Rabaza, O.; Ramon, A.; Rebolo, R.; Redondo, P.; Reffert, S.; Reinhart, S.; Rhode, P.; Rix, H. -W.; Rodler, F.; Rodriguez, E.; Rodriguez-Lopez, C.; Rodriguez Trinidad, A.; Rohloff, R. -R.; Rosich, A.; ! Sadegi, S.; Sanchez-Blanco, E.; Sanchez Carrasco, M. A.; Sanchez-Lopez, A.; Sanz-Forcada, J.; Sarkis, P.; Sarmiento, L. F.; Schaefer, S.; Schmitt, J. H. M. M.; Schiller, J.; Schoefer, P.; Solano, E.; Stahl, O.; Strachan, J. B. P.; Stuermer, J.; Suarez, J. C.; Tabernero, H. M.; Tala, M.; Tulloch, S. M.; Ulbrich, R. -G.; Veredas, G.; Vico Linares, J. I.; Vilardell, F.; Wagner, K.; Winkler, J.; Wolthoff, V.; Xu, W.; Yan, F.; Zapatero Osorio, M. R. Bibcode: 2017yCat..36099005R Altcode: We analyzed data from the CARMENES VIS channel and HIRES/Keck. The CARMENES measurements were taken in the context of the CARMENES search for exoplanets around M dwarfs. The CARMENES instrument consists of two channels: the VIS channel obtains spectra at a resolution of R=94600 in the wavelength range 520-960nm, while the NIR channel yields spectra of R=80400 covering 960-1710nm. Both channels are calibrated in wavelength with hollow-cathode lamps and use temperature- and pressure-stabilized Fabry-Perot etalons to interpolate the wavelength solution and simultaneously monitor the spectrograph drift during nightly operations (Bauer et al., 2015A&A...581A.117B).

(1 data file). Title: VizieR Online Data Catalog: CARMENES radial velocity curves of 7 M-dwarf (Trifonov+, 2018) Authors: Trifonov, T.; Kuerster, M.; Zechmeister, M.; Tal-Or, L.; Caballero, J. A.; Quirrenbach, A.; Amado, P. J.; Ribas, I.; Reiners, A.; Reffert, S.; Dreizler, S.; Hatzes, A. P.; Kaminski, A.; Launhardt, R.; Henning, T.; Montes, D.; Bejar, V. J. S.; Mundt, R.; Pavlov, A.; Schmitt, J. H. M. M.; Seifert, W.; Morales, J. C.; Nowak, G.; Jeffers, S. V.; Rodriguez-Lopez, C.; Del Burgo, C.; Anglada-Escude, G.; Lopez-Santiago, J.; Mathar, R. J.; Ammler-von Eiff, M.; Guenther, E. W.; Barrado, D.; Gonzalez Hernandez, J. I.; Mancini, L.; Stuermer, J.; Abril, M.; Aceituno, J.; Alonso-Floriano, F. J.; Antona, R.; Anwand-Heerwart, H.; Arroyo-Torres, B.; Azzaro, M.; Baroch, D.; Bauer, F. F.; Becerril, S.; Benitez, D.; Berdinas, Z. M.; Bergond, G.; Bluemcke, M.; Brinkmoeller, M.; Cano, J.; Cardenas Vazquez, M. C.; Casal, E.; Cifuentes, C.; Claret, A.; Colome, J.; Cortes-Contreras, M.; Czesla, S.; Diez-Alonso, E.; Feiz, C.; Fernandez, M.; Ferro, I. M.; Fuhrmeister, B.; Galadi-Enriquez, D.; Garcia-Piquer, A.; Garcia Vargas, M. L.; Gesa, L.; Gomez Galera, V.; Gonzalez-Peinado, R.; Groezinger, U.; Grohnert, S.; Guardia, J.; Guijarro, A.; de Guindos, E.; Gutierrez-Soto, J.; Hagen, H. -J.; Hauschildt, P. H.; Hedrosa, R. P.; Helmling, J.; Hermelo, I.; Hernandez Arabi, R.; Hernandez Castano, L.; Hernandez Hernando, F.; Herrero, E.; Huber, A.; Huke, P.; Johnson, E.; de Juan, E.; Kim, M.; Klein, R.; Klueter, J.; Klutsch, A.; Lafarga, M.; Lampon, M.; Lara, L. M.; Laun, W.; Lemke, U.; Lenzen, R.; Lopez Del Fresno, M.; Lopez-Gonzalez, J.; Lopez-Puertas, M.; Lopez Salas, J. F.; Luque, R.; Magan Madinabeitia, H.; Mall, U.; Mandel, H.; Marfil, E.; Marin Molina, J. A.; Maroto Fernandez, D.; Martin, E. L.; Martin-Ruiz, S.; Marvin, C. J.; Mirabet, E.; Moya, A.; Moreno-Raya, M. E.; Nagel, E.; Naranjo, V.; Nortmann, L.; Ofir, A.; Oreiro, R.; Palle, E.; Panduro, J.; Pascual, J.; Passegger, V. M.; Pedraz, S.; Perez-Calpena, A.; Perez Medialdea, D.; Perger, M.; Perryman, M. A. C.; Pluto, M.; Rabaza, O.; Ramon, A.; Rebolo, R.; Redondo, P.; Reinhardt, S.; Rhode, P.; Rix, H. -W.; Rodler, F.; Rodriguez, E.; Rodriguez Trinidad, A.; Rohlo, R. -R.; Rosich, A.; Sadegi, S.; Sanchez-Blanco, E.; Sanchez Carrasco, M. A.; Sanchez-Lopez, A.; Sanz-Forcada, J.; Sarkis, P.; Sarmiento, L. F.; Schaefer, S.; Schiller, J.; Schoefer, P.; Schweitzer, A.; Solano, E.; Stahl, O.; Strachan, J. B. P.; Suarez, J. C.; Tabernero, H. M.; Tala, M.; Tulloch, S. M.; Veredas, G.; Vico Linares, J. I.; Vilardel, F.; Wagner, K.; Winkler, J.; Woltho, V.; Xu, W.; Yan, F.; Zapatero Osorio, M. R. Bibcode: 2017yCat..36090117T Altcode: The two CARMENES spectrographs are grism cross-dispersed, white pupil, echelle spectrograph working in quasi-Littrow mode using a two-beam, two-slice image slicer. The visible spectrograph covers the wavelength range from 0.52um to 1.05um with 61 orders, a resolving power of R=94600, and a mean sampling of 2.8 pixels per resolution element.

The data presented in this paper were taken during the early phase of operation of the CARMENES visible-light spectrograph.

(8 data files). Title: Understanding stellar activity-induced radial velocity jitter using simultaneous K2 photometry and HARPS RV measurements Authors: Oshagh, M.; Santos, N. C.; Figueira, P.; Barros, S. C. C.; Donati, J. -F.; Adibekyan, V.; Faria, J. P.; Watson, C. A.; Cegla, H. M.; Dumusque, X.; Hébrard, E.; Demangeon, O.; Dreizler, S.; Boisse, I.; Deleuil, M.; Bonfils, X.; Pepe, F.; Udry, S. Bibcode: 2017A&A...606A.107O Altcode: 2017arXiv170701827O One of the best ways to improve our understanding of the stellar activity-induced signal in radial velocity (RV) measurements is through simultaneous high-precision photometric and RV observations. This is of prime importance to mitigate the RV signal induced by stellar activity and therefore unveil the presence of low-mass exoplanets. The K2 Campaign 7 and 8 fields of view were located in the southern hemisphere, and provided a unique opportunity to gather unprecedented simultaneous high-precision photometric observation with K2 and high-precision RV measurements with the HARPS spectrograph to study the relationship between photometric variability and RV jitter. We observed nine stars with different levels of activity, from quiet to very active. We first probed the presence of any meaningful relation between measured RV jitter and the simultaneous photometric variation, and also other activity indicators (such as BIS, FWHM, log R'HK, and F8) by evaluating the strength and significance of the monotonic correlation between RVs and each indicator. We found that for the case of very active stars, strong and significant correlations exist between almost all the observables and measured RVs; however, when we move towards lower activity levels the correlations become random, and we could not reach any conclusion regarding the tendency of correlations depending on the stellar activity level. Except for the F8 whose strong correlation with RV jitter persists over a wide range of stellar activity level, and thus our result suggests that F8 might be a powerful proxy for activity-induced RV jitter over a wide range of stellar activity. Moreover, we examine the capability of two state-of-the-art modeling techniques, namely the FF' method and SOAP2.0, to accurately predict the RV jitter amplitude using the simultaneous photometric observation. We found that for the very active stars both techniques can predict the amplitude of the RV jitter reasonably well; however, at lower activity levels the FF' method underpredicts the RV jitter amplitude.

RV measurements obtained from the HARPS pipeline are only available in electronic form at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/606/A107 Title: Hot horizontal branch stars in NGC 288 - effects of diffusion and stratification on their atmospheric parameters (Corrigendum) Authors: Moehler, S.; Dreizler, S.; LeBlanc, F.; Khalack, V.; Michaud, G.; Richer, J.; Sweigart, A. V.; Grundahl, F. Bibcode: 2017A&A...605C...4M Altcode: We found that the script to determine the masses of the stars contains two errors. This script and a related one have been used to determine masses of globular cluster stars and distances to field stars in 12 papers published between 1990 and 2014. While the numerical values need to be revised none of the conclusions are affected. We provide the updated numerical values and figures for all 12 publications here. In addition we describe the effects on those refereed publications that used the distances to the field stars. Title: VizieR Online Data Catalog: K2/HARPS measurements for 8 stars (Oshagh+, 2017) Authors: Oshagh, M.; Santos, N. C.; Figueira, P.; Barros, S. C. C.; Donati, J. -F.; Adibekyan, V.; Faria, J. P.; Watson, C. A.; Cegla, H. M.; Dumusque, X.; Hebrard, E.; Demangeon, O.; Dreizler, S.; Boisse, I.; Deleuil, M.; Bonfils, X.; Pepe, F.; Udry, S. Bibcode: 2017yCat..36060107O Altcode: Tables contain the radial velocity, BIS, FWHM, S-index, and logR'HK obtained from the HARPS pipeline for 8 stars in our sample.

(2 data files). Title: Exploring plausible formation scenarios for the planet candidate orbiting Proxima Centauri Authors: Coleman, G. A. L.; Nelson, R. P.; Paardekooper, S. J.; Dreizler, S.; Giesers, B.; Anglada-Escudé, G. Bibcode: 2017MNRAS.467..996C Altcode: 2016arXiv160806908C; 2017MNRAS.tmp..175C We present a study of four different formation scenarios that may be able to explain the origin of the recently announced planet ('Proxima b') orbiting Proxima Centauri. The aim is to examine how the formation scenarios differ in their predictions for the multiplicity of the Proxima system, the water/volatile content of Proxima b and its orbital eccentricity, so that these can be tested by future observations. A scenario of in situ formation via giant impacts from a locally enhanced disc of planetary embryos/planetesimals predicts that Proxima b will be in a multiplanet system with a measurably finite eccentricity. Assuming that the local solid enhancement needed to form a Proxima b analogue arises because of the inwards drift of solids in the form of small planetesimals/boulders, this scenario also results in Proxima b analogues being only moderately endowed with water/volatiles. A scenario in which multiple embryos form, migrate and mutually collide within a gas disc results in Proxima b being a member of a multiple system, possibly displaying mean-motion resonances, but where the constituent members are Ocean planets due to accretion occurring mainly outside of the snowline. A scenario in which a single accreting embryo forms outside the snowline, and migrates inwards while accreting planetesimals/pebbles results in Proxima b being an isolated Ocean planet on a circular orbit. A scenario in which Proxima b formed via pebble accretion interior to the snowline produces a dry planet on a circular orbit. Future observations that characterize the physical and orbital properties of Proxima b, and any additional planets in the system, will provide valuable insights into the formation history of this neighbouring planetary system. Title: How eclipse time variations, eclipse duration variations, and radial velocities can reveal S-type planets in close eclipsing binaries Authors: Oshagh, M.; Heller, R.; Dreizler, S. Bibcode: 2017MNRAS.466.4683O Altcode: 2016arXiv161004047O; 2016MNRAS.tmp.1555O While about a dozen transiting planets have been found in wide orbits around an inner, close stellar binary (so-called P-type planets), no planet has yet been detected orbiting only one star (a so-called S-type planet) in an eclipsing binary. This is despite a large number of eclipsing binary systems discovered with the Kepler telescope. Here we propose a new detection method for these S-type planets, which uses a correlation between the stellar radial velocities (RVs), eclipse timing variations (ETVs) and eclipse duration variations (EDVs). We test the capability of this technique by simulating a realistic benchmark system and demonstrate its detectability with existing high-accuracy RV and photometry instruments. We illustrate that with a small number of RV observations, the RV-ETV diagrams allows us to distinguish between prograde and retrograde planetary orbits and also the planetary mass can be estimated if the stellar cross-correlation functions can be disentangled. We also identify a new (though minimal) contribution of S-type planets to the Rossiter-McLaughlin effect in eclipsing stellar binaries. We finally explore possible detection of exomoons around transiting luminous giant planets and find that the precision required to detect moons in the RV curves of their host planets is of the order of cm s-1 and therefore not accessible with current instruments. Title: Faint-source-star planetary microlensing: the discovery of the cold gas-giant planet OGLE-2014-BLG-0676Lb Authors: Rattenbury, N. J.; Bennett, D. P.; Sumi, T.; Koshimoto, N.; Bond, I. A.; Udalski, A.; Shvartzvald, Y.; Maoz, D.; Jørgensen, U. G.; Dominik, M.; Street, R. A.; Tsapras, Y.; Abe, F.; Asakura, Y.; Barry, R.; Bhattacharya, A.; Donachie, M.; Evans, P.; Freeman, M.; Fukui, A.; Hirao, Y.; Itow, Y.; Li, M. C. A.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Nagakane, M.; Ohnishi, K.; Oyokawa, H.; Saito, To.; Sharan, A.; Sullivan, D. J.; Suzuki, D.; Tristram, P. J.; Yonehara, A.; Poleski, R.; Skowron, J.; Mróz, P.; Szymański, M. K.; Soszyński, I.; Pietrukowicz, P.; Kozłowski, S.; Ulaczyk, K.; Wyrzykowski, Ł.; Friedmann, M.; Kaspi, S.; Alsubai, K.; Browne, P.; Andersen, J. M.; Bozza, V.; Calchi Novati, S.; Damerdji, Y.; Diehl, C.; Dreizler, S.; Elyiv, A.; Giannini, E.; Hardis, S.; Harpsøe, K.; Hinse, T. C.; Liebig, C.; Hundertmark, M.; Juncher, D.; Kains, N.; Kerins, E.; Korhonen, H.; Mancini, L.; Martin, R.; Mathiasen, M.; Rabus, M.; Rahvar, S.; Scarpetta, G.; Skottfelt, J.; Snodgrass, C.; Surdej, J.; Taylor, J.; Tregloan-Reed, J.; Vilela, C.; Wambsganss, J.; Williams, A.; D'Ago, G.; Bachelet, E.; Bramich, D. M.; Figuera Jaimes, R.; Horne, K.; Menzies, J.; Schmidt, R.; Steele, I. A. Bibcode: 2017MNRAS.466.2710R Altcode: 2016arXiv161203511R We report the discovery of a planet - OGLE-2014-BLG-0676Lb- via gravitational microlensing. Observations for the lensing event were made by the following groups: Microlensing Observations in Astrophysics; Optical Gravitational Lensing Experiment; Wise Observatory; RoboNET/Las Cumbres Observatory Global Telescope; Microlensing Network for the Detection of Small Terrestrial Exoplanets; and μ-FUN. All analyses of the light-curve data favour a lens system comprising a planetary mass orbiting a host star. The most-favoured binary lens model has a mass ratio between the two lens masses of (4.78 ± 0.13) × 10-3. Subject to some important assumptions, a Bayesian probability density analysis suggests the lens system comprises a 3.09_{-1.12}^{+1.02} MJ planet orbiting a 0.62_{-0.22}^{+0.20} M host star at a deprojected orbital separation of 4.40_{-1.46}^{+2.16} au. The distance to the lens system is 2.22_{-0.83}^{+0.96} kpc. Planet OGLE-2014-BLG-0676Lb provides additional data to the growing number of cool planets discovered using gravitational microlensing against which planetary formation theories may be tested. Most of the light in the baseline of this event is expected to come from the lens and thus high-resolution imaging observations could confirm our planetary model interpretation. Title: Exoplanetary atmospheric sodium revealed by orbital motion. Narrow-band transmission spectroscopy of HD 189733b with UVES Authors: Khalafinejad, S.; von Essen, C.; Hoeijmakers, H. J.; Zhou, G.; Klocová, T.; Schmitt, J. H. M. M.; Dreizler, S.; Lopez-Morales, M.; Husser, T. -O.; Schmidt, T. O. B.; Collet, R. Bibcode: 2017A&A...598A.131K Altcode: 2016arXiv161001610K Context. During primary transits, the spectral signatures of exoplanet atmospheres can be measured using transmission spectroscopy. We can obtain information on the upper atmosphere of these planets by investigating the exoplanets' excess sodium absorption in the optical region. However, a number of factors can affect the observed sodium absorption signature. We present a detailed model correcting for systematic biases to yield an accurate depth for the sodium absorption in HD 189733b.
Aims: The goal of this work is to accurately measure the atomspheric sodium absorption light curve in HD 189733b, correcting for the effects of stellar differential limb-darkening, stellar activity, and a "bump" caused by the changing radial velocity of the exoplanet. In fact, owing to the high cadence and quality of our data, it is the first time that the last feature can be detected even by visual inspection.
Methods: We use 244 high-resolution optical spectra taken by the UVES instrument mounted at the VLT. Our observations cover a full transit of HD 189733b, with a cadence of 45 s. To probe the transmission spectrum of sodium we produce excess light curves integrating the stellar flux in passbands of 1 Å, 1.5 Å, and 3 Å inside the core of each sodium D-line. We model the effects of external sources on the excess light curves, which correspond to an observed stellar flare beginning close to mid-transit time and the wavelength dependent limb-darkening effects. In addition, by characterizing the effect of the changing radial velocity and Doppler shifts of the planetary sodium lines inside the stellar sodium lines, we estimate the depth and width of the exoplanetary sodium feature.
Results: We estimate the shape of the planetary sodium line by a Gaussian profile with an equivalent width of 0.0023 ± 0.0010Å, thereby confirming the presence of sodium in the atmosphere of HD 189733b with excess absorption levels of 0.72 ± 0.25%, 0.34 ± 0.11%, and 0.20 ± 0.06% for the integration bands of 1 Å, 1.5 Å, and 3 Å, respectively. Using the equivalent width of the planetary sodium line, we produce a first order estimate of the number density of sodium in the exoplanet atmosphere. 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 Bibcode: 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.
Aims: We aim to use solar twins to characterise the relationship between planet architecture and stellar chemical composition.
Methods: We obtained high-precision (1 m s-1) 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.
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 (<1 m s-1). Engulfment of a rocky planet of 6 Earth masses can explain the enhancement in both lithium and the refractory elements.
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: No Evidence for Activity Correlations in the Radial Velocities of Kapteyn’s Star Authors: Anglada-Escudé, G.; Tuomi, M.; Arriagada, P.; Zechmeister, M.; Jenkins, J. S.; Ofir, A.; Dreizler, S.; Gerlach, E.; Marvin, C. J.; Reiners, A.; Jeffers, S. V.; Butler, R. Paul; Vogt, S. S.; Amado, P. J.; Rodríguez-López, C.; Berdiñas, Z. M.; Morin, J.; Crane, J. D.; Shectman, S. A.; Díaz, M. R.; Sarmiento, L. F.; Jones, H. R. A. Bibcode: 2016ApJ...830...74A Altcode: 2015arXiv150609072A Stellar activity may induce Doppler variability at the level of a few m s-1 which can then be confused by the Doppler signal of an exoplanet orbiting the star. To first order, linear correlations between radial velocity measurements and activity indices have been proposed to account for any such correlation. The likely presence of two super-Earths orbiting Kapteyn’s star was reported in Anglada-Escudé et al., but this claim was recently challenged by Robertson et al., who argued for evidence of a rotation period (143 days) at three times the orbital period of one of the proposed planets (Kapteyn’s b, P = 48.6 days) and the existence of strong linear correlations between its Doppler signal and activity data. By re-analyzing the data using global statistics and model comparison, we show that such a claim is incorrect given that (1) the choice of a rotation period at 143 days is unjustified, and (2) the presence of linear correlations is not supported by the data. We conclude that the radial velocity signals of Kapteyn’s star remain more simply explained by the presence of two super-Earth candidates orbiting it. We note that analysis of time series of activity indices must be executed with the same care as Doppler time series. We also advocate for the use of global optimization procedures and objective arguments, instead of claims based on residual analyses which are prone to biases and incorrect interpretations. Title: The GTC exoplanet transit spectroscopy survey. IV. Confirmation of the flat transmission spectrum of HAT-P-32b Authors: Nortmann, L.; Pallé, E.; Murgas, F.; Dreizler, S.; Iro, N.; Cabrera-Lavers, A. Bibcode: 2016A&A...594A..65N Altcode: 2016arXiv160406041N We observed the hot Jupiter HAT-P-32b (also known as HAT-P-32Ab) to determine its optical transmission spectrum by measuring the wavelength-dependent, planet-to-star radius ratios in the region between 518-918 nm. We used the OSIRIS instrument at the Gran Telescopio CANARIAS (GTC) in long-slit spectroscopy mode, placing HAT-P-32 and a reference star in the same slit and obtaining a time series of spectra covering two transit events. Using the best quality data set, we were able to yield 20 narrowband transit light curves, with each passband spanning a 20 nm wide interval. After removal of all systematic noise signals and light curve modeling, the uncertainties for the resulting radius ratios lie between 337 and 972 ppm. The radius ratios show little variation with wavelength, suggesting a high altitude cloud layer masking any atmospheric features. Alternatively, a strong depletion in alkali metals or a much smaller than expected planetary atmospheric scale height could be responsible for the lack of atmospheric features. Our result of a flat transmission spectrum is consistent with a previous ground-based study of the optical spectrum of this planet. This agreement between independent results demonstrates that ground-based measurements of exoplanet atmospheres can give reliable and reproducible results despite the fact that the data often is heavily affected by systematic noise as long as the noise source is well understood and properly corrected. We also extract an optical spectrum of the M-dwarf companion HAT-P-32B. Using PHOENIX stellar atmosphere models we determine an effective temperature of Teff = 3187+60-71 K, which is slightly colder than previous studies relying only on broadband infrared data.

The 20 narrowband and white light curves are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/594/A65 Title: Search for Transits by the Earth Analogue around Proxima Centauri Authors: Jenkins, James; Harrington, Joseph; Challener, Ryan; Rojo, Patricio; Kempton, Eliza; Ramirez, Ricardo; Ofir, Aviv; Ribas, Ignasi; Kipping, David; Rodriguez-Lopez, Cristina; Dreizler, Stefan; Freudenthal, Jantje; Rodriguez-Martinez, Eloy; Anglada-Escude, Guillem Bibcode: 2016sptz.prop13155J Altcode: We will search for transits of the recently discovered Proxima Centauri b. Radial-velocity (RV) data indicate a planet with >1.5 Me (Earth masses) and an equilibrium temperature of 230 K (assuming 0.3 albedo and complete heat redistribution). Comparing to Earth's 255 K equilibrium temperature, the planet may be an excellent candidate to host life, and its proximity, at just 1.3 pc, makes it particularly favorable for observation, compared to more distant planets. It is thus the exoplanet with the highest priority for characterization. Due to the red-dwarf star's high activity level, the small size of the planet, and the orbital period, optical ground-based transit surveys have not achieved the sensitivity needed to detect the transit, but Spitzer easily can. The Pale Red Dot project, the planet's discoverers, thus request observations that should find any transit with 99% confidence, and that will characterize the atmosphere with transits at both Spitzer wavelengths. Title: A terrestrial planet candidate in a temperate orbit around Proxima Centauri Authors: Anglada-Escudé, Guillem; Amado, Pedro J.; Barnes, John; Berdiñas, Zaira M.; Butler, R. Paul; Coleman, Gavin A. L.; de La Cueva, Ignacio; Dreizler, Stefan; Endl, Michael; Giesers, Benjamin; Jeffers, Sandra V.; Jenkins, James S.; Jones, Hugh R. A.; Kiraga, Marcin; Kürster, Martin; López-González, María J.; Marvin, Christopher J.; Morales, Nicolás; Morin, Julien; Nelson, Richard P.; Ortiz, José L.; Ofir, Aviv; Paardekooper, Sijme-Jan; Reiners, Ansgar; Rodríguez, Eloy; Rodríguez-López, Cristina; Sarmiento, Luis F.; Strachan, John P.; Tsapras, Yiannis; Tuomi, Mikko; Zechmeister, Mathias Bibcode: 2016Natur.536..437A Altcode: 2016arXiv160903449A At a distance of 1.295 parsecs, the red dwarf Proxima Centauri (α Centauri C, GL 551, HIP 70890 or simply Proxima) is the Sun’s closest stellar neighbour and one of the best-studied low-mass stars. It has an effective temperature of only around 3,050 kelvin, a luminosity of 0.15 per cent of that of the Sun, a measured radius of 14 per cent of the radius of the Sun and a mass of about 12 per cent of the mass of the Sun. Although Proxima is considered a moderately active star, its rotation period is about 83 days (ref. 3) and its quiescent activity levels and X-ray luminosity are comparable to those of the Sun. Here we report observations that reveal the presence of a small planet with a minimum mass of about 1.3 Earth masses orbiting Proxima with a period of approximately 11.2 days at a semi-major-axis distance of around 0.05 astronomical units. Its equilibrium temperature is within the range where water could be liquid on its surface. Title: CARMENES: an overview six months after first light Authors: Quirrenbach, A.; Amado, P. J.; Caballero, J. A.; Mundt, R.; Reiners, A.; Ribas, I.; Seifert, W.; Abril, M.; Aceituno, J.; Alonso-Floriano, F. J.; Anwand-Heerwart, H.; Azzaro, M.; Bauer, F.; Barrado, D.; Becerril, S.; Bejar, V. J. S.; Benitez, D.; Berdinas, Z. M.; Brinkmöller, M.; Cardenas, M. C.; Casal, E.; Claret, A.; Colomé, J.; Cortes-Contreras, M.; Czesla, S.; Doellinger, M.; Dreizler, S.; Feiz, C.; Fernandez, M.; Ferro, I. M.; Fuhrmeister, B.; Galadi, D.; Gallardo, I.; Gálvez-Ortiz, M. C.; Garcia-Piquer, A.; Garrido, R.; Gesa, L.; Gómez Galera, V.; González Hernández, J. I.; Gonzalez Peinado, R.; Grözinger, U.; Guàrdia, J.; Guenther, E. W.; de Guindos, E.; Hagen, H. -J.; Hatzes, A. P.; Hauschildt, P. H.; Helmling, J.; Henning, T.; Hermann, D.; Hernández Arabi, R.; Hernández Castaño, L.; Hernández Hernando, F.; Herrero, E.; Huber, A.; Huber, K. F.; Huke, P.; Jeffers, S. V.; de Juan, E.; Kaminski, A.; Kehr, M.; Kim, M.; Klein, R.; Klüter, J.; Kürster, M.; Lafarga, M.; Lara, L. M.; Lamert, A.; Laun, W.; Launhardt, R.; Lemke, U.; Lenzen, R.; Llamas, M.; Lopez del Fresno, M.; López-Puertas, M.; López-Santiago, J.; Lopez Salas, J. F.; Magan Madinabeitia, H.; Mall, U.; Mandel, H.; Mancini, L.; Marin Molina, J. A.; Maroto Fernández, D.; Martín, E. L.; Martín-Ruiz, S.; Marvin, C.; Mathar, R. J.; Mirabet, E.; Montes, D.; Morales, J. C.; Morales Muñoz, R.; Nagel, E.; Naranjo, V.; Nowak, G.; Palle, E.; Panduro, J.; Passegger, V. M.; Pavlov, A.; Pedraz, S.; Perez, E.; Pérez-Medialdea, D.; Perger, M.; Pluto, M.; Ramón, A.; Rebolo, R.; Redondo, P.; Reffert, S.; Reinhart, S.; Rhode, P.; Rix, H. -W.; Rodler, F.; Rodríguez, E.; Rodríguez López, C.; Rohloff, R. R.; Rosich, A.; Sanchez Carrasco, M. A.; Sanz-Forcada, J.; Sarkis, P.; Sarmiento, L. F.; Schäfer, S.; Schiller, J.; Schmidt, C.; Schmitt, J. H. M. M.; Schöfer, P.; Schweitzer, A.; Shulyak, D.; Solano, E.; Stahl, O.; Storz, C.; Tabernero, H. M.; Tala, M.; Tal-Or, L.; Ulbrich, R. -G.; Veredas, G.; Vico Linares, J. I.; Vilardell, F.; Wagner, K.; Winkler, J.; Zapatero Osorio, M. -R.; Zechmeister, M.; Ammler-von Eiff, M.; Anglada-Escudé, G.; del Burgo, C.; Garcia-Vargas, M. L.; Klutsch, A.; Lizon, J. -L.; Lopez-Morales, M.; Ofir, A.; Pérez-Calpena, A.; Perryman, M. A. C.; Sánchez-Blanco, E.; Strachan, J. B. P.; Stürmer, J.; Suárez, J. C.; Trifonov, T.; Tulloch, S. M.; Xu, W. Bibcode: 2016SPIE.9908E..12Q Altcode: The CARMENES instrument is a pair of high-resolution (R> 80,000) spectrographs covering the wavelength range from 0.52 to 1.71 μm, optimized for precise radial velocity measurements. It was installed and commissioned at the 3.5m telescope of the Calar Alto observatory in Southern Spain in 2015. The first large science program of CARMENES is a survey of 300 M dwarfs, which started on Jan 1, 2016. We present an overview of all subsystems of CARMENES (front end, fiber system, visible-light spectrograph, near-infrared spectrograph, calibration units, etalons, facility control, interlock system, instrument control system, data reduction pipeline, data flow, and archive), and give an overview of the assembly, integration, verification, and commissioning phases of the project. We show initial results and discuss further plans for the scientific use of CARMENES. Title: MICADO: first light imager for the E-ELT Authors: Davies, R.; Schubert, J.; Hartl, M.; Alves, J.; Clénet, Y.; Lang-Bardl, F.; Nicklas, H.; Pott, J. -U.; Ragazzoni, R.; Tolstoy, E.; Agocs, T.; Anwand-Heerwart, H.; Barboza, S.; Baudoz, P.; Bender, R.; Bizenberger, P.; Boccaletti, A.; Boland, W.; Bonifacio, P.; Briegel, F.; Buey, T.; Chapron, F.; Cohen, M.; Czoske, O.; Dreizler, S.; Falomo, R.; Feautrier, P.; Förster Schreiber, N.; Gendron, E.; Genzel, R.; Glück, M.; Gratadour, D.; Greimel, R.; Grupp, F.; Häuser, M.; Haug, M.; Hennawi, J.; Hess, H. J.; Hörmann, V.; Hofferbert, R.; Hopp, U.; Hubert, Z.; Ives, D.; Kausch, W.; Kerber, F.; Kravcar, H.; Kuijken, K.; Lang-Bardl, F.; Leitzinger, M.; Leschinski, K.; Massari, D.; Mei, S.; Merlin, F.; Mohr, L.; Monna, A.; Müller, F.; Navarro, R.; Plattner, M.; Przybilla, N.; Ramlau, R.; Ramsay, S.; Ratzka, T.; Rhode, P.; Richter, J.; Rix, H. -W.; Rodeghiero, G.; Rohloff, R. -R.; Rousset, G.; Ruddenklau, R.; Schaffenroth, V.; Schlichter, J.; Sevin, A.; Stuik, R.; Sturm, E.; Thomas, J.; Tromp, N.; Turatto, M.; Verdoes-Kleijn, G.; Vidal, F.; Wagner, R.; Wegner, M.; Zeilinger, W.; Ziegler, B.; Zins, G. Bibcode: 2016SPIE.9908E..1ZD Altcode: 2016arXiv160701954D MICADO will equip the E-ELT with a first light capability for diffraction limited imaging at near-infrared wavelengths. The instrument's observing modes focus on various flavours of imaging, including astrometric, high contrast, and time resolved. There is also a single object spectroscopic mode optimised for wavelength coverage at moderately high resolution. This contribution provides an overview of the key functionality of the instrument, outlining the scientific rationale for its observing modes. The interface between MICADO and the adaptive optics system MAORY that feeds it is summarised. The design of the instrument is discussed, focusing on the optics and mechanisms inside the cryostat, together with a brief overview of the other key sub-systems. Title: Can stellar activity make a planet seem misaligned? Authors: Oshagh, M.; Dreizler, S.; Santos, N. C.; Figueira, P.; Reiners, A. Bibcode: 2016A&A...593A..25O Altcode: 2016arXiv160703134O Several studies have shown that the occultation of stellar active regions by the transiting planet can generate anomalies in the high-precision transit light curves, and these anomalies may lead to an inaccurate estimate of the planetary parameters (e.g., the planet radius). Since the physics and geometry behind the transit light curve and the Rossiter-McLaughlin effect (spectroscopic transit) are the same, the Rossiter-McLaughlin observations are expected to be affected by the occultation of stellar active regions in a similar way. In this paper we perform a fundamental test on the spin-orbit angles as derived by Rossiter-McLaughlin measurements, and we examine the impact of the occultation of stellar active regions by the transiting planet on the spin-orbit angle estimations. Our results show that the inaccurate estimation on the spin-orbit angle due to stellar activity can be quite significant (up to ~30 deg), particularly for the edge-on, aligned, and small transiting planets. Therefore, our results suggest that the aligned transiting planets are the ones that can be easily misinterpreted as misaligned owing to the stellar activity. In other words, the biases introduced by ignoring stellar activity are unlikely to be the culprit for the highly misaligned systems. 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 Bibcode: 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.
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.
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.
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.
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-0.6) in contrast to previous, often-used scalings.

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 http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A156 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. Bibcode: 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&A...590A..32T). Stellar parameters for the other solar twins were obtained by Ramirez et al. (2014A&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.

(1 data file). Title: A Stellar Census in NGC 6397 with MUSE Authors: Kamann, S.; Husser, T. -O.; Wendt, M.; Bacon, R.; Brinchmann, J.; Dreizler, S.; Emsellem, E.; Krajnović, D.; Monreal-Ibero, A.; Roth, M. M.; Weilbacher, P. M.; Wisotzki, L. Bibcode: 2016Msngr.164...18K Altcode: The new and powerful integral-field spectrograph on the VLT, the Multi- Unit Spectroscopic Explorer (MUSE), was designed to search for distant galaxies to an unprecedented depth, but it is also capable of opening new science windows on the Galaxy. To demonstrate this capability, the globular cluster NGC 6397 was observed during the commissioning of MUSE in August 2014. We outline how the analysis of this unique dataset allowed us to assemble the largest spectroscopic sample of stars in a globular cluster to date. We also highlight the scientific applications that benefit from such MUSE data. Title: VizieR Online Data Catalog: GTC transit light curves of HAT-P-32b (Nortmann+, 2016) Authors: Nortmann, L.; Palle, E.; Murgas, F.; Dreizler, S.; Iro, N.; Cabrera-Lavers, A. Bibcode: 2016yCat..35940065N Altcode: We provide two transit light curves of the hot Jupiter HAT-P-32b obtained on the nights of 2012/09/15 and 2012/09/30 using the OSIRIS instrument at the 10.4-m GTC telescope. The data was obtained by using OSIRIS in broad slit spectroscopy mode and covering the wavelength region between 518nm-918nm. For the night of 2012/09/30 we further provide twenty narrowband light curves which were created by summing the flux over 20-nm-wide channels instead over the whole wavelength region. We provide several auxiliary parameters of the observations which we have used to correct the data from correlated noise. These auxiliary parameters are the position drift of the stars on the CCD detector in spatial and dispersion direction, air mass and seeing (FWHM).

(23 data files). Title: Erratum: A detailed census of variable stars in the globular cluster NGC 6333 (M9) from CCD differential photometry Authors: Arellano Ferro, A.; Bramich, D. M.; Figuera Jaimes, R.; Giridhar, Sunetra; Kains, N.; Kuppuswamy, K.; Jørgensen, U. G.; Alsubai, K. A.; Andersen, J. M.; Bozza, V.; Browne, P.; Calchi Novati, S.; Damerdji, Y.; Diehl, C.; Dominik, M.; Dreizler, S.; Elyiv, A.; Giannini, E.; Harpsøe, K.; Hessman, F. V.; Hinse, T. C.; Hundertmark, M.; Juncher, D.; Kerins, E.; Korhonen, H.; Liebig, C.; Mancini, L.; Mathiasen, M.; Penny, M. T.; Rabus, M.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Skottfelt, J.; Snodgrass, C.; Southworth, J.; Surdej, J.; Tregloan-Reed, J.; Vilela, C.; Wertz, O.; Mindstep Consortium Bibcode: 2016MNRAS.458.1188A Altcode: 2016MNRAS.tmp..123F No abstract at ADS Title: MUSE crowded field 3D spectroscopy of over 12 000 stars in the globular cluster NGC 6397. II. Probing the internal dynamics and the presence of a central black hole Authors: Kamann, S.; Husser, T. -O.; Brinchmann, J.; Emsellem, E.; Weilbacher, P. M.; Wisotzki, L.; Wendt, M.; Krajnović, D.; Roth, M. M.; Bacon, R.; Dreizler, S. Bibcode: 2016A&A...588A.149K Altcode: 2016arXiv160201643K We present a detailed analysis of the kinematics of the Galactic globular cluster NGC 6397 based on more than ~18 000 spectra obtained with the novel integral field spectrograph MUSE. While NGC 6397 is often considered a core collapse cluster, our analysis suggests a flattening of the surface brightness profile at the smallest radii. Although it is among the nearest globular clusters, the low velocity dispersion of NGC 6397 of < 5 km s-1 imposes heavy demands on the quality of the kinematical data. We show that despite its limited spectral resolution, MUSE reaches an accuracy of 1 km s-1 in the analysis of stellar spectra. We find slight evidence for a rotational component in the cluster and the velocity dispersion profile that we obtain shows a mild central cusp. To investigate the nature of this feature, we calculate spherical Jeans models and compare these models to our kinematical data. This comparison shows that if a constant mass-to-light ratio is assumed, the addition of an intermediate-mass black hole with a mass of 600 M brings the model predictions into agreement with our data, and therefore could be at the origin of the velocity dispersion profile. We further investigate cases with varying mass-to-light ratios and find that a compact dark stellar component can also explain our observations. However, such a component would closely resemble the black hole from the constant mass-to-light ratio models as this component must be confined to the central ~5″ of the cluster and must have a similar mass. Independent constraints on the distribution of stellar remnants in the cluster or kinematic measurements at the highest possible spatial resolution should be able to distinguish the two alternatives.

Based on observations obtained at the Very Large Telescope (VLT) of the European Southern Observatory, Paranal, Chile (ESO Programme ID 60.A-9100(C)) Title: MUSE crowded field 3D spectroscopy of over 12 000 stars in the globular cluster NGC 6397. I. The first comprehensive HRD of a globular cluster Authors: Husser, Tim-Oliver; Kamann, Sebastian; Dreizler, Stefan; Wendt, Martin; Wulff, Nina; Bacon, Roland; Wisotzki, Lutz; Brinchmann, Jarle; Weilbacher, Peter M.; Roth, Martin M.; Monreal-Ibero, Ana Bibcode: 2016A&A...588A.148H Altcode: 2016arXiv160201649H
Aims: We demonstrate the high multiplex advantage of crowded field 3D spectroscopy with the new integral field spectrograph MUSE by means of a spectroscopic analysis of more than 12 000 individual stars in the globular cluster NGC 6397.
Methods: The stars are deblended with a point spread function fitting technique, using a photometric reference catalogue from HST as prior, including relative positions and brightnesses. This catalogue is also used for a first analysis of the extracted spectra, followed by an automatic in-depth analysis via a full-spectrum fitting method based on a large grid of PHOENIX spectra.
Results: We analysed the largest sample so far available for a single globular cluster of 18 932 spectra from 12 307 stars in NGC 6397. We derived a mean radial velocity of vrad = 17.84 ± 0.07 km s-1 and a mean metallicity of [Fe/H] = -2.120 ± 0.002, with the latter seemingly varying with temperature for stars on the red giant branch (RGB). We determine Teff and [Fe/H] from the spectra, and log g from HST photometry. This is the first very comprehensive Hertzsprung-Russell diagram (HRD) for a globular cluster based on the analysis of several thousands of stellar spectra, ranging from the main sequence to the tip of the RGB. Furthermore, two interesting objects were identified; one is a post-AGB star and the other is a possible millisecond-pulsar companion.

Data products are available at http://muse-vlt.eu/scienceBased on observations obtained at the Very Large Telescope (VLT) of the European Southern Observatory, Paranal, Chile (ESO Programme ID 60.A-9100(C)). Title: Transmission Spectroscopy of HAT-P-32Ab with GTC/OSIRIS Authors: Nortmann, Lisa; Pallé, Enric; Murgas, Felipe; Dreizler, Stefan; Iro, Nicolas; Cabrera-Lavers, Antonio Bibcode: 2015ESS.....311120N Altcode: I will present one of the latest results of our GTC exoplanet transit spectroscopy survey. Over the last years our group has obtained ground-based optical (538 nm - 918 nm) spectrophotometric transit observations for several hot Jupiters including HAT-P-32Ab using the OSIRIS (Optical System for Imaging and low Resolution Integrated Spectroscopy) instrument at the Spanish 10-meter telescope GTC.I will discuss the source, nature and proper correction of instrument specific systematic noise we found to affect our data. After its correction, we were able to yield high quality results with a precision between 482 and 1703 ppm depending on the wavelength channel. We measure a flat optical transmission spectrum for HAT-P-32Ab, consistent with the results of Gibson et al. (2013, MNRAS, 436, 2974) obtained with GMOS at Gemini-North. This independent reproduction of consistent results re-establishes faith in the reliability of ground-based transmission spectroscopy and emphasizes the high potential of OSIRIS at the GTC as a tool to complement current and future space-based observations. Title: A temperature inversion in WASP-33b? Large Binocular Telescope occultation data confirm significant thermal flux at short wavelengths Authors: von Essen, C.; Mallonn, M.; Albrecht, S.; Antoci, V.; Smith, A. M. S.; Dreizler, S.; Strassmeier, K. G. Bibcode: 2015A&A...584A..75V Altcode: 2015arXiv150705963V We observed a secondary eclipse of WASP-33 b quasi-simultaneously in the optical (~0.55 μm) and the near-infrared (~1.05 μm) using the 2×8.4 m Large Binocular Telescope. WASP-33 is a δ Scuti star pulsating with periods comparable to the eclipse duration, making the determination of the eclipse depth challenging. We use previously determined oscillation frequencies to model and remove the pulsation signal from the light curves, isolating the secondary eclipse. The determined eclipse depth is ΔF = 1.03 ± 0.34 parts per thousand, corresponding to a brightness temperature of TB = 3398 ± 302 K. Combining previously published data with our new measurement we find the equilibrium temperature of WASP-33 b to be TB = 3358 ± 165 K. We compare all existing eclipse data to a blackbody spectrum, to a carbon-rich non-inverted model and to a solar composition model with an inverted temperature structure. We find that current available data on WASP-33 b's atmosphere can be best represented by a simple blackbody emission, without the need for more sophisticated atmospheric models with temperature inversions. Although our data cannot rule out models with or without a temperature inversion, they do confirm a high brightness temperature for the planet at short wavelengths. WASP-33 b is one of the hottest exoplanets known till date, and its equilibrium temperature is consistent with rapid reradiation of the absorbed stellar light and a low albedo.

The LBT is an international collaboration among institutions in the United States, Italy and Germany. LBT Corporation partners are: The University of Arizona on behalf of the Arizona university system; Instituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, the Leibniz-Institute for Astrophysics Potsdam, and Heidelberg University; The Ohio State University, and The Research Corporation, on behalf of The University of Notre Dame, University of Minnesota and University of Virginia.Appendix A is available in electronic form at http://www.aanda.org Title: Planets around post-common envelope binaries Authors: Dreizler, Stefan; Beuermann, Klaus; Hessman, Frederic; Husser, Tim-Oliver Bibcode: 2015ESS.....311702D Altcode: The timing method enables to search planets in extreme conditions, e.g. as companion to pulsars or as planets in post-common envelope binaries (PCEB). In both cases, the planetary systems have experience a dramatic evolution of the primary star.Eclipse time variations in PCEBs with white dwarfs and subdwarf-B stars as primaries have been interpreted as signatures from circumbinary planets and planetary systems. Several of these interpretations have been questioned later on, either due to dynamical instability of the proposed planetary systems or due to non-detection of the proposed companions. We will give an overview of our long-term monitoring of PCEB systems and the modelling in terms of Keplerian and Newtonian planetary orbits in order to assess the circumbinary planet scenario for these systems. We discuss the implications for the first-generation or second-generatoin planet scenario for these potential planets around these evolved stars. 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. Bibcode: 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. Bibcode: 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.
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.
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.
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.
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.

Table 3 and Fig. 5 are available in electronic form at http://www.aanda.org Title: Spectroscopic Surface Brightness Fluctuations: a new method to analyze the stellar population content of galaxies Authors: Walcher, C. Jakob; Mitzkus, Martin; Roth, Martin; Dreizler, Stefan Bibcode: 2015IAUGA..2194398W Altcode: Rare luminous phases of stellar evolution are important scientific targets because our understanding of them strongly influences what physical parameters we can recover from integrated spectra. (TP-)AGB stars have been the focus of much attention over the last decade, as their flux contribution to the spectra of intermediate age stellar populations is highly uncertain. We here present a new approach to this problem, which relies on Surface Brightness Fluctuations (SBF) with high spectral resolution - a domain that is opening up for the first time thanks to the new MUSE integral field unit at the VLT. We will present the SSBF technique, illustrating its power through simulations. We will then present the analysis of dedicated data obtained with MUSE, providing new benchmark constraints on the luminous stellar population of entire galaxies. Title: Spectroscopic Surface Brightness Fluctuations: Amplifying Bright Stars in Unresolved Stellar Populations Authors: Mitzkus, M.; Dreizler, S.; Roth, M. M. Bibcode: 2015ASPC..497..491M Altcode: We report on our early-stage efforts to resolve the Surface Brightness Fluctuations (SBFs) in the spectral dimension. Combining the diagnostic power of SBFs with the physical information content of spectra seems a tempting possibility to gain new insights into the bright stars in unresolved stellar populations. The new VLT integral field spectrograph MUSE is the first instrument that enables spectroscopic SBFs observationally. Title: Planet formation in post-common-envelope binaries Authors: Schleicher, D. R. G.; Dreizler, S.; Völschow, M.; Banerjee, R.; Hessman, F. V. Bibcode: 2015AN....336..458S Altcode: 2015arXiv150101656S To understand the evolution of planetary systems, it is important to investigate planets in highly evolved stellar systems, and to explore the implications of their observed properties with respect to potential formation scenarios. Observations suggest the presence of giant planets in post-common-envelope binaries (PCEBs). A particularly well-studied system with planetary masses of 1.7 M_J and 7.0 M_J is NN Ser. We show here that a pure first-generation scenario where the planets form before the common envelope (CE) phase and the orbits evolve due to the changes in the gravitational potential is inconsistent with the current data. We propose a second-generation scenario where the planets are formed from the material that is ejected during the CE, which may naturally explain the observed planetary masses. In addition, hybrid scenarios where the planets form before the CE and evolve due to the accretion of the ejected gas appear as a realistic possibility. Title: Periodicity and eclipse minima timing of CM Draconis. Authors: Vázquez-Martín, S.; Deeg, H. J.; Dreizler, S.; von Essen, C.; Kozhevnikov, V. P. Bibcode: 2015hsa8.conf..618V Altcode: Periodic deviations from a linear ephemeris of a binary star's eclipses can indicate the presence of a third body in orbit around both. Hints for such companion around the M4.5/M4.5 binary CMDra were published by Deeg et al. (2008). The assignment of a planet in the CMDra system can however only be accepted if the earlier observed periodicity trends can be verified through further observations over several years. For eclipsing binary stars of low mass, the method of eclipse minimum timing allows one to set mass limits for the detection of a third body. Deeg et al. (2008) concluded that the two possibilities for the source of CMDra's timing variations that remain valid are a planet of a few Jupiter masses on a two decade-long orbit, or an object on a century-to-millenium long orbit with masses 1.5M_J < M_{p} < 0.1M_{⊙}. However, they concluded that it is necessary to do continued observations of the timing of CMDra's eclipses to be decisive regarding the continued viability of the sinusoidal-fit-model, and hence, about the validity of a Jovian-type planet in a circumbinary orbiting around the system. Here we update the analysis of Deeg et al. (2008), including further data presented in Morales et al. (2009r) and new observations taken at Ural Observatory (2008-2013). Eclipse minimum times were obtained using the Kwee-van-Woerden method. Title: OGLE-2011-BLG-0265Lb: A Jovian Microlensing Planet Orbiting an M Dwarf Authors: Skowron, J.; Shin, I. -G.; Udalski, A.; Han, C.; Sumi, T.; Shvartzvald, Y.; Gould, A.; Dominis Prester, D.; Street, R. A.; Jørgensen, U. G.; Bennett, D. P.; Bozza, V.; Szymański, M. K.; Kubiak, M.; Pietrzyński, G.; Soszyński, I.; Poleski, R.; Kozłowski, S.; Pietrukowicz, P.; Ulaczyk, K.; Wyrzykowski, Ł.; OGLE Collaboration; Abe, F.; Bhattacharya, A.; Bond, I. A.; Botzler, C. S.; Freeman, M.; Fukui, A.; Fukunaga, D.; Itow, Y.; Ling, C. H.; Koshimoto, N.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Namba, S.; Ohnishi, K.; Philpott, L. C.; Rattenbury, N.; Saito, T.; Sullivan, D. J.; Suzuki, D.; Tristram, P. J.; Yock, P. C. M.; MOA Collaboration; Maoz, D.; Kaspi, S.; Friedmann, M.; Wise Group; Almeida, L. A.; Batista, V.; Christie, G.; Choi, J. -Y.; DePoy, D. L.; Gaudi, B. S.; Henderson, C.; Hwang, K. -H.; Jablonski, F.; Jung, Y. K.; Lee, C. -U.; McCormick, J.; Natusch, T.; Ngan, H.; Park, H.; Pogge, R. W.; Yee, J. C.; μFUN Collaboration; Albrow, M. D.; Bachelet, E.; Beaulieu, J. -P.; Brillant, S.; Caldwell, J. A. R.; Cassan, A.; Cole, A.; Corrales, E.; Coutures, Ch.; Dieters, S.; Donatowicz, J.; Fouqué, P.; Greenhill, J.; Kains, N.; Kane, S. R.; Kubas, D.; Marquette, J. -B.; Martin, R.; Menzies, J.; Pollard, K. R.; Ranc, C.; Sahu, K. C.; Wambsganss, J.; Williams, A.; Wouters, D.; PLANET Collaboration; Tsapras, Y.; Bramich, D. M.; Horne, K.; Hundertmark, M.; Snodgrass, C.; Steele, I. A.; RoboNet Collaboration; Alsubai, K. A.; Browne, P.; Burgdorf, M. J.; Calchi Novati, S.; Dodds, P.; Dominik, M.; Dreizler, S.; Fang, X. -S.; Gu, C. -H.; Hardis; Harpsøe, K.; Hessman, F. V.; Hinse, T. C.; Hornstrup, A.; Jessen-Hansen, J.; Kerins, E.; Liebig, C.; Lund, M.; Lundkvist, M.; Mancini, L.; Mathiasen, M.; Penny, M. T.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Skottfelt, J.; Southworth, J.; Surdej, J.; Tregloan-Reed, J.; Wertz, O.; MiNDSTEp Consortium Bibcode: 2015ApJ...804...33S Altcode: 2014arXiv1410.8252S We report the discovery of a Jupiter-mass planet orbiting an M-dwarf star that gave rise to the microlensing event OGLE-2011-BLG-0265. Such a system is very rare among known planetary systems and thus the discovery is important for theoretical studies of planetary formation and evolution. High-cadence temporal coverage of the planetary signal, combined with extended observations throughout the event, allows us to accurately model the observed light curve. However, the final microlensing solution remains degenerate, yielding two possible configurations of the planet and the host star. In the case of the preferred solution, the mass of the planet is {{M}p}=0.9+/- 0.3 {{M}J}, and the planet is orbiting a star with a mass M=0.22+/- 0.06 {{M}}. The second possible configuration (2σ away) consists of a planet with {{M}p}=0.6+/- 0.3 {{M}J} and host star with M=0.14+/- 0.06 {{M}}. The system is located in the Galactic disk 3-4 kpc toward the Galactic bulge. In both cases, with an orbit size of 1.5-2.0 AU, the planet is a “cold Jupiter”—located well beyond the “snow line” of the host star. Currently available data make the secure selection of the correct solution difficult, but there are prospects for lifting the degeneracy with additional follow-up observations in the future, when the lens and source star separate. Title: VizieR Online Data Catalog: MUSE 3D view of HDF-S (Bacon+, 2015) Authors: Bacon, R.; Brinchmann, J.; Richard, J.; Contini, T.; Drake, A.; Franx, M.; Tacchella, S.; Vernet, J.; Wisotzki, L.; Blaizot, J.; Bouche, N.; Bouwens, R.; Cantalupo, S.; Carollo, C. M.; Carton, D.; Caruana, J.; Clement, B.; Dreizler, S.; Epinat, B.; Guiderdoni, B.; Herenz, C.; Husser, T. -O.; Kamann, S.; Kerutt, J.; Kollatschny, W.; Krajnovic, D.; Lilly, S.; Martinsson, T.; Michel-Dansac, L.; Patricio, V.; Schaye, J.; Shirazi, M.; Soto, K.; Soucail, G.; Steinmetz, M.; Urrutia, T.; Weilbacher, P.; de Zeeuw, T. Bibcode: 2015yCat..35750075B Altcode: The HDFS was observed during six nights in July 25-29, 31 and August 2, 3 2014 of the last commissioning run of MUSE. We used the nominal wavelength range (4750-9300Å) and performed a series of exposures of 30min each.

(3 data files). Title: VizieR Online Data Catalog: MUSE 3D view of HDF-S (Bacon+, 2015) Authors: Bacon, R.; Brinchmann, J.; Richard, J.; Contini, T.; Drake, A.; Franx, M.; Tacchella, S.; Vernet, J.; Wisotzki, L.; Blaizot, J.; Bouche, N.; Bouwens, R.; Cantalupo, S.; Carollo, C. M.; Carton, D.; Caruana, J.; Clement, B.; Dreizler, S.; Epinat, B.; Guiderdoni, B.; Herenz, C.; Husser, T. -O.; Kamann, S.; Kerutt, J.; Kollatschny, W.; Krajnovic, D.; Lilly, S.; Martinsson, T.; Michel-Dansac, L.; Patricio, V.; Schaye, J.; Shirazi, M.; Soto, K.; Soucail, G.; Steinmetz, M.; Urrutia, T.; Weilbacher, P.; de Zeeuw, T. Bibcode: 2015yCat..35759075B Altcode: The HDFS was observed during six nights in July 25-29, 31 and August 2, 3 2014 of the last commissioning run of MUSE. We used the nominal wavelength range (4750-9300Å) and performed a series of exposures of 30min each.

(3 data files). Title: The MUSE 3D view of the Hubble Deep Field South Authors: Bacon, R.; Brinchmann, J.; Richard, J.; Contini, T.; Drake, A.; Franx, M.; Tacchella, S.; Vernet, J.; Wisotzki, L.; Blaizot, J.; Bouché, N.; Bouwens, R.; Cantalupo, S.; Carollo, C. M.; Carton, D.; Caruana, J.; Clément, B.; Dreizler, S.; Epinat, B.; Guiderdoni, B.; Herenz, C.; Husser, T. -O.; Kamann, S.; Kerutt, J.; Kollatschny, W.; Krajnovic, D.; Lilly, S.; Martinsson, T.; Michel-Dansac, L.; Patricio, V.; Schaye, J.; Shirazi, M.; Soto, K.; Soucail, G.; Steinmetz, M.; Urrutia, T.; Weilbacher, P.; de Zeeuw, T. Bibcode: 2015A&A...575A..75B Altcode: 2014arXiv1411.7667B We observed Hubble Deep Field South with the new panoramic integral-field spectrograph MUSE that we built and have just commissioned at the VLT. The data cube resulting from 27 h of integration covers one arcmin2 field of view at an unprecedented depth with a 1σ emission-line surface brightness limit of 1 × 10-19 erg s-1 cm-2 arcsec-2, and contains ~90 000 spectra. We present the combined and calibrated data cube, and we performed a first-pass analysis of the sources detected in the Hubble Deep Field South imaging. We measured the redshifts of 189 sources up to a magnitude I814 = 29.5, increasing the number of known spectroscopic redshifts in this field by more than an order of magnitude. We also discovered 26 Lyα emitting galaxies that are not detected in the HST WFPC2 deep broad-band images. The intermediate spectral resolution of 2.3 Å allows us to separate resolved asymmetric Lyα emitters, [O ii]3727 emitters, and C iii]1908 emitters, and the broad instantaneous wavelength range of 4500 Å helps to identify single emission lines, such as [O iii]5007, Hβ, and Hα, over a very wide redshift range. We also show how the three-dimensional information of MUSE helps to resolve sources that are confused at ground-based image quality. Overall, secure identifications are provided for 83% of the 227 emission line sources detected in the MUSE data cube and for 32% of the 586 sources identified in the HST catalogue. The overall redshift distribution is fairly flat to z = 6.3, with a reduction between z = 1.5 to 2.9, in the well-known redshift desert. The field of view of MUSE also allowed us to detect 17 groups within the field. We checked that the number counts of [O ii]3727 and Lyα emitters are roughly consistent with predictions from the literature. Using two examples, we demonstrate that MUSE is able to provide exquisite spatially resolved spectroscopic information on the intermediate-redshift galaxies present in the field. Thisunique data set can be used for a wide range of follow-up studies. We release the data cube, the associated products, and the source catalogue with redshifts, spectra, and emission-line fluxes.

Advanced data products are available at http://muse-vlt.eu/science. Based on observations made with ESO telescopes at the La Silla Paranal Observatory under program ID 60.A-9100(C).Appendices are available in electronic form at http://www.aanda.org 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. Bibcode: 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.
Aims: We determine the fundamental parameters of the 88 solar twin stars that have been chosen as targets for our experiment.
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(Teff) = 7 K, σ(log g) = 0.019, σ( [Fe/H] ) = 0.006 dex, σ(vt) = 0.016 km s-1. Reliable relative ages and highly precise masses were then estimated using theoretical isochrones.
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.
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.

Tables 2-4 are available in electronic form at http://www.aanda.org 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. Bibcode: 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 2) 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: Two planets around Kapteyn's star: a cold and a temperate super-Earth orbiting the nearest halo red dwarf. Authors: Anglada-Escude, G.; Arriagada, P.; Tuomi, M.; Zechmeister, M.; Jenkins, J. S.; Ofir, A.; Dreizler, S.; Gerlach, E.; Marvin, C. J.; Reiners, A.; Jeffers, S. V.; Butler, R. P.; Vogt, S. S.; Amado, P. J.; Rodriguez-Lopez, C.; Berdinas, Z. M.; Morin, J.; Crane, J. D.; Shectman, S. A.; Thompson, I. B.; Diaz, M.; Rivera, E.; Sarmiento, L. F.; Jones, H. R. A. Bibcode: 2014MNRAS.443L..89A Altcode: 2014arXiv1406.0818A Exoplanets of a few Earth masses can be now detected around nearby low-mass stars using Doppler spectroscopy. In this Letter, we investigate the radial velocity variations of Kapteyn's star, which is both a sub-dwarf M-star and the nearest halo object to the Sun. The observations comprise archival and new HARPS (High Accuracy Radial velocity Planet Searcher), High Resolution Echelle Spectrometer (HIRES) and Planet Finder Spectrograph (PFS) Doppler measurements. Two Doppler signals are detected at periods of 48 and 120 d using likelihood periodograms and a Bayesian analysis of the data. Using the same techniques, the activity indices and archival All Sky Automated Survey (ASAS-3) photometry show evidence for low-level activity periodicities of the order of several hundred days. However, there are no significant correlations with the radial velocity variations on the same time-scales. The inclusion of planetary Keplerian signals in the model results in levels of correlated and excess white noise that are remarkably low compared to younger G, K and M dwarfs. We conclude that Kapteyn's star is most probably orbited by two super-Earth mass planets, one of which is orbiting in its circumstellar habitable zone, becoming the oldest potentially habitable planet known to date. The presence and long-term survival of a planetary system seem a remarkable feat given the peculiar origin and kinematic history of Kapteyn's star. The detection of super-Earth mass planets around halo stars provides important insights into planet-formation processes in the early days of the Milky Way. Title: CARMENES ultra-stable cooling system: very promising results Authors: Mirabet, E.; Carvas, P.; Lizon, J. -L.; Becerril, S.; Rodríguez, E.; Abril, M.; Cárdenas, M. C.; Morales, R.; Pérez, D.; Sánchez Carrasco, M. A.; Amado, P. J.; Seifert, W.; Quirrenbach, A.; Caballero, J. A.; Ribas, I.; Reiners, A.; Dreizler, S. Bibcode: 2014SPIE.9151E..3YM Altcode: CARMENES is a high resolution spectrograph to detect planets through the variation of radial velocity, destined for the Calar Alto Observatory in Almeria, Spain. The optical bench has a working temperature of 140K with a 24 hours stability of ±0,1K; goal ±0,01K. It is enclosed with a radiation shield actively cooled with thermalized nitrogen gas that flows through strategically positioned heat exchangers to remove its radiative load. The cooling system has an external preparation unit (N2GPU), which provides the nitrogen gas through actively vaporizing liquid nitrogen with heating resistances and a three stage circuit flow, each one controlled by an independent PID. Since CARMENES is still in the construction phase, a dedicated test facility has been built in order to simulate the instrument and correctly establish the N2GPU parameters. Furthermore, the test facility allows a wide range of configurations set-ups, which enables a full characterization of the N2GPU and the cooling system. The N2GPU has been designed to offer a wide temperature range of thermally stabilized nitrogen gas flow, which apart from CARMENES could also be used to provide ultra-high thermal stability in other cryogenic instruments. The present paper shows the testing of the cooling performance, the hardware used and the very promising results obtained. Title: CARMENES instrument overview Authors: Quirrenbach, A.; Amado, P. J.; Caballero, J. A.; Mundt, R.; Reiners, A.; Ribas, I.; Seifert, W.; Abril, M.; Aceituno, J.; Alonso-Floriano, F. J.; Ammler-von Eiff, M.; Antona Jiménez, R.; Anwand-Heerwart, H.; Azzaro, M.; Bauer, F.; Barrado, D.; Becerril, S.; Béjar, V. J. S.; Benítez, D.; Berdiñas, Z. M.; Cárdenas, M. C.; Casal, E.; Claret, A.; Colomé, J.; Cortés-Contreras, M.; Czesla, S.; Doellinger, M.; Dreizler, S.; Feiz, C.; Fernández, M.; Galadí, D.; Gálvez-Ortiz, M. C.; García-Piquer, A.; García-Vargas, M. L.; Garrido, R.; Gesa, L.; Gómez Galera, V.; González Álvarez, E.; González Hernández, J. I.; Grözinger, U.; Guàrdia, J.; Guenther, E. W.; de Guindos, E.; Gutiérrez-Soto, J.; Hagen, H. -J.; Hatzes, A. P.; Hauschildt, P. H.; Helmling, J.; Henning, T.; Hermann, D.; Hernández Castaño, L.; Herrero, E.; Hidalgo, D.; Holgado, G.; Huber, A.; Huber, K. F.; Jeffers, S.; Joergens, V.; de Juan, E.; Kehr, M.; Klein, R.; Kürster, M.; Lamert, A.; Lalitha, S.; Laun, W.; Lemke, U.; Lenzen, R.; López del Fresno, Mauro; López Martí, B.; López-Santiago, J.; Mall, U.; Mandel, H.; Martín, E. L.; Martín-Ruiz, S.; Martínez-Rodríguez, H.; Marvin, C. J.; Mathar, R. J.; Mirabet, E.; Montes, D.; Morales Muñoz, R.; Moya, A.; Naranjo, V.; Ofir, A.; Oreiro, R.; Pallé, E.; Panduro, J.; Passegger, V. -M.; Pérez-Calpena, A.; Pérez Medialdea, D.; Perger, M.; Pluto, M.; Ramón, A.; Rebolo, R.; Redondo, P.; Reffert, S.; Reinhardt, S.; Rhode, P.; Rix, H. -W.; Rodler, F.; Rodríguez, E.; Rodríguez-López, C.; Rodríguez-Pérez, E.; Rohloff, R. -R.; Rosich, A.; Sánchez-Blanco, E.; Sánchez Carrasco, M. A.; Sanz-Forcada, J.; Sarmiento, L. F.; Schäfer, S.; Schiller, J.; Schmidt, C.; Schmitt, J. H. M. M.; Solano, E.; Stahl, O.; Storz, C.; Stürmer, J.; Suárez, J. C.; Ulbrich, R. G.; Veredas, G.; Wagner, K.; Winkler, J.; Zapatero Osorio, M. R.; Zechmeister, M.; Abellán de Paco, F. J.; Anglada-Escudé, G.; del Burgo, C.; Klutsch, A.; Lizon, J. L.; López-Morales, M.; Morales, J. C.; Perryman, M. A. C.; Tulloch, S. M.; Xu, W. Bibcode: 2014SPIE.9147E..1FQ Altcode: This paper gives an overview of the CARMENES instrument and of the survey that will be carried out with it during the first years of operation. CARMENES (Calar Alto high-Resolution search for M dwarfs with Exoearths with Near-infrared and optical Echelle Spectrographs) is a next-generation radial-velocity instrument under construction for the 3.5m telescope at the Calar Alto Observatory by a consortium of eleven Spanish and German institutions. The scientific goal of the project is conducting a 600-night exoplanet survey targeting ~ 300 M dwarfs with the completed instrument. The CARMENES instrument consists of two separate echelle spectrographs covering the wavelength range from 0.55 to 1.7 μm at a spectral resolution of R = 82,000, fed by fibers from the Cassegrain focus of the telescope. The spectrographs are housed in vacuum tanks providing the temperature-stabilized environments necessary to enable a 1 m/s radial velocity precision employing a simultaneous calibration with an emission-line lamp or with a Fabry-Perot etalon. For mid-M to late-M spectral types, the wavelength range around 1.0 μm (Y band) is the most important wavelength region for radial velocity work. Therefore, the efficiency of CARMENES has been optimized in this range. The CARMENES instrument consists of two spectrographs, one equipped with a 4k x 4k pixel CCD for the range 0.55 - 1.05 μm, and one with two 2k x 2k pixel HgCdTe detectors for the range from 0.95 - 1.7μm. Each spectrograph will be coupled to the 3.5m telescope with two optical fibers, one for the target, and one for calibration light. The front end contains a dichroic beam splitter and an atmospheric dispersion corrector, to feed the light into the fibers leading to the spectrographs. Guiding is performed with a separate camera; on-axis as well as off-axis guiding modes are implemented. Fibers with octagonal cross-section are employed to ensure good stability of the output in the presence of residual guiding errors. The fibers are continually actuated to reduce modal noise. The spectrographs are mounted on benches inside vacuum tanks located in the coudé laboratory of the 3.5m dome. Each vacuum tank is equipped with a temperature stabilization system capable of keeping the temperature constant to within +/-0.01°C over 24 hours. The visible-light spectrograph will be operated near room temperature, while the near-IR spectrograph will be cooled to ~ 140 K. The CARMENES instrument passed its final design review in February 2013. The MAIV phase is currently ongoing. First tests at the telescope are scheduled for early 2015. Completion of the full instrument is planned for the fall of 2015. At least 600 useable nights have been allocated at the Calar Alto 3.5m Telescope for the CARMENES survey in the time frame until 2018. A data base of M stars (dubbed CARMENCITA) has been compiled from which the CARMENES sample can be selected. CARMENCITA contains information on all relevant properties of the potential targets. Dedicated imaging, photometric, and spectroscopic observations are underway to provide crucial data on these stars that are not available in the literature. Title: VizieR Online Data Catalog: Kapteyn's star spectroscopic measurements (Anglada-Escude+ 2014) Authors: Anglada-Escude, G.; Arriagada, P.; Tuomi, M.; Zechmeister, M.; Jenkins, J. S.; Ofir, A.; Dreizler, S.; Gerlach, E.; Marvin, C. J.; Reiners, A.; Jeffers, S. V.; Butler, R. P.; Vogt, S. S.; Amado, P. J.; Rodriguez-Lopez, C.; Berdinas, Z. M.; Morin, J.; Crane, J. D.; Shectman, S. A.; Thompson, I. B.; Diaz, M.; Rivera, E.; Sarmiento, L. F.; Jones, H. R. A. Bibcode: 2014yCat..74439089A Altcode: Time-series of spectroscopic measurements used in the paper. Median value and a perspective acceleration were subtracted to each RVs set (Ins. 1 is HARPS, 2 is HIRES, 3 is PFS). Measurements of the FWHM, BIS of the cross-correlation profiles and measurements of the S-index are provided for HARPS data only. Uncertainty in the FWHM is 2.5 times the uncertainty in BIS. Check (2012ApJS..200...15A), for more detailed definitions of the measurements and their uses.

(1 data file). Title: TRIPP: Time Resolved Imaging Photometry Package Authors: Geckeler, Ralf D.; Schuh, Sonja; Dreizler, Stefan; Deetjen, Jochen; Gleissner, Thomas; Risse, Patrick; Rauch, Thomas; Göhler, Eckart; Hügelmeyer, Simon; Husser, Tim-Oliver; Israel, Holger; Benlloch-Garcia, Sara; Pottschmidt, Katja; Wilms, Jörn Bibcode: 2014ascl.soft05008G Altcode: Written in IDL, TRIPP performs CCD time series reduction and analysis. It provides an on-line check of the incoming frames, performs relative aperture photometry and provides a set of time series tools, such as calculation of periodograms including false alarm probability determination, epoc folding, sinus fitting, and light curve simulations. Title: Hot horizontal branch stars in NGC 288 - effects of diffusion and stratification on their atmospheric parameters Authors: Moehler, S.; Dreizler, S.; LeBlanc, F.; Khalack, V.; Michaud, G.; Richer, J.; Sweigart, A. V.; Grundahl, F. Bibcode: 2014A&A...565A.100M Altcode: 2014arXiv1403.7397M Context. NGC 288 is a globular cluster with a well-developed blue horizontal branch (HB) covering the u-jump that indicates the onset of diffusion. It is therefore well suited to study the effects of diffusion in blue HB stars.
Aims: We compare observed abundances with predictions from stellar evolution models calculated with diffusion and from stratified atmospheric models. We verify the effect of using stratified model spectra to derive atmospheric parameters. In addition, we investigate the nature of the overluminous blue HB stars around the u-jump.
Methods: We defined a new photometric index sz from uvby measurements that is gravity-sensitive between 8000 K and 12 000 K. Using medium-resolution spectra and Strömgren photometry, we determined atmospheric parameters (Teff, log g) and abundances for the blue HB stars. We used both homogeneous and stratified model spectra for our spectroscopic analyses.
Results: The atmospheric parameters and masses of the hot HB stars in NGC 288 show a behaviour seen also in other clusters for temperatures between 9000 K and 14 000 K. Outside this temperature range, however, they instead follow the results found for such stars in ω Cen. The abundances derived from our observations are for most elements (except He and P) within the abundance range expected from evolutionary models that include the effects of atomic diffusion and assume a surface mixed mass of 10-7 M. The abundances predicted by stratified model atmospheres are generally significantly more extreme than observed, except for Mg. When effective temperatures, surface gravities, and masses are determined with stratified model spectra, the hotter stars agree better with canonical evolutionary predictions.
Conclusions: Our results show definite promise towards solving the long-standing problem of surface gravity and mass discrepancies for hot HB stars, but much work is still needed to arrive at a self-consistent solution.

Based on observations with the ESO Very Large Telescope at Paranal Observatory, Chile (proposal ID 71.D-0131).Tables 1 and 2 are available in electronic form at http://www.aanda.orgThe observed abundances plotted in Fig. 8 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/565/A100 Title: On the Current State of Ground-based Transmission Spectroscopy of Planet Atmospheres Authors: Nortmann, Lisa; Dreizler, Stefan; Bean, Jacob Bibcode: 2014IAUS..293..315N Altcode: In response to the large number of exoplanet detections, the characterization of these planets has become a major focus of exoplanet science. Transiting planets are of particular interest as they allow us to investigate the transmission of their atmospheres. Our group uses ground-based facilities like the ESO/VLT to probe the atmosphere of hot Jupiters with the technique of spectrophotometry. In our preliminary results for the hot Jupiters WASP-17b and WASP-31b we find the reachable precision to be limited by instrumental systematic noise rather than photon noise. We discuss the source of the noise and suggest two approaches to correct it. Title: Kepler-9 revisited 60% the mass with six times more data Authors: Dreizler, Stefan; Ofir, Aviv Bibcode: 2014arXiv1403.1372D Altcode: Kepler-9 was the first case where transit timing variations have been used to confirm the planets in this system. Following predictions of dramatic TTVs - larger than a week - we re-analyse the system based on the full Kepler data set. We re-processed all available data for Kepler-9 removing short and long term trends, measured the times of mid-transit and used those for dynamical analysis of the system. The newly determined masses and radii of Kepler-9b and -9c change the nature of these planets relative to the one described in Holman et al. 2010 (hereafter H10) with very low, but relatively well charcterised (to better than 7%), bulk densities of 0.18 and 0.14 g cm$^3$ (about 1/3 of the H10 value). We constrain the masses (45.1 and 31.0 M$_\oplus$, for Kepler-9b and -9c respectively) from photometry alone, allowing us to see possible indications for an outer non-transiting planet in the radial velocity data. At $2R_\oplus$ Kepler-9d is determined to be larger than suggested before - suggesting that it is a low-mass low-density planet. The comparison between the H10 analysis and our new analysis suggests that small formal error in the TTV inversion may be misleading if the data does not cover a significant fraction of the interaction time scale. Title: VizieR Online Data Catalog: NGC 288 hot horizontal branch stars abundances (Moehler+, 2014) Authors: Moehler, S.; Dreizler, S.; Leblanc, F.; Khalack, V.; Michaud, G.; Richer, J.; Sweigart, A. V.; Grundahl, F. Bibcode: 2014yCat..35650100M Altcode: 2014yCat..35659100M Temperatures, surface gravities, and abundances for hot (Teff>9000K) horizontal branch stars in NGC 288 as derived from medium-resolution FLAMES-GIRAFFE spectra (resolution about 0.7Å). Effective temperatures and surface gravities are derived from line profile fits. The abundances were derived via spectrum synthesis, using the presviously defined effective temperature and surface gravity. Errors are about ±5% in Teff, ±0.1 in logg, ±0.2 (He), ±0.28 (Mg), ±0.34 (Si, P, Fe), ±0.58 (Ti, Mn, Ni). 0.00 means that no abundance could be determined.

(2 data files). Title: Planet formation from the ejecta of common envelopes Authors: Schleicher, Dominik R. G.; Dreizler, Stefan Bibcode: 2014A&A...563A..61S Altcode: 2013arXiv1312.3479S Context. The close binary system NN Serpentis must have gone through a common envelope phase before the formation of its white dwarf. During this phase, a substantial amount of mass was lost from the envelope. The recently detected orbits of circumbinary planets are probably inconsistent with planet formation before the mass loss.
Aims: We explore whether new planets may have formed from the ejecta of the common envelope and derive the expected planetary mass as a function of radius.
Methods: We employed the Kashi & Soker model to estimate the amount of mass that is retained during the ejection event and inferred the properties of the resulting disk from the conservation of mass and angular momentum. The resulting planetary masses were estimated from models with and without radiative feedback.
Results: We show that the observed planetary masses can be reproduced for appropriate model parameters. Photoheating can stabilize the disks in the interior, potentially explaining the observed planetary orbits on scales of a few AU. We compare the expected mass scale of planets for 11 additional systems with observational results and find hints of two populations, one consistent with planet formation from the ejecta of common envelopes and the other a separate population that may have formed earlier.
Conclusions: The formation of the observed planets from the ejecta of common envelopes seems feasible. The model proposed here can be tested through refined observations of additional post-common envelope systems. While it appears observationally challenging to distinguish between the accretion on pre-existing planets and their growth from new fragments, it may be possible to further constrain the properties of the protoplanetary disk through additional observations of current planetary candidates and post-common envelope binary systems. Title: Evidence for an oscillation of the magnetic axis of the white dwarf in the polar DP Leonis Authors: Beuermann, K.; Dreizler, S.; Hessman, F. V.; Schwope, A. D. Bibcode: 2014A&A...562A..63B Altcode: 2014arXiv1401.1638B From 1979 to 2001, the magnetic axis of the white dwarf in the polar DP Leo slowly rotated by 50° in azimuth, possibly indicating a small asynchronism between the rotational and orbital periods of the magnetic white dwarf. Using the MONET/North telescope, we have obtained phase-resolved orbital light curves between 2009 and 2013, which show that this trend has not continued in recent years. Our data are consistent with the theoretically predicted oscillation of the magnetic axis of the white dwarf about an equilibrium orientation, which is defined by the competition between the accretion torque and the magnetostatic interaction of the primary and secondary star. Our data indicate an oscillation period of ~60 yr, an amplitude of about 25°, and an equilibrium orientation leading the connecting line of the two stars by about 7°. Title: An independent planet search in the Kepler dataset. II. An extremely low-density super-Earth mass planet around Kepler-87 Authors: Ofir, Aviv; Dreizler, Stefan; Zechmeister, Mathias; Husser, Tim-Oliver Bibcode: 2014A&A...561A.103O Altcode: 2013arXiv1310.2064O Context. The primary goal of the Kepler mission is the measurement of the frequency of Earth-like planets around Sun-like stars. However, the confirmation of the smallest of Kepler's candidates in long periods around FGK dwarfs is extremely difficult or even beyond the limit of current radial velocity technology. Transit timing variations (TTVs) may offer the possibility for these confirmations of near-resonant multiple systems by the mutual gravitational interaction of the planets.
Aims: We previously detected the second planet candidate in the KOI 1574 system. The two candidates have relatively long periods (about 114 d and 191 d) and are in 5:3 resonance. We therefore searched for TTVs in this particularly promising system.
Methods: The full Kepler data was detrended with the proven SARS pipeline. The entire data allowed one to search for TTVs of the above signals, and to search for additional transit-like signals.
Results: We detected strong anti-correlated TTVs of the 114 d and 191 d signals, dynamically confirming them as members of the same system. Dynamical simulations reproducing the observed TTVs allowed us to also determine the masses of the planets. We found KOI 1574.01 (hereafter Kepler-87 b) to have a radius of 13.49 ± 0.55 R and a mass of 324.2 ± 8.8 M, and KOI 1574.02 (Kepler-87 c) to have a radius of 6.14 ± 0.29 R and a mass of 6.4 ± 0.8 M. Both planets have low densities of 0.729 and 0.152 g cm-3, respectively, which is non-trivial for such cold and old (7-8 Gyr) planets. Specifically, Kepler-87 c is the lowest-density planet in the super-Earth mass range. Both planets are thus particularly amenable to modeling and planetary structure studies, and also present an interesting case where ground-based photometric follow-up of Kepler planets is very desirable. Finally, we also detected two more short-period super-Earth sized (<2 R) planetary candidates in the system, making the relatively high multiplicity of this system notable against the general paucity of multiple systems in the presence of giant planets like Kepler-87 b. Title: VizieR Online Data Catalog: WASP-15 and WASP-16 light curves (Southworth+, 2013) Authors: Southworth, J.; Mancini, L.; Browne, P.; Burgdorf, M.; Calchi Novati, S.; Dominik, M.; Gerner, T.; Hinse, T. C.; Jorgensen, U. G.; Kains, N.; Ricci, D.; Schafer, S.; Schonebeck, F.; Tregloan-Reed, J.; Alsubai, K. A.; Bozza, V.; Chen, G.; Dodds, P.; Dreizler, S.; Fang, X. -S.; Finet, F.; Gu, S. -H.; Hardis, S.; Harpsoe, K.; Henning, T.; Hundertmark, M.; Jessen-Hansen, J.; Kerins, E.; Kjeldsen, H.; Liebig, C.; Lund, M. N.; Lundkvist, M.; Mathiasen, M.; Nikolov, N.; Penny, M. T.; Proft, S.; Rahvar, S.; Sahu, K.; Scarpetta, G.; Skottfelt, J.; Snodgrass, C.; Surdej, J.; Wertz, O. Bibcode: 2013yCat..74341300S Altcode: Nine light curves of six transits of the extrasolar planetary systems WASP-15 and WASP-16 are presented. The data were obtained using the Danish 1.5m telescope and DFOSC camera, and the ESO/MPI 2.2m telescope and GROND imager, with substantial telescope defocussing in order to improve the photometric precision of the observations. A Bessell R filter was used with DFOSC. The observations with GROND were obtained simultaneously through four filters: Sloan g, r, i and z.

(3 data files). Title: VizieR Online Data Catalog: New Kepler planetary candidates (Ofir+, 2013) Authors: Ofir, A.; Dreizler, S. Bibcode: 2013yCat..35550058O Altcode: 2013yCat..35559058O We present first results of our efforts to re-analyze the Kepler photometric dataset, searching for planetary transits using an alternative processing pipeline to the one used by the Kepler mission The SARS pipeline was tried and tested extensively by processing all available CoRoT mission data. For this first paper of the series we used this pipeline to search for (additional) planetary transits only in a small subset of stars - the Kepler objects of interest (KOIs), which are already known to include at least one promising planet candidate.

(2 data files). Title: The eclipsing post-common envelope binary CSS21055: a white dwarf with a probable brown-dwarf companion Authors: Beuermann, K.; Dreizler, S.; Hessman, F. V.; Backhaus, U.; Boesch, A.; Husser, T. -O.; Nortmann, L.; Schmelev, A.; Springer, R. Bibcode: 2013A&A...558A..96B Altcode: 2013arXiv1312.5088B We report photometric observations of the eclipsing close binary CSS21055 (SDSS J141126+200911) that strongly suggest that the companion to the carbon-oxygen white dwarf is a brown dwarf with a mass between 0.030 and 0.074 M. The measured orbital period is 121.73 min and the totality of the eclipse lasts 125 s. If confirmed, CSS21055 would be the first detached eclipsing WD+BD binary. Spectroscopy in the eclipse could provide information about the companion's evolutionary state and atmospheric structure.

Light curves are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/558/A96 Title: VizieR Online Data Catalog: Vi light curves of NGC6333 variables (Arellano Ferro+, 2013) Authors: Arellano Ferro, A.; Bramich, D. M.; Figuera Jaimes, R.; Giridhar, S.; Kains, N.; Kuppuswamy, K.; Jorgensen, U. G.; Alsubai, K. A.; Andersen, J. M.; Bozza, V.; Browne, P.; Calchi Novati, S.; Damerdji, Y.; Diehl, C.; Dominik, M.; Dreizler, S.; Elyiv, A.; Giannini, E.; Harpsoe, K.; Hessman, F. V.; Hinse, T. C.; Hundertmark, M.; Juncher, D.; Kerins, E.; Korhonen, H.; Liebig, C.; Mancini, L.; Mathiasen, M.; Penny, M. T.; Rabus, M.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Skottfelt, J.; Snodgrass, C.; Southworth, J.; Surdej, J.; Tregloan-Reed, J.; Vilela, C.; Wertz, O. Bibcode: 2013yCat..74341220A Altcode: V and i time-series photometry for all confirmed variables in NGC 6333.

(2 data files). Title: A detailed census of variable stars in the globular cluster NGC 6333 (M9) from CCD differential photometry Authors: Arellano Ferro, A.; Bramich, D. M.; Figuera Jaimes, R.; Giridhar, Sunetra; Kains, N.; Kuppuswamy, K.; Jørgensen, U. G.; Alsubai, K. A.; Andersen, J. M.; Bozza, V.; Browne, P.; Calchi Novati, S.; Damerdji, Y.; Diehl, C.; Dominik, M.; Dreizler, S.; Elyiv, A.; Giannini, E.; Harpsøe, K.; Hessman, F. V.; Hinse, T. C.; Hundertmark, M.; Juncher, D.; Kerins, E.; Korhonen, H.; Liebig, C.; Mancini, L.; Mathiasen, M.; Penny, M. T.; Rabus, M.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Skottfelt, J.; Snodgrass, C.; Southworth, J.; Surdej, J.; Tregloan-Reed, J.; Vilela, C.; Wertz, O.; Mindstep Consortium Bibcode: 2013MNRAS.434.1220A Altcode: 2013MNRAS.tmp.1768A; 2013arXiv1306.3206A We report CCD V and I time series photometry of the globular cluster NGC 6333 (M9). The technique of difference image analysis has been used, which enables photometric precision better than 0.05 mag for stars brighter than V ∼ 19.0 mag, even in the crowded central regions of the cluster. The high photometric precision has resulted in the discovery of two new RRc stars, three eclipsing binaries, seven long-term variables and one field RRab star behind the cluster. A detailed identification chart and equatorial coordinates are given for all the variable stars in the field of our images of the cluster. Our data together with the literature V-data obtained in 1994 and 1995 allowed us to refine considerably the periods for all RR Lyrae stars. The nature of the new variables is discussed. We argue that variable V12 is a cluster member and an Anomalous Cepheid. Secular period variations, double-mode pulsations and/or the Blazhko-like modulations in some RRc variables are addressed. Through the light-curve Fourier decomposition of 12 RR Lyrae stars we have calculated a mean metallicity of [Fe/H]ZW = -1.70 ± 0.01(statistical) ± 0.14(systematic) or [Fe/H]_{text{UVES}}=-1.67 ± 0.01(statistical) ± 0.19(systematic). Absolute magnitudes, radii and masses are also estimated for the RR Lyrae stars. A detailed search for SX Phe stars in the Blue Straggler region was conducted but none were discovered. If SX Phe exist in the cluster then their amplitudes must be smaller than the detection limit of our photometry. The colour-magnitude diagram has been corrected for heavy differential reddening using the detailed extinction map of the cluster of Alonso-García et al. This has allowed us to set the mean cluster distance from two independent estimates; from the RRab and RRc absolute magnitudes, we find 8.04 ± 0.19 and 7.88 ± 0.30 kpc, respectively. Title: VizieR Online Data Catalog: CSS21055 light curves (Beuermann+, 2013) Authors: Beuermann, K.; Dreizler, S.; Hessman, F. V.; Backhaus, U.; Boesch, A.; Husser, T. -O.; Nortmann, L.; Schmelev, A.; Springer, R. Bibcode: 2013yCat..35580096B Altcode: 2013yCat..35589096B Tables contain the numerical values for the light curves presented in Figs. 1a, 1b, and 1c.

(3 data files). Title: High-precision photometry by telescope defocusing - V. WASP-15 and WASP-16 Authors: Southworth, John; Mancini, L.; Browne, P.; Burgdorf, M.; Calchi Novati, S.; Dominik, M.; Gerner, T.; Hinse, T. C.; Jørgensen, U. G.; Kains, N.; Ricci, D.; Schäfer, S.; Schönebeck, F.; Tregloan-Reed, J.; Alsubai, K. A.; Bozza, V.; Chen, G.; Dodds, P.; Dreizler, S.; Fang, X. -S.; Finet, F.; Gu, S. -H.; Hardis, S.; Harpsøe, K.; Henning, Th.; Hundertmark, M.; Jessen-Hansen, J.; Kerins, E.; Kjeldsen, H.; Liebig, C.; Lund, M. N.; Lundkvist, M.; Mathiasen, M.; Nikolov, N.; Penny, M. T.; Proft, S.; Rahvar, S.; Sahu, K.; Scarpetta, G.; Skottfelt, J.; Snodgrass, C.; Surdej, J.; Wertz, O. Bibcode: 2013MNRAS.434.1300S Altcode: 2013MNRAS.tmp.1750S; 2013arXiv1306.3509S We present new photometric observations of WASP-15 and WASP-16, two transiting extrasolar planetary systems with measured orbital obliquities but without photometric follow-up since their discovery papers. Our new data for WASP-15 comprise observations of one transit simultaneously in four optical passbands using GROND on the MPG/European Southern Observatory (ESO) 2.2 m telescope, plus coverage of half a transit from DFOSC on the Danish 1.54 m telescope, both at ESO La Silla. For WASP-16 we present observations of four complete transits, all from the Danish telescope. We use these new data to refine the measured physical properties and orbital ephemerides of the two systems. Whilst our results are close to the originally determined values for WASP-15, we find that the star and planet in the WASP-16 system are both larger and less massive than previously thought. Title: VizieR Online Data Catalog: Transiting planetary system WASP-17 (Southworth+, 2012) Authors: Southworth, J.; Hinse, T. C.; Dominik, M.; Fang, X. -S.; Harpsoe, K.; Jorgensen, U. G.; Kerins, E.; Liebig, C.; Mancini, L.; Skottfelt, J.; Anderson, D. R.; Smalley, B.; Tregloan-Reed, J.; Wertz, O.; Alsubai, K. A.; Bozza, V.; Calchi Novati, S.; Dreizler, S.; Gu, S. -H.; Hundertmark, M.; Jessen-Hansen, J.; Kains, N.; Kjeldsen, H.; Lund, M. N.; Lundkvist, M.; Mathiasen, M.; Penny, M. T.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Snodgrass, C.; Surdej, J. Bibcode: 2013yCat..74261338S Altcode: A light curve of four transits of the extrasolar planetary system WASP-17 is presented. The data were obtained using the Danish 1.5m telescope and DFOSC camera at ESO La Silla in 2012, with substantial telescope defocussing in order to improve the photometric precision of the observations. A Cousins R filter and exposure times of 120s were used.

(1 data file). Title: High angular resolution imaging and infrared spectroscopy of CoRoT candidates Authors: Guenther, E. W.; Fridlund, M.; Alonso, R.; Carpano, S.; Deeg, H. J.; Deleuil, M.; Dreizler, S.; Endl, M.; Gandolfi, D.; Gillon, M.; Guillot, T.; Jehin, E.; Léger, A.; Moutou, C.; Nortmann, L.; Rouan, D.; Samuel, B.; Schneider, J.; Tingley, B. Bibcode: 2013A&A...556A..75G Altcode: 2013arXiv1307.1660G Context. Studies of transiting extrasolar planets are of key importance for understanding the nature of planets outside our solar system because their masses, diameters, and bulk densities can be measured. An important part of transit-search programmes is the removal of false-positives. In the case of the CoRoT space mission, the majority of the false-positives are removed by a detailed analysis of the light curves and by seeing-limited imaging in- and out-of-transit. However, the critical question is how many of the candidates that passed all these tests are false-positives. Such false-positives can be caused by eclipsing binaries, which are either related or unrelated to the targets.
Aims: For our study we selected 25 CoRoT candidates that have already been screened against false-positives using detailed analysis of the light curves and seeing-limited imaging, which has transits that are between 0.7 and 0.05% deep. Our aim is to search for companion candidates that had not been recognized in previous observations.
Methods: We observed 20 candidates with the adaptive optics imager NaCo and 18 with the high-resolution infrared spectrograph CRIRES.
Results: We found previously unknown stars within 2'' of the targets in seven of the candidates. All of these are too faint and too close to the targets to have been previously detected with seeing-limited telescopes in the optical. Our study thus leads to the surprising results that if we remove all candidates excluded by the sophisticated analysis of the light-curve, as well as carrying out deep imaging with seeing-limited telescopes, still 28-35% of the remaining candidates are found to possess companions that are bright enough to be false-positives.
Conclusions: Given that the companion candidates cluster around the targets and that the J - K colours are consistent with physical companions, we conclude that the companion candidates are more likely to be physical companions rather than unrelated field stars.

Based on observations obtained at the European Southern Observatory at Paranal, Chile in programmes 282.C-5015A, 282.C-5015B, 282.C-5015C, 285.C-5045A, and 285.C-5045B, 086.C-0235A, 086.C-0235B, 088.C-0707A, 088.C-0707B, 090.C-0251A, 090.C-0251B, and 091.C-203(A).Appendices A and B are available in electronic form at http://www.aanda.org Title: The quest for companions to post-common envelope binaries. IV. The 2:1 mean-motion resonance of the planets orbiting NN Serpentis Authors: Beuermann, K.; Dreizler, S.; Hessman, F. V. Bibcode: 2013A&A...555A.133B Altcode: 2013arXiv1305.6494B We present 69 new mid-eclipse times of the young post-common envelope binary (PCEB) NN Ser, which was previously suggested to possess two circumbinary planets. We have interpreted the observed eclipse-time variations in terms of the light-travel time effect caused by two planets, exhaustively covering the multi-dimensional parameter space by fits in the two binary and ten orbital parameters. We supplemented the fits by stability calculations for all models with an acceptable χ2. An island of secularly stable 2:1 resonant solutions exists, which coincides with the global χ2 minimum. Our best-fit stable solution yields current orbital periods Po = 15.47 yr and Pi = 7.65 yr and eccentricities eo = 0.14 and ei = 0.22 for the outer and inner planets, respectively. The companions qualify as giant planets, with masses of 7.0 MJup and 1.7 MJup for the case of orbits coplanar with that of the binary. The two-planet model that starts from the present system parameters has a lifetime greater than 108 yr, which significantly exceeds the age of NN Ser of 106 yr as a PCEB. The resonance is characterized by libration of the resonant variable Θ1 and circulation of , the difference between the arguments of periapse of the two planets. No stable nonresonant solutions were found, and the possibility of a 5:2 resonance suggested previously by us is now excluded at the 99.3% confidence level.

Table 1 is available in electronic form at http://www.aanda.org Title: An independent planet search in the Kepler dataset. I. One hundred new candidates and revised Kepler objects of interest Authors: Ofir, A.; Dreizler, S. Bibcode: 2013A&A...555A..58O Altcode: 2012arXiv1206.5347O
Aims: We present first results of our efforts to re-analyze the Kepler photometric dataset, searching for planetary transits using an alternative processing pipeline to the one used by the Kepler mission
Methods: The SARS pipeline was tried and tested extensively by processing all available CoRoT mission data. For this first paper of the series we used this pipeline to search for (additional) planetary transits only in a small subset of stars - the Kepler objects of interest (KOIs), which are already known to include at least one promising planet candidate.
Results: Although less than 1% of the Kepler dataset are KOIs we are able to significantly update the overall statistics of planetary multiplicity: we find 84 new transit signals on 64 systems on these light curves (LCs) only, nearly doubling the number of transit signals in these systems. Forty-one of the systems were singly-transiting systems that are now multiply-transiting. This significantly reduces the chances of false positive in them. Notable among the new discoveries are KOI 435 as a new six-candidate system (of which kind only Kepler-11 was known before), KOI 277 (which includes two candidates in a 6:7 period commensurability that has anti-correlated transit timing variations) - all but validating the system, KOIs 719, 1574, and 1871 that have small planet candidates (1.15,2.05 and 1.71 R) in the habitable zone of their host star, and KOI 1843 that exhibits the shortest period (4.25 h) and is among the smallest (0.63 R) of all planet candidates. We are also able to reject 11 KOIs as eclipsing binaries based on photometry alone, update the ephemeris for five KOIs and otherwise discuss a number of other objects, which brings the total of new signals and revised KOIs in this study to more than one hundred. Interestingly, a large fraction, about ~1/3, of the newly detected candidates participate in period commensurabilities. Finally, we discuss the possible overestimation of parameter errors in the current list of KOIs and point out apparent problems in at least two of the parameters.
Conclusions: Our results strengthen previous analyses of the multi-transiting ensemble, and again highlight the great importance of this dataset. Nevertheless, we conclude that despite the phenomenal success of the Kepler mission, parallel analysis of the data by multiple teams is required to make full use of the data. Title: A new extensive library of PHOENIX stellar atmospheres and synthetic spectra Authors: Husser, T. -O.; Wende-von Berg, S.; Dreizler, S.; Homeier, D.; Reiners, A.; Barman, T.; Hauschildt, P. H. Bibcode: 2013A&A...553A...6H Altcode: 2013arXiv1303.5632H
Aims: We present a new library of high-resolution synthetic spectra based on the stellar atmosphere code PHOENIX that can be used for a wide range of applications of spectral analysis and stellar parameter synthesis.
Methods: The spherical mode of PHOENIX was used to create model atmospheres and to derive detailed synthetic stellar spectra from them. We present a new self-consistent way of describing micro-turbulence for our model atmospheres.
Results: The synthetic spectra cover the wavelength range from 500 Å to 5.5 μm with resolutions of R = 500 000 in the optical and near IR, R = 100 000 in the IR and Δλ = 0.1 Å in the UV. The parameter space covers 2300 K ≤ Teff ≤ 12 000 K, 0.0 ≤ log g ≤ +6.0, - 4.0 ≤ [Fe/H] ≤ +1.0, and - 0.2 ≤ [α/Fe] ≤ +1.2. The library is a work in progress and we expect to extend it up to Teff = 25 000 K. Title: CAFE: Calar Alto Fiber-fed Échelle spectrograph Authors: Aceituno, J.; Sánchez, S. F.; Grupp, F.; Lillo, J.; Hernán-Obispo, M.; Benitez, D.; Montoya, L. M.; Thiele, U.; Pedraz, S.; Barrado, D.; Dreizler, S.; Bean, J. Bibcode: 2013A&A...552A..31A Altcode: 2013arXiv1301.2066A We present here CAFE, the Calar Alto Fiber-fed Échelle spectrograph, a new instrument built at the Centro Astronomico Hispano Alemán (CAHA). CAFE is a single-fiber, high-resolution (R ~ 70 000) spectrograph, covering the wavelength range between 3650-9800 Å. It was built on the basis of the common design for Échelle spectrographs. Its main aim is to measure radial velocities of stellar objects up to V ~ 13-14 mag with a precision as good as a few tens of m s-1. To achieve this goal the design was simplified at maximum, removing all possible movable components, the central wavelength is fixed, as is the wavelength coverage; there is no filter wheel, etc. Particular care was taken with the thermal and mechanical stability. The instrument is fully operational and publically accessible at the 2.2 m telescope of the Calar Alto Observatory. In this article we describe (i) the design, summarizing its manufacturing phase; (ii) characterize the main properties of the instrument; (iii) describe the reduction pipeline; and (iv) show the results from the first light and commissioning runs. The preliminar results indicate that the instrument fulfills the specifications and can achieve the planned goals. In particular, the results show that the instrument is more efficient than anticipated, reaching a signal-to-noise of ~20 for a stellar object as faint as V ~ 14.5 mag in ~2700 s integration time. The instrument is a wonderful machine for exoplanetary research (by studying large samples of possible systems cotaining massive planets), galactic dynamics (highly precise radial velocities in moving groups or stellar associations), or astrochemistry. Title: A giant planet beyond the snow line in microlensing event OGLE-2011-BLG-0251 Authors: Kains, N.; Street, R. A.; Choi, J. -Y.; Han, C.; Udalski, A.; Almeida, L. A.; Jablonski, F.; Tristram, P. J.; Jørgensen, U. G.; Szymański, M. K.; Kubiak, M.; Pietrzyński, G.; Soszyński, I.; Poleski, R.; Kozłowski, S.; Pietrukowicz, P.; Ulaczyk, K.; Wyrzykowski, Ł.; Skowron, J.; Alsubai, K. A.; Bozza, V.; Browne, P.; Burgdorf, M. J.; Calchi Novati, S.; Dodds, P.; Dominik, M.; Dreizler, S.; Fang, X. -S.; Grundahl, F.; Gu, C. -H.; Hardis, S.; Harpsøe, K.; Hessman, F. V.; Hinse, T. C.; Hornstrup, A.; Hundertmark, M.; Jessen-Hansen, J.; Kerins, E.; Liebig, C.; Lund, M.; Lundkvist, M.; Mancini, L.; Mathiasen, M.; Penny, M. T.; Rahvar, S.; Ricci, D.; Sahu, K. C.; Scarpetta, G.; Skottfelt, J.; Snodgrass, C.; Southworth, J.; Surdej, J.; Tregloan-Reed, J.; Wambsganss, J.; Wertz, O.; Bajek, D.; Bramich, D. M.; Horne, K.; Ipatov, S.; Steele, I. A.; Tsapras, Y.; Abe, F.; Bennett, D. P.; Bond, I. A.; Botzler, C. S.; Chote, P.; Freeman, M.; Fukui, A.; Furusawa, K.; Itow, Y.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Miyake, N.; Muraki, Y.; Ohnishi, K.; Rattenbury, N.; Saito, T.; Sullivan, D. J.; Sumi, T.; Suzuki, D.; Suzuki, K.; Sweatman, W. L.; Takino, S.; Wada, K.; Yock, P. C. M.; Allen, W.; Batista, V.; Chung, S. -J.; Christie, G.; DePoy, D. L.; Drummond, J.; Gaudi, B. S.; Gould, A.; Henderson, C.; Jung, Y. -K.; Koo, J. -R.; Lee, C. -U.; McCormick, J.; McGregor, D.; Muñoz, J. A.; Natusch, T.; Ngan, H.; Park, H.; Pogge, R. W.; Shin, I. -G.; Yee, J.; Albrow, M. D.; Bachelet, E.; Beaulieu, J. -P.; Brillant, S.; Caldwell, J. A. R.; Cassan, A.; Cole, A.; Corrales, E.; Coutures, Ch.; Dieters, S.; Dominis Prester, D.; Donatowicz, J.; Fouqué, P.; Greenhill, J.; Kane, S. R.; Kubas, D.; Marquette, J. -B.; Martin, R.; Meintjes, P.; Menzies, J.; Pollard, K. R.; Williams, A.; Wouters, D.; Zub, M. Bibcode: 2013A&A...552A..70K Altcode: 2013arXiv1303.1184K
Aims: We present the analysis of the gravitational microlensing event OGLE-2011-BLG-0251. This anomalous event was observed by several survey and follow-up collaborations conducting microlensing observations towards the Galactic bulge.
Methods: Based on detailed modelling of the observed light curve, we find that the lens is composed of two masses with a mass ratio q = 1.9 × 10-3. Thanks to our detection of higher-order effects on the light curve due to the Earth's orbital motion and the finite size of source, we are able to measure the mass and distance to the lens unambiguously.
Results: We find that the lens is made up of a planet of mass 0.53 ± 0.21 MJ orbiting an M dwarf host star with a mass of 0.26 ± 0.11 M. The planetary system is located at a distance of 2.57 ± 0.61 kpc towards the Galactic centre. The projected separation of the planet from its host star is d = 1.408 ± 0.019, in units of the Einstein radius, which corresponds to 2.72 ± 0.75 AU in physical units. We also identified a competitive model with similar planet and host star masses, but with a smaller orbital radius of 1.50 ± 0.50 AU. The planet is therefore located beyond the snow line of its host star, which we estimate to be around ~1-1.5 AU. Title: CARMENES: Blue planets orbiting red dwarfs Authors: Quirrenbach, A.; Amado, P. J.; Caballero, J. A.; Mandel, H.; Mundt, R.; Reiners, A.; Ribas, I.; Sánchez Carrasco, M. A.; Seifert, W.; Azzaro, M.; Galadí, D.; Alonso-Floriano, F. J.; Dreizler, S.; Montes, D.; Rhode, P.; Stürmer, J. Bibcode: 2013EPJWC..4705006Q Altcode: The CARMENES (Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs) consortium, consisting of eleven Spanish and German institutions, has been established to conduct a radial-velocity survey of M dwarfs with the 3.5 m telescope at the Calar Alto Observatory. This survey will target ∼300 M stars, with emphasis on spectral types M4V and later. The CARMENES instrument is currently under construction; it consists of two independent échelle spectrographs covering the wavelength ranges 0.55 …1.05 μm and 0.95 …1.7 μm, respectively, at a spectral resolution of R = 82,000. The spectrographs are fed by fibers from the Cassegrain focus of the telescope; calibration is performed simultaneously with emission-line lamps. The optical benches of the spectrographs are housed in vacuum tanks and climatic chambers, which provide the temperature-stabilized environments necessary to enable a 1 m/s radial velocity precision. Title: Flux and color variations of the doubly imaged quasar UM673 Authors: Ricci, D.; Elyiv, A.; Finet, F.; Wertz, O.; Alsubai, K.; Anguita, T.; Bozza, V.; Browne, P.; Burgdorf, M.; Calchi Novati, S.; Dodds, P.; Dominik, M.; Dreizler, S.; Gerner, T.; Glitrup, M.; Grundahl, F.; Hardis, S.; Harpsøe, K.; Hinse, T. C.; Hornstrup, A.; Hundertmark, M.; Jørgensen, U. G.; Kains, N.; Kerins, E.; Liebig, C.; Maier, G.; Mancini, L.; Masi, G.; Mathiasen, M.; Penny, M.; Proft, S.; Rahvar, S.; Scarpetta, G.; Sahu, K.; Schäfer, S.; Schönebeck, F.; Schmidt, R.; Skottfelt, J.; Snodgrass, C.; Southworth, J.; Thöne, C. C.; Wambsganss, J.; Zimmer, F.; Zub, M.; Surdej, J. Bibcode: 2013A&A...551A.104R Altcode: 2013arXiv1302.0766R
Aims: With the aim of characterizing the flux and color variations of the multiple components of the gravitationally lensed quasar UM673 as a function of time, we have performed multiepoch and multiband photometric observations with the Danish telescope at the La Silla Observatory.
Methods: The observations were carried out in the VRi spectral bands during four seasons (2008-2011). We reduced the data using the point spread function photometric technique as well as aperture photometry.
Results: Our results show for the brightest lensed component some significant decrease in flux between the first two seasons (+ 0.09/+ 0.11/+ 0.05 mag) and a subsequent increase during the following ones (- 0.11/- 0.11/- 0.10 mag) in the V/R/i spectral bands, respectively. Comparing our results with previous studies, we find smaller color variations between these seasons as compared with previous ones. We also separate the contribution of the lensing galaxy from that of the fainter and close lensed component.

Based on data collected by MiNDSTEp with the Danish 1.54 m telescope at the ESO La Silla ObservatoryLight curves are only available in electronic from at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/551/A104 Title: VizieR Online Data Catalog: Lensed QSO UM673/Q0142-100 VRi light curves (Ricci+, 2013) Authors: Ricci, D.; Elyiv, A.; Finet, F.; Wertz, O.; Alsubai, K.; Anguita, T.; Bozza, V.; Browne, P.; Burgdorf, M.; Calchi Novati, S.; Dodds, P.; Dominik, M.; Dreizler, S.; Gerner, T.; Glitrup, M.; Grundahl, F.; Hardis, S.; Harpsoe, K.; Hinse, T. C.; Hornstrup, A.; Hundertmark, M.; Jorgensen, U. G.; Kains, N.; Kerins, E.; Liebig, C.; Maier, G.; Mancini, L.; Masi, G.; Mathiasen, M.; Penny, M.; Proft, S.; Rahvar, S.; Scarpetta, G.; Sahu, K.; Schaefer, S.; Schoenebeck, F.; Schmidt, R.; Skottfelt, J.; Snodgrass, C.; Southworth, J.; Thoene, C. C.; Wambsganss, J.; Zimmer, F.; Zub, M.; Surdej, J. Bibcode: 2013yCat..35510104R Altcode: 2013yCat..35519104R The Table contains the light curves, in the V, R, and i bands, of the two lensed components of the quasar UM673. The Table also contains the light curve of the "B+G" component, obtained by superposing the flux of the fainter B component and the flux of the lens galaxy.

(1 data file). Title: MOA-2010-BLG-073L: An M-dwarf with a Substellar Companion at the Planet/Brown Dwarf Boundary Authors: Street, R. A.; Choi, J. -Y.; Tsapras, Y.; Han, C.; Furusawa, K.; Hundertmark, M.; Gould, A.; Sumi, T.; Bond, I. A.; Wouters, D.; Zellem, R.; Udalski, A.; RoboNet Collaboration; Snodgrass, C.; Horne, K.; Dominik, M.; Browne, P.; Kains, N.; Bramich, D. M.; Bajek, D.; Steele, I. A.; Ipatov, S.; MOA Collaboration; Abe, F.; Bennett, D. P.; Botzler, C. S.; Chote, P.; Freeman, M.; Fukui, A.; Harris, P.; Itow, Y.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Miyake, N.; Muraki, Y.; Nagayama, T.; Nishimaya, S.; Ohnishi, K.; Rattenbury, N.; Saito, To.; Sullivan, D. J.; Suzuki, D.; Sweatman, W. L.; Tristram, P. J.; Wada, K.; Yock, P. C. M.; OGLE Collaboration; Szymański, M. K.; Kubiak, M.; Pietrzyński, G.; Soszyński, I.; Poleski, R.; Ulaczyk, K.; Wyrzykowski, Ł.; μFUN Collaboration; Yee, J.; Dong, S.; Shin, I. -G.; Lee, C. -U.; Skowron, J.; De Almeida, L. Andrade; DePoy, D. L.; Gaudi, B. S.; Hung, L. -W.; Jablonski, F.; Kaspi, S.; Klein, N.; Hwang, K. -H.; Koo, J. -R.; Maoz, D.; Muñoz, J. A.; Pogge, R. W.; Polishhook, D.; Shporer, A.; McCormick, J.; Christie, G.; Natusch, T.; Allen, B.; Drummond, J.; Moorhouse, D.; Thornley, G.; Knowler, M.; Bos, M.; Bolt, G.; PLANET Collaboration; Beaulieu, J. -P.; Albrow, M. D.; Batista, V.; Brillant, S.; Caldwell, J. A. R.; Cassan, A.; Cole, A.; Corrales, E.; Coutures, Ch.; Dieters, S.; Dominis Prester, D.; Donatowicz, J.; Fouqué, P.; Bachelet, E.; Greenhill, J.; Kane, S. R.; Kubas, D.; Marquette, J. -B.; Martin, R.; Menzies, J.; Pollard, K. R.; Sahu, K. C.; Wambsganss, J.; Williams, A.; Zub, M.; MiNDSTEp; Alsubai, K. A.; Bozza, V.; Burgdorf, M. J.; Calchi Novati, S.; Dodds, P.; Dreizler, S.; Finet, F.; Gerner, T.; Hardis, S.; Harpsøe, K.; Hessman, F.; Hinse, T. C.; Jørgensen, U. G.; Kerins, E.; Liebig, C.; Mancini, L.; Mathiasen, M.; Penny, M. T.; Proft, S.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Schäfer, S.; Schönebeck, F.; Southworth, J.; Surdej, J. Bibcode: 2013ApJ...763...67S Altcode: 2012arXiv1211.3782S We present an analysis of the anomalous microlensing event, MOA-2010-BLG-073, announced by the Microlensing Observations in Astrophysics survey on 2010 March 18. This event was remarkable because the source was previously known to be photometrically variable. Analyzing the pre-event source light curve, we demonstrate that it is an irregular variable over timescales >200 days. Its dereddened color, (V - I) S, 0, is 1.221 ± 0.051 mag, and from our lens model we derive a source radius of 14.7 ± 1.3 R , suggesting that it is a red giant star. We initially explored a number of purely microlensing models for the event but found a residual gradient in the data taken prior to and after the event. This is likely to be due to the variability of the source rather than part of the lensing event, so we incorporated a slope parameter in our model in order to derive the true parameters of the lensing system. We find that the lensing system has a mass ratio of q = 0.0654 ± 0.0006. The Einstein crossing time of the event, t E = 44.3 ± 0.1 days, was sufficiently long that the light curve exhibited parallax effects. In addition, the source trajectory relative to the large caustic structure allowed the orbital motion of the lens system to be detected. Combining the parallax with the Einstein radius, we were able to derive the distance to the lens, DL = 2.8 ± 0.4 kpc, and the masses of the lensing objects. The primary of the lens is an M-dwarf with M L, 1 = 0.16 ± 0.03 M , while the companion has M L, 2 = 11.0 ± 2.0 M J, putting it in the boundary zone between planets and brown dwarfs. Title: Microlensing Binaries with Candidate Brown Dwarf Companions Authors: Shin, I. -G.; Han, C.; Gould, A.; Udalski, A.; Sumi, T.; Dominik, M.; Beaulieu, J. -P.; Tsapras, Y.; Bozza, V.; Szymański, M. K.; Kubiak, M.; Soszyński, I.; Pietrzyński, G.; Poleski, R.; Ulaczyk, K.; Pietrukowicz, P.; Kozłowski, S.; Skowron, J.; Wyrzykowski, Ł.; OGLE Collaboration; Abe, F.; Bennett, D. P.; Bond, I. A.; Botzler, C. S.; Freeman, M.; Fukui, A.; Furusawa, K.; Hayashi, F.; Hearnshaw, J. B.; Hosaka, S.; Itow, Y.; Kamiya, K.; Kilmartin, P. M.; Kobara, S.; Korpela, A.; Lin, W.; Ling, C. H.; Makita, S.; Masuda, K.; Matsubara, Y.; Miyake, N.; Muraki, Y.; Nagaya, M.; Nishimoto, K.; Ohnishi, K.; Okumura, T.; Omori, K.; Perrott, Y. C.; Rattenbury, N.; Saito, To.; Skuljan, L.; Sullivan, D. J.; Suzuki, D.; Sweatman, W. L.; Tristram, P. J.; Wada, K.; Yock, P. C. M.; MOA Collaboration; Christie, G. W.; Depoy, D. L.; Dong, S.; Gal-Yam, A.; Gaudi, B. S.; Hung, L. -W.; Janczak, J.; Kaspi, S.; Maoz, D.; McCormick, J.; McGregor, D.; Moorhouse, D.; Muñoz, J. A.; Natusch, T.; Nelson, C.; Pogge, R. W.; Tan, T. -G.; Polishook, D.; Shvartzvald, Y.; Shporer, A.; Thornley, G.; Malamud, U.; Yee, J. C.; Choi, J. -Y.; Jung, Y. -K.; Park, H.; Lee, C. -U.; Park, B. -G.; Koo, J. -R.; μFUN Collaboration; Bajek, D.; Bramich, D. M.; Browne, P.; Horne, K.; Ipatov, S.; Snodgrass, C.; Steele, I.; Street, R.; Alsubai, K. A.; Burgdorf, M. J.; Calchi Novati, S.; Dodds, P.; Dreizler, S.; Fang, X. -S.; Grundahl, F.; Gu, C. -H.; Hardis, S.; Harpsøe, K.; Hinse, T. C.; Hundertmark, M.; Jessen-Hansen, J.; Jørgensen, U. G.; Kains, N.; Kerins, E.; Liebig, C.; Lund, M.; Lundkvist, M.; Mancini, L.; Mathiasen, M.; Hornstrup, A.; Penny, M. T.; Proft, S.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Skottfelt, J.; Southworth, J.; Surdej, J.; Tregloan-Reed, J.; Wertz, O.; Zimmer, F.; Albrow, M. D.; Batista, V.; Brillant, S.; Caldwell, J. A. R.; Calitz, J. J.; Cassan, A.; Cole, A.; Cook, K. H.; Corrales, E.; Coutures, Ch.; Dieters, S.; Dominis Prester, D.; Donatowicz, J.; Fouqué, P.; Greenhill, J.; Hill, K.; Hoffman, M.; Kane, S. R.; Kubas, D.; Marquette, J. -B.; Martin, R.; Meintjes, P.; Menzies, J.; Pollard, K. R.; Sahu, K. C.; Wambsganss, J.; Williams, A.; Vinter, C.; Zub, M. Bibcode: 2012ApJ...760..116S Altcode: 2012arXiv1208.2323S Brown dwarfs are important objects because they may provide a missing link between stars and planets, two populations that have dramatically different formation histories. In this paper, we present the candidate binaries with brown dwarf companions that are found by analyzing binary microlensing events discovered during the 2004-2011 observation seasons. Based on the low mass ratio criterion of q < 0.2, we found seven candidate events: OGLE-2004-BLG-035, OGLE-2004-BLG-039, OGLE-2007-BLG-006, OGLE-2007-BLG-399/MOA-2007-BLG-334, MOA-2011-BLG-104/OGLE-2011-BLG-0172, MOA-2011-BLG-149, and MOA-201-BLG-278/OGLE-2011-BLG-012N. Among them, we are able to confirm that the companions of the lenses of MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149 are brown dwarfs by determining the mass of the lens based on the simultaneous measurement of the Einstein radius and the lens parallax. The measured masses of the brown dwarf companions are 0.02 ± 0.01 M and 0.019 ± 0.002 M for MOA-2011-BLG-104/OGLE-2011-BLG-0172 and MOA-2011-BLG-149, respectively, and both companions are orbiting low-mass M dwarf host stars. More microlensing brown dwarfs are expected to be detected as the number of lensing events with well-covered light curves increases with new-generation searches. Title: TMAP: Tübingen NLTE Model-Atmosphere Package Authors: Werner, Klaus; Dreizler, Stefan; Rauch, Thomas Bibcode: 2012ascl.soft12015W Altcode: The Tübingen NLTE Model-Atmosphere Package (TMAP) is a tool to calculate stellar atmospheres in spherical or plane-parallel geometry in hydrostatic and radiative equilibrium allowing departures from local thermodynamic equilibrium (LTE) for the population of atomic levels. It is based on the Accelerated Lambda Iteration (ALI) method and is able to account for line blanketing by metals. All elements from hydrogen to nickel may be included in the calculation with model atoms which are tailored for the aims of the user. Title: A brown dwarf orbiting an M-dwarf: MOA 2009-BLG-411L Authors: Bachelet, E.; Fouqué, P.; Han, C.; Gould, A.; Albrow, M. D.; Beaulieu, J. -P.; Bertin, E.; Bond, I. A.; Christie, G. W.; Heyrovský, D.; Horne, K.; Jørgensen, U. G.; Maoz, D.; Mathiasen, M.; Matsunaga, N.; McCormick, J.; Menzies, J.; Nataf, D.; Natusch, T.; Oi, N.; Renon, N.; Tsapras, Y.; Udalski, A.; Yee, J. C.; Batista, V.; Bennett, D. P.; Brillant, S.; Caldwell, J. A. R.; Cassan, A.; Cole, A.; Cook, K. H.; Coutures, C.; Dieters, S.; Dominik, M.; Dominis Prester, D.; Donatowicz, J.; Greenhill, J.; Kains, N.; Kane, S. R.; Marquette, J. -B.; Martin, R.; Pollard, K. R.; Sahu, K. C.; Street, R. A.; Wambsganss, J.; Williams, A.; Zub, M.; PLANET Collaboration; Bos, M.; Dong, Subo; Drummond, J.; Gaudi, B. S.; Graff, D.; Janczak, J.; Kaspi, S.; Kozłowski, S.; Lee, C. -U.; Monard, L. A. G.; Muñoz, J. A.; Park, B. -G.; Pogge, R. W.; Polishook, D.; Shporer, A.; Fun Collaboration; Abe, F.; Botzler, C. S.; Fukui, A.; Furusawa, K.; Hearnshaw, J. B.; Itow, Y.; Korpela, A. V.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Miyake, N.; Muraki, Y.; Ohnishi, K.; Rattenbury, N. J.; Saito, To.; Sullivan, D.; Sumi, T.; Suzuki, D.; Sweatman, W. L.; Tristram, P. J.; Wada, K.; MOA Collaboration; Allan, A.; Bode, M. F.; Bramich, D. M.; Clay, N.; Fraser, S. N.; Hawkins, E.; Kerins, E.; Lister, T. A.; Mottram, C. J.; Saunders, E. S.; Snodgrass, C.; Steele, I. A.; Wheatley, P. J.; ROBONET-II Collaboration; Bozza, V.; Browne, P.; Burgdorf, M. J.; Calchi Novati, S.; Dreizler, S.; Finet, F.; Glitrup, M.; Grundahl, F.; HarpsøE, K.; Hessman, F. V.; Hinse, T. C.; Hundertmark, M.; Liebig, C.; Maier, G.; Mancini, L.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Skottfelt, J.; Southworth, J.; Surdej, J.; Zimmer, F.; Mindstep Consortium Bibcode: 2012A&A...547A..55B Altcode: Context. Caustic crossing is the clearest signature of binary lenses in microlensing. In the present context, this signature is diluted by the large source star but a detailed analysis has allowed the companion signal to be extracted.
Aims: MOA 2009-BLG-411 was detected on August 5, 2009 by the MOA-Collaboration. Alerted as a high-magnification event, it was sensitive to planets. Suspected anomalies in the light curve were not confirmed by a real-time model, but further analysis revealed small deviations from a single lens extended source fit.
Methods: Thanks to observations by all the collaborations, this event was well monitored. We first decided to characterize the source star properties by using a more refined method than the classical one: we measure the interstellar absorption along the line of sight in five different passbands (VIJHK). Secondly, we model the lightcurve by using the standard technique: make (s,q,α) grids to look for local minima and refine the results by using a downhill method (Markov chain Monte Carlo). Finally, we use a Galactic model to estimate the physical properties of the lens components.
Results: We find that the source star is a giant G star with radius 9 R. The grid search gives two local minima, which correspond to the theoretical degeneracy s ≡ s-1. We find that the lens is composed of a brown dwarf secondary of mass MS = 0.05 M orbiting a primary M-star of mass MP = 0.18 M. We also reveal a new mass-ratio degeneracy for the central caustics of close binaries.
Conclusions: As far as we are aware, this is the first detection using the microlensing technique of a binary system in our Galaxy composed of an M-star and a brown dwarf.

Appendix is available in electronic form at http://www.aanda.org Title: High-precision photometry by telescope defocusing - IV. Confirmation of the huge radius of WASP-17 b Authors: Southworth, John; Hinse, T. C.; Dominik, M.; Fang, X. -S.; Harpsøe, K.; Jørgensen, U. G.; Kerins, E.; Liebig, C.; Mancini, L.; Skottfelt, J.; Anderson, D. R.; Smalley, B.; Tregloan-Reed, J.; Wertz, O.; Alsubai, K. A.; Bozza, V.; Calchi Novati, S.; Dreizler, S.; Gu, S. -H.; Hundertmark, M.; Jessen-Hansen, J.; Kains, N.; Kjeldsen, H.; Lund, M. N.; Lundkvist, M.; Mathiasen, M.; Penny, M. T.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Snodgrass, C.; Surdej, J. Bibcode: 2012MNRAS.426.1338S Altcode: 2012arXiv1207.5797S We present photometric observations of four transits in the WASP-17 planetary system, obtained using telescope defocusing techniques and with scatters reaching 0.5 mmag per point. Our revised orbital period is 4.0 ± 0.6 s longer than previous measurements, a difference of 6.6σ, and does not support the published detections of orbital eccentricity in this system. We model the light curves using the JKTEBOP code and calculate the physical properties of the system by recourse to five sets of theoretical stellar model predictions. The resulting planetary radius, Rb = 1.932 ± 0.052 ± 0.010 RJup (statistical and systematic errors, respectively), provides confirmation that WASP-17 b is the largest planet currently known. All 14 planets with radii measured to be greater than 1.6 RJup are found around comparatively hot (Teff > 5900 K) and massive (MA > 1.15 M) stars. Chromospheric activity indicators are available for eight of these stars, and all imply a low activity level. The planets have small or zero orbital eccentricities, so tidal effects struggle to explain their large radii. The observed dearth of large planets around small stars may be natural but could also be due to observational biases against deep transits, if these are mistakenly labelled as false positives and so not followed up. Based on data collected by MiNDSTEp with the Danish 1.54-m telescope at the ESO La Silla Observatory.Royal Society University Research Fellow. Title: A New Type of Ambiguity in the Planet and Binary Interpretations of Central Perturbations of High-magnification Gravitational Microlensing Events Authors: Choi, J. -Y.; Shin, I. -G.; Han, C.; Udalski, A.; Sumi, T.; Gould, A.; Bozza, V.; Dominik, M.; Fouqué, P.; Horne, K.; Szymański, M. K.; Kubiak, M.; Soszyński, I.; Pietrzyński, G.; Poleski, R.; Ulaczyk, K.; Pietrukowicz, P.; Kozłowski, S.; Skowron, J.; Wyrzykowski, Ł.; OGLE Collaboration; Abe, F.; Bennett, D. P.; Bond, I. A.; Botzler, C. S.; Chote, P.; Freeman, M.; Fukui, A.; Furusawa, K.; Itow, Y.; Kobara, S.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Miyake, N.; Muraki, Y.; Ohmori, K.; Ohnishi, K.; Rattenbury, N. J.; Saito, To.; Sullivan, D. J.; Suzuki, D.; Suzuki, K.; Sweatman, W. L.; Takino, S.; Tristram, P. J.; Wada, K.; Yock, P. C. M.; MOA Collaboration; Bramich, D. M.; Snodgrass, C.; Steele, I. A.; Street, R. A.; Tsapras, Y.; RoboNet Collaboration; Alsubai, K. A.; Browne, P.; Burgdorf, M. J.; Calchi Novati, S.; Dodds, P.; Dreizler, S.; Fang, X. -S.; Grundahl, F.; Gu, C. -H.; Hardis, S.; Harpsøe, K.; Hinse, T. C.; Hornstrup, A.; Hundertmark, M.; Jessen-Hansen, J.; Jørgensen, U. G.; Kains, N.; Kerins, E.; Liebig, C.; Lund, M.; Lunkkvist, M.; Mancini, L.; Mathiasen, M.; Penny, M. T.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Skottfelt, J.; Southworth, J.; Surdej, J.; Tregloan-Reed, J.; Wambsganss, J.; Wertz, O.; MiNDSTEp Consortium; Almeida, L. A.; Batista, V.; Christie, G.; DePoy, D. L.; Dong, Subo; Gaudi, B. S.; Henderson, C.; Jablonski, F.; Lee, C. -U.; McCormick, J.; McGregor, D.; Moorhouse, D.; Natusch, T.; Ngan, H.; Pogge, R. W.; Tan, T. -G.; Thornley, G.; Yee, J. C.; μFUN Collaboration; Albrow, M. D.; Bachelet, E.; Beaulieu, J. -P.; Brillant, S.; Cassan, A.; Cole, A. A.; Corrales, E.; Coutures, C.; Dieters, S.; Dominis Prester, D.; Donatowicz, J.; Greenhill, J.; Kubas, D.; Marquette, J. -B.; Menzies, J. W.; Sahu, K. C.; Zub, M.; PLANET Collaboration Bibcode: 2012ApJ...756...48C Altcode: 2012arXiv1204.4789C High-magnification microlensing events provide an important channel to detect planets. Perturbations near the peak of a high-magnification event can be produced either by a planet or a binary companion. It is known that central perturbations induced by both types of companions can be generally distinguished due to the essentially different magnification pattern around caustics. In this paper, we present a case of central perturbations for which it is difficult to distinguish the planetary and binary interpretations. The peak of a lensing light curve affected by this perturbation appears to be blunt and flat. For a planetary case, this perturbation occurs when the source trajectory passes the negative perturbation region behind the back end of an arrowhead-shaped central caustic. For a binary case, a similar perturbation occurs for a source trajectory passing through the negative perturbation region between two cusps of an astroid-shaped caustic. We demonstrate the degeneracy for two high-magnification events of OGLE-2011-BLG-0526 and OGLE-2011-BLG-0950/MOA-2011-BLG-336. For OGLE-2011-BLG-0526, the χ2 difference between the planetary and binary model is ~3, implying that the degeneracy is very severe. For OGLE-2011-BLG-0950/MOA-2011-BLG-336, the stellar binary model is formally excluded with Δχ2 ~ 105 and the planetary model is preferred. However, it is difficult to claim a planet discovery because systematic residuals of data from the planetary model are larger than the difference between the planetary and binary models. Considering that two events observed during a single season suffer from such a degeneracy, it is expected that central perturbations experiencing this type of degeneracy is common. Title: CARMENES. I: instrument and survey overview Authors: Quirrenbach, Andreas; Amado, Pedro J.; Seifert, Walter; Sánchez Carrasco, Miguel A.; Mandel, Holger; Caballero, Jose A.; Mundt, Reinhard; Ribas, Ignasi; Reiners, Ansgar; Abril, Miguel; Aceituno, Jesus; Alonso-Floriano, Javier; Ammler-von Eiff, Matthias; Anglada-Escude, Guillem; Antona Jiménez, Regina; Anwand-Heerwart, Heiko; Barrado y Navascués, David; Becerril, Santiago; Bejar, Victor; Benitez, Daniel; Cardenas, Concepcion; Claret, Antonio; Colome, Josep; Cortés-Contreras, Miriam; Czesla, Stefan; del Burgo, Carlos; Doellinger, Michaela; Dorda, R.; Dreizler, Stefan; Feiz, Carmen; Fernandez, Matilde; Galadi, David; Garrido, Rafael; González Hernández, Jonay; Guardia, Josep; Guenther, Eike; de Guindos, Enrique; Gutiérrez-Soto, Juan; Hagen, Hans J.; Hatzes, Artie; Hauschildt, Peter; Helmling, Jens; Henning, Thomas; Herrero, Enrique; Huber, Armin; Huber, Klaus; Jeffers, Sandra; Joergens, Viki; de Juan, Enrique; Kehr, M.; Klutsch, Alexis; Kürster, Martin; Lalitha, S.; Laun, Werner; Lemke, Ulrike; Lenzen, Rainer; Lizon, Jean-Louis; López del Fresno, Mauro; López-Morales, Mercedes; López-Santiago, Javier; Mall, Ulrich; Martin, Eduardo; Martín-Ruiz, Susana; Mirabet, Eduard; Montes, David; Morales, Juan Carlos; Morales Muñoz, Rafael; Moya, Andres; Naranjo, Vianak; Oreiro, Raquel; Pérez Medialdea, David; Pluto, Michael; Rabaza, Ovidio; Ramon, Alejandro; Rebolo, Rafael; Reffert, Sabine; Rhode, Petra; Rix, Hans-Walter; Rodler, Florian; Rodríguez, Eloy; Rodríguez López, Cristina; Rodríguez Pérez, Emilio; Rodriguez Trinidad, A.; Rohloff, Ralf-Reiner; Sánchez-Blanco, Ernesto; Sanz-Forcada, Jorge; Schäfer, Sebastian; Schiller, Jörg; Schmidt, Christof; Schmitt, Jürgen; Solano, Enrique; Stahl, Otmar; Storz, Clemens; Stürmer, Julian; Suarez, Juan Carlos; Thiele, Ulrich; Ulbrich, Rainer; Vidal-Dasilva, Manuela; Wagner, Karl; Winkler, Johannes; Xu, Wenli; Zapatero Osorio, Maria Rosa; Zechmeister, Mathias Bibcode: 2012SPIE.8446E..0RQ Altcode: CARMENES (Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs) is a next-generation instrument for the 3.5m telescope at the Calar Alto Observatory, built by a consortium of eleven Spanish and German institutions. The CARMENES instrument consists of two separate échelle spectrographs covering the wavelength range from 0.55 μm to 1.7 μm at a spectral resolution of R = 82, 000, fed by fibers from the Cassegrain focus of the telescope. Both spectrographs are housed in temperature-stabilized vacuum tanks, to enable a long-term 1 m/s radial velocity precision employing a simultaneous calibration with Th-Ne and U-Ne emission line lamps. CARMENES has been optimized for a search for terrestrial planets in the habitable zones (HZs) of low-mass stars, which may well provide our first chance to study environments capable of supporting the development of life outside the Solar System. With its unique combination of optical and near-infrared ´echelle spectrographs, CARMENES will provide better sensitivity for the detection of low-mass planets than any comparable instrument, and a powerful tool for discriminating between genuine planet detections and false positives caused by stellar activity. The CARMENES survey will target 300 M dwarfs in the 2014 to 2018 time frame. Title: CARMENES. II: optical and opto-mechanical design Authors: Seifert, W.; Sánchez Carrasco, M. A.; Xu, W.; Cárdenas, M. C.; Sánchez-Blanco, E.; Becerril, S.; Feiz, C.; Ramón, A.; Dreizler, S.; Rohde, P.; Quirrenbach, A.; Amado, P. J.; Ribas, I.; Reiners, A.; Mandel, H.; Caballero, J. A. Bibcode: 2012SPIE.8446E..33S Altcode: CARMENES is a fiber-fed high-resolution échelle spectrograph for the Calar Alto 3.5m telescope. The instrument is built by a German-Spanish consortium under the lead of the Landessternwarte Heidelberg. The search for planets around M dwarfs with a radial velocity accuracy of 1 m/s is the main focus of the planned science. Two channels, one for the visible, another for the near-infrared, will allow observations in the complete wavelength range from 550 to 1700 nm. To ensure the stability, the instrument is working in vacuum in a thermally controlled environment. The optical design of both channels of the instrument and the front-end, as well as the opto-mechanical design, are described. Title: Characterizing Low-mass Binaries from Observation of Long-timescale Caustic-crossing Gravitational Microlensing Events Authors: Shin, I. -G.; Han, C.; Choi, J. -Y.; Udalski, A.; Sumi, T.; Gould, A.; Bozza, V.; Dominik, M.; Fouqué, P.; Horne, K.; Szymański, M. K.; Kubiak, M.; Soszyński, I.; Pietrzyński, G.; Poleski, R.; Ulaczyk, K.; Pietrukowicz, P.; Kozłowski, S.; Skowron, J.; Wyrzykowski, Ł.; OGLE Collaboration; Abe, F.; Bennett, D. P.; Bond, I. A.; Botzler, C. S.; Chote, P.; Freeman, M.; Fukui, A.; Furusawa, K.; Itow, Y.; Kobara, S.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Miyake, N.; Muraki, Y.; Ohmori, K.; Ohnishi, K.; Rattenbury, N. J.; Saito, To.; Sullivan, D. J.; Suzuki, D.; Suzuki, K.; Sweatman, W. L.; Takino, S.; Tristram, P. J.; Wada, K.; Yock, P. C. M.; MOA Collaboration; Bramich, D. M.; Snodgrass, C.; Steele, I. A.; Street, R. A.; Tsapras, Y.; RoboNet Collaboration; Alsubai, K. A.; Browne, P.; Burgdorf, M. J.; Calchi Novati, S.; Dodds, P.; Dreizler, S.; Fang, X. -S.; Grundahl, F.; Gu, C. -H.; Hardis, S.; Harpsøe, K.; Hinse, T. C.; Hornstrup, A.; Hundertmark, M.; Jessen-Hansen, J.; Jørgensen, U. G.; Kains, N.; Kerins, E.; Liebig, C.; Lund, M.; Lunkkvist, M.; Mancini, L.; Mathiasen, M.; Penny, M. T.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Skottfelt, J.; Southworth, J.; Surdej, J.; Tregloan-Reed, J.; Wambsganss, J.; Wertz, O.; MiNDSTEp Consortium; Almeida, L. A.; Batista, V.; Christie, G.; DePoy, D. L.; Dong, Subo; Gaudi, B. S.; Henderson, C.; Jablonski, F.; Lee, C. -U.; McCormick, J.; McGregor, D.; Moorhouse, D.; Natusch, T.; Ngan, H.; Park, S. -Y.; Pogge, R. W.; Tan, T. -G.; Thornley, G.; Yee, J. C.; μFUN Collaboration; Albrow, M. D.; Bachelet, E.; Beaulieu, J. -P.; Brillant, S.; Cassan, A.; Cole, A. A.; Corrales, E.; Coutures, C.; Dieters, S.; Dominis Prester, D.; Donatowicz, J.; Greenhill, J.; Kubas, D.; Marquette, J. -B.; Menzies, J. W.; Sahu, K. C.; Zub, M.; PLANET Collaboration Bibcode: 2012ApJ...755...91S Altcode: 2012arXiv1204.2869S Despite the astrophysical importance of binary star systems, detections are limited to those located in small ranges of separations, distances, and masses and thus it is necessary to use a variety of observational techniques for a complete view of stellar multiplicity across a broad range of physical parameters. In this paper, we report the detections and measurements of two binaries discovered from observations of microlensing events MOA-2011-BLG-090 and OGLE-2011-BLG-0417. Determinations of the binary masses are possible by simultaneously measuring the Einstein radius and the lens parallax. The measured masses of the binary components are 0.43 M and 0.39 M for MOA-2011-BLG-090 and 0.57 M and 0.17 M for OGLE-2011-BLG-0417 and thus both lens components of MOA-2011-BLG-090 and one component of OGLE-2011-BLG-0417 are M dwarfs, demonstrating the usefulness of microlensing in detecting binaries composed of low-mass components. From modeling of the light curves considering full Keplerian motion of the lens, we also measure the orbital parameters of the binaries. The blended light of OGLE-2011-BLG-0417 comes very likely from the lens itself, making it possible to check the microlensing orbital solution by follow-up radial-velocity observation. For both events, the caustic-crossing parts of the light curves, which are critical for determining the physical lens parameters, were resolved by high-cadence survey observations and thus it is expected that the number of microlensing binaries with measured physical parameters will increase in the future. Title: MOA 2010-BLG-477Lb: Constraining the Mass of a Microlensing Planet from Microlensing Parallax, Orbital Motion, and Detection of Blended Light Authors: Bachelet, E.; Shin, I. -G.; Han, C.; Fouqué, P.; Gould, A.; Menzies, J. W.; Beaulieu, J. -P.; Bennett, D. P.; Bond, I. A.; Dong, Subo; Heyrovský, D.; Marquette, J. -B.; Marshall, J.; Skowron, J.; Street, R. A.; Sumi, T.; Udalski, A.; Abe, L.; Agabi, K.; Albrow, M. D.; Allen, W.; Bertin, E.; Bos, M.; Bramich, D. M.; Chavez, J.; Christie, G. W.; Cole, A. A.; Crouzet, N.; Dieters, S.; Dominik, M.; Drummond, J.; Greenhill, J.; Guillot, T.; Henderson, C. B.; Hessman, F. V.; Horne, K.; Hundertmark, M.; Johnson, J. A.; Jørgensen, U. G.; Kandori, R.; Liebig, C.; Mékarnia, D.; McCormick, J.; Moorhouse, D.; Nagayama, T.; Nataf, D.; Natusch, T.; Nishiyama, S.; Rivet, J. -P.; Sahu, K. C.; Shvartzvald, Y.; Thornley, G.; Tomczak, A. R.; Tsapras, Y.; Yee, J. C.; Batista, V.; Bennett, C. S.; Brillant, S.; Caldwell, J. A. R.; Cassan, A.; Corrales, E.; Coutures, C.; Dominis Prester, D.; Donatowicz, J.; Kubas, D.; Martin, R.; Williams, A.; Zub, M.; PLANET Collaboration; de Almeida, L. Andrade; DePoy, D. L.; Gaudi, B. S.; Hung, L. -W.; Jablonski, F.; Kaspi, S.; Klein, N.; Lee, C. -U.; Lee, Y.; Koo, J. -R.; Maoz, D.; Muñoz, J. A.; Pogge, R. W.; Polishook, D.; Shporer, A.; μFUN Collaboration; Abe, F.; Botzler, C. S.; Chote, P.; Freeman, M.; Fukui, A.; Furusawa, K.; Harris, P.; Itow, Y.; Kobara, S.; Ling, C. H.; Masuda, K.; Matsubara, Y.; Miyake, N.; Ohmori, K.; Ohnishi, K.; Rattenbury, N. J.; Saito, To.; Sullivan, D. J.; Suzuki, D.; Sweatman, W. L.; Tristram, P. J.; Wada, K.; Yock, P. C. M.; MOA Collaboration; Szymański, M. K.; Soszyński, I.; Kubiak, M.; Poleski, R.; Ulaczyk, K.; Pietrzyński, G.; Wyrzykowski, Ł.; OGLE Collaboration; Kains, N.; Snodgrass, C.; Steele, I. A.; RoboNet Collaboration; Alsubai, K. A.; Bozza, V.; Browne, P.; Burgdorf, M. J.; Calchi Novati, S.; Dodds, P.; Dreizler, S.; Finet, F.; Gerner, T.; Hardis, S.; Harpsøe, K.; Hinse, T. C.; Kerins, E.; Mancini, L.; Mathiasen, M.; Penny, M. T.; Proft, S.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Schäfer, S.; Schönebeck, F.; Southworth, J.; Surdej, J.; Wambsganss, J.; MiNDSTEp Consortium Bibcode: 2012ApJ...754...73B Altcode: 2012arXiv1205.6323B Microlensing detections of cool planets are important for the construction of an unbiased sample to estimate the frequency of planets beyond the snow line, which is where giant planets are thought to form according to the core accretion theory of planet formation. In this paper, we report the discovery of a giant planet detected from the analysis of the light curve of a high-magnification microlensing event MOA 2010-BLG-477. The measured planet-star mass ratio is q = (2.181 ± 0.004) × 10-3 and the projected separation is s = 1.1228 ± 0.0006 in units of the Einstein radius. The angular Einstein radius is unusually large θE = 1.38 ± 0.11 mas. Combining this measurement with constraints on the "microlens parallax" and the lens flux, we can only limit the host mass to the range 0.13 < M/M < 1.0. In this particular case, the strong degeneracy between microlensing parallax and planet orbital motion prevents us from measuring more accurate host and planet masses. However, we find that adding Bayesian priors from two effects (Galactic model and Keplerian orbit) each independently favors the upper end of this mass range, yielding star and planet masses of M * = 0.67+0.33 - 0.13 M and mp = 1.5+0.8 - 0.3 M JUP at a distance of D = 2.3 ± 0.6 kpc, and with a semi-major axis of a = 2+3 - 1 AU. Finally, we show that the lens mass can be determined from future high-resolution near-IR adaptive optics observations independently from two effects, photometric and astrometric. Title: The quest for companions to post-common envelope binaries. III. A reexamination of HW Virginis Authors: Beuermann, K.; Dreizler, S.; Hessman, F. V.; Deller, J. Bibcode: 2012A&A...543A.138B Altcode: 2012arXiv1206.3080B We report new mid-eclipse times of the short-period sdB/dM binary HW Virginis, which differ substantially from the times predicted by a previous model. The proposed orbits of the two planets in that model are found to be unstable. We present a new secularly stable solution, which involves two companions orbiting HW Vir with periods of 12.7 yr and 55 ± 15 yr. For orbits coplanar with the binary, the inner companion is a giant planet with mass M3 sin i3 ≃ 14 MJup and the outer one a brown dwarf or low-mass star with a mass of M4 sin i4 = 30-120 MJup. Using the mercury6 code, we find that such a system would be stable over more than 107 yr, in spite of the sizeable interaction. Our model fits the observed eclipse-time variations by the light-travel time effect alone, without invoking any additional process, and provides support for the planetary hypothesis of the eclipse-time variations in close binaries. The signature of non-Keplerian orbits may be visible in the data. Title: Characterizing Lenses and Lensed Stars of High-magnification Single-lens Gravitational Microlensing Events with Lenses Passing over Source Stars Authors: Choi, J. -Y.; Shin, I. -G.; Park, S. -Y.; Han, C.; Gould, A.; Sumi, T.; Udalski, A.; Beaulieu, J. -P.; Street, R.; Dominik, M.; Allen, W.; Almeida, L. A.; Bos, M.; Christie, G. W.; Depoy, D. L.; Dong, S.; Drummond, J.; Gal-Yam, A.; Gaudi, B. S.; Henderson, C. B.; Hung, L. -W.; Jablonski, F.; Janczak, J.; Lee, C. -U.; Mallia, F.; Maury, A.; McCormick, J.; McGregor, D.; Monard, L. A. G.; Moorhouse, D.; Muñoz, J. A.; Natusch, T.; Nelson, C.; Park, B. -G.; Pogge, R. W.; "TG" Tan, T. -G.; Thornley, G.; Yee, J. C.; μFUN Collaboration; Abe, F.; Barnard, E.; Baudry, J.; Bennett, D. P.; Bond, I. A.; Botzler, C. S.; Freeman, M.; Fukui, A.; Furusawa, K.; Hayashi, F.; Hearnshaw, J. B.; Hosaka, S.; Itow, Y.; Kamiya, K.; Kilmartin, P. M.; Kobara, S.; Korpela, A.; Lin, W.; Ling, C. H.; Makita, S.; Masuda, K.; Matsubara, Y.; Miyake, N.; Muraki, Y.; Nagaya, M.; Nishimoto, K.; Ohnishi, K.; Okumura, T.; Omori, K.; Perrott, Y. C.; Rattenbury, N.; Saito, To.; Skuljan, L.; Sullivan, D. J.; Suzuki, D.; Suzuki, K.; Sweatman, W. L.; Takino, S.; Tristram, P. J.; Wada, K.; Yock, P. C. M.; MOA Collaboration; Szymański, M. K.; Kubiak, M.; Pietrzyński, G.; Soszyński, I.; Poleski, R.; Ulaczyk, K.; Wyrzykowski, Ł.; Kozłowski, S.; Pietrukowicz, P.; OGLE Collaboration; Albrow, M. D.; Bachelet, E.; Batista, V.; Bennett, C. S.; Bowens-Rubin, R.; Brillant, S.; Cassan, A.; Cole, A.; Corrales, E.; Coutures, Ch.; Dieters, S.; Dominis Prester, D.; Donatowicz, J.; Fouqué, P.; Greenhill, J.; Kane, S. R.; Menzies, J.; Sahu, K. C.; Wambsganss, J.; Williams, A.; Zub, M.; PLANET Collaboration; Allan, A.; Bramich, D. M.; Browne, P.; Clay, N.; Fraser, S.; Horne, K.; Kains, N.; Mottram, C.; Snodgrass, C.; Steele, I.; Tsapras, Y.; RoboNet Collaboration; Alsubai, K. A.; Bozza, V.; Burgdorf, M. J.; Calchi Novati, S.; Dodds, P.; Dreizler, S.; Finet, F.; Gerner, T.; Glitrup, M.; Grundahl, F.; Hardis, S.; Harpsøe, K.; Hinse, T. C.; Hundertmark, M.; Jørgensen, U. G.; Kerins, E.; Liebig, C.; Maier, G.; Mancini, L.; Mathiasen, M.; Penny, M. T.; Proft, S.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Schäfer, S.; Schönebeck, F.; Skottfelt, J.; Surdej, J.; Southworth, J.; Zimmer, F.; MiNDSTEp Consortium Bibcode: 2012ApJ...751...41C Altcode: 2011arXiv1111.4032C We present the analysis of the light curves of nine high-magnification single-lens gravitational microlensing events with lenses passing over source stars, including OGLE-2004-BLG-254, MOA-2007-BLG-176, MOA-2007-BLG-233/OGLE-2007-BLG-302, MOA-2009-BLG-174, MOA-2010-BLG-436, MOA-2011-BLG-093, MOA-2011-BLG-274, OGLE-2011-BLG-0990/MOA-2011-BLG-300, and OGLE-2011-BLG-1101/MOA-2011-BLG-325. For all of the events, we measure the linear limb-darkening coefficients of the surface brightness profile of source stars by measuring the deviation of the light curves near the peak affected by the finite-source effect. For seven events, we measure the Einstein radii and the lens-source relative proper motions. Among them, five events are found to have Einstein radii of less than 0.2 mas, making the lenses very low mass star or brown dwarf candidates. For MOA-2011-BLG-274, especially, the small Einstein radius of θE ~ 0.08 mas combined with the short timescale of t E ~ 2.7 days suggests the possibility that the lens is a free-floating planet. For MOA-2009-BLG-174, we measure the lens parallax and thus uniquely determine the physical parameters of the lens. We also find that the measured lens mass of ~0.84 M is consistent with that of a star blended with the source, suggesting that the blend is likely to be the lens. Although we did not find planetary signals for any of the events, we provide exclusion diagrams showing the confidence levels excluding the existence of a planet as a function of the separation and mass ratio. Title: KIC 4247791: a SB4 system with two eclipsing binaries (2EBs). A quadruple system? Authors: Lehmann, H.; Zechmeister, M.; Dreizler, S.; Schuh, S.; Kanzler, R. Bibcode: 2012A&A...541A.105L Altcode: 2012arXiv1202.6552L Context. KIC 4247791 is an eclipsing binary observed by the Kepler satellite mission.
Aims: We wish to determine the nature of its components and in particular the origin of a shallow dip in its Kepler light curve that previous investigations have been unable to explain in a unique way.
Methods: We analyse newly obtained high-resolution spectra of the star using synthetic spectra based on atmosphere models, derive the radial velocities of the stellar components from cross-correlation with a synthetic template, and calculate the orbital solution. We use the JKTEBOP program to model the Kepler light curve of KIC 4247791.
Results: We find KIC 4247791 to be a SB4 star. The radial velocity variations of its four components can be explained by two separate eclipsing binaries. In contradiction to previous photometric findings, we show that the observed composite spectrum as well as the derived masses of all four of its components correspond to spectral type F.
Conclusions: The observed small dip in the light curve is not caused by a transit-like phenomenon but by the eclipses of the second binary system. We find evidence that KIC 4247791 might belong to the very rare hierarchical SB4 systems with two eclipsing binaries.

Based on observations with the 2-m Alfred-Jensch-Telescope of the Thüringer Landessternwarte Tautenburg. Title: VizieR Online Data Catalog: Planetary transit candidates in CoRoT LRa01 field (Carone+, 2012) Authors: Carone, L.; Gandolfi, D.; Cabrera, J.; Hatzes, A. P.; Deeg, H. J.; Csizmadia, Sz.; Paetzold, M.; Weingrill, J.; Aigrain, S.; Alonso, R.; Alapini, A.; Almenara, J. -M.; Auvergne, M.; Baglin, A.; Barge, P.; Bonomo, A. S.; Borde, P.; Bouchy, F.; Bruntt, H.; Carpano, S.; Cochran, W. D.; Deleuil, M.; Diaz, R. F.; Dreizler, S.; Dvorak, R.; Eisloeffel, J.; Eigmueller, P.; Endl, M.; Erikson, A.; Ferraz-Mello, S.; Fridlund, M.; Gazzano, J. -C.; Gibson, N.; Gillon, M.; Gondoin, P.; Grziwa, S.; Guenther, E. W.; Guillot, T.; Hartmann, M.; Havel, M.; Hebrard, G.; Jorda, L.; Kabath, P.; Leger, A.; Llebaria, A.; Lammer, H.; Lovis, C.; MacQueen, P. J.; Mayor, M.; Mazeh, T.; Moutou, C.; Nortmann, L.; Ofir, A.; Ollivier, M.; Parviainen, H.; Pepe, F.; Pont, F.; Queloz, D.; Rabus, M.; Rauer, H.; Regulo, C.; Renner, S.; de La, Reza R.; Rouan, D.; Santerne, A.; Samuel, B.; Schneider, J.; Shporer, A.; Stecklum, B.; Tal-Or, L.; Tingley, B.; Udry, S.; Wuchterl, G. Bibcode: 2012yCat..35380112C Altcode: 2012yCat..35389112C We present the list of planetary transit candidates from the CoRoT LRa01 star field in the Monoceros constellation toward the Galactic anti-center direction. The CoRoT observations of LRa01 lasted from 24 October 2007 to 3 March 2008.

We acquired and analyzed 7470 chromatic and 3938 monochromatic lightcurves. Instrumental noise and stellar variability were treated with several filtering tools by different teams from the CoRoT community. Different transit search algorithms were applied to the lightcurves.

(4 data files). Title: The quest for companions to post-common envelope binaries. II. NSVS14256825 and HS0705+6700 Authors: Beuermann, K.; Breitenstein, P.; Debski, B.; Diese, J.; Dubovsky, P. A.; Dreizler, S.; Hessman, F. V.; Hornoch, K.; Husser, T. -O.; Pojmanski, G.; Wolf, M.; Woźniak, P. R.; Zasche, P.; Denk, B.; Langer, M.; Wagner, C.; Wahrenberg, D.; Bollmann, T.; Habermann, F. N.; Haustovich, N.; Lauser, M.; Liebing, F.; Niederstadt, F. Bibcode: 2012A&A...540A...8B Altcode: 2012arXiv1202.5990B We report new mid-eclipse times of the two close binaries NSVS14256825 and HS0705+6700, harboring an sdB primary and a low-mass main-sequence secondary. Both objects display clear variations in their measured orbital period, which can be explained by the action of a third object orbiting the binary. If this interpretation is correct, the third object in NSVS14256825 is a giant planet with a mass of roughly 12 MJup. For HS0705+6700, we provide evidence that strengthens the case for the suggested periodic nature of the eclipse time variation and reduces the uncertainties in the parameters of the brown dwarf implied by that model. The derived period is 8.4 yr and the mass is 31 MJup, if the orbit is coplanar with the binary. This research is part of the PlanetFinders project, an ongoing collaboration between professional astronomers and student groups at high schools. Title: News of the MUSE Authors: Bacon, R.; Accardo, M.; Adjali, L.; Anwand, H.; Bauer, S. -M.; Blaizot, J.; Boudon, D.; Brinchmann, J.; Brotons, L.; Caillier, P.; Capoani, L.; Carollo, M.; Comin, M.; Contini, T.; Cumani, C.; Daguis, E.; Deiries, S.; Delabre, B.; Dreizler, S.; Dubois, J. -P.; Dupieux, M.; Dupuy, C.; Emsellem, E.; Fleischmann, A.; François, M.; Gallou, G.; Gharsa, T.; Girard, N.; Glindemann, A.; Guiderdoni, B.; Hahn, T.; Hansali, G.; Hofmann, D.; Jarno, A.; Kelz, A.; Kiekebusch, M.; Knudstrup, J.; Koehler, C.; Kollatschny, W.; Kosmalski, J.; Laurent, F.; Le Floch, M.; Lilly, S.; Lizon à L'Allemand, J. -L.; Loupias, M.; Manescau, A.; Monstein, C.; Nicklas, H.; Niemeyer, J.; Olaya, J. -C.; Palsa, R.; Parès, L.; Pasquini, L.; Pécontal-Rousset, A.; Pello, R.; Petit, C.; Piqueras, L.; Popow, E.; Reiss, R.; Remillieux, A.; Renault, E.; Rhode, P.; Richard, J.; Roth, J.; Rupprecht, G.; Schaye, J.; Slezak, E.; Soucail, G.; Steinmetz, M.; Streicher, O.; Stuik, R.; Valentin, H.; Vernet, J.; Weilbacher, P.; Wisotzki, L.; Yerle, N.; Zins, G. Bibcode: 2012Msngr.147....4B Altcode: We report on progress of the Multi Unit Spectroscopic Explorer (MUSE), a second generation VLT panoramic integral field spectrograph. MUSE is now in its final phase of integration, testing and validation in Europe. The instrument is described and some results of its measured performance are shown. Title: Microlensing Binaries Discovered through High-magnification Channel Authors: Shin, I. -G.; Choi, J. -Y.; Park, S. -Y.; Han, C.; Gould, A.; Sumi, T.; Udalski, A.; Beaulieu, J. -P.; Dominik, M.; Allen, W.; Bos, M.; Christie, G. W.; Depoy, D. L.; Dong, S.; Drummond, J.; Gal-Yam, A.; Gaudi, B. S.; Hung, L. -W.; Janczak, J.; Kaspi, S.; Lee, C. -U.; Mallia, F.; Maoz, D.; Maury, A.; McCormick, J.; Monard, L. A. G.; Moorhouse, D.; Muñoz, J. A.; Natusch, T.; Nelson, C.; Park, B. -G.; Pogge, R. W.; Polishook, D.; Shvartzvald, Y.; Shporer, A.; Thornley, G.; Yee, J. C.; μFUN Collaboration; Abe, F.; Bennett, D. P.; Bond, I. A.; Botzler, C. S.; Fukui, A.; Furusawa, K.; Hayashi, F.; Hearnshaw, J. B.; Hosaka, S.; Itow, Y.; Kamiya, K.; Kilmartin, P. M.; Kobara, S.; Korpela, A.; Lin, W.; Ling, C. H.; Makita, S.; Masuda, K.; Matsubara, Y.; Miyake, N.; Muraki, Y.; Nagaya, M.; Nishimoto, K.; Ohnishi, K.; Okumura, T.; Omori, K.; Perrott, Y. C.; Rattenbury, N.; Saito, To.; Skuljan, L.; Sullivan, D. J.; Suzuki, D.; Sweatman, W. L.; Tristram, P. J.; Wada, K.; Yock, P. C. M.; MOA Collaboration; Szymański, M. K.; Kubiak, M.; Pietrzyński, G.; Soszyński, I.; Poleski, R.; Ulaczyk, K.; Wyrzykowski, Ł.; Kozłowski, S.; Pietrukowicz, P.; OGLE Collaboration; Albrow, M. D.; Batista, V.; Bramich, D. M.; Brillant, S.; Caldwell, J. A. R.; Calitz, J. J.; Cassan, A.; Cole, A.; Cook, K. H.; Corrales, E.; Coutures, Ch.; Dieters, S.; Dominis Prester, D.; Donatowicz, J.; Fouqué, P.; Greenhill, J.; Hoffman, M.; Jørgensen, U. G.; Kane, S. R.; Kubas, D.; Marquette, J. -B.; Martin, R.; Meintjes, P.; Menzies, J.; Pollard, K. R.; Sahu, K. C.; Wambsganss, J.; Williams, A.; Vinter, C.; Zub, M.; PLANET Collaboration; Allan, A.; Browne, P.; Horne, K.; Snodgrass, C.; Steele, I.; Street, R.; Tsapras, Y.; RoboNet Collaboration; Alsubai, K. A.; Bozza, V.; Browne, P.; Burgdorf, M. J.; Calchi Novati, S.; Dodds, P.; Dreizler, S.; Finet, F.; Gerner, T.; Glitrup, M.; Grundahl, F.; Hardis, S.; Harpsøe, K.; Hessman, F. V.; Hinse, T. C.; Hundertmark, M.; Kains, N.; Kerins, E.; Liebig, C.; Maier, G.; Mancini, L.; Mathiasen, M.; Penny, M. T.; Proft, S.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Schäfer, S.; Schönebeck, F.; Skottfelt, J.; Surdej, J.; Southworth, J.; Zimmer, F.; MiNDSTEp Consortium Bibcode: 2012ApJ...746..127S Altcode: 2011arXiv1109.3295S Microlensing can provide a useful tool to probe binary distributions down to low-mass limits of binary companions. In this paper, we analyze the light curves of eight binary-lensing events detected through the channel of high-magnification events during the seasons from 2007 to 2010. The perturbations, which are confined near the peak of the light curves, can be easily distinguished from the central perturbations caused by planets. However, the degeneracy between close and wide binary solutions cannot be resolved with a 3σ confidence level for three events, implying that the degeneracy would be an important obstacle in studying binary distributions. The dependence of the degeneracy on the lensing parameters is consistent with a theoretical prediction that the degeneracy becomes severe as the binary separation and the mass ratio deviate from the values of resonant caustics. The measured mass ratio of the event OGLE-2008-BLG-510/MOA-2008-BLG-369 is q ~ 0.1, making the companion of the lens a strong brown dwarf candidate. Title: The quest for companions to post-common envelope binaries. I. Searching a sample of stars from the CSS and SDSS Authors: Backhaus, U.; Bauer, S.; Beuermann, K.; Diese, J.; Dreizler, S.; Hessman, F. V.; Husser, T. -O.; Klapdohr, K. -H.; Möllmanns, J.; Schünecke, R.; Dette, J.; Dubbert, J.; Miosga, T.; Rochus Vogel, A. L.; Simons, S.; Biriuk, S.; Debrah, M.; Griemens, M.; Hahn, A.; Möller, T.; Pawlowski, M.; Schweizer, M.; Speck, A. -L.; Zapros, C.; Bollmann, T.; Habermann, F. N.; Haustovich, N.; Lauser, M.; Liebing, F.; Niederstadt, F.; Hoppen, K.; Kindermann, D.; Küppers, F.; Rauch, B.; Althoff, F.; Horstmann, M.; Kellerman, J. N.; Kietz, R.; Nienaber, T.; Sauer, M.; Secci, A.; Wüllner, L. Bibcode: 2012A&A...538A..84B Altcode: 2012arXiv1201.2098B As part of an ongoing collaboration between student groups at high schools and professional astronomers, we have searched for the presence of circum-binary planets in a bona-fide unbiased sample of twelve post-common envelope binaries (PCEBs) from the Catalina Sky Survey (CSS) and the Sloan Digital Sky Survey (SDSS). Although the present ephemerides are significantly more accurate than previous ones, we find no clear evidence for orbital period variations between 2005 and 2011 or during the 2011 observing season. The sparse long-term coverage still permits O-C variations with a period of years and an amplitude of tens of seconds, as found in other systems. Our observations provide the basis for future inferences about the frequency with which planet-sized or brown-dwarf companions have either formed in these evolved systems or survived the common envelope (CE) phase. Title: Planetary transit candidates in the CoRoT LRa01 field Authors: Carone, L.; Gandolfi, D.; Cabrera, J.; Hatzes, A. P.; Deeg, H. J.; Csizmadia, Sz.; Pätzold, M.; Weingrill, J.; Aigrain, S.; Alonso, R.; Alapini, A.; Almenara, J. -M.; Auvergne, M.; Baglin, A.; Barge, P.; Bonomo, A. S.; Bordé, P.; Bouchy, F.; Bruntt, H.; Carpano, S.; Cochran, W. D.; Deleuil, M.; Díaz, R. F.; Dreizler, S.; Dvorak, R.; Eislöffel, J.; Eigmüller, P.; Endl, M.; Erikson, A.; Ferraz-Mello, S.; Fridlund, M.; Gazzano, J. -C.; Gibson, N.; Gillon, M.; Gondoin, P.; Grziwa, S.; Günther, E. W.; Guillot, T.; Hartmann, M.; Havel, M.; Hébrard, G.; Jorda, L.; Kabath, P.; Léger, A.; Llebaria, A.; Lammer, H.; Lovis, C.; MacQueen, P. J.; Mayor, M.; Mazeh, T.; Moutou, C.; Nortmann, L.; Ofir, A.; Ollivier, M.; Parviainen, H.; Pepe, F.; Pont, F.; Queloz, D.; Rabus, M.; Rauer, H.; Régulo, C.; Renner, S.; de La Reza, R.; Rouan, D.; Santerne, A.; Samuel, B.; Schneider, J.; Shporer, A.; Stecklum, B.; Tal-Or, L.; Tingley, B.; Udry, S.; Wuchterl, G. Bibcode: 2012A&A...538A.112C Altcode: 2011arXiv1110.2384C Context. CoRoT is a pioneering space mission whose primary goals are stellar seismology and extrasolar planets search. Its surveys of large stellar fields generate numerous planetary candidates whose lightcurves have transit-like features. An extensive analytical and observational follow-up effort is undertaken to classify these candidates.
Aims: We present the list of planetary transit candidates from the CoRoT LRa01 star field in the Monoceros constellation toward the Galactic anti-center direction. The CoRoT observations of LRa01 lasted from 24 October 2007 to 3 March 2008.
Methods: We acquired and analyzed 7470 chromatic and 3938 monochromatic lightcurves. Instrumental noise and stellar variability were treated with several filtering tools by different teams from the CoRoT community. Different transit search algorithms were applied to the lightcurves.
Results: Fifty-one stars were classified as planetary transit candidates in LRa01. Thirty-seven (i.e., 73% of all candidates) are "good" planetary candidates based on photometric analysis only. Thirty-two (i.e., 87% of the "good" candidates) have been followed-up. At the time of writing twenty-two cases were solved and five planets were discovered: three transiting hot-Jupiters (CoRoT-5b, CoRoT-12b, and CoRoT-21b), the first terrestrial transiting planet (CoRoT-7b), and another planet in the same system (CoRoT-7c, detected by radial velocity survey only). Evidence of another non-transiting planet in the CoRoT-7 system, namely CoRoT-7d, was recently found as well.

The CoRoT space mission, launched on December 27, 2006, has been developed and is operated by CNES, with contributions of Austria, Belgium, Brazil, ESA (RSSD and Science Program), Germany and Spain. Title: Transiting exoplanets from the CoRoT space mission. XXI. CoRoT-19b: a low density planet orbiting an old inactive F9V-star Authors: Guenther, E. W.; Díaz, R. F.; Gazzano, J. -C.; Mazeh, T.; Rouan, D.; Gibson, N.; Csizmadia, Sz.; Aigrain, S.; Alonso, R.; Almenara, J. M.; Auvergne, M.; Baglin, A.; Barge, P.; Bonomo, A. S.; Bordé, P.; Bouchy, F.; Bruntt, H.; Cabrera, J.; Carone, L.; Carpano, S.; Cavarroc, C.; Deeg, H. J.; Deleuil, M.; Dreizler, S.; Dvorak, R.; Erikson, A.; Ferraz-Mello, S.; Fridlund, M.; Gandolfi, D.; Gillon, M.; Guillot, T.; Hatzes, A.; Havel, M.; Hébrard, G.; Jehin, E.; Jorda, L.; Lammer, H.; Léger, A.; Moutou, C.; Nortmann, L.; Ollivier, M.; Ofir, A.; Pasternacki, Th.; Pätzold, M.; Parviainen, H.; Queloz, D.; Rauer, H.; Samuel, B.; Santerne, A.; Schneider, J.; Tal-Or, L.; Tingley, B.; Weingrill, J.; Wuchterl, G. Bibcode: 2012A&A...537A.136G Altcode: 2011arXiv1112.1035G Context. Observations of transiting extrasolar planets are of key importance to our understanding of planets because their mass, radius, and mass density can be determined. These measurements indicate that planets of similar mass can have very different radii. For low-density planets, it is generally assumed that they are inflated owing to their proximity to the host-star. To determine the causes of this inflation, it is necessary to obtain a statistically significant sample of planets with precisely measured masses and radii.
Aims: The CoRoT space mission allows us to achieve a very high photometric accuracy. By combining CoRoT data with high-precision radial velocity measurements, we derive precise planetary radii and masses. We report the discovery of CoRoT-19b, a gas-giant planet transiting an old, inactive F9V-type star with a period of four days.
Methods: After excluding alternative physical configurations mimicking a planetary transit signal, we determine the radius and mass of the planet by combining CoRoT photometry with high-resolution spectroscopy obtained with the echelle spectrographs SOPHIE, HARPS, FIES, and SANDIFORD. To improve the precision of its ephemeris and the epoch, we observed additional transits with the TRAPPIST and Euler telescopes. Using HARPS spectra obtained during the transit, we then determine the projected angle between the spin of the star and the orbit of the planet.
Results: We find that the host star of CoRoT-19b is an inactive F9V-type star close to the end of its main-sequence life. The host star has a mass M = 1.21 ± 0.05 M and radius R = 1.65 ± 0.04 R. The planet has a mass of MP = 1.11 ± 0.06 MJup and radius of RP = 1.29 ± 0.03 RJup. The resulting bulk density is only ρ = 0.71 ± 0.06 g cm-3, which is much lower than that for Jupiter.
Conclusions: The exoplanet CoRoT-19b is an example of a giant planet of almost the same mass as Jupiter but a ≈30% larger radius.

The CoRoT space mission, launched on December 27, 2006, has been developed and is operated by the CNES, with the contribution of Austria, Belgium, Brazil, ESA (RSSD and Science Program), Germany and Spain. Partly based on observations obtained at the European Southern Observatory at Paranal, Chile in program 184.C-0639, and partly based on observations conducted at McDonald Observatory. Title: A new extensive library of synthetic stellar spectra from PHOENIX atmospheres and its application to fitting VLT MUSE spectra Authors: Husser, T. -O.; Kamann, S.; Dreizler, S.; Hauschildt, Peter H. Bibcode: 2012ASInC...6...71H Altcode: 2012arXiv1203.1941H We present a new library of synthetic spectra based on the stellar atmosphere code phx. It covers the wavelength range from 500 Å to 55 000 Å with a resolution of R=500 000 in the optical and near IR, R=100 000 in the IR and &Delta&;lambda;=0.1 Å in the UV. The parameter space covers 2 300 K ≤ T_{eff} ≤ 8 000 K, 0.0 ≤ log(g) ≤ +6.0, -4.0 ≤ [Fe/H] ≤ +1.0 and -0.3 ≤ [α/Fe] ≤ +0.8. The library is work-in-progress and going to be extended to at least T_{eff}=25 000 K. We use a new self-consistent way of describing the microturbulence for our model atmospheres. The entire library of synthetic spectra will be available for download. Furthermore we present a method for fitting spectra, especially designed to work with the new 2nd generation VLT instrument muse. We show that we can determine stellar parameters (T_{eff}, log(g), [Fe/H] and [α/Fe]) and even single element abundances. Title: Evidence for planets in post-common envelope binaries Authors: Dreizler, S.; Beuermann, K.; Hesman, F. V. Bibcode: 2012MmSAI..83..498D Altcode: In the recent years, several circum-binary planets orbiting post-common envelope systems have been announced. Some of the derived planetary parameters have been questioned by others. We therefore present an investigation of the current status in this dynamically evolving field. False positive scenarios for the eclipse time variations are therefore discussed. We also present an update on new measurements on NN Ser and shortly address the quest for the frequency of planets in post-common envelope systems. Title: Discovery and Mass Measurements of a Cold, 10 Earth Mass Planet and Its Host Star Authors: Muraki, Y.; Han, C.; Bennett, D. P.; Suzuki, D.; Monard, L. A. G.; Street, R.; Jorgensen, U. G.; Kundurthy, P.; Skowron, J.; Becker, A. C.; Albrow, M. D.; Fouqué, P.; Heyrovský, D.; Barry, R. K.; Beaulieu, J. -P.; Wellnitz, D. D.; Bond, I. A.; Sumi, T.; Dong, S.; Gaudi, B. S.; Bramich, D. M.; Dominik, M.; Abe, F.; Botzler, C. S.; Freeman, M.; Fukui, A.; Furusawa, K.; Hayashi, F.; Hearnshaw, J. B.; Hosaka, S.; Itow, Y.; Kamiya, K.; Korpela, A. V.; Kilmartin, P. M.; Lin, W.; Ling, C. H.; Makita, S.; Masuda, K.; Matsubara, Y.; Miyake, N.; Nishimoto, K.; Ohnishi, K.; Perrott, Y. C.; Rattenbury, N. J.; Saito, To.; Skuljan, L.; Sullivan, D. J.; Sweatman, W. L.; Tristram, P. J.; Wada, K.; Yock, P. C. M.; MOA Collaboration; Christie, G. W.; DePoy, D. L.; Gorbikov, E.; Gould, A.; Kaspi, S.; Lee, C. -U.; Mallia, F.; Maoz, D.; McCormick, J.; Moorhouse, D.; Natusch, T.; Park, B. -G.; Pogge, R. W.; Polishook, D.; Shporer, A.; Thornley, G.; Yee, J. C.; μFUN Collaboration; Allan, A.; Browne, P.; Horne, K.; Kains, N.; Snodgrass, C.; Steele, I.; Tsapras, Y.; RoboNet Collaboration; Batista, V.; Bennett, C. S.; Brillant, S.; Caldwell, J. A. R.; Cassan, A.; Cole, A.; Corrales, R.; Coutures, Ch.; Dieters, S.; Dominis Prester, D.; Donatowicz, J.; Greenhill, J.; Kubas, D.; Marquette, J. -B.; Martin, R.; Menzies, J.; Sahu, K. C.; Waldman, I.; Williams, A.; Zub, M.; PLANET Collaboration; Bourhrous, H.; Matsuoka, Y.; Nagayama, T.; Oi, N.; Randriamanakoto, Z.; IRSF Observers; Bozza, V.; Burgdorf, M. J.; Calchi Novati, S.; Dreizler, S.; Finet, F.; Glitrup, M.; Harpsøe, K.; Hinse, T. C.; Hundertmark, M.; Liebig, C.; Maier, G.; Mancini, L.; Mathiasen, M.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Skottfelt, J.; Surdej, J.; Southworth, J.; Wambsganss, J.; Zimmer, F.; MiNDSTEp Consortium; Udalski, A.; Poleski, R.; Wyrzykowski, Ł.; Ulaczyk, K.; Szymański, M. K.; Kubiak, M.; Pietrzyński, G.; Soszyński, I.; OGLE Collaboration Bibcode: 2011ApJ...741...22M Altcode: 2011arXiv1106.2160M We present the discovery and mass measurement of the cold, low-mass planet MOA-2009-BLG-266Lb, performed with the gravitational microlensing method. This planet has a mass of mp = 10.4 ± 1.7 M and orbits a star of mass M sstarf = 0.56 ± 0.09 Msun at a semimajor axis of a = 3.2{+1.9\atop -0.5} AU and an orbital period of P = 7.6{+7.7\atop -1.5} yrs. The planet and host star mass measurements are enabled by the measurement of the microlensing parallax effect, which is seen primarily in the light curve distortion due to the orbital motion of the Earth. But the analysis also demonstrates the capability to measure the microlensing parallax with the Deep Impact (or EPOXI) spacecraft in a heliocentric orbit. The planet mass and orbital distance are similar to predictions for the critical core mass needed to accrete a substantial gaseous envelope, and thus may indicate that this planet is a "failed" gas giant. This and future microlensing detections will test planet formation theory predictions regarding the prevalence and masses of such planets. Title: CAFE: Calar Alto Fiber-fed Echelle spectrograph Authors: Sánchez, S. F.; Aceituno, J.; Thiele, U.; Grupp, F.; Dreizler, S.; Bean, J.; Benitez, D. Bibcode: 2011hsa6.conf..783S Altcode: The Calar Alto Fiber-fed Echelle spectrograph (CAFE) is an instrument underconstruction at CAHA to replace FOCES, the high-resolution echellespectrograph at the 2.2 m telescope of the observatory. FOCES is a property ofthe Observatory of the Munich University, and it was recalled it from Calar Altoin 2009. The instrument comprised a substantial fraction of thetelescope time during its operational life-time, and it is due to that it wastaken the decision to build a replacement.CAFE shares its basic characteristics with those of FOCES. However, significantimprovements have been introduced in the original design, the quality of thematerials, and the overall stability of the system. In particular: (i) a newcalibration Iodine cell is foreseen to operate together with the standard ThArlamps; (ii) the optical quality of all the components has been selected to belambda/20, instead of the original lambda/10; (iii) an isolated room hasbeen selected to place the instrument, termalized and stabilized againstvibrations (extensive tests have been performed to grant the stability); (iv)most of the mobile parts in FOCES has been substituted by fixed elements, toincrease the stability of the system; and finally (v) a new more efficientCCD, with a smaller pixel has been acquired. It is expected that the overallefficiency and the quality of the data will be significantly improved withrespect to its precesor. In particular, CAFE is design and built to achieveresolutions of R ∼ 70000, which will be kept in the final acquired data,allowing it to compete with current operational extrasolar planets hunters.After two years of work all the components are in place. The instrument is nowfinally assembled, and we are performing the the first alignment tests. It isexpected that the commissioning on the laboratory will finish at the end of2010, followed by the commissioning on telescope along the first semester of2011. If everything goes well, we will offer the instrument in a shared-riskmode for the second semester of 2011. Title: MOA-2009-BLG-387Lb: a massive planet orbiting an M dwarf Authors: Batista, V.; Gould, A.; Dieters, S.; Dong, S.; Bond, I.; Beaulieu, J. P.; Maoz, D.; Monard, B.; Christie, G. W.; McCormick, J.; Albrow, M. D.; Horne, K.; Tsapras, Y.; Burgdorf, M. J.; Calchi Novati, S.; Skottfelt, J.; Caldwell, J.; Kozłowski, S.; Kubas, D.; Gaudi, B. S.; Han, C.; Bennett, D. P.; An, J.; MOA Collaboration; Abe, F.; Botzler, C. S.; Douchin, D.; Freeman, M.; Fukui, A.; Furusawa, K.; Hearnshaw, J. B.; Hosaka, S.; Itow, Y.; Kamiya, K.; Kilmartin, P. M.; Korpela, A.; Lin, W.; Ling, C. H.; Makita, B. S.; Masuda, K.; Matsubara, Y.; Miyake, N.; Muraki, Y.; Nagaya, M.; Nishimoto, K.; Ohnishi, K.; Okumura, T.; Perrott, Y. C.; Rattenbury, N.; Saito, To.; Sullivan, D. J.; Sumi, T.; Sweatman, W. L.; Tristram, P. J.; von Seggern, E.; Yock, P. C. M.; PLANET Collaboration; Brillant, S.; Calitz, J. J.; Cassan, A.; Cole, A.; Cook, K.; Coutures, C.; Dominis Prester, D.; Donatowicz, J.; Greenhill, J.; Hoffman, M.; Jablonski, F.; Kane, S. R.; Kains, N.; Marquette, J. -B.; Martin, R.; Martioli, E.; Meintjes, P.; Menzies, J.; Pedretti, E.; Pollard, K.; Sahu, K. C.; Vinter, C.; Wambsganss, J.; Watson, R.; Williams, A.; Zub, M.; FUN Collaboration; Allen, W.; Bolt, G.; Bos, M.; DePoy, D. L.; Drummond, J.; Eastman, J. D.; Gal-Yam, A.; Gorbikov, E.; Higgins, D.; Janczak, J.; Kaspi, S.; Lee, C. -U.; Mallia, F.; Maury, A.; Monard, L. A. G.; Moorhouse, D.; Morgan, N.; Natusch, T.; Ofek, E. O.; Park, B. -G.; Pogge, R. W.; Polishook, D.; Santallo, R.; Shporer, A.; Spector, O.; Thornley, G.; Yee, J. C.; MiNDSTEp Consortium; Bozza, V.; Browne, P.; Dominik, M.; Dreizler, S.; Finet, F.; Glitrup, M.; Grundahl, F.; Harpsøe, K.; Hessman, F. V.; Hinse, T. C.; Hundertmark, M.; Jørgensen, U. G.; Liebig, C.; Maier, G.; Mancini, L.; Mathiasen, M.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Southworth, J.; Surdej, J.; Zimmer, F.; RoboNet Collaboration; Allan, A.; Bramich, D. M.; Snodgrass, C.; Steele, I. A.; Street, R. A. Bibcode: 2011A&A...529A.102B Altcode: 2011arXiv1102.0558B
Aims: We report the discovery of a planet with a high planet-to-star mass ratio in the microlensing event MOA-2009-BLG-387, which exhibited pronounced deviations over a 12-day interval, one of the longest for any planetary event. The host is an M dwarf, with a mass in the range 0.07 M < Mhost < 0.49 M at 90% confidence. The planet-star mass ratio q = 0.0132 ± 0.003 has been measured extremely well, so at the best-estimated host mass, the planet mass is mp = 2.6 Jupiter masses for the median host mass, M = 0.19 M.
Methods: The host mass is determined from two "higher order" microlensing parameters. One of these, the angular Einstein radius θE = 0.31 ± 0.03 mas has been accurately measured, but the other (the microlens parallax πE, which is due to the Earth's orbital motion) is highly degenerate with the orbital motion of the planet. We statistically resolve the degeneracy between Earth and planet orbital effects by imposing priors from a Galactic model that specifies the positions and velocities of lenses and sources and a Kepler model of orbits.
Results: The 90% confidence intervals for the distance, semi-major axis, and period of the planet are 3.5 kpc < DL < 7.9 kpc, 1.1 AU < a < 2.7 AU, and 3.8 yr < P < 7.6 yr, respectively.

Photometric data is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/529/A102 Title: XMM-Newton observations of the X-ray soft polar QS Telescopii Authors: Traulsen, I.; Reinsch, K.; Schwope, A. D.; Burwitz, V.; Dreizler, S.; Schwarz, R.; Walter, F. M. Bibcode: 2011A&A...529A.116T Altcode: 2011arXiv1103.4575T Context. On the basis of XMM-Newton observations, we investigate the energy balance of selected magnetic cataclysmic variables, which have shown an extreme soft-to-hard X-ray flux ratio in the ROSAT All-Sky Survey.
Aims: We intend to establish the X-ray properties of the system components, their flux contributions, and the accretion geometry of the X-ray soft polar QS Tel. In the context of high-resolution X-ray analyses of magnetic cataclysmic variables, this study will contribute to better understanding the accretion processes on magnetic white dwarfs.
Methods: During an intermediate high state of accretion of QS Tel, we have obtained 20 ks of XMM-Newton data, corresponding to more than two orbital periods, accompanied by simultaneous optical photometry and phase-resolved spectroscopy. We analyze the multi-wavelength spectra and light curves and compare them to former high- and low-state observations.
Results: Soft emission at energies below 2 keV dominates the X-ray light curves. The complex double-peaked maxima are disrupted by a sharp dip in the very soft energy range (0.1-0.5 keV), where the count rate abruptly drops to zero. The EPIC spectra are described by a minimally absorbed black body at 20 eV and two partially absorbed mekal plasma models with temperatures around 0.2 and 3 keV. The black-body-like component arises from one mainly active, soft X-ray bright accretion region nearly facing the mass donor. Parts of the plasma emission might be attributed to the second, virtually inactive pole. High soft-to-hard X-ray flux ratios and hardness ratios demonstrate that the high-energy emission of QS Tel is substantially dominated by its X-ray soft component.

Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. Title: VizieR Online Data Catalog: Hot HB stars in ω Cen (Moehler+, 2011) Authors: Moehler, S.; Dreizler, S.; Lanz, T.; Bono, G.; Sweigart, A. V.; Calamida, A.; Nonino, M. Bibcode: 2011yCat..35260136M Altcode: 2011yCat..35269136M Moderately high resolution spectra of hot HB stars in the globular cluster omega Cen were analysed for radial velocity variations, atmospheric parameters, and abundances using LTE and non-LTE model atmospheres.

The spectroscopic data were obtained in 2005 (4 observations) and in 2006 (5 observations) in Service Mode using the MEDUSA mode of the multi-object fiber spectrograph FLAMES + GIRAFFE on the UT2 Telescope of the VLT. We used the low spectroscopic resolution mode with the spectral range 3964Å-4567Å (LR2, R=6400) and observed spectra for a total of 109 blue hook and canonical blue HB/EHB star candidates (see Table 1) and for 17 sky background positions. Each observation had an exposure time of 2550s to keep the total execution time of the observing block shorter than one hour.

(3 data files). Title: Flux and color variations of the quadruply imaged quasar HE 0435-1223 Authors: Ricci, D.; Poels, J.; Elyiv, A.; Finet, F.; Sprimont, P. G.; Anguita, T.; Bozza, V.; Browne, P.; Burgdorf, M.; Calchi Novati, S.; Dominik, M.; Dreizler, S.; Glitrup, M.; Grundahl, F.; Harpsøe, K.; Hessman, F.; Hinse, T. C.; Hornstrup, A.; Hundertmark, M.; Jørgensen, U. G.; Liebig, C.; Maier, G.; Mancini, L.; Masi, G.; Mathiasen, M.; Rahvar, S.; Scarpetta, G.; Skottfelt, J.; Snodgrass, C.; Southworth, J.; Teuber, J.; Thöne, C. C.; Wambsganß, J.; Zimmer, F.; Zub, M.; Surdej, J. Bibcode: 2011A&A...528A..42R Altcode: 2011arXiv1101.3664R
Aims: We present VRi photometric observations of the quadruply imaged quasarHE0435-1223, carried out with the Danish 1.54 m telescope at the La Silla Observatory. Our aim was to monitor and study the magnitudes and colors of each lensed component as a function of time.
Methods: We monitored the object during two seasons (2008 and 2009) in the VRi spectral bands, and reduced the data with two independent techniques: difference imaging and point spread function (PSF) fitting.
Results: Between these two seasons, our results show an evident decrease in flux by ≈ 0.2-0.4 magnitudes of the four lensed components in the three filters. We also found a significant increase ( ≈ 0.05-0.015) in their V - R and R - i color indices.
Conclusions: These flux and color variations are very likely caused by intrinsic variations of the quasar between the observed epochs. Microlensing effects probably also affect the brightest "A" lensed component.

Based on data collected by MiNDSTEp with the Danish 1.54 m telescope at the ESO La Silla Observatory. Tables 5-7 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/528/A42 Title: VizieR Online Data Catalog: MOA-2007-BLG-387Lb light curve I band (Batista+, 2011) Authors: Batista, V.; Gould, A.; Dieters, S.; Dong, Subo; Bond, I.; Beaulieu, J. P.; Maoz, D.; Monard, B.; Christie, G. W.; McCormick, J.; Albrow, M. D.; Horne, K.; Tsapras, Y.; Burgdorf, M. J.; Calchi Novati, S.; Skottfelt, J.; Caldwell, J.; Kozlowski, S.; Kubas, D.; Gaudi, B. S.; Han, C.; Bennett1, D. P.; An, J.; Abe, F.; Botzler, C. S.; Douchin, D.; Freeman, M.; Fukui, A.; Furusawa, K.; Hearnshaw, J. B.; Hosaka, S.; Itow, Y.; Kamiya, K.; Kilmartin, P. M.; Korpela, A.; Lin, W.; Ling, C. H.; Makita, S.; Masuda, K.; Matsubara, Y.; Miyake, N.; Muraki, Y.; Nagaya, M.; Nishimoto, K.; Ohnishi, K.; Okumura, T.; Perrott, Y. C.; Rattenbury, N.; Saito, To.; Sullivan, D. J.; Sumi, T.; Sweatman, W. L.; Tristram, P. J.; von Seggern, E.; Yock P. C. M.; MOA Collaboration; Brillant, S.; Calitz, J. J.; Cassan, A.; Cole, A.; Cook, K.; Coutures, C.; Dominis Prester, D.; Donatowicz, J.; Greenhill, J.; Hoffman, M.; Jablonski, F.; Kane, S. R.; Kains, N.; Marquette, J. -B.; Martin, R.; Martioli, E.; Meintjes, P.; Menzies, J.; Pedretti, E.; Pollard, K.; Sahu, K. C.; Vinter, C.; Wambsganss, J.; Watson, R.; Williams, A.; Zub, M.; PLANET Collaboration; Allen, W.; Bolt, G.; Bos, M.; DePoy, D. L.; Drummond, J.; Eastman, J. D.; Gal-Yam, A.; Gorbikov, E.; Higgins, D.; Janczak, J.; Kaspi, S.; Lee, C. -U.; Mallia, F.; Maury, A.; Monard, L. A. G.; Moorhouse, D.; Morgan, N.; Natusch, T.; Ofek, E. O.; Park, B. -G.; Pogge, R. W.; Polishook, D.; Santallo, R.; Shporer, A.; Spector, O.; Thornley, G.; Yee, J. C.; μ Collaboration; Bozza, V.; Browne, P.; Dominik, M.; Dreizler, S.; Finet, F.; Glitrup, M.; Grundah, F.; Harpsoe, K.; Hessman, F. V.; Hinse, T. C.; Hundertmark, M.; Jorgensen, U. G.; Liebig, C.; Maier, G.; Mancini, L.; Mathiasen, M.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Southworth, J.; Surdej, J.; Zimmer, F. Bibcode: 2011yCat..35290102B Altcode: 2011yCat..35299102B The RoboNet collaboration also followed the event with their three 2m robotic telescopes : the Faulkes Telescopes The microlensing event MOA-2009-BLG-387 was alerted North (FTN) and South (FTS) in Hawaii and Australia by the MOA collaboration (Microlensing Observations in (Siding Springs Observatory) respectively, and the Liverpool Astrophysics) on 24 July 2009 at 15:08 UT, HJD'=HJD-24500000=5037.13, a few days before the first caustic entry. Many observatories obtained data of the event. The celestial coordinates of the event are RA=17:53:50.79 and DE=-33:59:25 (J2000.0) corresponding to Galactic coordinates: l=+356.56, b=-4.097.

(1 data file). Title: The Planets around the post-Common Envelope Binary NN Serpentis Authors: Hessman, Frederic V.; Beuermann, Klaus; Dreizler, Stefan; Marsh, Tom R.; Parsons, Steven G.; Copperwheat, Chris M.; Winget, Don E.; Miller, George F.; Hermes, James J.; Schreiber, Matthias R.; Kley, Wilhelm; Dhillon, Vik S.; Littlefair, Stuart P. Bibcode: 2011AIPC.1331..281H Altcode: 2011arXiv1102.0508H We have detected 2 circumbinary planets around the close binary system NN Serpentis using the orbital time delay effect measured via the sharp eclipses of the white dwarf primary. The present pre-cataclysmic binary was formed when the original ~2 Msolar primary expanded into a red giant, causing the secondary star to drop from its original orbit at a separation of about 1.4 A.U. down to its current separation at 0.0043 A.U. A quasi-adiabatic evolution of the circumbinary planets' orbits during the common-envelope phase would have placed them in unstable configurations, suggesting that they may have suffered significant orbital drag effects and were originally in much larger orbits. Alternatively, they may have been created as 2nd-generation planets during the last million years from the substantial amount of material lost during the creation of the binary, making them the youngest planets known. Either solution shows how little we actually understand about planetary formation. Title: A much lower density for the transiting extrasolar planet WASP-7 Authors: Southworth, J.; Dominik, M.; Jørgensen, U. G.; Rahvar, S.; Snodgrass, C.; Alsubai, K.; Bozza, V.; Browne, P.; Burgdorf, M.; Calchi Novati, S.; Dodds, P.; Dreizler, S.; Finet, F.; Gerner, T.; Hardis, S.; Harpsøe, K.; Hellier, C.; Hinse, T. C.; Hundertmark, M.; Kains, N.; Kerins, E.; Liebig, C.; Mancini, L.; Mathiasen, M.; Penny, M. T.; Proft, S.; Ricci, D.; Sahu, K.; Scarpetta, G.; Schäfer, S.; Schönebeck, F.; Surdej, J. Bibcode: 2011A&A...527A...8S Altcode: 2010arXiv1012.5181S We present the first high-precision photometry of the transiting extrasolar planetary system WASP-7, obtained using telescope defocussing techniques and reaching a scatter of 0.68 mmag per point. We find that the transit depth is greater and that the host star is more evolved than previously thought. The planet has a significantly larger radius (1.330 ± 0.093 RJup versus ; RJup) and much lower density (0.41 ± 0.10 ρJup versus ; ρJup) and surface gravity (13.4 ± 2.6 m s-2 versus ; m s-2) than previous measurements showed. Based on the revised properties it is no longer an outlier in planetary mass-radius and period-gravity diagrams. We also obtain a more precise transit ephemeris for the WASP-7 system.

Based on data collected by MiNDSTEp with the Danish 1.54 m telescope at the ESO La Silla Observatory.Lightcurves data is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/527/A8 Title: A Sub-Saturn Mass Planet, MOA-2009-BLG-319Lb Authors: Miyake, N.; Sumi, T.; Dong, Subo; Street, R.; Mancini, L.; Gould, A.; Bennett, D. P.; Tsapras, Y.; Yee, J. C.; Albrow, M. D.; Bond, I. A.; Fouqué, P.; Browne, P.; Han, C.; Snodgrass, C.; Finet, F.; Furusawa, K.; Harpsøe, K.; Allen, W.; Hundertmark, M.; Freeman, M.; Suzuki, D.; Abe, F.; Botzler, C. S.; Douchin, D.; Fukui, A.; Hayashi, F.; Hearnshaw, J. B.; Hosaka, S.; Itow, Y.; Kamiya, K.; Kilmartin, P. M.; Korpela, A.; Lin, W.; Ling, C. H.; Makita, S.; Masuda, K.; Matsubara, Y.; Muraki, Y.; Nagayama, T.; Nishimoto, K.; Ohnishi, K.; Perrott, Y. C.; Rattenbury, N.; Saito, To.; Skuljan, L.; Sullivan, D. J.; Sweatman, W. L.; Tristram, P. J.; Wada, K.; Yock, P. C. M.; MOA Collaboration; Bolt, G.; Bos, M.; Christie, G. W.; DePoy, D. L.; Drummond, J.; Gal-Yam, A.; Gaudi, B. S.; Gorbikov, E.; Higgins, D.; Hwang, K. -H.; Janczak, J.; Kaspi, S.; Lee, C. -U.; Koo, J. -R.; Kozłowski, S.; Lee, Y.; Mallia, F.; Maury, A.; Maoz, D.; McCormick, J.; Monard, L. A. G.; Moorhouse, D.; Muñoz, J. A.; Natusch, T.; Ofek, E. O.; Pogge, R. W.; Polishook, D.; Santallo, R.; Shporer, A.; Spector, O.; Thornley, G.; μFUN Collaboration; Allan, A.; Bramich, D. M.; Horne, K.; Kains, N.; Steele, I.; RoboNet Collaboration; Bozza, V.; Burgdorf, M. J.; Calchi Novati, S.; Dominik, M.; Dreizler, S.; Glitrup, M.; Hessman, F. V.; Hinse, T. C.; Jørgensen, U. G.; Liebig, C.; Maier, G.; Mathiasen, M.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Skottfelt, J.; Southworth, J.; Surdej, J.; Wambsganss, J.; Zimmer, F.; MiNDSTEp Consortium; Batista, V.; Beaulieu, J. P.; Brillant, S.; Cassan, A.; Cole, A.; Corrales, E.; Coutures, Ch.; Dieters, S.; Greenhill, J.; Kubas, D.; Menzies, J.; PLANET Collaboration Bibcode: 2011ApJ...728..120M Altcode: 2010arXiv1010.1809M We report the gravitational microlensing discovery of a sub-Saturn mass planet, MOA-2009-BLG-319Lb, orbiting a K- or M-dwarf star in the inner Galactic disk or Galactic bulge. The high-cadence observations of the MOA-II survey discovered this microlensing event and enabled its identification as a high-magnification event approximately 24 hr prior to peak magnification. As a result, the planetary signal at the peak of this light curve was observed by 20 different telescopes, which is the largest number of telescopes to contribute to a planetary discovery to date. The microlensing model for this event indicates a planet-star mass ratio of q = (3.95 ± 0.02) × 10-4 and a separation of d = 0.97537 ± 0.00007 in units of the Einstein radius. A Bayesian analysis based on the measured Einstein radius crossing time, t E, and angular Einstein radius, θE, along with a standard Galactic model indicates a host star mass of M L = 0.38+0.34 -0.18 M sun and a planet mass of M p = 50+44 -24 M , which is half the mass of Saturn. This analysis also yields a planet-star three-dimensional separation of a = 2.4+1.2 -0.6 AU and a distance to the planetary system of D L = 6.1+1.1 -1.2 kpc. This separation is ~2 times the distance of the snow line, a separation similar to most of the other planets discovered by microlensing. Title: The hot horizontal-branch stars in ω Centauri Authors: Moehler, S.; Dreizler, S.; Lanz, T.; Bono, G.; Sweigart, A. V.; Calamida, A.; Nonino, M. Bibcode: 2011A&A...526A.136M Altcode: 2010arXiv1009.3191M Context. UV observations of some massive globular clusters have revealed a significant population of stars hotter and fainter than the hot end of the horizontal branch (HB), the so-called blue hook stars. This feature might be explained either by the late hot flasher scenario where stars experience the helium flash while on the white dwarf cooling curve or by the progeny of the helium-enriched sub-population postulated to exist in some clusters. Previous spectroscopic analyses of blue hook stars in ω Cen and NGC 2808 support the late hot flasher scenario, but the stars contain much less helium than expected and the predicted C and N enrichment cannot be verified.
Aims: We compare the observed effective temperatures, surface gravities, helium abundances, and carbon line strengths (where detectable) of our targets stars with the predictions of the two aforementioned scenarios.
Methods: Moderately high resolution spectra of hot HB stars in the globular cluster ω Cen were analysed for radial velocity variations, atmospheric parameters, and abundances using LTE and non-LTE model atmospheres.
Results: We find no evidence of close binaries among our target stars. All stars below 30 000 K are helium-poor and very similar to HB stars observed in that temperature range in other globular clusters. In the temperature range 30 000 K to 50 000 K, we find that 28% of our stars are helium-poor ({log{n_He}/{n_H}} < -1.6), while 72% have roughly solar or super-solar helium abundance ({log{n_He}/{n_H}} ≥ -1.5). We also find that carbon enrichment is strongly correlated with helium enrichment, with a maximum carbon enrichment of 3% by mass.
Conclusions: A strong carbon enrichment in tandem with helium enrichment is predicted by the late hot flasher scenario, but not by the helium-enrichment scenario. We conclude that the helium-rich HB stars in ω Cen cannot be explained solely by the helium-enrichment scenario invoked to explain the blue main sequence.

Based on observations with the ESO Very Large Telescope at Paranal Observatory, Chile (proposal IDs 075.D-0280(A) and 077.D-0021(A)). Title: The giant planet orbiting the cataclysmic binary DP Leonis Authors: Beuermann, K.; Buhlmann, J.; Diese, J.; Dreizler, S.; Hessman, F. V.; Husser, T. -O.; Miller, G. F.; Nickol, N.; Pons, R.; Ruhr, D.; Schmülling, H.; Schwope, A. D.; Sorge, T.; Ulrichs, L.; Winget, D. E.; Winget, K. I. Bibcode: 2011A&A...526A..53B Altcode: 2010arXiv1011.3905B Planets orbiting post-common envelope binaries provide fundamental information on planet formation and evolution, especially for the yet nearly unexplored class of circumbinary planets. We searched for such planets in DP Leo, an eclipsing short-period binary, which shows long-term eclipse-time variations. Using published, reanalysed, and new mid-eclipse times of the white dwarf in DP Leo, obtained between 1979 and 2010, we find agreement with the light-travel-time effect produced by a third body in an elliptical orbit. In particular, the measured binary period in 2009/2010 and the implied radial velocity coincide with the values predicted for the motion of the binary and the third body around the common center of mass. The orbital period, semi-major axis, and eccentricity of the third body are Pc = 28.0 ± 2.0 yrs, ac = 8.2 ± 0.4 AU, and ec = 0.39 ± 0.13. Its mass of sin i_ c M_c = 6.1 ± 0.5 MJup qualifies it as a giant planet. It formed either as a first generation object in a protoplanetary disk around the original binary or as a second generation object in a disk formed in the common envelope shed by the progenitor of the white dwarf. Even a third generation origin in matter lost from the present accreting binary can not be entirely excluded. We searched for, but found no evidence for a fourth body. Title: Giant Transiting Planets Observations with LAIWO Authors: Nikolov, N.; Moyano, M.; Henning, T.; Dreizler, S.; Mundt, R. Bibcode: 2011EPJWC..1106004N Altcode: We present preliminary single field results on a search for transiting extrasolar planets with the LAIWO wide field optical CCD camera, attached to the 1-m telescope at the Wise Observatory. With a 3 min integration time, the system achieved a few mmag precision for the brightest stars in a field of view of one square degree. We detect several periodic variables and a few transit-like events. The promising candidates will be followed-up in the near future. Title: VizieR Online Data Catalog: Transiting planetary system WASP-7 (Southworth+, 2011) Authors: Southworth, J.; Dominik, M.; Jorgensen, U. G.; Rahvar, S.; Snodgrass, C.; Alsubai, K.; Bozza, V.; Browne, P.; Burgdorf, M.; Calchi Novati, S.; Dodds, P.; Dreizler, S.; Finet, F.; Gerner, T.; Hardis, S.; Harpsoe, K.; Hellier, C.; Hinse, T. C.; Hundertmark, M.; Kains, N.; Kerins, E.; Liebig, C.; Mancini, L.; Mathiasen, M.; Penny, M. T.; Proft, S.; Ricci, D.; Scarpetta, G.; Schaefer, S.; Schoenebeck, F.; Surdej, J. Bibcode: 2011yCat..35270008S Altcode: 2011yCat..35279008S A light curve of one transit of the extrasolar planetary system WASP-7 is presented. The data were obtained using the Danish 1.5m telescope and DFOSC camera at ESO La Silla in 2010, with substantial telescope defocussing in order to improve the photometric precision of the observations. A Johnson I filter and exposure times of 60s were used.

(1 data file). Title: VizieR Online Data Catalog: VRi light curves of the lensed QSO HE 0435-1223 (Ricci+, 2011) Authors: Ricci, D.; Poels, J.; Elyiv, A.; Finet, F.; Sprimont, P. G.; Anguita, T.; Bozza, V.; Browne, P.; Burgdorf, M.; Calchi Novati, S.; Dominik, M.; Dreizler, S.; Glitrup, M.; Grundahl, F.; Harps, K.; Hessman, F.; Hinse, T. C.; Hornstrup, A.; Hundertmark, M.; Jorgensen, U. G.; Liebig, C.; Maier, G.; Mancini, L.; Masi, G.; Mathiasen, M.; Rahvar, S.; Scarpetta, G.; Skottfelt, J.; Snodgrass, C.; Southworth, J.; Teuber, J.; Thone, C. C.; Wambsganss, J.; Zimmer, F.; Zub, M.; Surdej, J. Bibcode: 2011yCat..35280042R Altcode: 2011yCat..35289042R Tables contain the light curves of the 4 components of the quasar, in the V, R, and i bands.

(3 data files). Title: Asteroseismology of solar-type stars with Kepler: III. Ground-based data Authors: Molenda-Żakowicz, J.; Bruntt, H.; Sousa, S.; Frasca, A.; Biazzo, K.; Huber, D.; Ireland, M.; Bedding, T.; Stello, D.; Uytterhoeven, K.; Dreizler, S.; De Cat, P.; Briquet, M.; Catanzaro, G.; Karoff, C.; Frandsen, S.; Spezzi, L. Bibcode: 2010AN....331..981M Altcode: 2010arXiv1005.0986M We report on the ground-based follow-up program of spectroscopic and photometric observations of solar-like asteroseismic targets for the Kepler space mission. These stars constitute a large group of more than a thousand objects which are the subject of an intensive study by the Kepler Asteroseismic Science Consortium Working Group 1 (KASC WG-1). In the current work we will discuss the methods we use to determine the fundamental stellar atmospheric parameters using high-quality stellar spectra. These provide essential constraints for the asteroseismic modelling and make it possible to verify the parameters in the Kepler Input Catalogue (KIC). Title: ERRATUM: "Physical Properties of the 0.94 Day Period Transiting Planetary System WASP-18" (2009, ApJ, 707, 167) Authors: Southworth, John; Hinse, T. C.; Dominik, M.; Glitrup, M.; Jørgensen, U. G.; Liebig, C.; Mathiasen, M.; Anderson, D. R.; Bozza, V.; Browne, P.; Burgdorf, M.; Calchi Novati, S.; Dreizler, S.; Finet, F.; Harpsøe, K.; Hessman, F.; Hundertmark, M.; Maier, G.; Mancini, L.; Maxted, P. F. L.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Skottfelt, J.; Snodgrass, C.; Surdej, J.; Zimmer, F. Bibcode: 2010ApJ...723.1829S Altcode: No abstract at ADS Title: OGLE-2009-BLG-092/MOA-2009-BLG-137: A Dramatic Repeating Event with the Second Perturbation Predicted by Real-time Analysis Authors: Ryu, Y. -H.; Han, C.; Hwang, K. -H.; Street, R.; Udalski, A.; Sumi, T.; Fukui, A.; Beaulieu, J. -P.; Gould, A.; Dominik, M.; Abe, F.; Bennett, D. P.; Bond, I. A.; Botzler, C. S.; Furusawa, K.; Hayashi, F.; Hearnshaw, J. B.; Hosaka, S.; Itow, Y.; Kamiya, K.; Kilmartin, P. M.; Korpela, A.; Lin, W.; Ling, C. H.; Makita, S.; Masuda, K.; Matsubara, Y.; Miyake, N.; Muraki, Y.; Nishimoto, K.; Ohnishi, K.; Perrott, Y. C.; Rattenbury, N.; Saito, To.; Skuljan, L.; Sullivan, D. J.; Suzuki, D.; Sweatman, W. L.; Tristram, P. J.; Wada, K.; Yock, P. C. M.; MOA Collaboration; Szymański, M. K.; Kubiak, M.; Pietrzyński, G.; Poleski, R.; Soszyński, I.; Szewczyk, O.; Wyrzykowski, Ł.; Ulaczyk, K.; OGLE Collaboration; Bos, M.; Christie, G. W.; Depoy, D. L.; Gal-Yam, A.; Gaudi, B. S.; Kaspi, S.; Lee, C. -U.; Maoz, D.; McCormick, J.; Monard, B.; Moorhouse, D.; Pogge, R. W.; Polishook, D.; Shvartzvald, Y.; Shporer, A.; Thornley, G.; Yee, J. C.; μFUN Collaboration; Albrow, M. D.; Batista, V.; Brillant, S.; Cassan, A.; Cole, A.; Corrales, E.; Coutures, Ch.; Dieters, S.; Fouqué, P.; Greenhill, J.; Menzies, J.; PLANET Collaboration; Allan, A.; Bramich, D. M.; Browne, P.; Horne, K.; Kains, N.; Snodgrass, C.; Steele, I.; Tsapras, Y.; RoboNet Collaboration; Bozza, V.; Burgdorf, M. J.; Calchi Novati, S.; Dreizler, S.; Finet, F.; Glitrup, M.; Grundahl, F.; Harpsøe, K.; Hessman, F. V.; Hinse, T. C.; Hundertmark, M.; Jørgensen, U. G.; Liebig, C.; Maier, G.; Mancini, L.; Mathiasen, M.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Skottfelt, J.; Surdej, J.; Southworth, J.; Wambsganss, J.; Zimmer, F.; MiNDSTEp Collaboration Bibcode: 2010ApJ...723...81R Altcode: 2010arXiv1009.0338R We report the result of the analysis of a dramatic repeating gravitational microlensing event OGLE-2009-BLG-092/MOA-2009-BLG-137, for which the light curve is characterized by two distinct peaks with perturbations near both peaks. We find that the event is produced by the passage of the source trajectory over the central perturbation regions associated with the individual components of a wide-separation binary. The event is special in the sense that the second perturbation, occurring ~100 days after the first, was predicted by the real-time analysis conducted after the first peak, demonstrating that real-time modeling can be routinely done for binary and planetary events. With the data obtained from follow-up observations covering the second peak, we are able to uniquely determine the physical parameters of the lens system. We find that the event occurred on a bulge clump giant and it was produced by a binary lens composed of a K- and M-type main-sequence stars. The estimated masses of the binary components are M 1 = 0.69 ± 0.11 M sun and M 2 = 0.36 ± 0.06 M sun, respectively, and they are separated in projection by r bottom = 10.9 ± 1.3 AU. The measured distance to the lens is D L = 5.6 ± 0.7 kpc. We also detect the orbital motion of the lens system. Title: A Precise Asteroseismic Age and Radius for the Evolved Sun-like Star KIC 11026764 Authors: Metcalfe, T. S.; Monteiro, M. J. P. F. G.; Thompson, M. J.; Molenda-Żakowicz, J.; Appourchaux, T.; Chaplin, W. J.; Doǧan, G.; Eggenberger, P.; Bedding, T. R.; Bruntt, H.; Creevey, O. L.; Quirion, P. -O.; Stello, D.; Bonanno, A.; Silva Aguirre, V.; Basu, S.; Esch, L.; Gai, N.; Di Mauro, M. P.; Kosovichev, A. G.; Kitiashvili, I. N.; Suárez, J. C.; Moya, A.; Piau, L.; García, R. A.; Marques, J. P.; Frasca, A.; Biazzo, K.; Sousa, S. G.; Dreizler, S.; Bazot, M.; Karoff, C.; Frandsen, S.; Wilson, P. A.; Brown, T. M.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kjeldsen, H.; Campante, T. L.; Fletcher, S. T.; Handberg, R.; Régulo, C.; Salabert, D.; Schou, J.; Verner, G. A.; Ballot, J.; Broomhall, A. -M.; Elsworth, Y.; Hekker, S.; Huber, D.; Mathur, S.; New, R.; Roxburgh, I. W.; Sato, K. H.; White, T. R.; Borucki, W. J.; Koch, D. G.; Jenkins, J. M. Bibcode: 2010ApJ...723.1583M Altcode: 2010arXiv1010.4329M The primary science goal of the Kepler Mission is to provide a census of exoplanets in the solar neighborhood, including the identification and characterization of habitable Earth-like planets. The asteroseismic capabilities of the mission are being used to determine precise radii and ages for the target stars from their solar-like oscillations. Chaplin et al. published observations of three bright G-type stars, which were monitored during the first 33.5 days of science operations. One of these stars, the subgiant KIC 11026764, exhibits a characteristic pattern of oscillation frequencies suggesting that it has evolved significantly. We have derived asteroseismic estimates of the properties of KIC 11026764 from Kepler photometry combined with ground-based spectroscopic data. We present the results of detailed modeling for this star, employing a variety of independent codes and analyses that attempt to match the asteroseismic and spectroscopic constraints simultaneously. We determine both the radius and the age of KIC 11026764 with a precision near 1%, and an accuracy near 2% for the radius and 15% for the age. Continued observations of this star promise to reveal additional oscillation frequencies that will further improve the determination of its fundamental properties. Title: Evidence for planets orbiting the post-common envelope binary NN Serpentis Authors: Dreizler, S.; Beuermann, K.; Hessman, F. V.; Marsh, T. R.; Parsons, S. G.; Dhillon, V. S.; Schreiber, M. R.; Kley, W.; Miller, G. F. Bibcode: 2010AIPC.1273..450D Altcode: From published and new mid-eclipse times obtained between 1988 and 2010 we find long-term eclipse time variations in the post-common envelope eclipsing binary NN Ser. We find strong evidence for two circum-binary planets in this system with orbital periods of Pc = 15.5 and Pd = 7.7 yrs, small eccentricities of ec~0 and ed~0.2 and lower mass limits of Mc sin ic = 6.9 and Mc sin ic = 2.2 MJup. The periods suggest that the planets are locked in a 2:1 resonance. A second solution with a 5:2 resonance and slightly modified planetary parameters results in a nearly equal reduced χ2. The progenitor system is estimated to consists of a ~2 Msolar primary and the present M dwarf secondary at ~1.5 AU distance. The first generation formation of planets and their survival in the later evolutionary stages or the second generation formation in the common envelope shed new light on planet formation and evolution. Title: Pathways towards Neptune-mass Planets around Very Low-mass Stars Authors: Dreizler, S.; Bean, J.; Seifahrt, A.; Hartman, H.; Nilsson, H.; Wiedemann, G.; Reiners, A.; Henry, T. J. Bibcode: 2010ASPC..430..127D Altcode: Radial velocities measured from near-infrared spectra are a potentially powerful tool to search for planets around low-mass stars. The radial velocity precision routinely obtained in the visible can, however, not be achieved in the NIR with existing techniques. In this paper, we describe a method for measuring high-precision radial velocities of a sample of the lowest-mass M dwarfs using CRIRES on the VLT. Our project makes use of a gas cell filled with ammonia to calibrate the instrument response similar to the iodine cell technique that has been used so successfully in the visible. Tests of the method based on the analysis of hundreds of spectra obtained for late M dwarfs over six months demonstrate that precisions of ∼5 m s-1 are obtainable over long timescales, and precisions better than 3 m s-1 can be obtained over timescales up to a week. This allows to search for low-mass planets, i.e., Neptune-mass or even Super-Earth planets around very low-mass stars or sub-stellar objects. Title: Two planets orbiting the recently formed post-common envelope binary NN Serpentis Authors: Beuermann, K.; Hessman, F. V.; Dreizler, S.; Marsh, T. R.; Parsons, S. G.; Winget, D. E.; Miller, G. F.; Schreiber, M. R.; Kley, W.; Dhillon, V. S.; Littlefair, S. P.; Copperwheat, C. M.; Hermes, J. J. Bibcode: 2010A&A...521L..60B Altcode: 2010arXiv1010.3608B Planets orbiting post-common envelope binaries provide fundamental information on planet formation and evolution. We searched for such planets in NN Ser ab, an eclipsing short-period binary that shows long-term eclipse time variations. Using published, reanalysed, and new mid-eclipse times of NN Ser ab obtained between 1988 and 2010, we find excellent agreement with the light-travel-time effect produced by two additional bodies superposed on the linear ephemeris of the binary. Our multi-parameter fits accompanied by N-body simulations yield a best fit for the objects NN Ser (ab)c and d locked in the 2:1 mean motion resonance, with orbital periods Pc ≃ 15.5 yrs and Pd ≃ 7.7 yrs, masses Mc sin ic ≃ 6.9 MJup and Md sin id ≃ 2.2 MJup and eccentricities ec ≃ 0 and ed ≃ 0.20. A secondary χ2 minimum corresponds to an alternative solution with a period ratio of 5:2. We estimate that the progenitor binary consisted of an A star with ~2 M_⊙ and the present M dwarf secondary at an orbital separation of ~1.5 AU. The survival of two planets through the common-envelope phase that created the present white dwarf requires fine tuning between the gravitational force and the drag force experienced by them in the expanding envelope. The alternative is a second-generation origin in a circumbinary disk created at the end of this phase. In that case, the planets would be extremely young with ages not exceeding the cooling age of the white dwarf of 106 yrs.

Table 3 is only available in electronic form at http://www.aanda.org Title: Ground-based Multisite Observations of Two Transits of HD 80606b Authors: Shporer, A.; Winn, J. N.; Dreizler, S.; Colón, K. D.; Wood-Vasey, W. M.; Choi, P. I.; Morley, C.; Moutou, C.; Welsh, W. F.; Pollaco, D.; Starkey, D.; Adams, E.; Barros, S. C. C.; Bouchy, F.; Cabrera-Lavers, A.; Cerutti, S.; Coban, L.; Costello, K.; Deeg, H.; Díaz, R. F.; Esquerdo, G. A.; Fernandez, J.; Fleming, S. W.; Ford, E. B.; Fulton, B. J.; Good, M.; Hébrard, G.; Holman, M. J.; Hunt, M.; Kadakia, S.; Lander, G.; Lockhart, M.; Mazeh, T.; Morehead, R. C.; Nelson, B. E.; Nortmann, L.; Reyes, F.; Roebuck, E.; Rudy, A. R.; Ruth, R.; Simpson, E.; Vincent, C.; Weaver, G.; Xie, J. -W. Bibcode: 2010ApJ...722..880S Altcode: 2010arXiv1008.4129S We present ground-based optical observations of the 2009 September and 2010 January transits of HD 80606b. Based on three partial light curves of the 2009 September event, we derive a midtransit time of Tc [HJD] = 2455099.196 ± 0.026, which is about 1σ away from the previously predicted time. We observed the 2010 January event from nine different locations, with most phases of the transit being observed by at least three different teams. We determine a midtransit time of Tc [HJD] = 2455210.6502 ± 0.0064, which is within 1.3σ of the time derived from a Spitzer observation of the same event. Title: EXOTIME: searching for planets around pulsating subdwarf B stars Authors: Schuh, Sonja; Silvotti, Roberto; Lutz, Ronny; Loeptien, Björn; Green, Elizabeth M.; Østensen, Roy H.; Leccia, Silvio; Kim, Seung-Lee; Fontaine, Gilles; Charpinet, Stéphane; Francœur, Myriam; Randall, Suzanna; Rodríguez-López, Cristina; Van Grootel, Valerie; Odell, Andrew P.; Paparó, Margit; Bognár, Zsófia; Pápics, Péter; Nagel, Thorsten; Beeck, Benjamin; Hundertmark, Markus; Stahn, Thorsten; Dreizler, Stefan; Hessman, Frederic V.; Dall'Ora, Massimo; Mancini, Dario; Cortecchia, Fausto; Benatti, Serena; Claudi, Riccardo; Janulis, Rimvydas Bibcode: 2010Ap&SS.329..231S Altcode: 2010arXiv1005.3461S; 2010Ap&SS.tmp..130S In 2007, a companion with planetary mass was found around the pulsating subdwarf B star V391 Pegasi with the timing method, indicating that a previously undiscovered population of substellar companions to apparently single subdwarf B stars might exist. Following this serendipitous discovery, the EXOTIME (<ExternalRef> <RefSource>http://www.na.astro.it/ silvotti/exotime/</RefSource> <RefTarget Address="http://www.na.astro.it/ silvotti/exotime/" TargetType="URL"/> </ExternalRef>) monitoring program has been set up to follow the pulsations of a number of selected rapidly pulsating subdwarf B stars on time scales of several years with two immediate observational goals:

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determine dot{P} of the pulsational periods P Title: CARMENES: Calar Alto high-resolution search for M dwarfs with exo-earths with a near-infrared Echelle spectrograph Authors: Quirrenbach, A.; Amado, P. J.; Mandel, H.; Caballero, J. A.; Mundt, R.; Ribas, I.; Reiners, A.; Abril, M.; Aceituno, J.; Afonso, C.; Barrado y Navascues, D.; Bean, J. L.; Béjar, V. J. S.; Becerril, S.; Böhm, A.; Cárdenas, M. C.; Claret, A.; Colomé, J.; Costillo, L. P.; Dreizler, S.; Fernández, M.; Francisco, X.; Galadí, D.; Garrido, R.; González Hernández, J. I.; Guàrdia, J.; Guenther, E. W.; Gutiérrez-Soto, F.; Joergens, V.; Hatzes, A. P.; Helmling, J.; Henning, T.; Herrero, E.; Kürster, M.; Laun, W.; Lenzen, R.; Mall, U.; Martin, E. L.; Martín-Ruiz, S.; Mirabet, E.; Montes, D.; Morales, J. C.; Morales Muñoz, R.; Moya, A.; Naranjo, V.; Rabaza, O.; Ramón, A.; Rebolo, R.; Reffert, S.; Rodler, F.; Rodríguez, E.; Rodríguez Trinidad, A.; Rohloff, R. R.; Sánchez Carrasco, M. A.; Schmidt, C.; Seifert, W.; Setiawan, J.; Solano, E.; Stahl, O.; Storz, C.; Suárez, J. C.; Thiele, U.; Wagner, K.; Wiedemann, G.; Zapatero Osorio, M. R.; del Burgo, C.; Sánchez-Blanco, E.; Xu, W. Bibcode: 2010SPIE.7735E..13Q Altcode: 2010SPIE.7735E..37Q CARMENES (Calar Alto high-Resolution search for M dwarfs with Exo-earths with Near-infrared and optical Echelle Spectrographs) is a next-generation instrument to be built for the 3.5m telescope at the Calar Alto Observatory by a consortium of Spanish and German institutions. Conducting a five-year exoplanet survey targeting ~ 300 M stars with the completed instrument is an integral part of the project. The CARMENES instrument consists of two separate spectrographs covering the wavelength range from 0.52 to 1.7 μm at a spectral resolution of R = 85, 000, fed by fibers from the Cassegrain focus of the telescope. The spectrographs are housed in a temperature-stabilized environment in vacuum tanks, to enable a 1m/s radial velocity precision employing a simultaneous ThAr calibration. Title: The MUSE second-generation VLT instrument Authors: Bacon, R.; Accardo, M.; Adjali, L.; Anwand, H.; Bauer, S.; Biswas, I.; Blaizot, J.; Boudon, D.; Brau-Nogue, S.; Brinchmann, J.; Caillier, P.; Capoani, L.; Carollo, C. M.; Contini, T.; Couderc, P.; Daguisé, E.; Deiries, S.; Delabre, B.; Dreizler, S.; Dubois, J.; Dupieux, M.; Dupuy, C.; Emsellem, E.; Fechner, T.; Fleischmann, A.; François, M.; Gallou, G.; Gharsa, T.; Glindemann, A.; Gojak, D.; Guiderdoni, B.; Hansali, G.; Hahn, T.; Jarno, A.; Kelz, A.; Koehler, C.; Kosmalski, J.; Laurent, F.; Le Floch, M.; Lilly, S. J.; Lizon, J. -L.; Loupias, M.; Manescau, A.; Monstein, C.; Nicklas, H.; Olaya, J. -C.; Pares, L.; Pasquini, L.; Pécontal-Rousset, A.; Pelló, R.; Petit, C.; Popow, E.; Reiss, R.; Remillieux, A.; Renault, E.; Roth, M.; Rupprecht, G.; Serre, D.; Schaye, J.; Soucail, G.; Steinmetz, M.; Streicher, O.; Stuik, R.; Valentin, H.,; Vernet, J.; Weilbacher, P.; Wisotzki, L.; Yerle, N. Bibcode: 2010SPIE.7735E..08B Altcode: 2010SPIE.7735E...7B Summary: The Multi Unit Spectroscopic Explorer (MUSE) is a second-generation VLT panoramic integral-field spectrograph currently in manufacturing, assembly and integration phase. MUSE has a field of 1x1 arcmin2 sampled at 0.2x0.2 arcsec2 and is assisted by the VLT ground layer adaptive optics ESO facility using four laser guide stars. The instrument is a large assembly of 24 identical high performance integral field units, each one composed of an advanced image slicer, a spectrograph and a 4kx4k detector. In this paper we review the progress of the manufacturing and report the performance achieved with the first integral field unit. Title: X-ray spectroscopy and photometry of the long-period polar AI Trianguli with XMM-Newton Authors: Traulsen, I.; Reinsch, K.; Schwarz, R.; Dreizler, S.; Beuermann, K.; Schwope, A. D.; Burwitz, V. Bibcode: 2010A&A...516A..76T Altcode: 2010arXiv1004.1629T Context. The energy balance of cataclysmic variables with strong magnetic fields is a central subject in understanding accretion processes on magnetic white dwarfs. With XMM-Newton, we perform a spectroscopic and photometric study of soft X-ray selected polars during their high states of accretion.
Aims: On the basis of X-ray and optical observations of the magnetic cataclysmic variable AI Tri, we derive the properties of the spectral components, their flux contributions, and the physical structure of the accretion region in soft polars.
Methods: We use multi-temperature approaches in our xspec modeling of the X-ray spectra to describe the physical conditions and the structures of the post-shock accretion flow and the accretion spot on the white-dwarf surface. In addition, we investigate the accretion geometry of the system by completing a timing analysis of the photometric data.
Results: Flaring soft X-ray emission from the heated surface of the white dwarf dominates the X-ray flux during roughly 70% of the binary cycle. This component deviates from a single black body and can be described by a superimposition of mildly absorbed black bodies with a Gaussian temperature distribution between kTbb,low := 2 eV and kTbb,high = 43.9+3.3-3.2 eV, and {N}_H,ISM = 1.5+0.8-0.7× 1020 cm-2. In addition, weaker hard X-ray emission is visible nearly all the time. The spectrum from the cooling post-shock accretion flow is most closely fitted by a combination of thermal plasma mekal models with temperature profiles adapted from prior stationary two-fluid hydrodynamic calculations. The resulting plasma temperatures lie between kT_MEKAL,{low} = 0.8+0.4-0.2 keV and kT_MEKAL,{high} = 20.0+9.9-6.1 keV; additional intrinsic, partial-covering absorption is on the order of NH,int = 3.3+2.5-1.2× 1023 cm-2. The soft X-ray light curves show a dip during the bright phase, which can be interpreted as self-absorption in the accretion stream. Phase-resolved spectral modeling supports the picture of one-pole accretion and self-eclipse. One of the optical light curves corresponds to an irregular mode of accretion. During a short XMM-Newton observation at the same epoch, the X-ray emission of the system is clearly dominated by the soft component.

Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. Title: The CRIRES Search for Planets at the Bottom of the Main Sequence Authors: Bean, J.; Seifahrt, A.; Hartman, H.; Nilsson, H.; Wiedemann, G.; Reiners, A.; Dreizler, S.; Henry, T. Bibcode: 2010Msngr.140...41B Altcode: We present the first results obtained from our ongoing search for planets around very low-mass stars and brown dwarfs using radial velocities measured with the CRIRES spectrograph on the VLT. High-precision radial velocity measurements for a large sample of these previously neglected stars are enabled by observing at near-infrared wavelengths and using a new type of gas cell that we have developed. Unprecedented long-term near-infrared radial velocity precisions of ~ 5 ms-1 have been demonstrated using CRIRES with the cell. As a first scientific result, data obtained for the very low-mass star VB 10 have been used to refute a claimed planet detection based on astrometry. These results demonstrate the unique sensitivity of our methodology, and confirm its power to detect planets, including potentially habitable ones, around the most numerous stars in the Galaxy. Title: Discovery of a nearby young brown dwarf binary candidate Authors: Reiners, A.; Seifahrt, A.; Dreizler, S. Bibcode: 2010A&A...513L...9R Altcode: 2010arXiv1003.1715R In near-infrared NaCo observations of the young brown dwarf 2MASS J0041353-562112, we discovered a companion a little less than a magnitude fainter than the primary. The binary candidate has a separation of 143 mas, and the spectral types of the two components are M 6.5 and M 9.0. Colors and flux ratios of the components are consistent with their locations being at the same distance minimizing the probability of the secondary being a background object. The brown dwarf is known to exhibit Li absorption constraining the age to be younger than ~ 200 Myr, and has been suspected of experiencing ongoing accretion, which implies an age as young as ~ 10 Myr. We estimate distance and orbital parameters of the binary as a function of age. For an age of 10 Myr, the distance to the system is 50 pc, the orbital period is 126 yr, and the masses of the components are ~ 30 and ~ 15 MJup. The binary brown dwarf fills a so far unoccupied region in the parameters mass and age; it is a valuable new benchmark object for brown dwarf atmospheric and evolutionary models.

Emmy Noether Fellow. Title: The CRIRES Search for Planets Around the Lowest-mass Stars. I. High-precision Near-infrared Radial Velocities with an Ammonia Gas Cell Authors: Bean, Jacob L.; Seifahrt, Andreas; Hartman, Henrik; Nilsson, Hampus; Wiedemann, Günter; Reiners, Ansgar; Dreizler, Stefan; Henry, Todd J. Bibcode: 2010ApJ...713..410B Altcode: 2009arXiv0911.3148B Radial velocities measured from near-infrared (NIR) spectra are a potentially powerful tool to search for planets around cool stars and sub-stellar objects. However, no technique currently exists that yields NIR radial velocity precision comparable to that routinely obtained in the visible. We are carrying out an NIR radial velocity planet search program targeting a sample of the lowest-mass M dwarfs using the CRIRES instrument on the Very Large Telescope. In this first paper in a planned series about the project, we describe a method for measuring high-precision relative radial velocities of these stars from K-band spectra. The method makes use of a glass cell filled with ammonia gas to calibrate the spectrograph response similar to the "iodine cell" technique that has been used very successfully in the visible. Stellar spectra are obtained through the ammonia cell and modeled as the product of a Doppler-shifted template spectrum of the object and a spectrum of the cell, convolved with a variable instrumental profile (IP) model. A complicating factor is that a significant number of telluric absorption lines are present in the spectral regions containing useful stellar and ammonia lines. The telluric lines are modeled simultaneously as well using spectrum synthesis with a time-resolved model of the atmosphere over the observatory. The free parameters in the complete model are the wavelength scale of the spectrum, the IP, adjustments to the water and methane abundances in the atmospheric model, telluric spectrum Doppler shift, and stellar Doppler shift. Tests of the method based on the analysis of hundreds of spectra obtained for late-M dwarfs over 6 months demonstrate that precisions of ~ 5 m s-1 are obtainable over long timescales, and precisions of better than 3 m s-1 can be obtained over timescales up to a week. The obtained precision is comparable to the predicted photon-limited errors, but primarily limited over long timescales by the imperfect modeling of the telluric lines.

Based on observations made with ESO Telescopes at the Paranal Observatories under program ID 182.C-0748. Title: The Asteroseismic Potential of Kepler: First Results for Solar-Type Stars Authors: Chaplin, W. J.; Appourchaux, T.; Elsworth, Y.; García, R. A.; Houdek, G.; Karoff, C.; Metcalfe, T. S.; Molenda-Żakowicz, J.; Monteiro, M. J. P. F. G.; Thompson, M. J.; Brown, T. M.; Christensen-Dalsgaard, J.; Gilliland, R. L.; Kjeldsen, H.; Borucki, W. J.; Koch, D.; Jenkins, J. M.; Ballot, J.; Basu, S.; Bazot, M.; Bedding, T. R.; Benomar, O.; Bonanno, A.; Brandão, I. M.; Bruntt, H.; Campante, T. L.; Creevey, O. L.; Di Mauro, M. P.; Doǧan, G.; Dreizler, S.; Eggenberger, P.; Esch, L.; Fletcher, S. T.; Frandsen, S.; Gai, N.; Gaulme, P.; Handberg, R.; Hekker, S.; Howe, R.; Huber, D.; Korzennik, S. G.; Lebrun, J. C.; Leccia, S.; Martic, M.; Mathur, S.; Mosser, B.; New, R.; Quirion, P. -O.; Régulo, C.; Roxburgh, I. W.; Salabert, D.; Schou, J.; Sousa, S. G.; Stello, D.; Verner, G. A.; Arentoft, T.; Barban, C.; Belkacem, K.; Benatti, S.; Biazzo, K.; Boumier, P.; Bradley, P. A.; Broomhall, A. -M.; Buzasi, D. L.; Claudi, R. U.; Cunha, M. S.; D'Antona, F.; Deheuvels, S.; Derekas, A.; García Hernández, A.; Giampapa, M. S.; Goupil, M. J.; Gruberbauer, M.; Guzik, J. A.; Hale, S. J.; Ireland, M. J.; Kiss, L. L.; Kitiashvili, I. N.; Kolenberg, K.; Korhonen, H.; Kosovichev, A. G.; Kupka, F.; Lebreton, Y.; Leroy, B.; Ludwig, H. -G.; Mathis, S.; Michel, E.; Miglio, A.; Montalbán, J.; Moya, A.; Noels, A.; Noyes, R. W.; Pallé, P. L.; Piau, L.; Preston, H. L.; Roca Cortés, T.; Roth, M.; Sato, K. H.; Schmitt, J.; Serenelli, A. M.; Silva Aguirre, V.; Stevens, I. R.; Suárez, J. C.; Suran, M. D.; Trampedach, R.; Turck-Chièze, S.; Uytterhoeven, K.; Ventura, R.; Wilson, P. A. Bibcode: 2010ApJ...713L.169C Altcode: 2010arXiv1001.0506C We present preliminary asteroseismic results from Kepler on three G-type stars. The observations, made at one-minute cadence during the first 33.5 days of science operations, reveal high signal-to-noise solar-like oscillation spectra in all three stars: about 20 modes of oscillation may be clearly distinguished in each star. We discuss the appearance of the oscillation spectra, use the frequencies and frequency separations to provide first results on the radii, masses, and ages of the stars, and comment in the light of these results on prospects for inference on other solar-type stars that Kepler will observe. Title: Discovery of a Red Giant with Solar-like Oscillations in an Eclipsing Binary System from Kepler Space-based Photometry Authors: Hekker, S.; Debosscher, J.; Huber, D.; Hidas, M. G.; De Ridder, J.; Aerts, C.; Stello, D.; Bedding, T. R.; Gilliland, R. L.; Christensen-Dalsgaard, J.; Brown, T. M.; Kjeldsen, H.; Borucki, W. J.; Koch, D.; Jenkins, J. M.; Van Winckel, H.; Beck, P. G.; Blomme, J.; Southworth, J.; Pigulski, A.; Chaplin, W. J.; Elsworth, Y. P.; Stevens, I. R.; Dreizler, S.; Kurtz, D. W.; Maceroni, C.; Cardini, D.; Derekas, A.; Suran, M. D. Bibcode: 2010ApJ...713L.187H Altcode: 2010arXiv1001.0399H Oscillating stars in binary systems are among the most interesting stellar laboratories, as these can provide information on the stellar parameters and stellar internal structures. Here we present a red giant with solar-like oscillations in an eclipsing binary observed with the NASA Kepler satellite. We compute stellar parameters of the red giant from spectra and the asteroseismic mass and radius from the oscillations. Although only one eclipse has been observed so far, we can already determine that the secondary is a main-sequence F star in an eccentric orbit with a semi-major axis larger than 0.5 AU and orbital period longer than 75 days. Title: The Proposed Giant Planet Orbiting VB 10 Does Not Exist Authors: Bean, Jacob L.; Seifahrt, Andreas; Hartman, Henrik; Nilsson, Hampus; Reiners, Ansgar; Dreizler, Stefan; Henry, Todd J.; Wiedemann, Günter Bibcode: 2010ApJ...711L..19B Altcode: We present high-precision relative radial velocities of the very low mass star VB 10 that were obtained over a time span of 0.61 years as part of an ongoing search for planets around stars at the end of the main sequence. The radial velocities were measured from high-resolution near-infrared spectra obtained using the CRIRES instrument on the Very Large Telescope with an ammonia gas cell. The typical internal precision of the measurements is 10 m s-1. These data do not exhibit significant variability and are essentially constant at a level consistent with the measurement uncertainties. Therefore, we do not detect the radial velocity variations of VB 10 expected due to the presence of an orbiting giant planet similar to that recently proposed by Pravdo & Shaklan based on apparent astrometric perturbations. In addition, we do not confirm the ~1 km s-1 radial velocity variability of the star tentatively detected by Zapatero Osorio and colleagues with lower precision measurements. Our measurements rule out planets with M p > 3 M Jup and the orbital period and inclination suggested by Pravdo & Shaklan at better than 5σ confidence. We conclude that the planet detection claimed by Pravdo & Shaklan is spurious on the basis of this result. Although the outcome of this work is a non-detection, it illustrates the potential of using ammonia cell radial velocities to detect planets around very low mass stars.

Based on observations made with ESO Telescopes at the Paranal Observatories under program ID 182.C-0748. Title: Detecting Planets Around Very Low Mass Stars with the Radial Velocity Method Authors: Reiners, A.; Bean, J. L.; Huber, K. F.; Dreizler, S.; Seifahrt, A.; Czesla, S. Bibcode: 2010ApJ...710..432R Altcode: 2009arXiv0909.0002R The detection of planets around very low-mass stars with the radial velocity (RV) method is hampered by the fact that these stars are very faint at optical wavelengths where the most high-precision spectrometers operate. We investigate the precision that can be achieved in RV measurements of low mass stars in the near-infrared (NIR) Y-, J-, and H-bands, and we compare it to the precision achievable in the optical assuming comparable telescope and instrument efficiencies. For early-M stars, RV measurements in the NIR offer no or only marginal advantage in comparison with optical measurements. Although they emit more flux in the NIR, the richness of spectral features in the optical outweighs the flux difference. We find that NIR measurement can be as precise as optical measurements in stars of spectral type ~M4, and from there the NIR gains in precision toward cooler objects. We studied potential calibration strategies in the NIR finding that a stable spectrograph with a ThAr calibration can offer enough wavelength stability for m s-1 precision. Furthermore, we simulate the wavelength-dependent influence of activity (cool spots) on RV measurements from optical to NIR wavelengths. Our spot simulations reveal that the RV jitter does not decrease as dramatically toward longer wavelengths as often thought. The jitter strongly depends on the details of the spots, i.e., on spot temperature and the spectral appearance of the spot. At low temperature contrast (~200 K), the jitter shows a decrease toward the NIR up to a factor of 10, but it decreases substantially less for larger temperature contrasts. Forthcoming NIR spectrographs will allow the search for planets with a particular advantage in mid- and late-M stars. Activity will remain an issue, but simultaneous observations at optical and NIR wavelengths can provide strong constraints on spot properties in active stars. Title: The CRIRES Search for Planets Around the Lowest-Mass Stars: Introduction and First Results Authors: Bean, Jacob; Seifahrt, A.; Reiners, A.; Dreizler, S.; Hartman, H.; Nilsson, H.; Wiedemann, G.; Henry, T. Bibcode: 2010AAS...21534807B Altcode: 2010BAAS...42..530B We are currently carrying out a search for planets around the lowest-mass stars using the CRIRES instrument at the VLT under the auspices of an ESO Large Programme. The main purposes of this work are to illuminate the correlation between stellar mass and planet formation, improve the census of planets, and identify new planets that can be followed-up for detailed study. We have developed, and are utilizing a new type of gas cell for obtaining high-precision radial velocities of late-type stars in the nIR spectral region. Observations in the nIR offer the advantages in that the targetted stars are bright enough for high-precision spectroscopy, and that the noise contribution from stellar activity is significantly reduced. We will give an introduction to the survey and present some preliminary results. Title: The CRIRES Search for Planets Around the Lowest-Mass Stars: High-Precision nIR Radial Velocities with a New Gas Cell Authors: Seifahrt, Andreas; Bean, J.; Hartman, H.; Nilsson, H.; Wiedemann, G.; Reiners, A.; Dreizler, S.; Henry, T. Bibcode: 2010AAS...21542114S Altcode: 2010BAAS...42..288S We are currently carrying out a search for planets around the lowest-mass stars using the CRIRES instrument at the VLT under the auspices of an ESO Large Programme. The main purposes of this work are to illuminate the correlation between stellar mass and planet formation, improve the census of planets, and identify new planets that can be followed-up for detailed study. We have developed, and are utilizing a new type of gas cell for obtaining high-precision radial velocities of late-type stars in the nIR spectral region. Observations in the nIR offer the advantages in that the targeted stars are bright enough for high-precision spectroscopy, and that the noise contribution from stellar activity is significantly reduced. We will describe the new gas cell and our radial velocity measurement algorithm, and present extensive tests of the obtained precision. Title: The CRIRES Search for Planets Around the Lowest-Mass Stars. II. The Proposed Giant Planet Orbiting VB10 Does Not Exist Authors: Bean, Jacob L.; Seifahrt, Andreas; Hartman, Henrik; Nilsson, Hampus; Reiners, Ansgar; Dreizler, Stefan; Henry, Todd J.; Wiedemann, Guenter Bibcode: 2009arXiv0912.0003B Altcode: We present high-precision relative radial velocities of the very low-mass star VB10 that were obtained over a time span of 0.61 yr as part of an ongoing search for planets around stars at the end of the main sequence. The radial velocities were measured from high-resolution near-infrared spectra obtained using the CRIRES instrument on the VLT with an ammonia gas cell. The typical internal precision of the measurements is 10 m/s. These data do not exhibit significant variability and are essentially constant at a level consistent with the measurement uncertainties. Therefore, we do not detect the radial velocity variations of VB10 expected due to the presence of an orbiting giant planet similar to that recently proposed by Pravdo and Shaklan based on apparent astrometric perturbations. In addition, we do not confirm the ~1 km/s radial velocity variability of the star tentatively detected by Zapatero Osorio and colleagues with lower precision measurements. Our measurements rule out planets with M_p > 3 M_Jup and the orbital period and inclination suggested by Pravdo and Shaklan at better than 5 sigma confidence. We conclude that the planet detection claimed by Pravdo and Shaklan is spurious on the basis of this result. Although the outcome of this work is a non-detection, it illustrates the potential of using ammonia cell radial velocities to detect planets around very low-mass stars. Title: Physical Properties of the 0.94-Day Period Transiting Planetary System WASP-18 Authors: Southworth, John; Hinse, T. C.; Dominik, M.; Glitrup, M.; Jørgensen, U. G.; Liebig, C.; Mathiasen, M.; Anderson, D. R.; Bozza, V.; Browne, P.; Burgdorf, M.; Calchi Novati, S.; Dreizler, S.; Finet, F.; Harpsøe, K.; Hessman, F.; Hundertmark, M.; Maier, G.; Mancini, L.; Maxted, P. F. L.; Rahvar, S.; Ricci, D.; Scarpetta, G.; Skottfelt, J.; Snodgrass, C.; Surdej, J.; Zimmer, F. Bibcode: 2009ApJ...707..167S Altcode: 2009arXiv0910.4875S We present high-precision photometry of five consecutive transits of WASP-18, an extrasolar planetary system with one of the shortest orbital periods known. Through the use of telescope defocusing we achieve a photometric precision of 0.47-0.83 mmag per observation over complete transit events. The data are analyzed using the JKTEBOP code and three different sets of stellar evolutionary models. We find the mass and radius of the planet to be M b = 10.43 ± 0.30 ± 0.24 M Jup and R b = 1.165 ± 0.055 ± 0.014 R Jup (statistical and systematic errors), respectively. The systematic errors in the orbital separation and the stellar and planetary masses, arising from the use of theoretical predictions, are of a similar size to the statistical errors and set a limit on our understanding of the WASP-18 system. We point out that seven of the nine known massive transiting planets (M b > 3 M Jup) have eccentric orbits, whereas significant orbital eccentricity has been detected for only four of the 46 less-massive planets. This may indicate that there are two different populations of transiting planets, but could also be explained by observational biases. Further radial velocity observations of low-mass planets will make it possible to choose between these two scenarios.

Based on data collected by MiNDSTEp with the Danish 1.54 m telescope at the ESO La Silla Observatory. Title: A hot white dwarf luminosity function from the Sloan Digital Sky Survey Authors: Krzesinski, J.; Kleinman, S. J.; Nitta, A.; Hügelmeyer, S.; Dreizler, S.; Liebert, J.; Harris, H. Bibcode: 2009A&A...508..339K Altcode: Aims. We present a hot white dwarf (WD) luminosity function (LF) using data taken from the Sloan Digital Sky Survey (SDSS) Data Release 4. We present and discuss a combined LF, along with separate DA and non-DA as LFs. We explore the completeness of our LFs and interpret a sudden drop in the non-DA LF near 2 M_bol as a transition of the non-DA WD atmosphere into the DA one during WD evolution. Our LF extends roughly between -0.5 < M_bol < 7 or equivalently, ∼ 120 000 K > T_eff > ∼25 000 K. Our LF should now be useful for estimates of recent star formation and for studies of neutrino and other potential particle emission losses in hot WDs.
Methods: To create a sample whose completeness can be characterized fully, we used stars whose spectra were obtained via the SDSS's “hot standard” target selection criteria. The hot standard stars were purposefully targeted to a high level of completeness by the SDSS for calibration purposes. We are fortunate that many of them are hot white dwarfs stars. We further limited the sample to stars with fitted temperatures exceeding 23 500 K and log{g} > 7.0. We determined stellar distances for our sample based on their absolute SDSS g filter magnitudes, derived from WD stellar atmosphere model fits to the SDSS stellar spectra.
Results: We compared our LF with those of other researchers where overlap occurs; however, our LFs are unique in their extension to the most luminous/hottest WDs. The cool end of our LF connects with the hot end of previously determined SDSS WD LFs and agreement here is quite good. It is also good with previous non-SDSS WD LFs. We note distinct differences between the DA and non-DA LFs and discuss the reliability of the DA LF at its hot end. We have extended the range of luminosities covered in the most recent WD LFs. The SDSS sample is understood quite well and its exploration should contribute to a number of new insights into early white dwarf evolution.
Title: The Transit Ingress and the Tilted Orbit of the Extraordinarily Eccentric Exoplanet HD 80606b Authors: Winn, Joshua N.; Howard, Andrew W.; Johnson, John Asher; Marcy, Geoffrey W.; Gazak, J. Zachary; Starkey, Donn; Ford, Eric B.; Colón, Knicole D.; Reyes, Francisco; Nortmann, Lisa; Dreizler, Stefan; Odewahn, Stephen; Welsh, William F.; Kadakia, Shimonee; Vanderbei, Robert J.; Adams, Elisabeth R.; Lockhart, Matthew; Crossfield, Ian J.; Valenti, Jeff A.; Dantowitz, Ronald; Carter, Joshua A. Bibcode: 2009ApJ...703.2091W Altcode: 2009arXiv0907.5205W We present the results of a transcontinental campaign to observe the 2009 June 5 transit of the exoplanet HD 80606b. We report the first detection of the transit ingress, revealing the transit duration to be 11.64 ± 0.25 hr and allowing more robust determinations of the system parameters. Keck spectra obtained at midtransit exhibit an anomalous blueshift, giving definitive evidence that the stellar spin axis and planetary orbital axis are misaligned. The Keck data show that the projected spin-orbit angle λ is between 32° and 87° with 68.3% confidence and between 14° and 142° with 99.73% confidence. Thus, the orbit of this planet is not only highly eccentric (e = 0.93) but is also tilted away from the equatorial plane of its parent star. A large tilt had been predicted, based on the idea that the planet's eccentric orbit was caused by the Kozai mechanism. Independently of the theory, it is worth noting that all three exoplanetary systems with known spin-orbit misalignments have massive planets on eccentric orbits, suggesting that those systems migrate through a different channel than lower mass planets on circular orbits. Title: 1D and 3D radiative transfer in circumstellar disks Authors: Hügelmeyer, S. D.; Dreizler, S.; Homeier, D.; Hauschildt, P. H.; Barman, T. Bibcode: 2009AIPC.1171...93H Altcode: We present our code for the calculation of the 1D structure and synthetic spectra of accretion disks. The code is an extension of the well-tested stellar atmosphere code PHOENIX and is therefore capable of including large lists of atomic and molecular lines as well as a large set of dust species. We assume the standard accretion disk model for geometrically thin disks and solve the radiative transfer equation in the vertical direction for a number of disk rings with different radii. The combination of these rings yields the total disk spectrum. Comparison to observations of the T Tauri star GQ Lup shows the capability of our code. Additionally, we will show first results of 3D radiative transfer calculations. We plan to investigate the effect of rotating disks on the line profile by means of a two-level atom. Title: Detecting circumstellar disks around gravitational microlenses Authors: Hundertmark, M.; Hessman, F. V.; Dreizler, S. Bibcode: 2009A&A...500..929H Altcode: 2009arXiv0904.1117H Aims: We investigate the chance of detecting proto-planetary or debris disks in stars that induce microlensing event (lenses), and consider the modification of the light curve shapes due to occultation and extinction by the disks, as well as the gravitational deflection caused by the additional mass.
Methods: The magnification of gravitational microlensing events is calculated using the ray shooting method. The occultation is taken into account by neglecting or weighting the images on the lens plane according to a transmission map of the corresponding disk for a point source point lens (PSPL) model. The estimated frequency of events is obtained by considering the possible inclinations and optical depths of the disk.
Results: We conclude that gravitational microlensing can be used, in principle, as a tool for detecting debris disks beyond 1 kpc, but estimate that each year around 1 debris disk is expected for lens stars of F, G, or K spectral type and about 10 debris disks might have shown signatures in existing datasets. Title: Spectral synthesis of circumstellar disks - application to white dwarf debris disks Authors: Hügelmeyer, S. D.; Dreizler, S.; Homeier, D.; Hauschildt, P. Bibcode: 2009JPhCS.172a2060H Altcode: 2009arXiv0905.0329H Gas and dust disks are common objects in the universe and can be found around various objects, e.g. young stars, cataclysmic variables, active galactic nuclei, or white dwarfs. The light that we receive from disks provides us with clues about their composition, temperature, and density. In order to better understand the physical and chemical dynamics of these disks, self-consistent radiative transfer simulations are inevitable. Therefore, we have developed a 1+1D radiative transfer code as an extension to the well-established model atmosphere code PHOENIX. We will show the potential of the application of our code to model the spectra of white dwarf debris disks. Title: Spectral analysis of 636 WD - M star binaries from the Sloan Digital Sky Survey (Data Release 6) Authors: Heller, R.; Homeier, D.; Dreizler, S.; Østensen, R. Bibcode: 2009JPhCS.172a2023H Altcode: We present a catalog of 857 WD (WD)-M star binaries from the sixth data release of the Sloan Digital Sky Survey (SDSS), most of them known before. For 636 of them, we give a spectral analysis and derive the basic parameters of the stellar constituents and their distances from Earth. Our purpose is to test the modeled spectra applied in the fitting procedure on the one hand and to confine the respective evolutionary scenarios on the other hand. We use a χ2 minimization technique in order to decompose each combined spectrum and yield independent parameter estimates for the components. 41 of the stellar duets in our spectroscopic sample are optically resolved on the respective SDSS images. Despite various selection effects, the fraction of 6.4 % of WD-M star binaries with orbital separation around 500 AU and orbital perdiods of ~ 104 yr is a criterion for evolutionary models of stellar binary systems. We find 20 out of 636 WDs being fitted as DOs, with 16 of them indicating TefWD around 40000K. This excess of cool DOs is most likely due to additional WDs in the DB-DO Teff range, for which no detailed fitting was done. Furthermore, we identify 70 very low-mass objects, meaning secondaries with masses smaller than about 0.1 Modot, as candidate substellar companions. A trend of WD masses towards higher values in a binary constellation compared to those of field WDs is compatible with our results. Title: SDSS DR4: Progress on the hot white dwarf luminosity function Authors: Krzesinski, J.; Nitta, A.; Kleinman, S. J.; Hügelmeyer, S.; Dreizler, S.; Liebert, J.; Harris, H. Bibcode: 2009JPhCS.172a2002K Altcode: A large collection of white dwarf (WD) spectra from Sloan Digital Sky Survey (SDSS) data release 4 (DR4) WD catalog data allowed us to obtain a luminosity function (LF) for the hottest WDs. The LF was calculated basing on spectra of the WDs from a special class of SDSS objects called hot standards (HS), for which the WD sample completeness can be estimated. WD distances were determined from the observed and absolute SDSS g filter magnitudes derived from WD stellar atmosphere model fits to the SDSS spectra. The result LF covers -0.5 up to 7 absolute bolometric magnitude range. It shows a slight disagreement at the cold end comparing to the literature LFs but it can be due to some problems with HS WD sample completeness estimations. It is clearly visible that the LF has unexpected plateau between 1.5 and 4 absolute bolometric magnitudes. There is nothing similar visible in a LF built only for non-DA WDs. The plateau might be real but we are concern that its existence can be connected to the problems with spectra calibration of the blue objects in SDSS DR4 data and lack of good stellar atmosphere models for the hottest DA white dwarfs. Title: Non-LTE spectral analyses of the lately discovered DB-gap white dwarfs from the SDSS Authors: Hügelmeyer, S. D.; Dreizler, S. Bibcode: 2009JPhCS.172a2048H Altcode: 2009arXiv0905.0331H For a long time, no hydrogen-deficient white dwarfs have been known that have effective temperature between 30 kK and < 45 kK, i. e. exceeding those of DB white dwarfs and having lower ones than DO white dwarfs. Therefore, this temperature range was long known as the DB-gap. Only recently, the SDSS provided spectra of several candidate DB-gap stars. First analyses based on model spectra calculated under the assumption of local thermodynamic equilibrium (LTE) confirmed that these stars had 30 kK < Teff < 45 kK (Eisenstein et al. 2006). It has been shown for DO white dwarfs that the relaxation of LTE is necessary to account for non local effects in the atmosphere caused by the intense radiation field. Therefore, we calculated a non-LTE model grid and re-analysed the aforementioned set of SDSS spectra. Our results confirm the existence of DB-gap white dwarfs. Title: On the possibility of detecting extrasolar planets' atmospheres with the Rossiter-McLaughlin effect Authors: Dreizler, S.; Reiners, A.; Homeier, D.; Noll, M. Bibcode: 2009A&A...499..615D Altcode: 2009arXiv0903.2217D Context: The detection of extrasolar planets' atmospheres requires very demanding observations. For planets that cannot be spatially separated from their host stars, i.e. the vast majority of planets, the transiting planets are the only ones to allow their atmospheres to be probed. This is possible from transmission spectroscopy or from measurements taken during the secondary eclipse. An alternative is to measure of the Rossiter-McLaughlin effect, which is sensitive to the size of the planetary radius. Since the radius is wavelength-dependent due to contributions of strong planetary absorption lines, this opens a path toward also probing planetary atmospheres with ground-based high-resolution spectroscopy.
Aims: The major goal of our numerical simulations is to provide a reliable estimate of the amplitude of the wavelength-dependent Rossiter-McLaughlin effect.
Methods: Our numerical simulations provide detailed phase-resolved synthetic spectra modeling the partly eclipsed stellar surface during the transit. With these spectra we can obtain Rossiter-McLaughlin curves for different wavelength regions and for a wavelength-dependent planetary radius. Curves from regions with high and low contributions of absorption lines within the planetary atmosphere can be compared. Observable quantities are derived from these differential effects.
Results: We applied our simulations to HD 209458. Our numerical simulations show that a detailed treatment of the limb-darkening for the synthetic spectra is important for a precise analysis. Compared to a parameterized limb-darkening law, systematic errors of 6 m s-1 occur. The wavelength dependency of the planetary atmospheres over the NaD-doublet produces a differential effect in the Rossiter-McLaughlin curve of 1.5 m s-1 for a star with a rotation velocity of 4.5 km s-1, which increases to 4 m s-1 for twice the rotation velocity.
Conclusions: As a tool for probing planetary atmospheres the Rossiter-McLaughlin effect requires phase-resolved, high signal-to-noise, high-resolution spectra taken with a stabilized spectrograph in order to obtain reliable results for slowly rotating (<10 m s-1) planet host stars. Stars with spectral type earlier than about F5 are a bit less demanding since the typically higher rotation velocity increases the amplitude of the effect to about 15 m s-1 for a star with v sin i = 25 km s-1. Title: Radiative transfer in circumstellar disks. I. 1D models for GQ Lupi Authors: Hügelmeyer, S. D.; Dreizler, S.; Hauschildt, P. H.; Seifahrt, A.; Homeier, D.; Barman, T. Bibcode: 2009A&A...498..793H Altcode: 2009arXiv0903.2381H We present a new code for the calculation of the 1D structure and synthetic spectra of accretion disks. The code is an extension of the general purpose stellar atmosphere code PHOENIX and is therefore capable of including extensive lists of atomic and molecular lines as well as dust in the calculations. We assume that the average viscosity can be represented by a critical Reynolds number in a geometrically thin disk and solve the structure and radiative transfer equations for a number of disk rings in the vertical direction. The combination of these rings provides the total disk structure and spectrum. Since the warm inner regions of protoplanetary disks show a rich molecular spectrum, they are well suited for a spectral analysis with our models. In this paper we test our code by comparing our models with high-resolution VLT CRIRES spectra of the T Tauri star GQ Lup. Title: OGLE2-TR-L9b: an exoplanet transiting a rapidly rotating F3 star Authors: Snellen, I. A. G.; Koppenhoefer, J.; van der Burg, R. F. J.; Dreizler, S.; Greiner, J.; de Hoon, M. D. J.; Husser, T. O.; Krühler, T.; Saglia, R. P.; Vuijsje, F. N. Bibcode: 2009A&A...497..545S Altcode: 2008arXiv0812.0599S Context: The photometric observations of the OGLE-II microlens monitoring campaign have been taken in the period 1997-2000. All light curves of this campaign have recently become public. Our analysis of these data has revealed 13 low-amplitude transiting objects among 15 700 stars in three Carina fields towards the Galactic disk. One of these objects, OGLE2-TR-L9 (P∼2.5 days), turned out to be an excellent transiting-planet candidate.
Aims: We report on our investigation of the true nature of OGLE2-TR-L9. By re-observing the photometric transit, we attempt to determine the transit parameters to high precision, and, by spectroscopic observations, to estimate the properties of the host star and determine the mass of the transiting object by means of radial-velocity measurements.
Methods: High precision photometric observations were obtained in g', r', i', and z' band simultaneously, using the new GROND detector, mounted on the MPI/ESO 2.2 m telescope at La Silla. Eight epochs of high-dispersion spectroscopic observations were obtained using the fiber-fed FLAMES/UVES Echelle spectrograph, mounted on ESO's Very Large Telescope at Paranal.
Results: The photometric transit, now more than 7 years after the last OGLE-II observations, was re-discovered only 8 min from its predicted time. The primary object is a rapidly rotating F3 star with v sin i=39.33±0.38 km s-1, T=6933±58 K, log g = 4.25±0.01, and [Fe/H] = -0.05±0.20. The transiting object is an extrasolar planet with M{p}=4.5±1.5 M{Jup} and R{p}=1.61±0.04 R{Jup}. Since this is the first planet detected orbiting a fast rotating star, the uncertainties in both the radial-velocity measurements and the planetary mass are larger than for most other planets discovered to date. The rejection of possible blend scenarios was based on a quantitative analysis of the multi-color photometric data. A stellar-blend scenario of an early F-star with a faint eclipsing-binary system is excluded, due to 1) the consistency between the spectroscopic parameters of the star and the mean density of the transited object as determined from the photometry, and 2) the excellent agreement between the transit signal as observed at four different wavelengths.

Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile (280.C-5036(A)). Title: VizieR Online Data Catalog: Spectral analysis of 636 SDSS WD-M binaries (Heller+, 2009) Authors: Heller, R.; Homeier, D.; Dreizler, S.; Oestensen, R. Bibcode: 2009yCat..34960191H Altcode: We present a catalog of 857 WD-M star binaries from the Sloan Digital Sky Survey (SDSS), most of which were previously identified by other authors, and the results of our spectral analysis for a subsample of 636 WD-M composite spectra. Our automatic fitting procedure bases on a chi2 minimization technique, yielding a decomposition of each combined spectrum and a derivation of independent parameter estimates for both components. On the respective photometric data from the SDSS, we also find 41 optically resolved binaries. We also investigated the spectra for hydrogen and helium emission.

(3 data files). Title: The planet-hosting subdwarf B star V 391 Pegasi is a hybrid pulsator Authors: Lutz, R.; Schuh, S.; Silvotti, R.; Bernabei, S.; Dreizler, S.; Stahn, T.; Hügelmeyer, S. D. Bibcode: 2009A&A...496..469L Altcode: 2009arXiv0901.4523L Context: A noticeable fraction of subdwarf B stars shows either short-period (p-mode) or long-period (g-mode) luminosity variations, with two objects so far known to exhibit hybrid behaviour, i.e. showing both types of modes at the same time. The pulsating subdwarf B star V 391 Pegasi (or HS 2201+2610), which is close to the two known hybrid pulsators in the log g-T_eff plane, has recently been discovered to host a planetary companion.
Aims: In order to learn more about the planetary companion and its possible influence on the evolution of its host star (subdwarf B star formation is still not well understood), an accurate characterisation of the host star is required. As part of an ongoing effort to significantly improve the asteroseismic characterisation of the host star, we investigate the low-frequency behaviour of HS 2201+2610.
Methods: We obtained rapid high signal-to-noise photometric CCD (B-filter) and PMT (clear-filter) data at 2 m-class telescopes and carried out a careful frequency analysis of the light curves.
Results: In addition to the previously known short-period luminosity variations in the range 342 s-367 s, we find a long-period variation with a period of 54 mn and an amplitude of 0.15 per cent. This can most plausibly be identified with a g-mode pulsation, so that HS 2201+2610 is a new addition to the short list of hybrid sdB pulsators.
Conclusions: Along with the previously known pulsating subdwarf B stars HS 0702+6043 and Balloon 090100001 showing hybrid behaviour, the new hybrid HS 2201+2610 is the third member of this class. This important property of HS 2201+2610 can lead to a better characterisation of this planet-hosting star, helping the characterisation of its planetary companion as well. Current pulsation models cannot yet reproduce hybrid sdBV stars particularly well and improved pulsation models for this object have to include the hybrid behaviour.

Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto,

operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC). Title: Spectral analysis of 636 white dwarf-M star binaries from the sloan digital sky survey Authors: Heller, R.; Homeier, D.; Dreizler, S.; Østensen, R. Bibcode: 2009A&A...496..191H Altcode: Context: We present a catalog of 857 white dwarf (WD)-M binaries from the sixth data release (DR6) of the Sloan Digital Sky Survey (SDSS), most of which were previously identified. For 636 of them, we complete a spectral analysis and derive the basic parameters of their stellar constituents and their distances from Earth.
Aims: We attempt to measure fundamental parameters of these systems by completing spectral analyses. We propose to test models typically applied in fitting procedures and constrain likely and appropriate evolutionary scenarios for the systems.
Methods: We use a χ2 minimization technique to decompose each combined spectrum and derive independent parameter estimates for its components. The possibility of alignment by chance is demoted to statistical insignificance, hence, we use physical interaction of the binary constituents as input parameter. Additionally, we check the corresponding photometric data from the SDSS to find optically resolved systems.
Results: Forty-one of the stellar duets in our spectroscopic sample are optically resolved in their respective SDSS images. For these systems, we also derive a minimum true spatial separation and a lower limit to their orbital periods, typically which are some 104 yr. Spectra of 167 stellar duets show significant hydrogen emission and in most cases no additional He i or He ii features. We also find that 20 of the 636 WDs are fitted to be DOs, with 16 measured to have TeffWD around 40 000 K. Furthermore, we identify 70 very low-mass objects (VLMOs), which are secondaries of masses smaller than about 0.1 M, to be candidate substellar companions.
Conclusions: Although various selection effects may play a role, the fraction 6.4% of WD-M star binaries with orbital separations of around 500 AU is a criterion for evolutionary models of stellar binary systems. Of the 167 spectra with hydrogen emission, 8 had already been found to be post-common envelope binaries (PCEBs) and 4 are systems with strong irradiation processes on the M dwarf. The remaining 155 Balmer-emitting binaries probably harbor an active M dwarf (dM), corresponding to a fraction of 24.4%. The excess of cool DOs is most likely due to additional WDs in the DB-DO Teff range, for which no detailed fitting was completed. The trend of the M stars being closer to Earth than the WD component is probably due to an underestimation of the theoretical M star radii. Title: Long-term EXOTIME photometry and follow-up spectroscopy of the sdB pulsator HS 0702+6043 Authors: Lutz, R.; Schuh, S.; Silvotti, R.; Kruspe, R.; Dreizler, S. Bibcode: 2009CoAst.159...94L Altcode: 2009arXiv0901.4514L Pulsating subdwarf B (sdB) stars oscillate in short-period p modes or long-period g modes. HS 0702+6043 (DW Lyn) is one of a few objects to show characteristics of both types and is hence classified as a hybrid pulsator. It is one of our targets in the EXOTIME program to search for planetary companions around extreme horizontal branch objects. In addition to the standard exercise in asteroseismology to probe the instantaneous inner structure of a star, measured changes in the pulsation frequencies as derived from an O--C diagram can be compared to theoretical evolutionary time scales. Based on the photometric data available so far, we are able to derive a high-resolution frequency spectrum and to report our efforts to construct a multi-season O--C diagram. Additionally, we have gathered time-resolved spectroscopic data in order to constrain stellar parameters and to derive mode parameters as well as radial and rotational velocities. Title: Spectral synthesis of inner gaseous protoplanetary disks with PHOENIX Authors: Hügelmeyer, S. D.; Dreizler, S.; Homeier, D.; Hauschildt, P. H.; Barman, T. Bibcode: 2009AIPC.1094..389H Altcode: 2009csss...15..389H The inner gaseous regions of protoplanetary disks are of special interest in the formation and evolution of planets and stars because they are the likely birthplaces of planets and serve as the accretion reservoir for young stars. The study of inner disks may give rise to a better understanding of the dynamics, physical and chemical structure, and gas content of the region. As a first step, we have developed a 1+1D disk radiative transfer package as an extension to the well established multipurpose stellar atmosphere program PHOENIX. The solution of the equations of momentum and energy conservation as well as the radiative transfer equation is adopted for the physical conditions in and the geometry of disks. Irradiation by the central star is treated in detail. Comparison of our models with high-resolution infrared spectra will enable us to constrain the structure, dynamics, and gas content of disks, and thus give new insights on the physical processes governing star and planet formation. Additionally, we present our current construction site: a 3D radiative transfer code for accretion disks. Title: Spectral Analysis of 636 White Dwarf-M Star Binaries from the Sloan Digital Sky Survey Authors: Heller, R.; Homeier, D.; Dreizler, S.; Østensen, R. Bibcode: 2009AIPC.1094..931H Altcode: 2009csss...15..931H; 2008arXiv0811.1508H We present a catalog of 857 white dwarf-M binaries from the sixth data release of the Sloan Digital Sky Survey (SDSS), most of them known before. For 636 of them, we give a spectral analysis and derive the basic parameters of the stellar constituents and their distances from Earth. The analysis shall give a statistically relevant statement about the fundamental parameters of such systems. Our purpose is to test the models applied in the fitting procedure on the one hand and to confine the respective evolutionary scenarios on the other hand. The χ2 minimization technique we use, in order to decompose each combined spectrum and yield independent parameter estimates for the components, differs from that typically applied to break down combined spectra. In the corresponding SDSS photometric data we find 41 optically resolved systems. For these we also derive a minimum real spatial separation and a lower limit for the orbital periods-typically some 104 yr. 167 spectra show significant hydrogen emission and mostly no additional He I or He II features. Furthermore, we identify 70 very low-mass objects, meaning secondaries with masses smaller than about 0.1 Msolar, as candidate substellar companions. Title: New Science Opportunities Offered by MUSE Authors: Bacon, R.; Bauer, S.; Brau-Nogué, S.; Caillier, P.; Capoani, L.; Carollo, M.; Contini, T.; Daguisé, E.; Delabre, B.; Dreizler, S.; Dubois, J. P.; Dupieux, M.; Dupin, J.; Emsellem, E.; Ferruit, P.; Francois, M.; Franx, M.; Gallou, G.; Gerssen, J.; Guiderdoni, B.; Hansali, G.; Hofmann, D.; Jarno, A.; Kelz, A.; Koehler, C.; Kollatschny, W.; Kosmalski, J.; Laurent, F.; Lilly, S.; Lizon, J.; Loupias, M.; Monstein, C.; Moultaka, J.; Nicklas, H.; Parés, L.; Pasquini, L.; Pecontal, A.; Pello, R.; Petit, C.; Manescau, A.; Reiss, R.; Remillieux, A.; Renault, E.; Roth, M.; Schaye, J.; Steinmetz, M.; Ströbele, S.; Stuik, R.; Weilbacher, P.; Wisotzki, L.; Wozniak, H. Bibcode: 2009ASSP....9..331B Altcode: 2009svlt.conf..331B The Multi Unit Spectroscopic Explorer MUSE [MUSE public web site: http://muse.univ-lyon1.fr] is one of the second generation VLT instruments. MUSE is a wide-field optical integral field spectrograph operating in the visible wavelength range with improved spatial resolution. The MUSE Consortium consists of groups at Lyon (PI institute, CRAL), Gottingen (IAG), Potsdam (AIP), Leiden (NOVA), Toulouse (LATT), Zurich (ETH) and ESO. The project is currently in its final design phase. Manufacturing, assembly and integration will start after the Final Design Review which is foreseen for late 2008. The Preliminary acceptance in Europe is scheduled for mid 2011 and the instrument shall be in operation at Paranal in 2012. Title: Multi-wavelength photometric variation of PG 1605+072 Authors: Schuh, S.; Dreizler, S.; Heber, U.; Jeffery, C. S.; O'Toole, S. J.; Cordes, O.; Stahn, T.; Lutz, R.; Tillich, A.; Wet and MSST Collaborations Bibcode: 2008CoAst.157...35S Altcode: 2008arXiv0812.4857S In a large coordinated attempt to further our understanding of the p-mode pulsating sdB star PG 1605+072, the Multi-Site Spectroscopic Telescope (MSST) collaboration has obtained simultaneous time-resolved spectroscopic and photometric observations. The photometry was extended by additional WET data which increased the time base. This contribution outlines the analysis of the MSST photometric light curve, including the four-colour BUSCA data from which chromatic amplitudes have been derived, as well as supplementary FUV spectra and light curves from two different epochs. These results have the potential to complement the interpretation of the published spectroscopic information. Title: Long-term photometric monitoring of the hybrid subdwarf B pulsator HS 0702+6043 Authors: Lutz, R.; Schuh, S.; Silvotti, R.; Kruspe, R.; Dreizler, S. Bibcode: 2008CoAst.157..185L Altcode: 2008arXiv0812.4859L Pulsating subdwarf B stars oscillate in short-period p-modes or long-period g-modes. HS 0702 +6043 is one of the three objects currently known to show characteristics of both types and hence is classified as hybrid pulsator. We briefly present our analysis of the g-mode domain of this star, but focus on the first results from long-term photometric monitoring in particular of the p-mode oscillations. We present a high-resolution frequency spectrum, and report on our efforts to construct a multi-season O C diagram. Additionally to the standard (although nontrivial) exercise in asteroseismology to probe the instantaneous inner structure of a star, measured changes in the pulsation frequencies as derived from an O C diagram can be compared to theoretical evolutionary timescales. Within the EXOTIME program, we also use this same data to search for planetary companions around extreme horizontal branch objects (”asteroseismic planets”). Title: A Hubble Space Telescope transit light curve for GJ 436b Authors: Bean, J. L.; Benedict, G. F.; Charbonneau, D.; Homeier, D.; Taylor, D. C.; McArthur, B.; Seifahrt, A.; Dreizler, S.; Reiners, A. Bibcode: 2008A&A...486.1039B Altcode: 2008arXiv0806.0851B We present time series photometry for six partial transits of GJ 436b obtained with the Fine Guidance Sensor instrument on the Hubble Space Telescope (HST). Our analysis of these data yields independent estimates of the host star's radius Rstar = 0.505+0.029-0.020 R, and the planet's orbital period P = 2.643882^+0.000060-0.000058 d, orbital inclination i = 85.80° +0.21°-0.25°, mean central transit time Tc = 2 454 455.279241+0.00026-0.00025 HJD, and radius Rp = 4.90+0.45-0.33 R. The radius we determine for the planet is larger than the previous findings from analyses of an infrared light curve obtained with the Spitzer Space Telescope. Although this discrepancy has a 92% formal significance (1.7σ), it might be indicative of systematic errors that still influence the analyses of even the highest-precision transit light curves. Comparisons of all the measured radii to theoretical models suggest that GJ 436b has a H/He envelope of 10% by mass. We point out the similarities in structure between this planet and Uranus and Neptune and discuss possible parallels between these planets' formation environments and dynamical evolution. We also find that the transit times for GJ 436b are constant to within 10 s over the 11 planetary orbits that the HST data span. However, the ensemble of published values exhibits a long-term drift and our mean transit time is 128 s later than that expected from the Spitzer ephemeris. The sparseness of the currently available data hinders distinguishing between an error in the orbital period or perturbations arising from an additional object in the system as the cause of the apparent trend. Assuming the drift is due to an error in the orbital period we obtain an improved estimate for it of P = 2.643904 ± 0.000005 d. This value and our measured transit times will serve as important benchmarks in future studies of the GJ 436 system.

Table 2 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/486/1039 Title: VizieR Online Data Catalog: HST transit light curve for GJ436b (Bean+, 2008) Authors: Bean, J. L.; Benedict, G. F.; Charbonneau, D.; Homeier, D.; Taylor, D. C.; McArthur, B.; Seifahrt, A.; Dreizler, S.; Reiners, A. Bibcode: 2008yCat..34861039B Altcode: This is Table 2 from the above paper. It contains photometric time series of 6 partial transits for GJ436b obtained with the FGS instrument on HST. The first column gives the visit number, the second one gives the date as Heliocentric Julian Days (HJD), the third one gives the flux in 60 second bins normalized by the reference star observations, and the fourth one gives the statistical noise for each measurement.

(1 data file). Title: Hot DO and DB White Dwarfs from the Sloan Digital Sky Survey Authors: Liebert, J.; Krzesinski, J.; Hügelmeyer, S.; Dreizler, S. Bibcode: 2008ASPC..391..227L Altcode: Hot DB and DO stars found in the Sloan Digital Sky Survey are analyzed. We note first that the mass distribution of DB stars determined by others has a very similar mean to that for samples of DA stars, but lacks low and high mass outliers. Our working hypothesis is that the missing high mass DB stars may simply be observed as hot DQ white dwarfs. The recent discovery of DB stars in the alleged ``DB gap'' at 30,000 - 45,000 K is discussed. Temperatures are estimated from both fits to the spectra and to the energy distributions. A deficit of stars in this range still seems likely, which would imply that about 10% of DA evolve into DB stars below 30,000 K. We are working towards a preliminary luminosity function of DO-DB white dwarfs. Title: XMM-Newton Observations of Two Soft X-Ray Selected Magnetic CVs Authors: Traulsen, I.; Reinsch, K.; Dreizler, S. Bibcode: 2008ASPC..391..287T Altcode: The two AM Her type systems AI Tri and QS Tel have been monitored with the X-ray satellite XMM-Newton with 20 ksec exposures each and additional optical photometry at several sites during high and intermediate high states of accretion. The light curves are dominated by highly variable soft X-ray emission arising from the accretion heated surface of the white dwarf primary in addition to a weaker hard component reflecting the contribution of the multi-temperature thermal plasma emission from the post-shock accretion column. A mildly absorbed blackbody plus MEKAL plasma emission with variable element abundances describe the associated spectra. Evident discrepancies between the observed X-ray spectrum and the blackbody approximation emphasize the need for accurate models including radiative transfer to reproduce the white dwarf's contribution in a more realistic way. Title: New Views of the Horizontal Branch in ω Centauri Authors: Moehler, S.; Dreizler, S.; Lanz, T.; Bono, G.; Sweigart, A. V.; Calamida, A.; Monelli, M.; Nonino, M. Bibcode: 2008ASPC..392...47M Altcode: UV observations of some massive globular clusters uncovered a significant population of very hot stars below the hot end of the horizontal branch, the so-called blue hook stars. This feature might be explained either by the late hot flasher scenario where stars experience the helium flash while on the white dwarf cooling curve or by the helium-rich sub-population recently postulated to exist in some clusters. Previous spectroscopic analyses of blue hook stars in ω Cen and NGC 2808 support the late hot flasher scenario, but the stars were found to contain much less helium than expected and the predicted carbon and nitrogen enrichment could not be verified. New moderately high resolution spectra of stars at the hot end of the blue horizontal branch in ω Cen were analysed for atmospheric parameters ( Teff, log g, and log{nHe}/{nH}) and abundances using LTE and non-LTE model atmospheres. In the temperature range 30,000 K to 50,000 K we find that 35% of our stars are helium-poor (log{nHe/{nH} < -2), 51% have solar helium abundance within a factor of 3 (-1.5 ≤ log{nHe}/{nH} ≤ -0.5) and 14% are helium-rich (log{nHe/{nH} > -0.4). We also find carbon enrichment along with helium enrichment, with a maximum carbon abundance of 3% by mass. At least 14% of the hottest horizontal branch stars in ωCen show helium abundances well above the highest predictions from the helium enrichment scenario (Y≈ 0.42, corresponding to log{nHe}/{nH} ≈ -0.74). In addition, the most helium-rich stars show high carbon abundances as predicted by the late hot flasher scenario. We conclude that the helium-rich horizontal branch stars in ω Cen cannot be explained solely by the helium-enrichment scenario invoked to explain the blue main sequence. Title: MUSE: A Second-Generation Integral-Field Spectrograph for the VLT Authors: McDermid, R. M.; Bacon, R.; Bauer, S.; Boehm, P.; Boudon, D.; Brau-Nogué, S.; Caillier, P.; Capoani, L.; Carollo, C. M.; Champavert, N.; Contini, T.; Daguisé, E.; Delabre, B.; Devriendt, J.; Dreizler, S.; Dubois, J.; Dupieux, M.; Dupin, J. P.; Emsellem, E.; Ferruit, P.; Franx, M.; Gallou, G.; Gerssen, J.; Guiderdoni, B.; Hahn, T.; Hofmann, D.; Jarno, A.; Kelz, A.; Koehler, C.; Kollatschny, W.; Kosmalski, J.; Laurent, F.; Lilly, S. J.; Lizon, J. L.; Loupias, M.; Manescau, A.; Monstein, C.; Nicklas, H.; Parès, L.; Pasquini, L.; Pécontal-Rousset, A.; Pécontal, E.; Pello, R.; Petit, C.; Picat, J. -P.; Popow, E.; Quirrenbach, A.; Reiss, R.; Renault, E.; Roth, M.; Schaye, J.; Soucail, G.; Steinmetz, M.; Stroebele, S.; Stuik, R.; Weilbacher, P.; Wisotzki, L.; Wozniak, H.; de Zeeuw, P. T. Bibcode: 2008eic..work..325M Altcode: The Multi Unit Spectroscopic Explorer (MUSE) is a second-generation instrument in development for the Very Large Telescope (VLT) of the European Southern Observatory (ESO), due to begin operation in 2011/12. MUSE will be an extremely powerful integral-field spectrograph fed by a new multiple-laser adaptive optics system on the VLT. In its usual operating mode, MUSE will, in a single observation, produce a 3-dimensional data cube consisting of 90,000 R 3000 spectra, each covering a full spectral octave (480-930 nm), and fully sampling a contiguous 1×1 arcmin2 field with 0.2×0.2 arcsec2 apertures. A high-resolution mode will increase the spatial sampling to 0.025 arcsec per pixel. MUSE is built around a novel arrangement of 24 identical spectrographs (each comparable to a 1st generation VLT instrument), which are fed by a set of 24 precision image slicers. MUSE is designed for stability, with only 2 modes, and virtually no moving parts, allowing very long exposures to be accumulated. Together with high throughput, this ensures that MUSE will have extreme sensitivity for observing faint objects. We overview the technical and scientific aspects of MUSE, highlighting the key challenges for dealing with the unprecedented quantity and complexity of the data, and the integration with the VLT adaptive optics facility (AOF) - a key development on the path to extremely large telescopes (ELTs). Title: The pulsation modes of the pre-white dwarf PG 1159-035 Authors: Costa, J. E. S.; Kepler, S. O.; Winget, D. E.; O'Brien, M. S.; Kawaler, S. D.; Costa, A. F. M.; Giovannini, O.; Kanaan, A.; Mukadam, A. S.; Mullally, F.; Nitta, A.; Provençal, J. L.; Shipman, H.; Wood, M. A.; Ahrens, T. J.; Grauer, A.; Kilic, M.; Bradley, P. A.; Sekiguchi, K.; Crowe, R.; Jiang, X. J.; Sullivan, D.; Sullivan, T.; Rosen, R.; Clemens, J. C.; Janulis, R.; O'Donoghue, D.; Ogloza, W.; Baran, A.; Silvotti, R.; Marinoni, S.; Vauclair, G.; Dolez, N.; Chevreton, M.; Dreizler, S.; Schuh, S.; Deetjen, J.; Nagel, T.; Solheim, J. -E.; Gonzalez Perez, J. M.; Ulla, A.; Barstow, M.; Burleigh, M.; Good, S.; Metcalfe, T. S.; Kim, S. -L.; Lee, H.; Sergeev, A.; Akan, M. C.; Çakırlı, Ö.; Paparo, M.; Viraghalmy, G.; Ashoka, B. N.; Handler, G.; Hürkal, Ö.; Johannessen, F.; Kleinman, S. J.; Kalytis, R.; Krzesinski, J.; Klumpe, E.; Larrison, J.; Lawrence, T.; Meištas, E.; Martinez, P.; Nather, R. E.; Fu, J. -N.; Pakštienė, E.; Rosen, R.; Romero-Colmenero, E.; Riddle, R.; Seetha, S.; Silvestri, N. M.; Vučković, M.; Warner, B.; Zola, S.; Althaus, L. G.; Córsico, A. H.; Montgomery, M. H. Bibcode: 2008A&A...477..627C Altcode: 2007arXiv0711.2244C Context: PG 1159-035, a pre-white dwarf with Teff≃ 140 000 K, is the prototype of both two classes: the PG 1159 spectroscopic class and the DOV pulsating class. Previous studies of PG 1159-035 photometric data obtained with the Whole Earth Telescope (WET) showed a rich frequency spectrum allowing the identification of 122 pulsation modes. Analyzing the periods of pulsation, it is possible to measure the stellar mass, the rotational period and the inclination of the rotation axis, to estimate an upper limit for the magnetic field, and even to obtain information about the inner stratification of the star.
Aims: We have three principal aims: to increase the number of detected and identified pulsation modes in PG 1159-035, study trapping of the star's pulsation modes, and to improve or constrain the determination of stellar parameters.
Methods: We used all available WET photometric data from 1983, 1985, 1989, 1993 and 2002 to identify the pulsation periods.
Results: We identified 76 additional pulsation modes, increasing to 198 the number of known pulsation modes in PG 1159-035, the largest number of modes detected in any star besides the Sun. From the period spacing we estimated a mass M/M_⊙ = 0.59 ± 0.02 for PG 1159-035, with the uncertainty dominated by the models, not the observation. Deviations in the regular period spacing suggest that some of the pulsation modes are trapped, even though the star is a pre-white dwarf and the gravitational settling is ongoing. The position of the transition zone that causes the mode trapping was calculated at r_c/R_star = 0.83 ± 0.05. From the multiplet splitting, we calculated the rotational period P_rot = 1.3920 ± 0.0008 days and an upper limit for the magnetic field, B < 2000 G. The total power of the pulsation modes at the stellar surface changed less than 30% for ℓ = 1 modes and less than 50% for ℓ = 2 modes. We find no evidence of linear combinations between the 198 pulsation mode frequencies. PG 1159-035 models have not significative convection zones, supporting the hypothesis that nonlinearity arises in the convection zones in cooler pulsating white dwarf stars.

Tables [see full textsee full text]-[see full textsee full text] are only available in electronic form at http://www.aanda.org Title: An Implementation of the Ray Shooting Method Authors: Hundertmark, M.; Hessman, F.; Dreizler, S. Bibcode: 2008mmc..confE..53H Altcode: 2008PoS....54E..53H No abstract at ADS Title: Light Curve Analysis of the Hybrid SdB PulsatorsHS 0702+6043 and HS 2201+2610 Authors: Lutz, R.; Schuh, S.; Silvotti, R.; Dreizler, S.; Green, E. M.; Fontaine, G.; Stahn, T.; Hügelmeyer, S. D.; Husser, T. -O. Bibcode: 2008ASPC..392..339L Altcode: 2007arXiv0710.4871L We present the detection of low-amplitude, long-period g-modes in two individual sdBV stars which are known to be p-mode pulsators. Only few of these hybrid objects, showing both p- and g-modes, are known today. We resolve the g-mode domain in HS 0702+6043 and add HS 2201+2610 to the list of hybrid pulsators. To discover the low-amplitude g-modes, a filtering algorithm based on wavelet transformations was applied to denoise observational data. Title: Testing the Tidal Heating Hypothesis for the Transiting Exoplanets HAT-P-1b and TrES-4b Authors: Armstrong, Amber; Bean, J. L.; McArthur, B.; Reiners, A.; Dreizler, S.; Benedict, G. F. Bibcode: 2007AAS...21113409A Altcode: 2007BAAS...39..969A One of the most interesting results that has emerged from the detection and study of transiting exoplanets is that some Hot Jupiters have larger radii, and thus lower densities, than models predict. A few mechanisms have been suggested as the cause of this, including one hypothesis that there is an unknown source of internal heat inflating these planets. Such a source of heat could be the dissipation of energy arising from the ongoing tidal circularization of the planets' eccentric orbits. However, the tidal circularization timescale for such close in planets is predicted to be at least an order of magnitude shorter than the putative ages of the systems. Therefore, if an inflated Hot Jupiter's orbital eccentricity is truly non-zero, there must be a perturber - possibly an additional undiscovered planet - in the system to regularly excite its eccentricity. We are currently carrying out high cadence and high precision radial velocity measurements of the host stars to inflated Hot Jupiters with the

Hobby-Eberly-Telescope to constrain their orbital eccentricities, search for additional planets in the systems, and ultimately test the tidal heating hypothesis. We present here preliminary results for the systems HAT-P-1 and TrES-4. At the time of this writing, TrES-4b is by far the lowest density exoplanet and the most discrepant from theoretical models.

Support for this work was provided by NASA through grants GO-10103, GO-10610, and GO-10989 from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA

contract NAS5-26555. Title: The hottest horizontal-branch stars in ω Centauri. Late hot flasher vs. helium enrichment Authors: Moehler, S.; Dreizler, S.; Lanz, T.; Bono, G.; Sweigart, A. V.; Calamida, A.; Monelli, M.; Nonino, M. Bibcode: 2007A&A...475L...5M Altcode: 2007arXiv0709.2839M Context: UV observations of some massive globular clusters have revealed a significant population of very hot stars below the hot end of the horizontal branch (HB), the so-called blue hook stars. This feature might be explained either as a result of the late hot flasher scenario where stars experience the helium flash while on the white dwarf cooling curve or by the progeny of the helium-enriched sub-population recently postulated to exist in some clusters. Previous spectroscopic analyses of blue hook stars in ω Cen and NGC 2808 support the late hot flasher scenario, but the stars contain much less helium than expected and the predicted C, N enrichment could not be verified.
Aims: We compare observed effective temperatures, surface gravities, and abundances of He, C, and N of blue hook and canonical extreme horizontal branch (EHB) star candidates to the predictions of the two scenarios.
Methods: Moderately high resolution spectra of stars at the hot end of the blue HB in the globular cluster ω Cen were analysed for atmospheric parameters and abundances using LTE and non-LTE model atmospheres.
Results: In the temperature range 30 000 K to 50 000 K we find that 35% of our stars are helium-poor (log{{n_He}/{n_H}} < -2), 51% have solar helium abundance within a factor of 3 (-1.5 ⪉ log{{n_He}/{n_H}} ⪉ -0.5) and 14% are helium-rich (log{{n_He}/{n_H}}} > -0.4). We also find carbon enrichment strongly correlated with helium enrichment, with a maximum carbon enrichment of 3% by mass.
Conclusions: At least 14% of the hottest HB stars in ω Cen show helium abundances well above the highest predictions from the helium enrichment scenario (Y = 0.42 corresponding to log{{n_He}/{n_H}} ≈ -0.74). In addition, the most helium-rich stars show strong carbon enrichment, as predicted by the late hot flasher scenario. We conclude that the helium-rich HB stars in ω Cen cannot be explained solely by the helium-enrichment scenario invoked to explain the blue main sequence.

Based on observations

with the ESO Very Large Telescope at Paranal Observatory, Chile

(proposal IDs 075.D-0280(A) and 077.D-0021(A)). Title: XMM-Newton Observations of Soft X-Ray Selected Magnetic CVs Authors: Traulsen, Iris; Reinsch, Klaus; Dreizler, Stefan Bibcode: 2007AN....328..712T Altcode: No abstract at ADS Title: SDSS DR4: Hot White Dwarf Luminosity Function Authors: Krzesinski, J.; Kleinman, S. J.; Nitta, A.; Hügelmeyer, S. D.; Dreizler, S. Bibcode: 2007ASPC..372...65K Altcode: A large, nearly complete, magnitude-limited, spectroscopically-identified sample of hot white dwarf stars presented in the Sloan Digital Sky Survey (SDSS) Data Release 4 White Dwarf Catalog tep{p8_eis06} allowed us to construct the hot end of a SDSS white dwarf luminosity function (LF). The LF covers an approximate temperature range of 23,000 K to 100,000 K and is based on the distances and absolute bolometric magnitudes determined from stellar models. The sample is dominated by DA type white dwarfs, but it also contains DB, DAO, DO and PG 1159 type stars. We present our new LF, compare it to previous work tep{p8_har06}, and comment on sample completeness. Title: X-Ray Spectroscopy and Photometry of the Accreting White Dwarf in AI Tri Authors: Traulsen, I.; Reinsch, K.; Dreizler, S.; Schwarz, R. Bibcode: 2007ASPC..372..553T Altcode: Based on recent X-ray observations with the XMM-Newton satellite, we present first results of our spectroscopic and photometric analysis of the accretion region on the white dwarf in the long-period magnetic cataclysmic variable AI Tri. Our XMM-Newton observation covers for the first time uninterruptedly a complete binary orbital period. The shape of the X-ray light curve is highly variable with strong flares, occurring mainly in the soft energy range over about 70% of the binary orbit. Weaker hard X-ray emission is visible nearly all the time. The ultraviolet light curve, obtained in the UVM2 filter at an effective wavelength of 231 nm, has a similar shape but higher amplitude than the optical and near UV light curves reported during high states of accretion. The X-ray spectrum is dominated by soft X-ray emission which can be described in good approximation by a mildly absorbed blackbody component with kTbb = 36.8+1.8-1.4 {eV} and NH = 3.08+0.51-0.42 \cdot 1020 {cm}-2. In addition, weak emission from a thermal plasma is present and iron Kα at 6.4 keV and iron L emission around 0.9 keV can be identified. Title: Abell 43 and PG 0122+200: a Look at the Beginning and at the End of the PG 1159 Instability Strip Authors: Vauclair, G.; Solheim, J. -E.; Fu, J. -N.; Chevreton, M.; Dolez, N.; O'Brien, M. S.; Mukadam, A. S.; Kim, S. -L.; Park, B. -G.; Handler, G.; Medupe, R.; Wood, M.; González Perez, J.; Hashimoto, O.; Kinugasa, K.; Taguchi, H.; Kambe, E.; Dobrovolskas, V.; Provencal, J. L.; Dreizler, S.; Schuh, S.; Leibowitz, E. M.; Lipkin, Y.; Zhang, X. -B.; Paparo, M.; Szeidl, B.; Virághalmy, G.; Zsuffa, D. Bibcode: 2007ASPC..372..641V Altcode: While Abell 43 is entering the PG 1159 instability strip, in fact as an "hybrid-PG 1159" nucleus of a planetary nebula, PG 0122+200 presently defines its red edge. So these two stars define the limits of the instability strip along the evolutionary sequence from the planetary nebula nuclei to the pre-white dwarf PG 1159 stars. We describe the new observations that have been obtained recently on these two extreme PG 1159 pulsators. Abell 43, the second discovered "hybrid-PG 1159" pulsator after HS 2324+3944, is a multi-periodic low amplitude pulsator with the longest period observed so far in PG 1159 pulsators. As it shows amplitude variations, follow-up observations are needed to obtain a sufficient number of frequencies to start an asteroseismological analysis. We summarize the status of the presently available data. On PG 0122+200, new observations were obtained in 2001 and 2002. Together with previous data, they allow us to detect 23 frequencies, including seven triplets and two single frequencies. We interpret the triplets as ℓ=1 modes split by rotation and confirm an average rotation period of 1.55 days. From the up-dated average period spacing of 22.9 s, we derive a mass of 0.59 ± 0.02 M, in better agreement with the spectroscopically derived mass than from previous estimates, and a luminosity log(L/L)= 1.3 ± 0.5. The uncertainty on the luminosity is dominated by the poorly determined surface gravity. We discuss the impact of that new mass determination on the predicted neutrino luminosity. Title: Spectral Analyses of 16 DAO White Dwarfs from the Sloan Digital Sky Survey Authors: Hügelmeyer, S. D.; Dreizler, S.; Rauch, T.; Krzesiński, J. Bibcode: 2007ASPC..372..187H Altcode: 2006astro.ph.10744H We present a spectral analysis of 16 DAO from the Sloan Digital Sky Survey Data Release 4. With our NLTE H+He model grid, we derived photospheric parameters for these objects. We compare our new results to literature values and divide the DAOs into two distinct groups: post-AGB and EHB progenitors. Title: Observational Constraints on the Evolutionary Connection between PG 1159 Stars and DO White Dwarfs Authors: Hügelmeyer, S. D.; Dreizler, S.; Werner, K.; Krzesinski, J.; Nitta, A.; Kleinman, S. J. Bibcode: 2007ASPC..372..249H Altcode: 2006astro.ph.10746H The Sloan Digital Sky Survey has provided spectra of a large number of new PG 1159 stars and DO white dwarfs. This increase in known hot H-deficient compact objects significantly improves the statistics and helps to investigate late stages of stellar evolution. We have finished our analyses of nine PG 1159 stars and 23 DO white dwarfs by means of detailed NLTE model atmospheres. From the optical SDSS spectra, effective temperatures, surface gravities, and element abundances are derived by using our new automated χ^2--fitting in order to place the observed objects in an evolutionary context. Especially the connection between PG 1159 stars and DO white dwarfs has been investigated. Title: BMBF funded projects at Göttingen Authors: Kollatschny, Wolfram; Hofmann, Denni; Dreizler, Stefan; Nicklas, Harald; Zetzl, Matthias; Köhler, Christof Bibcode: 2007AN....328..710K Altcode: No abstract at ADS Title: Spectral Analysis and Constraints on the Nature of the Ultra-Compact Binary RX J0806.3+1527 Authors: Reinsch, K.; Steiper, J.; Dreizler, S. Bibcode: 2007ASPC..372..419R Altcode: RX J0806.3+1527 has been discovered as a luminous soft X-ray source during the ROSAT All-Sky Survey and is suspected to be a double-degenerate white dwarf binary with the shortest known orbital period of 321 s. We have performed the first NLTE analysis of its optical spectrum which consists of a blue continuum with weak emission lines superimposed. Using a grid of hot white dwarf atmospheres including illumination effects we have derived an abundance ratio (He/H) ≈ 0.1 (by number) and a comparably low surface gravity log{g} = 6 of the irradiated system component. The observed flux implies a distance d ≈ 2.0 kpc to the system. Our findings provide new constrains for the different models proposed for the nature of this peculiar binary. The donor must have about solar composition. If line emission arises from its irradiated side it could be either a low-mass white dwarf or a substellar object. Alternatively, line emission could arise from an accretion column standing several white dwarf radii above the photosphere of the accretor. Such conditions are encountered in systems with comparably low field strengths and high mass-flow rates. Title: Investigation of transit-selected exoplanet candidates from the MACHO survey Authors: Hügelmeyer, S. D.; Dreizler, S.; Homeier, D.; Reiners, A. Bibcode: 2007A&A...469.1163H Altcode: 2007arXiv0704.1366H Context: Planets outside our solar system transiting their host star, i.e. those with an orbital inclination near 90°, are of special interest to derive physical properties of extrasolar planets. With the knowledge of the host star's physical parameters, the planetary radius can be determined. Combined with spectroscopic observations the mass and therefore the density can be derived from Doppler-measurements. Depending on the brightness of the host star, additional information, e.g. about the spin-orbit alignment between the host star and planetary orbit, can be obtained.
Aims: The last few years have witnessed a growing success of transit surveys. Among other surveys, the MACHO project provided nine potential transiting planets, several of them with relatively bright parent stars. The photometric signature of a transit event is, however, insufficient to confirm the planetary nature of the faint companion. The aim of this paper therefore is a determination of the spectroscopic parameters of the host stars as well as a dynamical mass determination through Doppler-measurements.
Methods: We obtained follow-up high-resolution spectra for five stars selected from the MACHO sample, which are consistent with transits of low-luminosity objects. Radial velocities were determined by means of cross-correlation with model spectra. The MACHO light-curves were compared to simulations based on the physical parameters of the system derived from the radial velocities and spectral analyses.
Results: We show that all transit light-curves of the exoplanet candidates analysed in this work can be explained by eclipses of stellar objects, hence none of the five transiting objects is a planet.

Based on observations made with ESO Telescopes

at the La Silla or Paranal Observatories under programme ID

075.C-0526(A). Title: Analyzing SN 2003Z with PHOENIX Authors: Knop, S.; Hauschildt, P. H.; Baron, E.; Dreizler, S. Bibcode: 2007A&A...469.1077K Altcode: 2009arXiv0902.1867K Aims:We present synthetic spectra around maximum for the type II supernova SN 2003Z, which was first detected on January 29.7 2003. Comparison with observed spectra aim at the determination of physical parameters for SN 2003Z.
Methods: Synthetic spectra are calculated with our stellar atmosphere code PHOENIX. It solves the special relativistic equation of radiative transfer, including large NLTE-calculations and line blanketing by design, in 1-dimensional spherical symmetry. The observed spectra were obtained at the 3.5 m telescope at Calar Alto. The TWIN instrument was used so that a spectral range from about 3600 to 7500 Å was covered. The spectra were taken on Feb. 4, 5, 9, and 11, 2003.
Results: The physical parameters of the models give the luminosities, a range of possible velocity profiles for the SN, an estimate of the colour excess, and the observed metalicity.

Based on observations collected at the Centro Astronómico Hispano Alemán (CAHA) at Calar Alto, operated jointly by the Max-Planck Institut für Astronomie and the Instituto de Astrofísica de Andalucía (CSIC). Title: X-Ray Spectroscopy and Photometry of the long-period Polar AI Tri with XMM-Newton Authors: Traulsen, I.; Reinsch, K.; Dreizler, S. Bibcode: 2007xnnd.confP...4T Altcode: No abstract at ADS Title: MONET, HET and SALT and asteroseismological observations and theory in Göttingen Authors: Schuh, S.; Hessman, F. V.; Dreizler, S.; Kollatschny, W.; Glatzel, W. Bibcode: 2007CoAst.150..317S Altcode: The Göttingen stellar astrophysics group, headed by Stefan Dreizler, conducts research on extrasolar planets and their host stars, on lower-main sequence stars, and on evolved compact objects, in particular hot white dwarfs (including PG 1159 objects, magnetic WDs and cataclysmic variables), and subdwarf B stars. In addition to sophisticated NLTE spectral analyses of these stars, which draw on the extensive stellar atmosphere modelling experience of the group, we actively develop and apply a variety of photometric monitoring and time-resolved spectroscopic techniques to address time-dependent phenomena. With the new instrumentational developments described below, we plan to continue the study of variable white dwarfs (GW Vir, DB and ZZ Ceti variables) and in particular sdB EC 14026 and PG 1617 pulsators which already constitute a main focus, partly within the Whole Earth Telescope (WET/DARC), http://www.physics.udel.edu/~jlp/darc/) collaboration, on a new level. Additional interest is directed towards strange mode instabilities in Wolf Rayet stars. Title: Asteroseismology of the PG 1159 star PG 0122+200 Authors: Fu, J. -N.; Vauclair, G.; Solheim, J. -E.; Chevreton, M.; Dolez, N.; O'Brien, M. S.; Kim, S. -L.; Park, B. -G.; Handler, G.; Medupe, R.; Wood, M.; Gonzalez Perez, J.; Hashimoto, O.; Kinugasa, K.; Taguchi, H.; Kambe, E.; Provencal, J.; Dreizler, S.; Schuh, S.; Leibowitz, E.; Lipkin, Y.; Zhang, X. -B.; Paparo, M.; Szeidl, B.; Virághalmy, G.; Zsuffa, D. Bibcode: 2007A&A...467..237F Altcode: Context: The variable pre-white dwarf PG 1159 stars (GW Vir) are g-mode non-radial pulsators. Asteroseismology puts strong constraints on their global parameters and internal structure. PG 0122+200 defines the red edge of the instability strip and its evolutionary timescale is predicted to be dominated by neutrino emission. Its study offers the opportunity to better understand the instability mechanism and to validate the physics of the neutrino production in dense plasma.
Aims: To achieve such a goal requires determining precisely its fundamental parameters. This is the goal of this paper.
Methods: We present new multi-site photometric observations obtained in 2001 and 2002. Together with previous data, they allow us to detect 23 frequencies, composed of 7 triplets and 2 single frequencies, which are used to constrain its internal structure and derive its fundamental parameters.
Results: All the observed frequencies correspond to ℓ=1 g-modes. The period distribution shows a signature of mode trapping from which we constrain the He-rich envelope mass fraction to be -6.0≤ log(qy) ≤ -5.3. The comparison of the mode trapping amplitudes among GW Vir stars suggests that the mass-loss efficiency must decrease significantly below T_eff≤ 140 kK. We measure an average period spacing of 22.9 s from which we derive a mass of 0.59±0.02 M. From the triplets we measure a mean rotational splitting of 3.74 μHz and a rotational period of 1.55 days. We derive an upper limit to the magnetic field of B≤4×103 G. The luminosity (log L/L = 1.3±0.5) and the distance (D = 0.7^+1.0_-0.4 kpc) are only weakly constrained due to the large uncertainty on the spectroscopically derived surface gravity and the absence of a measured parallax.
Conclusions: From the asteroseismic mass, the ratio of the neutrino luminosity on the photon luminosity is 1.6±0.2 confirming that the PG 0122+200 evolutionary time scale should be dominated by neutrino cooling. A measurement of dot{P} for the largest amplitude untrapped modes should verify this prediction.

Based on data obtained at the Haute-Provence Observatory, INSU/CNRS, France; the Nordic Optical Telescope, La Palma, Spain; the Xinglong station of National Astronomical Observatories, China; the Bohyunsan Observatory, South-Korea; the Gunma Astrophysical Observatory, Japan; the Teide Observatory, Tenerife, Spain; the Calar Alto Observatory, Spain; the Kitt Peak National Observatory, Arizona, USA; the McDonald Observatory, Texas, USA; the South Africa Astronomical Observatory, South Africa; the Wise Observatory, Israel and the Piszkéstető Observatory, Hungary. Title: Spectral types of planetary host star candidates from OGLE III Authors: Dreizler, S.; Schuh, S.; Homeier, D. Bibcode: 2007A&A...464..367D Altcode: 2007astro.ph..1718D Context: The Optical Gravitational Lensing Experiment project has recently provided the OGLE III list of low-luminosity object transits from campaigns #3 and #4, reporting 40 new objects exhibiting the low-amplitude photometric eclipses expected for exoplanets. Compared to previous OGLE targets, these OGLE III candidates have been more restrictively selected and may contain low-mass planets.
Aims: We have secured follow-up low-resolution spectroscopy for 28 candidates out of this list (and one from the OGLE Carina fields) to obtain an independent characterization of the primary stars by spectral classification and thus better constrain the parameters of their companions.
Methods: We fed the constraints from these results back into an improved light curve solution. Together with the radius ratios from the transit measurements, we derived the radii of the low-luminosity companions. This allows us to examine the possible sub-stellar nature of these objects.
Results: Sixteen of the companions can be clearly identified as low-mass stars orbiting a main sequence primary, while 10 more objects are likely to have red giant primaries and therefore also host a stellar companion; 3 possibly have a sub-stellar nature (R≤ 0.15 R_⊙).
Conclusions: .The planetary nature of these objects should therefore be confirmed by dynamical mass determinations. Title: Hot subdwarfs from the ESO supernova Ia progenitor survey. II. Atmospheric parameters of subdwarf O stars Authors: Stroeer, A.; Heber, U.; Lisker, T.; Napiwotzki, R.; Dreizler, S.; Christlieb, N.; Reimers, D. Bibcode: 2007A&A...462..269S Altcode: 2006astro.ph..9718S Aims: We address the origin and evolutionary status of hot subdwarf stars by studying the optical spectral properties of 58 subdwarf O (sdO) stars. Combining them with the results of our previously studied subdwarf B (sdB) stars, we aim at investigating possible evolutionary links.
Methods: We analyse high-resolution (R > 18 000), high-quality optical spectra of sdO stars obtained with the ESO VLT UVES echelle spectrograph in the course of the ESO Supernova Ia Progenitor Survey (SPY). Effective temperatures, surface gravities, and photospheric helium abundances are determined simultaneously by fitting the profiles of hydrogen and helium lines using dedicated synthetic spectra calculated from an extensive grid of NLTE model atmospheres.
Results: We find spectroscopic or photometric evidence for cool companions to eight sdO stars, as well as a binary consisting of two sdO stars. A clear correlation between helium abundances and the presence of carbon and/or nitrogen lines is found: below solar helium abundance, no sdO star shows C or N lines. In contrast, C and/or N lines are present in the spectra of all sdO stars with supersolar helium abundance. We thus use the solar helium abundance to divide our sample into helium-deficient and helium-enriched sdO stars. While helium-deficient sdO stars are scattered in a wide range of the {T_eff}-log(g)-diagram, most of the helium-enriched sdO stars cluster in a narrow region at temperatures between 40 000 and 50 000 K and gravities between log g=5.5 and 6.0.
Conclusions: . An evolutionary link between sdB stars and sdO stars appears plausible only for the helium-deficient sdO stars. They probably have evolved away from the extreme horizontal branch; i.e., they are the likely successors to sdB stars. In contrast, the atmospheric properties of helium-enriched sdO stars cannot be explained with canonical single-star evolutionary models. Alternative scenarios for both single-star (late hot flasher) and binary evolution (white-dwarf merger; post-RGB evolution) fail to reproduce the observed properties of helium-enriched sdO stars in detail. While we regard the post-RGB scenario as inappropriate, the white-dwarf merger and the late hot-flasher scenarios remain viable to explain the origin of helium-enriched sdO stars.

Based

on observations collected at the Paranal Observatory of the European

Southern Observatory for programme No. 165.H-0588(A) and 167.D-0407(A). Title: Spectral analyses of eighteen hot H-deficient (pre-) white dwarfs from the Sloan Digital Sky Survey Data Release 4 Authors: Hügelmeyer, S. D.; Dreizler, S.; Homeier, D.; Krzesiński, J.; Werner, K.; Nitta, A.; Kleinman, S. J. Bibcode: 2006A&A...454..617H Altcode: 2006astro.ph..5551H Context: .The Sloan Digital Sky Survey Data Release 4 has provided spectra of several new PG 1159 stars and DO white dwarfs. This increase in known hot H-deficient compact objects significantly improves the statistics and helps to investigate late stages of stellar evolution.
Aims: .From the optical SDSS spectra, effective temperatures and surface gravities are derived in order to place the observed objects in an evolutionary context. Especially the connection between PG 1159 stars and DO white dwarfs shall be investigated.
Methods: .Using our non-LTE model atmospheres and applying χ2-fitting techniques, we determine stellar parameters and their errors. We derive total stellar masses for the DO white dwarfs using model evolutionary tracks.
Results: .We confirm three PG 1159 stars, with one showing ultra-high excitation ion features, and one sdO which we originally classified as a PG 1159 star. Additionally, we re-analysed the known PG 1159 star, PG 1424+535, with our new models. Furthermore, we present the first spectral analyses of thirteen DO white dwarfs, three of which show M-star features in their spectra, while two display ultra-high excitation ion features.
Title: The D/H Ratio towards PG 0038+199 Authors: Williger, G. M.; Oliveira, C.; Hébrard, G.; Dupuis, J.; Dreizler, S. Bibcode: 2006ASPC..348...97W Altcode: We determine the D/H ratio in the interstellar medium toward the DO white dwarf PG 0038+199 using spectra from the Far Ultraviolet Spectroscopic Explorer (FUSE), with ground-based support from Keck H IRES. We employ curve of growth, apparent optical depth and profile fitting techniques to measure column densities and limits of many other species which allow us to determine related ratios such as D/O, D/N and the H2 fraction. We estimate a distance to PG 0038+199 of 297+164-104 pc (1σ). We find column densities log N(H I) = 20.41± 0.08, log N(D I) = 15.75± 0.08 and log N(H2) = 19.33± 0.04, yielding a molecular hydrogen fraction of 14± 2% (all 2σ errors). [D I + HD]/[H I + 2H2] toward PG 0038+199 is 1.91+0.52-0.42× 10-5 (2σ). There is no evidence of component structure on the scale of Δ v > 8 km s-1 based on Na I, but there is marginal evidence for structure on smaller scales. The D/H value is high compared to the majority of recent D/H measurements, but consistent with the values for two other measurements at similar distances. D/O is in agreement with other distant measurements. The scatter in D/H values beyond ∼ 100 pc remains a challenge for Galactic chemical evolution. Title: Probing unexplored territories with MUSE: a second generation instrument for the VLT Authors: Bacon, R.; Bauer, S.; Boehm, P.; Boudon, D.; Brau-Nogué, S.; Caillier, P.; Capoani, L.; Carollo, C. M.; Champavert, N.; Contini, T.; Daguisé, E.; Dallé, D.; Delabre, B.; Devriendt, J.; Dreizler, S.; Dubois, J.; Dupieux, M.; Dupin, J. P.; Emsellem, E.; Ferruit, P.; Franx, M.; Gallou, G.; Gerssen, J.; Guiderdoni, B.; Hahn, T.; Hofmann, D.; Jarno, A.; Kelz, A.; Koehler, C.; Kollatschny, W.; Kosmalski, J.; Laurent, F.; Lilly, S. J.; Lizon, J.; Loupias, M.; Lynn, S.; Manescau, A.; McDermid, R. M.; Monstein, C.; Nicklas, H.; Parès, L.; Pasquini, L.; Pécontal-Rousset, A.; Pécontal, E.; Pello, R.; Petit, C.; Picat, J. -P.; Popow, E.; Quirrenbach, A.; Reiss, R.; Renault, E.; Roth, M.; Schaye, J.; Soucail, G.; Steinmetz, M.; Stroebele, S.; Stuik, R.; Weilbacher, P.; Wozniak, H.; de Zeeuw, P. T. Bibcode: 2006SPIE.6269E..0JB Altcode: 2006astro.ph..6329B; 2006SPIE.6269E..17B The Multi Unit Spectroscopic Explorer (MUSE) is a second-generation VLT panoramic integral-field spectrograph under preliminary design study. MUSE has a field of 1x1 arcmin2 sampled at 0.2x0.2 arcsec2 and is assisted by the VLT ground layer adaptive optics ESO facility using four laser guide stars. The simultaneous spectral range is 0.465-0.93 μm, at a resolution of R~3000. MUSE couples the discovery potential of a large imaging device to the measuring capabilities of a high-quality spectrograph, while taking advantage of the increased spatial resolution provided by adaptive optics. This makes MUSE a unique and tremendously powerful instrument for discovering and characterizing objects that lie beyond the reach of even the deepest imaging surveys. MUSE has also a high spatial resolution mode with 7.5x7.5 arcsec2 field of view sampled at 25 milli-arcsec. In this mode MUSE should be able to obtain diffraction limited data-cubes in the 0.6-0.93 μm wavelength range. Although the MUSE design has been optimized for the study of galaxy formation and evolution, it has a wide range of possible applications; e.g. monitoring of outer planets atmosphere, environment of young stellar objects, super massive black holes and active nuclei in nearby galaxies or massive spectroscopic surveys of stellar fields in the Milky Way and nearby galaxies. Title: Probing Unexplored Territories with MUSE: a Second-Generation Instrument for the VLT Authors: Bacon, Roland; Bauer, Svend; Böhm, Petra; Boudon, Didier; Brau-Nogue, Sylvie; Caillier, Patrick; Capoani, Lionel; Carollo, C. Marcella; Champavert, Nicolas; Contini, Thierry; Daguise, Eric; Dalle, Didier; Delabre, Bernard; Devriendt, Julien; Dreizler, Stefan; Dubois, Jean-Pierre; Dupieux, Michel; Dupin, Jean-Pierre; Emsellem, Eric; Ferruit, Pierre; Franx, Marijn; Gallou, Gérard; Gerssen, Joris; Guiderdoni, Bruno; Hahn, Thomas; Hofmann, Denni; Jarno, Aurélien; Kelz, Andreas; Koehler, Christof; Kollatschny, Wolfram; Kosmalski, Johan; Laurent, Florence; Lilly, Simon J.; Lizon, Jean-Louis; Loupias, Magali; Lynn, Stéphanie; Manescau, Antonio; McDermid, Richard M.; Monstein, Christian; Nicklas, Harals; Perès, Laurent; Pasquini, Luca; Pécontal, Emmanuel; Pécontal-Rousset, Arlette; Pello, Roser; Petit, Chantal; Picat, Jean-Pierre; Popow, Emil; Quirrenbach, Andreas; Reiss, Roland; Renault, Edgar; Roth, Martin; Schaye, Joop; Soucail, Geneviève; Steinmetz, Matthias; Ströbele, Stefan; Stuik, Remko; Weilbacher, Peter; Wozniak, Herve; de Zeeuw, P. Tim Bibcode: 2006Msngr.124....5B Altcode: The Multi Unit Spectroscopic Explorer (MUSE) is a second-generation VLT panoramic integral-field spectrograph presently under preliminary design study. MUSE has a field of 1 × 1 arcmin2 sampled at 0.2 × 0.2 arcsec2 and is assisted by the VLT ground layer adaptive optics ESO facility using four laser guide stars. The simultaneous spectral range is 0.465-0.93 μm, at a resolution of R ~ 3000. MUSE couples the discovery potential of a large imaging device to the measuring capabilities of a high-quality spectrograph, while taking advantage of the increased spatial resolution provided by adaptive optics. MUSE has also a high spatial resolution mode with 7.5 × 7.5 arcsec2 field of view sampled at 25 milli-arcsec. In this mode MUSE should be able to obtain diffraction-limited data cubes in the 0.6-0.93 μm wavelength range. Title: VLT spectroscopy and non-LTE modeling of the C/O-dominated accretion disks in two ultracompact X-ray binaries Authors: Werner, K.; Nagel, T.; Rauch, T.; Hammer, N. J.; Dreizler, S. Bibcode: 2006A&A...450..725W Altcode: 2006astro.ph..1546W Aims.We present new medium-resolution high-S/N optical spectra of the ultracompact low-mass X-ray binaries 4U 0614+091 and 4U 1626-67, taken with the ESO Very Large Telescope. They are pure emission line spectra and the lines are identified as due to CII-IV and OII-III.
Methods: .Line identification is corroborated by first results from modeling the disk spectra with detailed non-LTE radiation transfer calculations. Hydrogen and helium lines are lacking in the observed spectra.
Results: .Our models confirm the deficiency of H and He in the disks. The lack of neon lines suggests an Ne abundance of less than about 10 percent (by mass), however, this result is uncertain due to possible shortcomings in the model atom. These findings suggest that the donor stars are eroded cores of C/O white dwarfs with no excessive neon overabundance. This would contradict earlier claims of Ne enrichment concluded from X-ray observations of circumbinary material, which was explained by crystallization and fractionation of the white dwarf core.
Title: SDSS J212531.92-010745.9 - the first definite PG 1159 close binary system Authors: Nagel, T.; Schuh, S.; Kusterer, D. -J.; Stahn, T.; Hügelmeyer, S. D.; Dreizler, S.; Gänsicke, B. T.; Schreiber, M. R. Bibcode: 2006A&A...448L..25N Altcode: 2006astro.ph..1512N Aims.The archival spectrum of SDSS J212531.92-010745.9 shows not only the typical signature of a PG 1159 star, but also indicates the presence of a companion. Our aim was the proof of the binary nature of this object and the determination of its orbital period.Methods.We performed time-series photometry of SDSS J212531.92-010745.9. We observed the object during 10 nights, spread over one month, with the Tübingen 80 cm and the Göttingen 50 cm telescopes. We fitted the observed light curve with a sine and simulated the light curve of this system with the nightfall program. Furthermore, we compared the spectrum of SDSS J212531.92-010745.9 with NLTE models, the results of which also constrain the light curve solution. Results.An orbital period of 6.95616(33) h with an amplitude of 0.354(3) mag is derived from our observations. A pulsation period could not be detected. For the PG 1159 star we found, as preliminary results from comparison with our NLTE models, Teff ~ 90 000 K, log g ~ 7.60, and the abundance ratio C/He ~ 0.05 by number fraction. For the companion we obtained with a mean radius of 0.4 ± 0.1~R, a mass of 0.4 ± 0.1~M, and a temperature of 8200 K on the irradiated side, good agreement between the observed light curve and the nightfall simulation, but we do not regard those values as final. Title: Giant Transiting Planets Observations GITPO Authors: Afonso, C.; Henning, Th.; Weldrake, D.; Mazeh, T.; Dreizler, S. Bibcode: 2006dies.conf...79A Altcode: 2006IAUCo.200...79A The search for extrasolar planets is nowadays one of the most promising science drivers in Astronomy. The radial velocity technique proved to be successful in planet hunting, harvesting more than a hundred planets to date. In these last recent years, the transit method has come to fruition, with the detection of seven Jupiter-mass extrasolar transiting planets in close-in orbits ({ AU). Currently, the radius of planets can only be determined from transiting planets, representing the principal motivation and strength of this technique. The MPIA is presently building the Large Area Imager (LAIWO) for the 1m telescope in the Wise Observatory, Israel. LAIWO will have a field of view of one square degree. An intensive search for extra-solar planets will be performed with the 1m Wise telescope, together with the 1.2m MONET telescope in Texas. We will monitor three fields at a given time during three years and more than 200 nights per year. We expect several dozens of extra-solar planets. Title: The Msst Campaign: 4 M Spectroscopy of PG 1605+072 Authors: Jeffery, C. S.; Heber, U.; Dreizler, S.; O'Toole, S. J.; Schuh, S. L.; Woolf, V. M.; Falter, S.; Nitta, A.; Kleinman, S.; Krzesinski, J.; Billères, M. Bibcode: 2006BaltA..15..321J Altcode: 2006OAst...15..321J The MultiSite Spectroscopic Telescope (MSST) campaign aimed to provide a detailed view of the short-period pulsating subdwarf B star PG 1605+ 072. We present results from the part of the campaign undertaken on 4 m telescopes in 2002 May and June. Title: Exciting new features in the frequency spectrum of the EC 14026 star HS 0702+6043. Simultaneous g-modes and p-modes in a sdB pulsator Authors: Schuh, S.; Huber, J.; Dreizler, S.; Green, E. M.; Stahn, T.; Randall, S.; Husser, T. -O.; Heber, U.; O'Toole, S.; Fontaine, G. Bibcode: 2006MmSAI..77..480S Altcode: 2005astro.ph.10832S The discovery of a long-period g-mode oscillation in the previously known short-period p-mode sdB pulsator HS 0702+6043 makes this star an extraordinary object, unique as a member of the family of sdB pulsators, and one of the very few known pulsating stars overall exhibiting excited modes along both the acoustic and gravity branches of the nonradial pulsation spectrum. Because p-modes and g-modes probe different regions of a pulsating star, HS 0702+6043 holds a tremendous potential for asteroseismological investigations. We present preliminary results from the first extended campaign on this object. Title: Subluminous O Stars Authors: Heber, U.; Hirsch, H.; Ströer, A.; O'Toole, S.; Haas, S.; Dreizler, S. Bibcode: 2006BaltA..15...91H Altcode: 2006OAst...15...91H We report results of spectral analyses of sdO stars selected from the Supernova Ia Progenitor Survey, the Hamburg Quasar Survey and the Sloan Digital Sky Survey and based on state-of-the-art NLTE model atmospheres. By combining the sdO with the sdB samples we discuss trends of the atmospheric parameters in order to search for evidence for possible evolutionary linkage. The He-sdO stars are found to cluster near Teff = 45 000 K, log g = 5.5, whereas the number of sdO stars in this area is very small. The ``cooler'' sdO stars seem to form an extension to the sdB sequences. A couple of sdO stars are obviously evolved from the extended horizontal branch and reach temperatures as high as 80 000 K. We conjecture that the He-sdO stars and sdO/sdB stars have a different evolutionary origin. This is corroborated by the much lower binary frequency of the former. Strong enrichments of iron group elements are discovered for hydrogen-rich sdO stars as well as for sdB stars from high resolution UV spectra and have severe implications for the temperature scale. We finally highlight the discovery of a hyper-velocity He-sdO star with a radial velocity of 708 kms unbound to the Galaxy. Title: An Approach to a Stability Analysis of a SDO Star Authors: Rodríguez-López, C.; Moya, A.; Garrido, R.; MacDonald, J.; Ulla, A.; Dreizler, S.; Hügelmeyer, S. D.; Manteiga, M. Bibcode: 2006BaltA..15..313R Altcode: 2006OAst...15..313R A stability analysis of a structural model of an sdO star is presented. A non-adiabatic code of oscillations is used to search for modes in the frequency range 0.4 to 15 mHz. All of the computed modes were found to be stable. We draw attention, however, to three different stability regions. Title: HS 0702+6043: a star showing both short-period p-mode and long-period g-mode oscillations Authors: Schuh, S.; Huber, J.; Dreizler, S.; Heber, U.; O'Toole, S. J.; Green, E. M.; Fontaine, G. Bibcode: 2006A&A...445L..31S Altcode: 2005astro.ph.10831S Context: .The hot subdwarf B star HS 0702+6043 is known as a large-amplitude, short-period p-mode pulsator of the EC 14026 type. Its atmospheric parameters place it at the common boundary between the empirical instability regions of the EC 14026 variables and the typically cooler long-period g-mode pulsators of the PG 1716 kind.
Aims: .We analyse and interpret the photometric variability of HS 0702+6043 in order to explore its asteroseismological potential.
Methods: .We report on rapid wide band CCD photometric observations to follow up on and confirm the serendipitous discovery of multiperiodic long-period luminosity variations with typical time scales of ~1 h in HS 0702+6043, in addition to the two previously known pulsations at 363 s and 383 s. In particular, we isolate a relatively low-amplitude (~4 mmag), long-period (3538±130 s) light variation.
Results: .We argue that the most likely origin for this luminosity variation is the presence of an excited g-mode pulsation. If confirmed, HS 0702+6043 would constitute a rare addition to the very select class of pulsating stars showing simultaneously parts of their pressure and gravity mode pulsation spectra. The asteroseismological potential of such stars is immense, and HS 0702+6043 thus becomes a target of choice for future investigations. While our discovery appears consistent with the location of HS 0702+6043 at the common boundary between the two families of pulsating sdB stars, it does challenge theory's current description of stability and driving mechanisms in pulsating B subdwarfs.
Conclusions: . Title: Light and Heavy Metal Abundances in Hot Central Stars of Planetary Nebulae Authors: Werner, Klaus; Hoffmann, Agnes I. D.; Jahn, Dorothee; Rauch, Thomas; Reiff, Elke; Traulsen, Iris; Kruk, Jeffrey W.; Dreizler, Stefan Bibcode: 2005AIPC..804..129W Altcode: 2005astro.ph..8108W We present new results from our spectral analyses of very hot central stars achieved since the last IAU Symposium on planetary nebulae held in Canberra 2001. The analyses are mainly based on UV and far-UV spectroscopy performed with the Hubble Space Telescope and the Far Ultraviolet Spectroscopic Explorer but also on ground-based observations performed at the Very Large Telescope and other observatories. We report on temperature, gravity, and abundance determinations for the CNO elements of hydrogen-rich central stars. In many hydrogen-deficient central stars (spectral type PG1159) we discovered particular neon and fluorine lines, which are observed for the very first time in any astrophysical object. Their analysis strongly confirms the idea that these stars exhibit intershell matter as a consequence of a late helium-shell flash. Title: On the most metal-poor PN and its binary central star Authors: Napiwotzki, R.; Tovmassian, G.; Richer, M. G.; Stasińska, G.; Peña, M.; Drechsel, H.; Dreizler, S.; Rauch, T. Bibcode: 2005AIPC..804..173N Altcode: 2005astro.ph..9801N PN G135.9+55.9 is the most metal-poor PN known in our Galaxy. The central star resides in a short-period binary system with a compact component, probably a white dwarf. We describe new observations, which allowed us to determine the orbital period. The lower limit for the combined mass of both stars is close to the Chandrasekhar limit for white dwarfs, making this binary a possible progenitor of a supernova type Ia. The binary system must have recently emerged from a common envelope phase. Title: High-resolution extreme ultraviolet spectroscopy of G191-B2B: structure of the stellar photosphere and the surrounding interstellar medium Authors: Barstow, M. A.; Cruddace, R. G.; Kowalski, M. P.; Bannister, N. P.; Yentis, D.; Lapington, J. S.; Tandy, J. A.; Hubeny, I.; Schuh, S.; Dreizler, S.; Barbee, T. W. Bibcode: 2005MNRAS.362.1273B Altcode: 2005MNRAS.tmp..749B We have continued our detailed analysis of the high-resolution (R= 4000) spectroscopic observation of the DA white dwarf G191-B2B, obtained by the Joint Astrophysical Plasmadynamic Experiment (J-PEX) normal incidence sounding rocket-borne telescope, comparing the observed data with theoretical predictions for both homogeneous and stratified atmosphere structures. We find that the former models give the best agreement over the narrow waveband covered by J-PEX, in conflict with what is expected from previous studies of the lower resolution but broader wavelength coverage Extreme Ultraviolet Explorer spectra. We discuss the possible limitations of the atomic data and our understanding of the stellar atmospheres that might give rise to this inconsistency. In our earlier study, we obtained an unusually high ionization fraction for the ionized HeII present along the line of sight to the star. In the present paper, we obtain a better fit when we assume, as suggested by Space Telescope Imaging Spectrograph results, that this HeII resides in two separate components. When one of these is assigned to the local interstellar cloud, the implied He ionization fraction is consistent with measurements along other lines of sight. However, the resolving power and signal-to-noise available from the instrument configuration used in this first successful J-PEX flight are not sufficient to clearly identify and prove the existence of the two components. Title: Spectral analyses of DO white dwarfs and PG 1159 stars from the Sloan Digital Sky Survey Authors: Hügelmeyer, S. D.; Dreizler, S.; Werner, K.; Krzesiński, J.; Nitta, A.; Kleinman, S. J. Bibcode: 2005A&A...442..309H Altcode: 2005astro.ph..8101H We present a model atmosphere analysis of ten new DO white dwarfs and five new PG 1159 stars discovered in the Sloan Digital Sky Survey DR1, DR2 and DR3. This is a significant increase in the number of known DOs and PG 1159 stars. DO white dwarfs are situated on the white dwarf cooling sequence from the upper hot end (T_eff ≈ 120 000 K) down to the DB gap (T_eff ≈ 45 000 K). PG 1159 stars on the other hand feature effective temperatures which exceed T_eff = 65 000 K with an upper limit of T_eff = 200 000 K and are the proposed precursors of DO white dwarfs. Improved statistics are necessary to investigate the evolutionary link between these two types of stars. From optical SDSS spectra effective temperatures, surface gravities and element abundances are determined by means of non-LTE model atmospheres. Title: The MultiSite Spectroscopic Telescope campaign: 2 m spectroscopy of the V361 Hya variable PG 1605+072 Authors: O'Toole, S. J.; Heber, U.; Jeffery, C. S.; Dreizler, S.; Schuh, S. L.; Woolf, V. M.; Falter, S.; Green, E. M.; For, B. -Q.; Hyde, E. A.; Kjeldsen, H.; Mauch, T.; White, B. A. Bibcode: 2005A&A...440..667O Altcode: 2005astro.ph..6722O We present results and analysis for the 2 m spectroscopic part of the MultiSite Spectroscopic Telescope (MSST) campaign undertaken in May/June 2002. The goal of the project was to observe the pulsating subdwarf B star PG 1605+072 simultaneously in velocity and photometry and to resolve as many of the >50 known modes as possible, which will allow a detailed asteroseismological analysis. We have obtained over 150 h of spectroscopy, leading to an unprecedented noise level of only 207 m s-1. We report here the detection of 20 frequencies in velocity, with two more likely just below our detection threshold. In particular, we detect 6 linear combinations, making PG 1605+072 only the second star known to show such frequencies in velocity. We investigate the phases of these combinations and their parent modes and find relationships between them that cannot be easily understood based on current theory. These observations, when combined with our simultaneous photometry, should allow asteroseismology of this most complicated of sdB pulsators. Title: Modelling C/O/Ne dominated accretion discs in ultra-compact X-ray binaries Authors: Hammer, N. J.; Kusterer, D. -J.; Nagel, T.; Rauch, T.; Werner, K.; Dreizler, S. Bibcode: 2005ASPC..330..333H Altcode: We present synthetic UV/optical NLTE spectra for the accretion disc in the ultra-compact LMXB 4U 1626-67. By assuming a radial α-disc structure, we perform full non-LTE radiative transfer calculations to compute the detailed vertical structure of the disc. Comparing our results with HST spectra confirms that the disc is H and He depleted, but mainly composed of C and O. Title: Detection of planetary transits using wavelet analysis and genetic algorithms. Authors: Husser, T. -O.; Dreizler, S.; Solanki, S.; Thomas, R. Bibcode: 2005AN....326R.628H Altcode: No abstract at ADS Title: Automated Difference Imaging for extrasolar planet searches. Authors: Israel, H.; Hessman, F. V.; Dreizler, S.; Schuh, S. Bibcode: 2005AN....326..629I Altcode: No abstract at ADS Title: NLTE Spectral Analysis of Accretion Discs in Ultracompact X-ray Binaries Authors: Nagel, T.; Hammer, N. J.; Rauch, T.; Werner, K.; Dreizler, S. Bibcode: 2005ASPC..330...73N Altcode: We present first results of a NLTE spectral analysis of the accretion discs in the ultracompact X-ray binaries 4U 0614+091 and 4U 1626-67, performed with our accretion disc code AcDc. We show, that it is possible to give an upper limit for the abundances of hydrogen. The emission line features seen in the spectrum of 4U 1626-67 can be modeled qualitatively with irradiation of the accretion disc by the central neutron star. Title: The Spectral Variability of Pulsating Stars: PG 1159-035 Authors: Stahn, T.; Dreizler, S.; Werner, K. Bibcode: 2005ASPC..334..545S Altcode: 2005astro.ph..2013S With 10m class telescopes as well as with time-tagging detectors on board of HST and FUSE, the analysis of time-resolved spectra for pulsating white dwarfs becomes feasible. We present simulated time-resolved spectra for the hot pulsating white dwarf PG 1159-035 and compare these models with observational data of the 516 s mode based on HST-STIS spectroscopy. A determination of the pulsation mode by the spectral variability of PG 1159-035 seems to be impossible for the moment. Title: Spectral Analyses of DO White Dwarfs and PG1159 Stars from the Sloan Digital Sky Survey Authors: Huegelmeyer, S. D.; Dreizler, S.; Werner, K.; Nitta, A.; Kleinman, S. J.; Krzesiński, J. Bibcode: 2005ASPC..334..233H Altcode: 2005astro.ph..1252H SDSS (DR1 and DR2) has recently proposed 7 new DO white dwarfs as well as 6 new PG1159 stars. This is a significant increase in the known number of DOs and PG1159 stars. Our spectral analyses provide stellar parameters which can then be used to derive constraints for the evolution of H-deficient white dwarfs. A comprehensive understanding of these objects is still severely hampered by low-number statistics. Title: Investigation of the Spectral Variability of PG 1159-035 Authors: Dreizler, S.; Werner, K.; Stahn, T. Bibcode: 2005ASPC..334..512D Altcode: Based on HST-STIS spectra of PG 1159-035, a hot, variable white dwarf, we investigate the response of the stellar atmosphere to pulsations. The observations are compared to theoretical model atmospheres which allows to derive an amplitude for the variation of the effective temperature of about 1 250 K. Additionally, we derive amplitudes for radial velocity variations with 4.5 km s-1 for the second strongest optical mode. Title: NLTE Analysis of the Ultra-short Period White-Dwarf Binary RX J0806.3+1527 Authors: Steiper, J.; Reinsch, K.; Dreizler, S. Bibcode: 2005ASPC..334..399S Altcode: 2005astro.ph..1255S RX J0806.3+1527 is suspected to be a double-degenerate white dwarf binary. We present first results of our NLTE analysis of its optical spectrum. The VLT/FORS1 data show a composite spectrum consisting of a blue continuum and superimposed emission lines of the He II Pickering series and, possibly, the H Balmer series. Our models are based on hot white dwarf atmospheres and include illumination effects onto the secondary star. The physical parameters and chemical abundances derived from the comparison of the observed spectrum with a grid of model atmospheres provide constraints on the true nature of this enigmatic binary and on the models proposed so far. Title: HST and FUSE Spectroscopy of Hot Hydrogen-Rich Central Stars of Planetary Nebulae Authors: Traulsen, I.; Hoffmann, A. I. D.; Rauch, T.; Werner, K.; Dreizler, S.; Kruk, J. W. Bibcode: 2005ASPC..334..325T Altcode: 2004astro.ph.11403T High-resolution UV spectra, obtained with HST and FUSE, enable us to analyse hot hydrogen-rich central stars in detail. Up to now, optical hydrogen and helium lines have been used to derive temperature and surface gravity. Those lines, however, are rather insensitive; in particular, neutral helium lines have completely vanished in the hottest central stars. Therefore, we have concentrated on ionization balances of metals, which have a rich line spectrum in the UV, to establish a new temperature scale for our sample. Furthermore, we have determined abundances of light metals, which had been poorly known before. They show considerable variation from star to star. We present results of quantitative spectral analyses performed with non-LTE model atmospheres. Title: Subluminous O Stars from the ESO Supernova Progenitor Survey - Observation versus Theory Authors: Ströer, A.; Heber, U.; Lisker, T.; Napiwotzki, R.; Dreizler, S. Bibcode: 2005ASPC..334..309S Altcode: 2004astro.ph.10433S The ESO Supernova Progenitor Survey (SPY) has identified 58 (mostly helium-rich) subluminous O stars. We use the Balmer line strength to distinguish sdO from He-sdO (no Balmer lines) and present the results of the analyses of high resolution optical VLT-UVES spectra using an extensive grid of NLTE atmosphere models covering a large range in Teff, log{g} and helium abundances. The stellar atmospheric parameters are derived from line profile fits using a χ2 technique. The resulting distribution in the (Teff, log{g}) diagram as well as the luminosity function are discussed in the context of stellar evolution scenarios. By combining our results with those for the sdB stars from SPY (Lisker et al. 2004) we discuss the implications for binary population synthesis models of Han et al. (2003). Models with a low CEE efficiency and a constant mass ratio distribution provide a reasonable explanation of the observed properties of the SPY sample of sdB and sdO stars indicating that the sdO stars form the hot and luminous extension of the sdB sequence. However, for the He-sdO stars none of the considered evolution scenarios are in agreement with the measured parameters of our programme stars. We conclude that He-sdO stars are formed by a different process than the sdB and sdO stars. Title: Successors of White Dwarfs -- Blue Hook Stars and the Late Hot Flasher Scenario Authors: Moehler, S.; Sweigart, A. V.; Landsman, W. B.; Hammer, N. J.; Dreizler, S. Bibcode: 2005ASPC..334...73M Altcode: Recent UV observations of massive globular clusters show a significant population of hot stars fainter than the zero-age horizontal branch (``blue hook'' stars), which cannot be explained by canonical stellar evolution. Stars which experience unusually large mass loss on the red giant branch and which subsequently undergo the helium core flash while descending the white dwarf cooling curve could populate this region. Such objects should show higher temperatures than the hottest canonical horizontal branch stars and should have helium- and carbon-rich atmospheres. As a test of this late hot flasher scenario, we have obtained and analysed medium resolution spectra of a sample of blue hook stars to derive their atmospheric parameters. While these parameters generally support the late hot flasher scenario there remain important differences between our observational results and theoretical predictions. Title: Metal Abundances in Hot DA White Dwarfs Authors: Schuh, S.; Barstow, M. A.; Dreizler, S. Bibcode: 2005ASPC..334..237S Altcode: 2004astro.ph.11643S We compare measured element abundances in hot DA white dwarfs from UV observations to predictions from our self-consistent non-LTE model atmosphere diffusion calculations. Title: Iron Abundance in Hydrogen-Rich Central Stars of Planetary Nebulae Authors: Hoffmann, A. I. D.; Traulsen, I.; Rauch, T.; Werner, K.; Dreizler, S.; Kruk, J. W. Bibcode: 2005ASPC..334..321H Altcode: 2004astro.ph.11404H We report on an on-going analysis of high-resolution UV spectra of hot hydrogen-rich central stars of planetary nebulae (CSPN), obtained with the Hubble Space Telescope and FUSE. Since UV spectra of many CSPN are dominated by Fe and Ni lines, we intend to use them as temperature indicators to check the CSPN temperature scale we have derived earlier from CNO ionization balances. Furthermore, the observed line strengths of heavy metals show large variations between different objects suggesting a possible spread in abundances. We will determine abundances of iron group elements by quantitative spectral analyses with non-LTE model atmospheres. Title: On Possible Oxygen/Neon White Dwarfs: H1504+65 and the White Dwarf Donors in Ultracompact X-ray Binaries Authors: Werner, K.; Hammer, N. J.; Nagel, T.; Rauch, T.; Dreizler, S. Bibcode: 2005ASPC..334..165W Altcode: 2004astro.ph.10690W We discuss the possibility to detect O/Ne white dwarfs by evidence for Ne overabundances. The hottest known WD, H1504+65, could be the only single WD for which we might be able to prove its O/Ne nature directly. Apart from this, strong Ne abundances are known or suspected only from binary systems, namely from a few novae, and from a handful of LMXBs. We try to verify the hypothesis that the latter might host strongly ablated O/Ne WD donors, by abundance analyses of the accretion disks in these systems. In any case, to conclude on O/Ne WDs just by strong Ne overabundances is problematic, because Ne enrichment also occurs by settling of this species into the core of C/O WDs. Title: Discovery of a Long-Period Photometric Variation in the V361 Hya Star HS 0702+6043 Authors: Schuh, S.; Huber, J.; Green, E. M.; O'Toole, S. J.; Dreizler, S.; Heber, U.; Fontaine, G. Bibcode: 2005ASPC..334..530S Altcode: 2004astro.ph.11640S We report the discovery of a long-period g-mode oscillation in the previously known short-period p-mode sdB pulsator HS 0702+6043. This makes this star an extraordinary object, unique as a member of the family of sdB pulsators, and one of the very few known pulsating stars overall exhibiting excited modes along both the acoustic and gravity branches of the nonradial pulsation spectrum. Because p-modes and g-modes probe different regions of a pulsating star, HS 0702+6043 holds a tremendous potential for future detailed asteroseismological investigations. Title: Rotation Velocities of DA White Dwarfs with Convective Atmospheres} Authors: Karl, C.; Heber, U.; Napiwotzki, R.; Dreizler, S.; Koester, D.; Reid, I. N. Bibcode: 2005ASPC..334..241K Altcode: The sharp H{α} NLTE line cores of hydrogen rich (DA) white dwarfs allow their projected rotational velocities to be determined. High resolution optical spectra of 22 stars obtained with the Keck I telescope are matched by synthetic spectra computed from a grid of NLTE model atmospheres. We concentrate preferentially on hydrogen-rich white dwarfs with convective atmospheres, i.e. with Teff < 14 000 K. Previous analyses found DA white dwarfs hotter than 14 000 K to be very slow rotators and rarely show any spectroscopically detectable rotation. For 19 of our program stars we were able to derive projected rotational velocities or upper limits. Combining our results with those from two similar studies (Heber et al 1997, paper I and Koester et al. 1998, paper II), we have obtained information of 56 DA white dwarfs. The fraction of rotating DA white dwarfs whose line profiles can be matched for a vanishing projected rotation velocities is high for hot white dwarfs with radiative atmospheres (25 out of 28) with upper limits ranging from 1 kms-1 to 24 kms-1, whereas amongst the cool white dwarfs with presumably convective atmospheres only for a few stars (8 out of 22) no additional line broadening has to be invoked to explain their observed Hα line profiles resulting in upper limits to v sin i of 7 kms-1 to 35 kms-1. Title: Rotation velocities of white dwarfs. III. DA stars with convective atmospheres Authors: Karl, C. A.; Napiwotzki, R.; Heber, U.; Dreizler, S.; Koester, D.; Reid, I. N. Bibcode: 2005A&A...434..637K Altcode: The sharp Hα NLTE line cores of hydrogen-rich (DA) white dwarfs allow their projected rotational velocities to be determined. High resolution optical spectra of 22 stars obtained with the Keck I telescope are matched by synthetic spectra computed from a grid of NLTE model atmospheres. In this paper, the third in a series on white dwarf rotation, we concentrate preferentially on DA white dwarfs with convective atmospheres, i.e. with Teff < 14 000 K. Previous analyses found DA white dwarfs hotter than 14 000 K to be very slow rotators and rarely show any spectroscopically detectable rotation. For 19 of our programme stars we were able to derive projected rotational velocities or upper limits. No rotation could be detected for seven stars in our sample. However twelve stars show significant line broadening. In the case of the ZZ Ceti star G 117-B15A, the observed Hα line profile cannot be matched by a rotationally broadened profile as its line core is too narrow. Combining our results with those from two similar studies, we have obtained information on the rotation or other line broadening mechanisms (such as caused by magnetic fields) of 56 DA white dwarfs. The fraction of rotating DA white dwarfs whose line profiles can be matched for a vanishing projected rotation velocity is high for hot white dwarfs with radiative atmospheres (25 out of 28). Amongst the cool white dwarfs with presumedly convective atmospheres, only for a few stars (8 out of 22) has no additional line broadening to be invoked to explain their observed Hα line profiles. We conjecture that the physics of Hα line formation in convective DA white dwarf atmospheres is not yet sufficiently well understood and additional observational and theoretical efforts have to be made. Title: The D/H Ratio toward PG 0038+199 Authors: Williger, Gerard M.; Oliveira, Cristina; Hébrard, Guillaume; Dupuis, Jean; Dreizler, Stefan; Moos, H. Warren Bibcode: 2005ApJ...625..210W Altcode: 2005astro.ph..1320W We determine the D/H ratio in the interstellar medium toward the DO white dwarf PG 0038+199 using spectra from the Far Ultraviolet Spectroscopic Explorer (FUSE), with ground-based support from Keck HIRES. We employ curve-of-growth, apparent optical depth, and profile-fitting techniques to measure the column densities and limits of many other species (H2, Na I, C I, C II, C III, N I, N II, O I, Si II, P II, S III, Ar I, and Fe II), which allows us to determine related ratios such as D/O, D/N, and the H2 fraction. Our efforts are concentrated on measuring gas-phase D/H, which is key to understanding Galactic chemical evolution, and comparing it to predictions from big bang nucleosynthesis. We find column densities logN(HI)=20.41+/-0.08, logN(DI)=15.75+/-0.08, and logN(H2)=19.33+/-0.04, yielding a molecular hydrogen fraction of 0.14+/-0.02 (2 σ errors), with an excitation temperature of 143+/-5 K. The high H I column density implies that PG 0038+199 lies outside of the Local Bubble; we estimate its distance to be 297+164-104 pc (1 σ). [DI+HD]/[HI+2H2] toward PG 0038+199 is 1.91+0.52-0.42×10-5 (2 σ). There is no evidence of component structure on the scale of Δv>8 km s-1, based on Na I, but there is marginal evidence for structure on smaller scales. The D/H value is high compared to the majority of recent D/H measurements but consistent with the values for two other measurements at similar distances. D/O is in agreement with other distant measurements. The scatter in D/H values beyond ~100 pc remains a challenge for Galactic chemical evolution.

This paper is dedicated in memory of Ervin J. Williger, father of the first author, who passed away on 2003 September 13. His enthusiastic support and encouragement were essential to its successful completion.

Based on data from the Far Ultraviolet Spectroscopic Explorer and the W. M. Keck Observatory. Title: Whole Earth Telescope observations of BPM 37093: A seismological test of crystallization theory in white dwarfs Authors: Kanaan, A.; Nitta, A.; Winget, D. E.; Kepler, S. O.; Montgomery, M. H.; Metcalfe, T. S.; Oliveira, H.; Fraga, L.; da Costa, A. F. M.; Costa, J. E. S.; Castanheira, B. G.; Giovannini, O.; Nather, R. E.; Mukadam, A.; Kawaler, S. D.; O'Brien, M. S.; Reed, M. D.; Kleinman, S. J.; Provencal, J. L.; Watson, T. K.; Kilkenny, D.; Sullivan, D. J.; Sullivan, T.; Shobbrook, B.; Jiang, X. J.; Ashoka, B. N.; Seetha, S.; Leibowitz, E.; Ibbetson, P.; Mendelson, H.; Meištas, E. G.; Kalytis, R.; Ališauskas, D.; O'Donoghue, D.; Buckley, D.; Martinez, P.; van Wyk, F.; Stobie, R.; Marang, F.; van Zyl, L.; Ogloza, W.; Krzesinski, J.; Zola, S.; Moskalik, P.; Breger, M.; Stankov, A.; Silvotti, R.; Piccioni, A.; Vauclair, G.; Dolez, N.; Chevreton, M.; Deetjen, J.; Dreizler, S.; Schuh, S.; Gonzalez Perez, J. M.; Østensen, R.; Ulla, A.; Manteiga, M.; Suarez, O.; Burleigh, M. R.; Barstow, M. A. Bibcode: 2005A&A...432..219K Altcode: 2004astro.ph.11199K BPM 37093 is the only hydrogen-atmosphere white dwarf currently known which has sufficient mass (~1.1 M) to theoretically crystallize while still inside the ZZ Ceti instability strip (Teff∼12 000 K). As a consequence, this star represents our first opportunity to test crystallization theory directly. If the core is substantially crystallized, then the inner boundary for each pulsation mode will be located at the top of the solid core rather than at the center of the star, affecting mainly the average period spacing. This is distinct from the “mode trapping” caused by the stratified surface layers, which modifies the pulsation periods more selectively. In this paper we report on Whole Earth Telescope observations of BPM 37093 obtained in 1998 and 1999. Based on a simple analysis of the average period spacing we conclude that a large fraction of the total stellar mass is likely to be crystallized.

Based on observations obtained at: Observatório do Pico dos Dias (OPD) Brazil, the European Southern Observatory (ESO) Chile, South African Astronomical Observatory (SAAO), Mt. John University Observatory (MJUO) New Zealand, Siding Spring Observatory (SSO) Australia, and Cerro Tololo Inter-American Observatory (CTIO), a division of the National Optical Astronomy Observatories, which is operated by the Association of Universities for Research in Astronomy, Inc. under cooperative agreement with the National Science Foundation. Title: Stellar atmosphere modeling in the era of 10m class telescopes Authors: Dreizler, S. Bibcode: 2005AIPC..752...13D Altcode: In this paper, I briefly summarize the basic ingredients for modeling stellar atmospheres. The progress in the numerical solution techniques has evolved in parallel to the rapid development of observing facilities. The modeling of stellar atmospheres in particular and stellar astrophysics in general are therefore important ingredients for our understanding of stellar, galactic and cosmic evolution. Title: Giant Transiting Planets Observations - GITPO Authors: Afonso, C.; Henning, Th.; Weldrake, D.; Mazeh, T.; Dreizler, S. Bibcode: 2005prpl.conf.8047A Altcode: 2005LPICo1286.8047A No abstract at ADS Title: AcDc - A new code for the NLTE spectral analysis of accretion discs: application to the helium CV AM CVn Authors: Nagel, T.; Dreizler, S.; Rauch, T.; Werner, K. Bibcode: 2004A&A...428..109N Altcode: 2004astro.ph..8352N We present a recently developed code for detailed NLTE calculations of accretion disc spectra of cataclysmic variables and compact X-ray binaries. Assuming a radial structure of a standard α-disc, the disc is divided into concentric rings. For each disc ring the solution of the radiation transfer equation and the structure equations, comprising the hydrostatic and radiative equilibrium, the population of the atomic levels as well as charge and particle conservation, is done self-consistently. Metal-line blanketing and irradiation by the central object are taken into account. As a first application, we show the influence of different disc parameters on the disc spectrum for the helium cataclysmic variable AM CVn. Title: Modeling He-rich Disks in AM CVn Binaries Authors: Nagel, T.; Rauch, T.; Dreizler, S.; Werner, K. Bibcode: 2004RMxAC..20..228N Altcode: 2004IAUCo.194..228N We have developed a new code for the calculation of synthetic spectra and vertical structures of accretion disks in cataclysmic variables and compact X-ray binaries. Here we present results for the CV system AM CVn. Title: Modeling of Oxygen-Neon Dominated Accretion Disks in Ultracompact X-ray Binaries: 4U 1626-67 Authors: Werner, K.; Nagel, T.; Dreizler, S.; Rauch, T. Bibcode: 2004RMxAC..20..146W Altcode: 2003astro.ph.12561W; 2004IAUCo.194..146W We report on first results of computing synthetic spectra from H/He-poor accretion disks in ultracompact LMXBs. We aim at the determination of the chemical composition of the very low-mass donor star, which is the core of a former C/O white dwarf. The abundance analysis allows to draw conclusions on gravitational settling in WDs which is an important process affecting cooling times and pulsational g-mode periods. Title: HS 2237+8154: A new pre-CV just above the period gap Authors: Gänsicke, B. T.; Araujo-Betancor, S.; Hagen, H. -J.; Harlaftis, E. T.; Kitsionas, S.; Dreizler, S.; Engels, D. Bibcode: 2004RMxAC..20..271G Altcode: 2004IAUCo.194..271G We report follow-up observations of the new pre-cataclysmic variable HS 2237+8154, identified from the Hamburg Quasar Survey. The orbital period derived from ellipsoidal modulation observed in the R-band as well as from the Hα radial velocity variation is [orb] = 178.10±0.08 min. We briefly discuss the evolutionary state of this system. Title: The Rotational Velocity of Helium-rich Pre-White Dwarfs Authors: Rauch, T.; Köper, S.; Dreizler, S.; Werner, K.; Heber, U.; Reid, I. Neill Bibcode: 2004IAUS..215..573R Altcode: No abstract at ADS Title: MSST observations of the pulsating sdB star PG 1605+072 Authors: O'Toole, S. J.; Falter, S.; Heber, U.; Jeffery, C. S.; Dreizler, S.; Schuh, S. L.; MSST + Wet Teams, Bibcode: 2004Ap&SS.291..457O Altcode: 2003astro.ph..9061O We present the first results from the MultiSite Spectroscopic Telescope (MSST) observations of the sdBV star PG 1605+072. Pulsating sdB stars (also known as EC 14026 stars) offer the chance to gain new insights into the formation and evolution of extreme Horizontal Branch stars using the tools of asteroseismology. PG 1605+072 is an outstanding object in its class, with the richest frequency spectrum, the longest periods, and the largest variations. Title: Helium-rich EHB Stars in Globular Clusters Authors: Moehler, S.; Sweigart, A. V.; Landsman, W. B.; Dreizler, S. Bibcode: 2004Ap&SS.291..231M Altcode: 2003astro.ph..9768M Recent UV observations of the most massive Galactic globular clusters show a significant population of hot stars below the zero-age HB (“blue hook” stars), which cannot be explained by canonical stellar evolution. Stars which suffer unusually large mass loss on the red giant branch and thus experience the helium-core flash while descending the white dwarf cooling curve could populate this region. They should show higher temperatures than the hottest canonical HB stars and their atmospheres should be helium-rich and probably C/N-rich. We have obtained spectra of blue hook stars in ω Cen and NGC 2808 to test this possibility. Our analysis shows that the blue hook stars in these clusters reach effective temperatures well beyond the hot end of the canonical EHB and have higher helium abundances than canonical EHB stars. These results support the hypothesis that the blue hook stars arise from stars which ignite helium on the white dwarf cooling curve. Title: Discovery of Gravity-Mode Pulsators among Subdwarf B Stars: PG 1716+426, the Class Prototype Authors: Reed, M. D.; Green, E. M.; Callerame, K.; Seitenzahl, I. R.; White, B. A.; Hyde, E. A.; Giovanni, M. K.; Østensen, R.; Bronowska, A.; Jeffery, E. J.; Cordes, O.; Falter, S.; Edelmann, H.; Dreizler, S.; Schuh, S. L. Bibcode: 2004ApJ...607..445R Altcode: A new class of pulsating subdwarf B stars has recently been announced by Green and coworkers. Here we present a follow-up paper describing our observations and the pulsation structure of the class prototype PG 1716+426. The oscillations are multiperiodic with periods between 0.8 and 1.4 hr (180-340 μHz) and semiamplitudes less than 0.2%. We also observe that the periods and amplitudes appear variable, making the pulsation structure of PG 1716 complicated. The periods are an order of magnitude longer than those seen in EC 14026 (sdBV) stars, implying that they are gravity modes rather than pressure modes. As such, they represent a new class of variable star. Title: Multisite spectroscopic and photometric observations of the pulsating sdB star PG 1605+072 Authors: O'Toole, S. J.; Falter, S.; Heber, U.; Jeffery, C. S.; Dreizler, S.; Schuh, S. L.; Msst, The; Wet Teams Bibcode: 2004ASPC..310..230O Altcode: 2004IAUCo.193..230O; 2004vslg.conf..230O We present the first results from the MultiSite Spectroscopic Telescope (MSST) observations ofthe sd BV star PG 1605+072. Pulsating sdB stars (V361 Hya stars) offer the chance to gain new insights into the formation and evolution of extreme Horizontal Branch stars using the tools of asteroseismology. PG 1605+072 is an outstanding object in its class, with the richest frequency spectrum, the longest periods, and the largest variations. The MSST campaign took place in 2002 May/June and we present here the massive data set, madeup of 399 hr of photometry and 151 hr of spectroscopy. The overall aims of the project are to examine light/velocity amplitude ratios and phase differences, changes in equivalent width/line index, and λ-dependence of photometric amplitudes, and to use these properties for mode identification. Title: HS 2237+8154: On the onset of mass transfer or entering the period gap? Authors: Gänsicke, B. T.; Araujo-Betancor, S.; Hagen, H. -J.; Harlaftis, E. T.; Kitsionas, S.; Dreizler, S.; Engels, D. Bibcode: 2004A&A...418..265G Altcode: 2004astro.ph..2189G We report follow-up observations of a new white dwarf/red dwarf binary HS 2237+8154, identified as a blue variable star from the Hamburg Quasar Survey. Ellipsoidal modulation observed in the R band as well as the Hα radial velocity variations measured from time-resolved spectroscopy determine the orbital period to be Porb=178.10 ± 0.08 min. The optical spectrum of HS 2237+8154 is well described by a combination of a Teff=11 500 ± 1500 K white dwarf (assuming log g=8) and a dM 3.5 ± 0.5 secondary star. The distance implied from the flux scaling factors of both stellar components is d=105 ± 25 pc. Combining the constraints obtained from the radial velocity of the secondary and from the ellipsoidal modulation, we derive a binary inclination of i≃50°-70° and stellar masses of Mwd=0.47-0.67 M and Msec=0.2-0.4 M. All observations imply that the secondary star must be nearly Roche-lobe filling. Consequently, HS 2237+8154 may be either a pre-cataclysmic variable close to the start of mass transfer, or - considering its orbital period - a cataclysmic variable that terminated mass transfer and entered the period gap, or a hibernating nova.

Based in part on observations made at the 1.2 m telescope, located at Kryoneri Korinthias, and owned by the National Observatory of Athens, Greece, and with the Isaac Newton Telescope, which is 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 Astrofisica de Canarias. Title: Observations of the pulsating subdwarf B star Feige 48: Constraints on evolution and companions Authors: Reed, M. D.; Kawaler, S. D.; Zola, S.; Jiang, X. J.; Dreizler, S.; Schuh, S. L.; Deetjen, J. L.; Kalytis, R.; Meištas, E.; Janulis, R.; Ališauskas, D.; Krzesiński, J.; Vuckovic, M.; Moskalik, P.; Ogłoza, W.; Baran, A.; Stachowski, G.; Kurtz, D. W.; González Pérez, J. M.; Mukadam, A.; Watson, T. K.; Koen, C.; Bradley, P. A.; Cunha, M. S.; Kilic, M.; Klumpe, E. W.; Carlton, R. F.; Handler, G.; Kilkenny, D.; Riddle, R.; Dolez, N.; Vauclair, G.; Chevreton, M.; Wood, M. A.; Grauer, A.; Bromage, G.; Solheim, J. E.; Østensen, R.; Ulla, A.; Burleigh, M.; Good, S.; Hürkal, Ö.; Anderson, R.; Pakstiene, E. Bibcode: 2004MNRAS.348.1164R Altcode: 2003astro.ph.11476R Since pulsating subdwarf B (sdBV or EC14026) stars were first discovered, observational efforts have tried to realize their potential for constraining the interior physics of extreme horizontal branch stars. Difficulties encountered along the way include uncertain mode identifications and a lack of stable pulsation mode properties. Here we report on Feige 48, an sdBV star for which follow-up observations have been obtained spanning more than four years. These observations show some stable pulsation modes.

We resolve the temporal spectrum into five stable pulsation periods in the range 340-380 s with amplitudes less than 1 per cent, and two additional periods that appear in one data set each. The three largest amplitude periodicities are nearly equally spaced, and we explore the consequences of identifying them as a rotationally split l= 1 triplet by consulting a representative stellar model.

The general stability of the pulsation amplitudes and phases allows us to use the pulsation phases to constrain the time-scale of evolution for this sdBV star. Additionally, we are able to place interesting limits on any stellar or planetary companion to Feige 48. Title: Spectroscopic analyses of the blue hook stars in NGC 2808: A more stringent test of the late hot flasher scenario Authors: Moehler, S.; Sweigart, A. V.; Landsman, W. B.; Hammer, N. J.; Dreizler, S. Bibcode: 2004A&A...415..313M Altcode: 2003astro.ph.11215M Recent UV observations of the globular cluster NGC 2808 (Brown et al. \cite{brsw01}) show a significant population of hot stars fainter than the zero-age horizontal branch (``blue hook'' stars), which cannot be explained by canonical stellar evolution. Their results suggest that stars which experience unusually large mass loss on the red giant branch and which subsequently undergo the helium core flash while descending the white dwarf cooling curve could populate this region. Theory predicts that these ``late hot flashers'' should show higher temperatures than the hottest canonical horizontal branch stars and should have helium- and carbon-rich atmospheres. As a test of this late hot flasher scenario, we have obtained and analysed medium resolution spectra of a sample of blue hook stars in NGC 2808 to derive their atmospheric parameters. Using the same procedures, we have also re-analyzed our earlier spectra of the blue hook stars in ω Cen (Moehler et al. \cite{mosw02}) for comparison with the present results for NGC 2808. The blue hook stars in these two clusters are both hotter (Teff ≥35 000 K) and more helium-rich than canonical extreme horizontal branch stars in agreement with the late hot flasher scenario. Moreover, we find indications for carbon enhancement in the three most helium-enriched stars in NGC 2808. However, the blue hook stars still show some hydrogen in their atmospheres, perhaps indicating that some residual hydrogen survives a late hot flash and then later diffuses to the surface during the horizontal branch phase. We note that the presence of blue hook stars apparently depends mostly on the total mass of the globular cluster and not so much on its horizontal branch morphology.

Based on observations collected at the European Southern Observatory, Chile (ESO proposal 68.D-0248). Title: 2MASS J0516288+260738: a new low-mass eclipsing binary system. Authors: Schuh, S.; Drechsel, H.; Hauschildt, P.; Handler, G.; Endl, M.; Dreizler, S. Bibcode: 2004ANS...325R..84S Altcode: 2004ANS...325a..84S; 2004ANS...325..P09S No abstract at ADS Title: Asteroseismology of the β Cephei star ν Eridani - II. Spectroscopic observations and pulsational frequency analysis Authors: Aerts, C.; De Cat, P.; Handler, G.; Heiter, U.; Balona, L. A.; Krzesinski, J.; Mathias, P.; Lehmann, H.; Ilyin, I.; De Ridder, J.; Dreizler, S.; Bruch, A.; Traulsen, I.; Hoffmann, A.; James, D.; Romero-Colmenero, E.; Maas, T.; Groenewegen, M. A. T.; Telting, J. H.; Uytterhoeven, K.; Koen, C.; Cottrell, P. L.; Bentley, J.; Wright, D. J.; Cuypers, J. Bibcode: 2004MNRAS.347..463A Altcode: We undertook a multisite spectroscopic campaign for the β Cephei star ν Eridani. A total of 2294 high-resolution spectra were obtained from telescopes at 11 different observatories around the world. The time base of dedicated multisite observations is 88 d. To this data set we have added 148 older, previously unpublished spectra, such that the overall time-span of the 2442 spectra is 430 d. The analysis of the radial velocity variations derived from the SiIII triplet centred on 4560Å leads to 19 significant frequencies, of which seven correspond to independent pulsation frequencies. Five of these are members of multiplets with an average spacing of 0.018 +/- 0.002 cd-1. Our spectroscopic results agree well with those derived from a simultaneous multisite photometric campaign of the star, albeit that we do not recover their low frequency at 0.43218 cd-1. We find three different candidate frequencies below 1 cd-1 instead. We also find that the radial velocity amplitude of the main mode has increased by some 30 per cent over the last 15 years, which is consistent with the photometry data. We derive a relative equivalent width variation of 6.5 per cent, which is completely dominated by the main radial mode. The phase difference between the radial velocity and light variations for the main frequency is , which is clearly deviant from the adiabatic value and confirms the radial nature of the dominant mode. The spectral line broadening leads to an upper limit of 20 km s-1 for vsini, which is consistent with the long rotation period derived from the frequency splittings. Title: Time resolved spectroscopy of the sdB variable PG1605+072 Authors: Dreizler, Stefan Bibcode: 2004fuse.prop.C020D Altcode: The recent discovery of radial and nonradial mode pulsations in more than 20 sdB stars make them primary targets for asteroseismology to probe their internal structure and discern their evolutionary status; the latter is crucial for reasons as diverse as understanding the late stages of stellar evolution and the calibration of the observed ultraviolet upturn in giant elliptical galaxies as an age indicator. Central to any asteroseismological study is an identification of the pulsation modes. Photometric studies have failed to identify modes from optical light curves. Line profile and flux variations in the far ultraviolet offer a promising way to disentangle the pulsation modes by comparison with detailed model predictions. PG1605+072 is an outstanding target among the sdB variables because it displays the richest period spectrum (>50 pulsation periods), largest amplitudes and longest periods, which makes it the primary target for a spectroscopic FUV study. Title: 2MASS J0516288+260738: Discovery of the first eclipsing late K + Brown dwarf binary system? Authors: Schuh, S. L.; Handler, G.; Drechsel, H.; Hauschildt, P.; Dreizler, S.; Medupe, R.; Karl, C.; Napiwotzki, R.; Kim, S. -L.; Park, B. -G.; Wood, M. A.; Paparó, M.; Szeidl, B.; Virághalmy, G.; Zsuffa, D.; Hashimoto, O.; Kinugasa, K.; Taguchi, H.; Kambe, E.; Leibowitz, E.; Ibbetson, P.; Lipkin, Y.; Nagel, T.; Göhler, E.; Pretorius, M. L. Bibcode: 2003A&A...410..649S Altcode: 2003astro.ph..8329S We report the discovery of a new eclipsing system less than one arcminute south of the pulsating DB white dwarf KUV 05134+2605. The object could be identified with the point source 2MASS J0516288+260738 published by the Two Micron All Sky Survey. We present and discuss the first light curves as well as some additional colour and spectral information. The eclipse period of the system is 1.29 d, and, assuming this to be identical to the orbital period, the best light curve solution yields a mass ratio of m2/m1=0.11, a radius ratio of r2/r1~ 1 and an inclination of 74o. The spectral anaylsis results in a Teff=4200 K for the primary. On this basis, we suggest that the new system probably consists of a late K + Brown dwarf (which would imply a system considerably younger than ~0.01 Gyr to have r2/r1~ 1), and outline possible future observations.

This paper uses observations made at the Bohyunsan Optical Astronomy Observatory of Korea Astronomy Observatory, at the South African Astronomical Observatory (SAAO), at the 0.9 m telescope at Kitt Peak National Observatory recommissioned by the Southeastern Association for Research in Astronomy (SARA), at Gunma Astronomical Observatory established by Gunma prefecture, Japan, at the Florence and George Wise Observatory, operated by the Tel-Aviv University, Israel and at Piszkésteto, the mountain station of Konkoly Observatory of the Hungarian Academy of Science, Hungary.

This publication makes use of data products from the Two Micron All Sky Survey, a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center / California Institute of Technology, funded by the National Aeronautics and Space Administration and the National Science Foundation.

The Digitized Sky Survey was produced at the Space Telescope Science Institute under US Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. The plates were processed into the present compressed digital form with the permission of these institutions. Title: A Whole Earth Telescope campaign on the pulsating subdwarf B binary system PG 1336-018 (NY Vir) Authors: Kilkenny, D.; Reed, M. D.; O'Donoghue, D.; Kawaler, S. D.; Mukadam, A.; Kleinman, S. J.; Nitta, A.; Metcalfe, T. S.; Provencal, J. L.; Watson, T. K.; Sullivan, D. J.; Sullivan, T.; Shobbrook, R.; Jiang, X. J.; Joshi, S.; Ashoka, B. N.; Seetha, S.; Leibowitz, E.; Ibbetson, P.; Mendelson, H.; Meištas, E.; Kalytis, R.; Ališauskas, D.; Martinez, P.; van Wyk, F.; Stobie, R. S.; Marang, F.; Zola, S.; Krzesinski, J.; Ogłoza, W.; Moskalik, P.; Silvotti, R.; Piccioni, A.; Vauclair, G.; Dolez, N.; Chevreton, M.; Dreizler, S.; Schuh, S. L.; Deetjen, J. L.; Solheim, J. -E.; Gonzalez Perez, J. M.; Ulla, A.; Østensen, R.; Manteiga, M.; Suarez, O.; Burleigh, M.; Kepler, S. O.; Kanaan, A.; Giovannini, O. Bibcode: 2003MNRAS.345..834K Altcode: We present results from a multisite (`Whole Earth Telescope') photometric campaign on PG 1336-018, the close eclipsing binary system containing a pulsating subdwarf B (sdB) star. The main part of the campaign (1999 April) resulted in ~172 h of observations, representing a coverage of about 47 per cent, and additional data were obtained outside the core campaign. Periodogram analysis shows that the light variations are dominated by three frequencies near 5757, 5585 and 5369 μHz (~174, 179 and 186 s, respectively), although many frequencies are present, particularly in the range 5000-6000 μHz (~200-170 s). We identify, with some confidence, 28 frequencies down to a semi-amplitude of 0.0005 in fractional intensity (equivalent to about 0.5 mmag). It is clear that the pulsation frequencies of PG 1336-018 have changed substantially since the 1996 discovery observations were made, and that amplitude changes occur, at least in the dominant three frequencies, on relatively short time-scales (of the order of a day). On the assumption that the pulsating star is phase-locked in the binary system, we have searched for rotational splitting of frequencies near the orbital and half of the orbital period, but the results are confused by aliasing at those frequencies (due to the data gaps caused by the eclipses). A preliminary model qualitatively matches the distribution of frequencies in PG 1336-018, with some good individual correspondences, but cannot be considered adequate because geometric cancellation should hide some of the modes which are apparently detected. Analysis of the pulsations during eclipse recovers three of the strongest modes, but the limited eclipse data - which can, at best, be only about 9 per cent of the total - do not allow mode identification at this stage. Simulations indicate that an overall coverage of about 80 per cent would be required for this to be viable. An attempt was made to determine phase shifts in the pulsation frequencies as a way of directly measuring the size of the binary orbit, but the uncertainties in the method are comparable to the light travel time across the orbit (probably less than a second). Title: Synthetic Spectra of Accretion Disks Authors: Nagel, T.; Dreizler, S.; Werner, K. Bibcode: 2003ANS...324...64N Altcode: 2003ANS...324..P31N; 2003ANS...324b..64N No abstract at ADS Title: Analysis of the FUSE spectrum of the sdOB EC11481-2303 Authors: Hammer, N.; Deetjen, J. L.; Dreizler, S.; Werner, K.; Kruk, J. W. Bibcode: 2003ANS...324...72H Altcode: 2003ANS...324b..72H; 2003ANS...324..P51H No abstract at ADS Title: Spectral Types of Planetary Host Star Candidates: New Transiting Planets? Authors: Dreizler, S.; Rauch, T.; Hauschildt, P.; Schuh, S. L.; Kley, W.; Werner, K. Bibcode: 2003ANS...324....2D Altcode: 2003ANS...324..A03D; 2003ANS...324b...2D No abstract at ADS Title: HST UV-spectroscopy of Hot Central Stars of Planetary Nebulae Authors: Traulsen, I.; Hoffmann, A.; Dreizler, S.; Rauch, T.; Werner, K. Bibcode: 2003ANS...324..144T Altcode: 2003ANS...324c.144T; 2003ANS...324..P60T No abstract at ADS Title: Population Membership of White Dwarfs from the SPY Project Authors: Pauli, E. -M.; Napiwotzki, R.; Altmann, M.; Heber, U.; Dreizler, S.; Kerber, F.; Odenkirchen, M.; Spy Consortium Bibcode: 2003ANS...324...36P Altcode: 2003ANS...324b..36P; 2003ANS...324..G04P No abstract at ADS Title: Improved Results for Equilibrium Abundances from Diffusion Calculations Authors: Schuh, S. L.; Dreizler, S. Bibcode: 2003ANS...324...72S Altcode: 2003ANS...324..P50S; 2003ANS...324b..72S No abstract at ADS Title: To be or Not to Be a Late Hot Flasher Authors: Moehler, S.; Sweigart, A. V.; Landsman, W. B.; Dreizler, S. Bibcode: 2003ANS...324...79M Altcode: 2003ANS...324b..79M; 2003ANS...324..P66M No abstract at ADS Title: OGLE-TR-3: A possible new transiting planet Authors: Dreizler, S.; Hauschildt, P. H.; Kley, W.; Rauch, T.; Schuh, S. L.; Werner, K.; Wolff, B. Bibcode: 2003A&A...402..791D Altcode: 2003astro.ph..3183D Recently, 59 low-luminosity object transits were reported from the Optical Gravitational Lensing Experiment (OGLE). Our follow-up low-resolution spectroscopy of 16 candidates provided two objects, OGLE-TR-3 and OGLE-TR-10, which have companions with radii compatible with those of gas-giant planets. Further high-resolution spectroscopy revealed a very low velocity variation (<500 m s-1) of the host star OGLE-TR-3 which may be caused by its unseen companion. An analysis of the radial velocity and light curve results in M<2.5 MJup, R<1.6 RJup, and an orbital separation of about 5 Rsun, which makes it the planet with the shortest period known. This allows to identify the low-luminosity companion of OGLE-TR-3 as a possible new gas-giant planet. If confirmed, this makes OGLE-TR-3 together with OGLE-TR-56 the first extrasolar planets detected via their transit light curves.

Based on observations collected at the European Southern Observatory, Paranal, Chile (ESO Programme 269.C-5034). Title: Simultaneous time-series spectroscopy and multi-band photometry of the sdBV PG 1605+072 Authors: Falter, S.; Heber, U.; Dreizler, S.; Schuh, S. L.; Cordes, O.; Edelmann, H. Bibcode: 2003A&A...401..289F Altcode: 2003astro.ph..1604F We present time-series spectroscopy and multi-band photometry of the sdBV PG 1605+072 carried out simultaneously at the Calar Alto 2.2-m and 3.5-m telescopes. The periodogram analysis of the radial velocity curves reveals three frequencies at 2.078, 2.756, and 1.985 mHz for Hbeta and at 2.076, 2.753, and 1.978 mHz for Hgamma . The corresponding radial velocity amplitudes are 12.7, 8.0, and 7.9 km s-1 for Hbeta and 14.3, 6.5, and 7.2 km s-1 for Hgamma . Furthermore, we found five frequencies that are present in all wavelength bands of the BUSCA photometer. The frequencies detected in the radial velocity curves are recovered by the photometric measurements. Moreover, additional frequencies were present in the periodograms which could not be identified in all four bands simultaneously. The comparison of the amplitudes presented here with previous results from radial velocity and photometric observations of PG 1605+072 shows a significant change or even switch in the power of the modes within short time scales, i.e. about one year. No changes in frequency were registered and the phases of the modes show no wavelength dependency within our multi-band photometry.

Based on observations obtained at the German-Spanish Astronomical Center (DSAZ), Calar Alto, operated by the Max-Planck-Institut für Astronomie Heidelberg jointly with the Spanish National Commission for Astronomy. Title: The everchanging pulsating white dwarf GD358 Authors: Kepler, S. O.; Nather, R. E.; Winget, D. E.; Nitta, A.; Kleinman, S. J.; Metcalfe, T.; Sekiguchi, K.; Jiang, Xiaojun; Sullivan, D.; Sullivan, T.; Janulis, R.; Meistas, E.; Kalytis, R.; Krzesinski, J.; Ogoza, W.; Zola, S.; O'Donoghue, D.; Romero-Colmenero, E.; Martinez, P.; Dreizler, S.; Deetjen, J.; Nagel, T.; Schuh, S. L.; Vauclair, G.; Ning, Fu Jian; Chevreton, M.; Solheim, J. -E.; Gonzalez Perez, J. M.; Johannessen, F.; Kanaan, A.; Costa, J. E.; Murillo Costa, A. F.; Wood, M. A.; Silvestri, N.; Ahrens, T. J.; Jones, A. K.; Collins, A. E.; Boyer, M.; Shaw, J. S.; Mukadam, A.; Klumpe, E. W.; Larrison, J.; Kawaler, S.; Riddle, R.; Ulla, A.; Bradley, P. Bibcode: 2003A&A...401..639K Altcode: 2003astro.ph..1477K We report 323 hours of nearly uninterrupted time series photometric observations of the DBV star GD 358 acquired with the Whole Earth Telescope (WET) during May 23rd to June 8th, 2000. We acquired more than 232,000 independent measurements. We also report on 48 hours of time-series photometric observations in Aug 1996. We detected the non-radial g-modes consistent with degree ℓ=1 and radial order 8 to 20 and their linear combinations up to 6th order. We also detect, for the first time, a high amplitude ℓ=2 mode, with a period of 796 s. In the 2000 WET data, the largest amplitude modes are similar to those detected with the WET observations of 1990 and 1994, but the highest combination order previously detected was 4th order. At one point during the 1996 observations, most of the pulsation energy was transferred into the radial order k=8 mode, which displayed a sinusoidal pulse shape in spite of the large amplitude. The multiplet structure of the individual modes changes from year to year, and during the 2000 observations only the k=9 mode displays clear normal triplet structure. Even though the pulsation amplitudes change on timescales of days and years, the eigenfrequencies remain essentially the same, showing the stellar structure is not changing on any dynamical timescale.

Tables \ref{j96} to \ref{journal2} and \ref{combination} and Figs. \ref{gd358lc1}, \ref{dftchange}, \ref{an34dft}, \ref{pkh}, \ref{k16} and \ref{deltap8} are available only in the electronic form at http://www.edpsciences.org Title: Spectral analysis of sdB stars from the Hamburg Quasar Survey Authors: Edelmann, H.; Heber, U.; Hagen, H. -J.; Lemke, M.; Dreizler, S.; Napiwotzki, R.; Engels, D. Bibcode: 2003A&A...400..939E Altcode: 2003astro.ph..1602E We present the results of a spectral analysis of a large sample of subdwarf B stars selected from follow-up observations of candidates from the Hamburg Quasar Survey. Fundamental parameters (effective temperature, gravity, and helium abundance) were determined by matching synthetic line profiles calculated from model atmospheres to all hydrogen and helium absorption lines present in the observed optical spectra. The derived helium abundances are compared with the atmospheric parameters to search for possible trends. We discovered a correlation between the helium abundance and the effective temperature: the larger the temperature, the larger the photospheric helium content of sdB stars. Additionally, a separation into two sequences of sdB stars in the effective temperature - helium abundance plane is detected. We compared our analysis results with data from the literature. The stars from our sample are found to be somewhat more luminous. This can only partly be explained by NLTE effects. Three apparently normal B stars were discovered, which could be massive stars far away from the galactic plane (7-19 kpc). Radial velocities were measured for 23 stars from which we discovered a new radial velocity variable sdB star.

Based on Observations collected at the German-Spanish Astronomical Center (DSAZ), Calar Alto, operated by the Max-Planck-Institut für Astronomie Heidelberg jointly with the Spanish National Commission for Astronomy.

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 http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/400/939 Title: VizieR Online Data Catalog: Stellar parameters of 115 HQS sdB stars (Edelmann+, 2003) Authors: Edelmann, H.; Heber, U.; Hagen, H. -J.; Lemke, M.; Dreizler, S.; Napiwotzki, R.; Engels, D. Bibcode: 2003yCat..34000939E Altcode: We present the results of a spectral analysis of a large sample of subdwarf B stars selected from follow-up observations of candidates from the Hamburg Quasar Survey. Table 4 summarizes the results (effective temperatures, gravities, and helium abundances) of our analysis. Additionally, the equatorial and galactical coordinates, the B magnitudes and extinctions, the derived radial velocities, the absolute visual magnitudes, the distances from earth and from the galactic plane, and the references are given for all programme stars.

(3 data files). Title: FUSE Spectroscopy of the Two Prototype White Dwarfs With Signatures of a Super-hot Wind Authors: Werner, K.; Dreizler, S.; Kruk, J. W.; Sitko, M. L. Bibcode: 2003ASIB..105..171W Altcode: 2003whsw.conf..171W; 2002astro.ph..8506W; 2003whdw.conf..171W The O VIII phenomenon describes the occurrence of ultra-high ionization absorption lines of the CNO elements (e.g. O VIII, N VII, C VI, and even Ne X) in the optical spectra hot of DO WDs. Title: Temperature Correction Schemes Authors: Dreizler, S. Bibcode: 2003ASPC..288...69D Altcode: 2003sam..conf...69D The pro and contra for using temperature correction are discussed on the basis of our linearization scheme and our implementation of an Unsöld-Lucy temperature correction. I will show the improvements which partly overcome the typical weakness of the UL-scheme as well as our generalization to non-LTE. Title: FUSE Observations of the Central Star of Abell 78 Authors: Werner, K.; Dreizler, S.; Koesterke, L.; Kruk, J. W. Bibcode: 2003IAUS..209..239W Altcode: 2002astro.ph..1280W FUSE high resolution spectra of two PG1159 type central stars (K1-16 and NGC 7094) have revealed an unexpected iron deficiency of at least 1 or 2 dex (Miksa et al. 2002). Here we present early results of FUSE spectroscopy of the CSPN Abell 78. It is shown that iron is strongly deficient in this star, too. Title: TRIPP: An Aperture Photometry Package for the Reduction of CCD Time Series Images Authors: Schuh, S. L.; Dreizler, S.; Deetjen, J. L.; Göhler, E. Bibcode: 2003BaltA..12..167S Altcode: 2003OAst...12..167S TRIPP is an aperture photometry program designed with the purpose of extracting light curves from large sets of similar CCD frames typically obtained during time-resolved photometric monitoring campaigns such as, for example, WET runs. We describe its properties and usage with an emphasis on where the functionality of TRIPP may differ from similar programs, and try to outline both its strengths as well as the non-trivial issues where difficulties may arise. Title: NLTE Spectral Analysis of Iron Group Elements in the Hot Subluminous O-star BD+28° 4211 Authors: Ramspeck, M.; Haas, S.; Napiwotzki, R.; Heber, U.; Deetjen, J.; Dreizler, S. Bibcode: 2003ASPC..288..161R Altcode: 2003sam..conf..161R An analysis of UV spectra of BD+28circ4211 obtained with the STIS spectrograph onboard the HST is presented. The spectral analysis is based on NLTE model calculation, which deal with the lineblanketing of iron group elements in great detail. Improved model atoms for iron group elements were set up and new interband cross sections were calculated. Comparison with observation allowed, Mn and Cr lines to be identified for the first time. The abundances of Fe, Ni, Cr and Mn are determined and point to the presence of diffusion processes in the atmosphere of BD+28circ4211. Title: Analysis of FUSE and IUE spectra of the sdOB star EC11481-2303 Authors: Hammer, N. J.; Deetjen, J. L.; Dreizler, S.; Werner, K.; Kruk, J. W. Bibcode: 2003ASIB..105..103H Altcode: 2003whdw.conf..103H; 2003whsw.conf..103H No abstract at ADS Title: Towards asteroseismology of the non-radial pulsating sdB star PG 1605+072 Authors: Falter, S.; Heber, U.; Dreizler, S.; Schuh, S. L.; Cordes, O. Bibcode: 2003ASIB..105...73F Altcode: 2003whdw.conf...73F; 2002astro.ph.12489F; 2003whsw.conf...73F The recently discovered new class of sdB pulsators (sdBV) offers a powerful possibility for the investigation of their interior and thus their evolutionary history. The first step towards applying asteroseismologic tools is the identification of pulsation modes. We reoport on simultaneous spectroscopic and multi-band photometric time series observations of PG 1605+072 and analyse its radial velocity and light curve. Title: Vertical Structures and Spectra of Accretion Disks in Symbiotic Stars Authors: Nagel, T.; Dreizler, S.; Werner, K. Bibcode: 2003ASPC..303..482N Altcode: 2003ssps.conf..482N No abstract at ADS Title: Stellar Atmosphere and Accretion Disk Models for the Hot Component in Symbiotic Stars Authors: Werner, K.; Deetjen, J. L.; Dreizler, S.; Nagel, T.; Rauch, T. Bibcode: 2003ASPC..303..303W Altcode: 2003ssps.conf..303W; 2002astro.ph..8199W We describe our NLTE codes which allow the computation of synthetic spectra of hot stars and accretion disks. They can be combined to compute ionizing fluxes from the hot component in symbiotic stars. Title: Calculating Vertical Structures and Spectra of Accretion Disks with the New Code AcDc Authors: Nagel, T.; Dreizler, S.; Werner, K. Bibcode: 2003ASPC..288..641N Altcode: 2003sam..conf..641N We present a new code to calculate the vertical structure of accretion disks in cataclysmic variables. The disk is divided into concentric rings, each ring is treated like an independent plane-parallel radiating slab. We first calculate a gray LTE model and then a NLTE model of the ring. Finally we integrate over all ring spectra to get the spectrum of the full disk for a specific inclination angle. The system of hydrostatic and radiative equilibrium, atomic level populations and particle conservation is solved consistently with the radiative transfer.

This allows to calculate detailed theoretical spectra of accretion disks. Comparison with observations will allow to derive radial temperature distribution, mass accretion rate, viscosity and chemical composition. We also plan to compare our vertical structures to those of hydrodynamic simulations in order to estimate the influence of a detailed radiation transport on the stratification. Title: Transfer of Polarized Radiation - Practical Experience with the Accelerated Lambda Iteration Method Authors: Deetjen, J. L.; Dreizler, S.; Jordan, S.; Werner, K. Bibcode: 2003ASPC..288..617D Altcode: 2003sam..conf..617D Neutron stars and some of the white dwarfs have magnetic fields. The light emitted by these stars is polarized and can be characterized by the four Stokes components I, Q, U, and V. Therefore the polarized radiation transport equation differs significantly from the non-magnetic case. It is a system of linear differential equations coupled in I, Q, U, and V with depth dependent opacities and magneto-optical parameters. The most potential method, the accelerated lambda iteration, is presented in detail and practical experiences calculating neutron star atmospheres are reported. Title: Modeling C/O/Ne Dominated Accretion in Ultracompact X-ray Binaries Authors: Werner, K.; Nagel, T.; Dreizler, S.; Rauch, T. Bibcode: 2003gcfe.confE..35W Altcode: No abstract at ADS Title: Calculating spectra of accretion disks in AM CVn systems Authors: Nagel, T.; Dreizler, S.; Werner, K. Bibcode: 2003ASIB..105..357N Altcode: 2003whdw.conf..357N; 2003whsw.conf..357N No abstract at ADS Title: Discovery of A New Class of Pulsating Stars: Gravity-Mode Pulsators among Subdwarf B Stars Authors: Green, E. M.; Fontaine, G.; Reed, M. D.; Callerame, K.; Seitenzahl, I. R.; White, B. A.; Hyde, E. A.; Østensen, R.; Cordes, O.; Brassard, P.; Falter, S.; Jeffery, E. J.; Dreizler, S.; Schuh, S. L.; Giovanni, M.; Edelmann, H.; Rigby, J.; Bronowska, A. Bibcode: 2003ApJ...583L..31G Altcode: During the course of an ongoing CCD monitoring program to investigate low-level light variations in subdwarf B (sdB) stars, we have serendipitously discovered a new class of low-amplitude, multimode sdB pulsators with periods of the order of an hour. These periods are more than a factor of 10 longer than those of previously known multimode sdB pulsators (EC 14026 stars), implying that they are due to gravity modes rather than pressure modes. The longer period pulsators are found only among cooler sdB stars, where they are surprisingly common. The iron opacity instability that drives the short-period EC 14026 stars is effective only in hot sdB stars, leaving the driving mechanism for the deeper gravity modes in cool sdB stars currently unknown. We present the first observational results for our newly identified sdB variables and discuss possible implications. Title: FUSE Spectra of DO White Dwarfs Authors: Dreizler, S.; Werner, K.; Kruk, J. W. Bibcode: 2003ASIB..105..135D Altcode: 2003whsw.conf..135D; 2003whdw.conf..135D FUSE observations of DO white dwarfs allow to determine their photospheric abundances of trace elements (e.g. C, N, O, H, Fe, Ni,...). FUSE spectroscopy is ideal for this purpose since the FUV allows to explore a large variety of line transitions of various elements which are not detectable in existing optical or UV spectra of the targets. We present our analysis with non-LTE metal line blanketed model atmospheres. The results will be compared to our newly developed, self-consistent diffusion/radiative levitation calculations under non-LTE conditions. The observed metal abundances will serve as bench-marks for such kind of new calculations. Title: Metal abundances in PG1159 stars from Chandra and FUSE spectroscopy Authors: Werner, K.; Deetjen, J. L.; Dreizler, S.; Rauch, T.; Barstow, M. A.; Kruk, J. W. Bibcode: 2003ASIB..105..117W Altcode: 2002astro.ph..8505W; 2003whsw.conf..117W; 2003whdw.conf..117W We investigate FUSE spectra of three PG1159 stars and do not find any evidence for iron lines. From a comparison with NLTE models we conclude a deficiency of 1--1.5 dex. We speculate that iron was transformed into heavier elements. A soft X-ray Chandra spectrum of the unique H- and He-deficient star H1504+65 is analyzed. We find high neon and magnesium abundances and confirm that H1504+65 is the bare core of either a C-O or a O-Ne-Mg white dwarf. Title: Improved results for equilibrium abundances from diffusion calculations Authors: Schuh, S. L.; Dreizler, S.; Deetjen, J. L. Bibcode: 2003ASIB..105..147S Altcode: 2003whsw.conf..147S; 2003whdw.conf..147S No abstract at ADS Title: Computation of Element Diffusion in Non-LTE Stellar Atmosphere Models Authors: Schuh, S. L.; Dreizler, S. Bibcode: 2003ASPC..288..633S Altcode: 2003sam..conf..633S No abstract at ADS Title: Temperature Scale and Iron Abundances of Very Hot Central Stars of Planetary Nebulae (invited review) Authors: Werner, K.; Deetjen, J. L.; Dreizler, S.; Rauch, T.; Kruk, J. W. Bibcode: 2003IAUS..209..169W Altcode: 2002astro.ph..2012W The determination of effective temperatures of very hot central stars (Teff>70000K) by model atmosphere analyses of optical H and He line profiles is afflicted with considerable uncertainty, primarily due to the lack of neutral helium lines. Ionization balances of metals, accessible only with UV lines, allow more precise temperature estimates. The potential of iron lines is pointed out. At the same time iron and other metal abundances, hardly investigated until today, may be derived from UV spectra. We describe recent HST spectroscopy performed for this purpose. A search for iron lines in FUV spectra of the hottest H-deficient central stars (PG1159-type, Teff>100000K) taken with FUSE was unsuccessful. The derived deficiency is interpreted in terms of iron depletion due to n-capture nucleosynthesis in intershell matter, which is now exposed at the stellar surface as a consequence of a late He shell flash. Title: Modeling He-rich Disks in Am CVn Binaries Authors: Nagel, T.; Dreizler, S.; Rauch, T.; Werner, K. Bibcode: 2003gcfe.confE..34N Altcode: No abstract at ADS Title: Preliminary results of the WET Xcov22 campaign at Calar Alto Observatory Authors: Schuh, S. L.; Nagel, T.; Deetjen, J. L.; Dreizler, S.; Handler, G.; O'Brien, M. S.; Riddle, R.; Hürkal, Ö.; Pakstiene, E.; Klumpe, E.; Lawrence, T.; Vuckovic, M.; Zola, S.; Kawaler, S.; Kanaan, A.; Giovannini, O.; Kepler, S. O.; Mukadam, A.; Provencal, J.; Nitta, A.; Shipman, H.; Mullally, F.; Grauer, A.; Wood, M. A.; Bradley, P. A.; Kilic, M.; Sekiguchi, K.; Crowe, R.; Sullivan, D.; Rosen, R.; Clemens, C.; Jiang, Xiaojun; Janulis, R.; O'Donoghue, D.; Ogloza, W.; Baran, A.; Silvotti, R.; Marinoni, S.; Vauclair, G.; Dolez, N.; Chevreton, M.; Gonzalez, J. M.; Solheim, J. -E.; Ulla, A.; Burleigh, M.; Good, S.; Metcalfe, T.; da Costa, A. F. M.; Costa, J. E. S.; Kim, S. -L.; Lee, H.; Sergeev, A.; Akan, C.; Cakirli, Ö.; Paparo, M.; Viraghalmy, G. Bibcode: 2003ASIB..105..263S Altcode: 2003whdw.conf..263S; 2003whsw.conf..263S No abstract at ADS Title: WET Observations of GD 358 in 2000 Authors: Kepler, S. O.; Nather, E. R.; Winget, D. E.; Nitta, A.; Kleinman, S. J.; Metcalfe, T.; Sekiguchi, K.; Jiang, Xiaojun; Sullivan, D.; Sullivan, T.; Janulis, R.; Meištas, E. G.; Kalytis, R.; Krzesiński, J.; Ogłoza, W.; Zola, S.; O'Donoghue, D.; Romero-Colmenero, E.; Martinez, P.; Dreizler, S.; Deetjen, J.; Nagel, T.; Schuh, S. L.; Vauclair, G.; Fu, J. N.; Chevreton, M.; Solheim, J. -E.; Gonzalez Perez, J. M.; Johannessen, F.; Kanaan, A.; Costa, J. E.; Murillo Costa, A. F.; Wood, M. A.; Silvestri, N.; Ahrens, T. J.; Jones, A. Kyle; Collins, A. E.; Boyer, M.; Shaw, J. S.; Mukadam, A. S.; Klumpe, E. W.; Larrison, J.; Kawaler, S. D.; Riddle, R. L.; Ulla, A.; Bradley, P. Bibcode: 2003BaltA..12...45K Altcode: 2003OAst...12...45K We report on the 323 hours of nearly uninterrupted time series photometric observations of the DBV star GD 358 acquired with the Whole Earth Telescope (WET) during May 23 to June 8, 2000. We acquired more than 232000 independent measurements and detected the non-radial g-modes consistent with degree l=1 and radial order 8 to 20 and their linear combinations up to 6th order. We also detect, for the first time, a high amplitude l=2 mode, with a period of 796 s. In the 2000 WET data, the largest amplitude modes are similar to those detected with the WET observations of 1990 and 1994, but the highest combination order previously detected was 4th order. Title: Stratified NLTE Model Atmospheres for Hot Stars Authors: Dreizler, S.; Schuh, S. L. Bibcode: 2003IAUS..210...33D Altcode: No abstract at ADS Title: Photometric and Spectroscopic Monitoring of the sdBV star PG 1605+072: The Multi-Site Spectroscopic Telescope (MSST) Project Authors: Heber, U.; Dreizler, S.; Schuh, S. L.; O'Toole, S.; Jeffery, C. S.; Falter, S.; Woolf, V.; Ahmad, A.; Billeres, M.; Charpinet, S.; Cordes, O. -M.; For, B. -Q.; Green, E.; Hyde, E. A.; Jacob, A.; Kjeldsen, H.; Kleinman, S.; Krzesinski, J.; Lopes, I.; Marinoni, S.; Mauch, T.; Nitta, A.; O'Donoghue, D.; Østensen, R.; Pollacco, D.; Pereira, R.; Pereira, T.; Reed, M. D.; Silvotti, R.; Townsend, R.; Vuckovic, M.; White, B. A.; Jiang, Xiaojun Bibcode: 2003ASIB..105..105H Altcode: 2003whdw.conf..105H; 2002astro.ph.12447H; 2003whsw.conf..105H A small fraction of subluminous B stars show short-period, multiperiodic light variations and form the new class of pulsating star known as EC 14026 variables, after the prototype. The Multi-Site Spectroscopic Telescope (MSST) is a virtual instrument and is also the name of a collaboration that aims to open up a new observational window to provide access to a mode identification for and an asteroseismological analysis of the pulsating sdB star PG 1605+072. Although the primary aim is to obtain time resolved spectroscopy it also includes the most extended photometric monitoring campaign for PG 1605+072. Title: PG 1605+072 in WET XCov22: Support for the Multi Site Spectroscopic Telescope Authors: Schuh, S. L.; Heber, U.; Dreizler, S.; O'Toole, S.; Jeffery, C. S.; Falter, S.; Woolf, V. M.; Riddle, R. L.; Handler, G.; Hürkal, Ö.; Pakštiene, E.; Klumpe, E. W.; Laurance, T.; Vuckovic, M.; Zoa, S.; Kawaler, S. D.; Kanaan, A.; Monteiro, H.; Giovannini, O.; Kepler, S. O.; Mukadam, A.; Provencal, J. L.; Nitta, A.; Shipman, H.; Mullally, F.; Grauer, A.; Wood, M. A.; Bradley, P. A.; Kilic, M.; Sekiguchi, K.; Crowe, R.; Sullivan, D. J.; Rosen, R.; Clemens, C.; Jiang, Xiaojun; Janulis, R.; O'Donoghue, D.; Ogloza, W.; Baran, A.; Silvotti, R.; Marinoni, S.; Vauclair, G.; Dolez, N.; Chevreton, M.; Deetjen, J. L.; Nagel, T.; González Pérez, J. M.; Solheim, J. -E.; Østensen, R.; Ulla, A.; Burleigh, M.; Good, S.; Metcalfe, T. S.; da Costa, A. F. M.; Costa, J. E. S.; O'Brien, M. S.; Kim, S. -L.; Lee, H.; Sergeev, A.; Akan, C.; Cakirli, Ö.; Paparo, M.; Viraghalmy, G. Bibcode: 2003BaltA..12...55S Altcode: 2003OAst...12...55S The Multi-site Spectroscopic Telescope is a virtual instrument and the name of a collaboration that opens up a new observational window by combining continuous observations of spectroscopic variations and simultaneous photometric monitoring. This constitutes an enormous observational effort, but in return promises to finally provide access to a mode identification for and an asteroseismological analysis of the pulsating sdB star PG 1605+072. Multi-Site Spectroscopic Telescope observations for this object have been secured during a large coordinated campaign in May and June of the year 2002. The frequency resolution and coverage of the photometric time series has been noticeably enhanced by a significant contribution from the Whole Earth Telescope, which was used to observe PG 1605+072 as an alternate target during the WET XCov22 campaign, also conducted in May 2002. This paper briefly outlines the motivation for the MSST project and tries to give a first assessment of the overall quality of the data obtained, with a focus on the Whole Earth Telescope observations. Title: WET Observations of PG 1159--035 Authors: Costa, J. E. S.; Kepler, S. O.; Winget, D. E.; O'Brien, M. S.; Bond, H. E.; Kawaler, S. D.; Dreizler, S. Bibcode: 2003BaltA..12...23C Altcode: 2003OAst...12...23C PG 1159-035 has been observed with the Whole Earth Telescope on XCov3, 9, 19 and 22. In this work we present a brief summary of the campaigns. Title: Model Photospheres with Accelerated Lambda Iteration Authors: Werner, K.; Deetjen, J. L.; Dreizler, S.; Nagel, T.; Rauch, T.; Schuh, S. L. Bibcode: 2003ASPC..288...31W Altcode: 2002astro.ph..9535W; 2003sam..conf...31W We review the computational procedure to construct classical line-blanketed NLTE model atmospheres with the ALI method. In detail we discuss: Approximate Lambda Operators, fast solution techniques for non-linear rate equations, pre-conditioning of rate equations, super-level approach for heavy metal line-blanketing. Most recent successes and failures in applications are shortly presented. Title: The Rotational Velocity of Helium-rich Pre-White Dwarfs Authors: Rauch, T.; Koeper, S.; Dreizler, S.; Werner, K.; Heber, U.; Reid, I. N. Bibcode: 2002astro.ph.12163R Altcode: Previous investigations on hydrogen-rich white dwarfs generally yield only very small rotational velocities (v_rot sin i). We have analyzed line profiles in high-resolution optical spectra of eight hydrogen-deficient (pre-) white dwarfs and find deviations from the dominant Stark line broadening in five cases which, interpreted as an effect of stellar rotation, indicate projected rotational velocities of 40 - 70 km/sec. For the three least luminous stars upper limits of v_rot sin i = 15 - 25 km/sec could be derived only. The resulting velocities correlate with luminosity and mass. However, since the mass-loss rate is correlated to the luminosity of a star, the observed line profiles may be affected by a stellar wind as well. In the case of RX J2117.1+3412, this would solve discrepancies to results of pulsational modeling (v_rot sin i ~ 0). Title: Spectroscopic analyses of the ``blue hook'' stars in omega Centauri: A test of the late hot flasher scenario Authors: Moehler, S.; Sweigart, A. V.; Landsman, W. B.; Dreizler, S. Bibcode: 2002A&A...395...37M Altcode: 2002astro.ph..9028M omega Cen contains the largest population of very hot horizontal branch (HB) stars known in a globular cluster. Recent UV observations (Whitney et al. \cite{whro98}; D'Cruz et al. \cite{dcoc00}) show a significant population of hot stars below the zero-age horizontal branch (``blue hook'' stars), which cannot be explained by canonical stellar evolution. Stars which suffer unusually large mass loss on the red giant branch and thus experience the helium core flash while descending the white dwarf cooling curve could populate this region. Theory predicts that these ``late hot flashers'' should show higher temperatures than the hottest canonical HB stars and should have helium- and carbon-rich atmospheres. We obtained and analysed medium resolution spectra of a sample of blue hook stars to derive their atmospheric parameters. The blue hook stars are indeed both hotter (Teff >=35 000 K) and more helium-rich than classical extreme HB stars. In addition we find indications for a large enhancement of the carbon abundance relative to the cluster abundance. Title: Spectral types of planetary host star candidates: Two new transiting planets? Authors: Dreizler, S.; Rauch, T.; Hauschildt, P.; Schuh, S. L.; Kley, W.; Werner, K. Bibcode: 2002A&A...391L..17D Altcode: 2002astro.ph..7192D Recently, 46 low-luminosity object transits were reported from the Optical Gravitational Lensing Experiment. Our follow-up spectroscopy of the 16 most promising candidates provides a spectral classification of the primary. Together with the radius ratio from the transit measurements, we derived the radii of the low-luminosity companions. This allows to examine the possible sub-stellar nature of these objects. Fourteen of them can be clearly identified as low-mass stars. Two objects, OGLE-TR-03 and OGLE-TR-10 have companions with radii of 0.15 R_sun which is very similar to the radius of the transiting planet HD 209458 B. The planetary nature of these two objects should therefore be confirmed by dynamical mass determinations. Title: The temporal spectrum of the sdB pulsating star HS 2201+2610 at 2 ms resolution Authors: Silvotti, R.; Janulis, R.; Schuh, S. L.; Charpinet, S.; Oswalt, T.; Silvestri, N.; Gonzalez Perez, J. M.; Kalytis, R.; Meištas, E.; Ališauskas, D.; Marinoni, S.; Jiang, X. J.; Reed, M. D.; Riddle, R. L.; Bernabei, S.; Heber, U.; Bärnbantner, O.; Cordes, O.; Dreizler, S.; Goehler, E.; Østensen, R.; Bochanski, J.; Carlson, G. Bibcode: 2002A&A...389..180S Altcode: In this article we present the results of more than 180 hours of time-series photometry on the low gravity (log g=5.4, Teff=29 300 K, log He/H=-3.0 by number) sdB pulsating star HS 2201+2610, obtained between September 2000 and August 2001. The temporal spectrum is resolved and shows 5 close frequencies: three main signals at 2860.94, 2824.10 and 2880.69 mu Hz, with amplitudes of about 1%, 0.5% and 0.1% respectively, are detected from single run observations; two further peaks with very low amplitude (<0.07%) at 2738.01 and 2921.82 mu Hz are confirmed by phase analysis on several independent runs. Due to the small number of detected frequencies, it is not possible to obtain a univocal identification of the excited modes and perform a detailed seismological analysis of the star. No clear signatures of rotational splitting are seen. Nevertheless, the observed period spectrum is well inside the excited period window obtained from pulsation calculations with nonadiabatic models having effective temperature and surface gravity close to the spectroscopic estimates. Due to its relatively simple temporal spectrum, HS 2201+2610 is a very good candidate for trying to measure the secular variation of the pulsation periods in time. With this purpose a long-term monitoring of the star was started. The results of the first 11 months show amplitude variations up to ~ 20% on time-scales of months, which are probably real, and allow us to measure the pulsation frequencies with an unprecedented 0.02 mu Hz resolution. Based on observations obtained at the following telescopes: Loiano 1.5 m (Bologna Astronomical Observatory), Moletai 1.65 m (Institute of Theoretical Physics and Astronomy, Vilnius), Calar Alto 2.2 and 1.2 m (German-Spanish Astronomical Center operated by the Max-Plank-Institute für Astronomie Heidelberg jointly with the Spanish National Commission for Astronomy), SARA 0.9 m (Southeastern Association for Research in Astronomy, at Kitt Peak, Arizona), Tenerife 0.8 m (Instituto de Astrofisica de Canarias), NOT 2.6 m (operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias), Beijing 0.85 m (Beijing Astronomical Observatory), Fick 0.6 m (Iowa State University), Wendelstein 0.8 m (University of Munich). Title: Iron abundance in hot hydrogen-deficient central stars and white dwarfs from FUSE, HST, and IUE spectroscopy Authors: Miksa, S.; Deetjen, J. L.; Dreizler, S.; Kruk, J. W.; Rauch, T.; Werner, K. Bibcode: 2002A&A...389..953M Altcode: 2002astro.ph..5058M We present a first systematic investigation of the iron abundance in very hot (Teff >= 50 000 K) hydrogen-deficient post-AGB stars. Our sample comprises 16 PG 1159 stars and four DO white dwarfs. We use recent FUSE observations as well as HST and IUE archival data to perform spectral analyses with line blanketed NLTE model atmospheres. Iron is not detected in any PG 1159 star. In most cases this is compatible with a solar iron abundance due to limited quality of HST and IUE data, although the tendency to an iron underabundance may be recognized. However, the absence of iron lines in excellent FUSE spectra suggests an underabundance by at least 1 dex in two objects (K 1-16, NGC 7094). A similar result has been reported recently in the [WC]-PG 1159 transition object Abell 78 (Werner et al. \cite{Werner2002}). We discuss dust fractionation and s-process neutron-captures as possible origins. We also announce the first identification of sulfur in PG 1159 stars. Based on observations obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE), the Hubble Space Telescope (HST), and the International Ultraviolet Explorer (IUE). Title: Is RX J1856.5-3754 a Quark Star? Authors: Drake, Jeremy J.; Marshall, Herman L.; Dreizler, Stefan; Freeman, Peter E.; Fruscione, Antonella; Juda, Michael; Kashyap, Vinay; Nicastro, Fabrizio; Pease, Deron O.; Wargelin, Bradford J.; Werner, Klaus Bibcode: 2002ApJ...572..996D Altcode: 2002astro.ph..4159D Deep Chandra Low Energy Transmission Grating and High Resolution Camera spectroscopic observations of the isolated neutron star candidate RX J1856.5-3754 have been analyzed to search for metallic and resonance cyclotron spectral features and for pulsation behavior. As found from earlier observations, the X-ray spectrum is well represented by an ~60 eV (7×105 K) blackbody. No unequivocal evidence of spectral line or edge features has been found, arguing against metal-dominated models. The data contain no evidence for pulsation, and we place a 99% confidence upper limit of 2.7% on the unaccelerated pulse fraction over a wide frequency range from 10-4 to 100 Hz. We argue that the derived interstellar medium neutral hydrogen column density of 8×1019cm- 2<=NH<=1.1×1020 cm-2 favors the larger distance from two recent Hubble Space Telescope parallax analyses, placing RX J1856.5-3754 at ~140 pc instead of ~60 pc and in the outskirts of the R CrA dark molecular cloud. That such a comparatively rare region of high interstellar matter (ISM) density is precisely where an isolated neutron star reheated by accretion of ISM would be expected is either entirely coincidental or current theoretical arguments excluding this scenario for RX J1856.5-3754 are premature. Taken at face value, the combined observational evidence-a lack of spectral and temporal features and an implied radius of R=3.8-8.2 km that is too small for current neutron star models-points to a more compact object, such as allowed for quark matter equations of state. Title: HS0702+6043 - A new large amplitude sdB variable at the cool end of the instability region Authors: Dreizler, S.; Schuh, S. L.; Deetjen, J. L.; Edelmann, H.; Heber, U. Bibcode: 2002A&A...386..249D Altcode: We report on time series photometry of hot sdB stars from the Hamburg Schmidt survey carried out at the Calar Alto 1.23 m and 2.2 m telescopes. Among 14 spectroscopically selected candidates we detected oscillations in the sdB star HS0702+6043 with a period of 363 s and an amplitude of 29 mmag which is among the largest amplitude observed in sdBV stars. A second period of 382 s with a significantly smaller amplitude (3.8 mmag) might be present. Our NLTE model atmosphere analysis of the time-averaged optical spectra, obtained at the Calar Alto 3.5 m telescope, indicates that HS0702+6043 has Teff=28 400 K and log g=5.35. This places the star at the cool end of the theoretical sdBV instability strip (EC 14026 stars). Among the other thirteen sdB stars we confirmed the variablity of the previously discovered sdBV HS0815+4243 and identified twelve stars to be stable, for which we give upper limits for light variations. Based on observations collected at the German-Spanish Astronomical Center, Calar Alto, operated by the Max-Planck-Institut für Astronomie Heidelberg jointly with the Spanish National Commission for Astronomy. Title: Analysis of the FUSE spectrum of the sdOB EC 11481-2303. Authors: Hammer, N.; Deetjen, J. L.; Dreizler, S.; Werner, K.; Kruk, J. W. Bibcode: 2002AGAb...19R..96H Altcode: No abstract at ADS Title: PG 1325+101 and PG 2303+019: Two new large amplitude subdwarf B pulsators Authors: Silvotti, R.; Østensen, R.; Heber, U.; Solheim, J. -E.; Dreizler, S.; Altmann, M. Bibcode: 2002A&A...383..239S Altcode: We report the detection of short period oscillations in the sdB stars PG 1325+101 (B=13.8) and PG 2303+019 (alias HS 2303+0152, B=16.0) from time-series photometry made at the Nordic Optical Telescope of a sample of 21 candidates. Both stars are multi-mode pulsators with at least three distinct periods in the range 100-140 s, and relatively large amplitudes up to 2.6 and 1.6% respectively. Moreover PG 1325+101 shows the shortest pulsation period ever registered among sdBV stars, 68.9 s, which corresponds to the first harmonic of the main signal. Following previous temperature and gravity determinations for PG 1325+101 (Teff = 34 500 K, log g=6.1) and our NLTE model atmosphere analysis for PG 2303+019 (Teff = 35 200 K, log g=5.7), both stars are well inside the theoretical sdBV instability strip. Based on observations obtained at the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias; and at the German-Spanish Astronomical Center, Calar Alto, operated by the Max-Plank-Institute für Astronomie Heidelberg jointly with the Spanish National Commission for Astronomy. Title: Extremely Faint Blue-tail Stars in ω Centauri Authors: Moehler, S.; Napiwotzki, R.; Sweigart, A. V.; Landsman, W. B.; Dreizler, S. Bibcode: 2002ASPC..265..247M Altcode: 2002ocuw.conf..247M No abstract at ADS Title: AcDc -- A new code to calculate vertical structures and spectra of accretion disks Authors: Nagel, T.; Dreizler, S.; Werner, K. Bibcode: 2002ASPC..261..509N Altcode: 2002pcvr.conf..509N We are developing a new program which computes vertical structures and emergent spectra of accretion disks in CVs and AGN. It solves the radiation transfer equation together with the NLTE rate equations for atomic level populations using an ALI (Accelerated Lambda Iteration) scheme. First results are presented. Title: Spectral types of planetary host star candidates: new transiting planets ? Authors: Dreizler, S.; Rauch, T.; Hauschildt, P.; Schuh, S. L.; Kley, W.; Werner, K. Bibcode: 2002AGAb...19R...6D Altcode: No abstract at ADS Title: To be or not to be a late hot flasher. Authors: Moehler, S.; Sweigart, A. V.; Landsman, W. B.; Dreizler, S. Bibcode: 2002AGAb...19Q.104M Altcode: No abstract at ADS Title: Equilibrium abundances in hot DA white dwarfs as derived from self-consistent diffusion models. I. Analysis of spectroscopic EUVE data Authors: Schuh, S. L.; Dreizler, S.; Wolff, B. Bibcode: 2002A&A...382..164S Altcode: 2001astro.ph.11245S We present the first analysis of an EUV selected sample of hot DA white dwarfs using a new type of atmospheric models. These models take into account the interplay between gravitational settling and radiative acceleration to predict the chemical stratification from an equilibrium between the two forces while self-consistently solving for the atmospheric structure. In contrast to atmospheric models with the assumption of chemical homogeneity, the number of free parameters in the new models is reduced to the effective temperature and surface gravity alone. The overall good reproduction of observed EUV spectra reveals that these models are able to describe the physical conditions in hot DA white dwarf atmospheres correctly. A comparison with previous analyses highlights the improvements as well as the limits of our new models. Based on observations made with the EUVE Satellite. Title: The Origin of Hot Subluminous Horizontal-Branch Stars in ω Cen and NGC 2808 Authors: Sweigart, A. V.; Brown, T. M.; Moehler, S.; Lanz, T.; Landsman, W. B.; Hubeny, I.; Dreizler, S.; Napiwotzki, R. Bibcode: 2001AAS...19913704S Altcode: 2001BAAS...33.1512S Ultraviolet (UV) observations of the globular clusters ω Cen and NGC 2808 have revealed an unexpected population of hot subluminous stars lying up to 0.7 mag below the extreme horizontal branch (EHB) in the UV, which are not explained by canonical stellar models. In order to explore the evolutionary status of these stars, we have evolved a set of low-mass stars from the main sequence through the helium flash to the horizontal branch (HB) for a wide range in the mass loss along the red-giant branch (RGB). Stars with the largest mass loss evolve off the RGB to high effective temperatures before igniting helium in their cores. Our results indicate that the subluminous stars can be explained if these stars undergo a late helium flash while descending the white dwarf cooling curve. Under these conditions the convection zone produced by the helium flash will penetrate into the stellar envelope, thereby mixing the envelope hydrogen into the hot helium-burning interior, where it is rapidly consumed. Such ``flash-mixed'' stars will have helium- and carbon-rich envelopes and will lie at higher effective temperatures than the hottest canonical (i.e., unmixed) EHB stars. Using new stellar atmospheres, we show that these changes in the envelope abundances will suppress the UV flux in the spectra of the flash-mixed stars by the amount needed to explain the hot subluminous stars in ω Cen and NGC 2808. To test this evolutionary scenario, we have obtained medium resolution spectra of a sample of the hottest HB stars in ω Cen. We find that these stars are indeed helium-rich compared to classical EHB stars and also considerably hotter than the hottest EHB models without flash mixing. Title: Introduction to Volume 322 (5/6) Proceedings of the Joint-Discussion #1 and the Mini-Symposia #9 and #10 at the Joint European and National Astronomical Meeting (JENAM) for 2001 Authors: Strassmeier, K. G.; Staude, J.; Dreizler, S. Bibcode: 2001AN....322..271S Altcode: This volume of AN contains the proceedings of the Joint Discussion #1 (JD-1) ``Astronomy with Robotic Telescopes: Present and Future Projects'' and of the Mini Symposia #9 (MS-9) ``Hot subdwarfs, white dwarfs, and low-mass star evolution'', and #10 (MS-10) ``Large Telescopes for Solar Physics''. The meetings were held as part of the JENAM 2001 conference ``Five Days of Creation. Astronomy with Large Telescopes from Ground and Space'' in Munich, Germany, from September 10 through 15, 2001. Title: Four new subdwarf B pulsators Authors: Østensen, R.; Heber, U.; Silvotti, R.; Solheim, J. -E.; Dreizler, S.; Edelmann, H. Bibcode: 2001A&A...378..466O Altcode: We report the detection of short period oscillations in the sdB stars HS 0039+4302, HS 0444+0408, HS 1824+5745 and HS 2151+0857 from time-series photometry made at the Nordic Optical Telescope (NOT) of a sample of 55 candidates. Hence these four hot subdwarfs are new members of the EC 14026 class of pulsating sdB stars. HS 0039+4302 is a multi-mode pulsator with at least four distinct periods in the range between 182 and 234 s, and amplitudes up to 8 mma. HS 0444+0408 shows one dominant pulsation at 137 s (A ~ 12 mma) and a second weaker pulsation at 170 s (A ~ 3 mma). For HS 1824+5745 we find a single period of 139 s with an amplitude of about 5 mma. HS 2151+0857 shows four periods in the range 129-151 s with amplitudes between 2 and 5 mma. Our NLTE model atmosphere analysis of the time-averaged optical spectra place all stars well within the theoretical sdBV instability strip. Based on observations obtained at the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. }\fnmsep\thanks{ Based on observations collected at the German-Spanish Astronomical Center, Calar Alto, operated by the Max-Plank-Institute für Astronomie Heidelberg jointly with the Spanish National Commission for Astronomy. Based on observations collected at the European Southern Observatory, Chile (ESO No. 66.D-0031). Title: The extraordinarily bright optical afterglow of GRB 991208 and its host galaxy Authors: Castro-Tirado, A. J.; Sokolov, V. V.; Gorosabel, J.; Castro Cerón, J. M.; Greiner, J.; Wijers, R. A. M. J.; Jensen, B. L.; Hjorth, J.; Toft, S.; Pedersen, H.; Palazzi, E.; Pian, E.; Masetti, N.; Sagar, R.; Mohan, V.; Pandey, A. K.; Pandey, S. B.; Dodonov, S. N.; Fatkhullin, T. A.; Afanasiev, V. L.; Komarova, V. N.; Moiseev, A. V.; Hudec, R.; Simon, V.; Vreeswijk, P.; Rol, E.; Klose, S.; Stecklum, B.; Zapatero-Osorio, M. R.; Caon, N.; Blake, C.; Wall, J.; Heinlein, D.; Henden, A.; Benetti, S.; Magazzù, A.; Ghinassi, F.; Tommasi, L.; Bremer, M.; Kouveliotou, C.; Guziy, S.; Shlyapnikov, A.; Hopp, U.; Feulner, G.; Dreizler, S.; Hartmann, D.; Boehnhardt, H.; Paredes, J. M.; Martí, J.; Xanthopoulos, E.; Kristen, H. E.; Smoker, J.; Hurley, K. Bibcode: 2001A&A...370..398C Altcode: 2001astro.ph..2177C Broad-band optical observations of the extraordinarily bright optical afterglow of the intense gamma-ray burst GRB 991208 started ~2.1 days after the event and continued until 4 Apr. 2000. The flux decay constant of the optical afterglow in the R-band is -2.30 +/- 0.07 up to ~5 days, which is very likely due to the jet effect, and it is followed by a much steeper decay with constant -3.2 +/- 0.2, the fastest one ever seen in a GRB optical afterglow. A negative detection in several all-sky films taken simultaneously with the event, that otherwise would have reached naked eye brightness, implies either a previous additional break prior to ~2 days after the occurrence of the GRB (as expected from the jet effect) or a maximum, as observed in GRB 970508. The existence of a second break might indicate a steepening in the electron spectrum or the superposition of two events, resembling GRB 000301C. Once the afterglow emission vanished, contribution of a bright underlying supernova was found on the basis of the late-time R-band measurements, but the light curve is not sufficiently well sampled to rule out a dust echo explanation. Our redshift determination of z = 0.706 indicates that GRB 991208 is at 3.7 Gpc (for Ho = 60 km s-1 Mpc-1, OMEGAo = 1 and LAMDAo = 0), implying an isotropic energy release of 1.15 x 1053 erg which may be relaxed by beaming by a factor >102. Precise astrometry indicates that the GRB coincides within 0.2" with the host galaxy, thus supporting a massive star origin. The absolute magnitude of the galaxy is MB = -18.2, well below the knee of the galaxy luminosity function and we derive a star-forming rate of (11.5 +/- 7.1) Msun yr-1, which is much larger than the present-day rate in our Galaxy. The quasi-simultaneous broad-band photometric spectral energy distribution of the afterglow was determined ~3.5 day after the burst (Dec. 12.0) implying a cooling frequency nuc below the optical band, i.e. supporting a jet model with p = -2.30 as the index of the power-law electron distribution. Title: Detection of pulsations in three subdwarf B stars Authors: Østensen, R.; Solheim, J. -E.; Heber, U.; Silvotti, R.; Dreizler, S.; Edelmann, H. Bibcode: 2001A&A...368..175O Altcode: We report the detection of short period oscillations in the sdB stars HS 0815+4243, HS 2149+0847 and HS 2201+2610 from time-series photometry made at the Nordic Optical Telescope (NOT) from a sample of 31 candidates. Hence these three hot subdwarfs are new members of the EC 14026 class of pulsating sdB stars. One short period is detected for HS 0815+4243 (P ~ 126 s; A ~ 7 mma) and two short periods are seen for HS 2149+0847 (P ~ 142, 159 s; A ~ 11, 7 mma), whereas the single oscillation detected for HS 2201+2610 has a considerably longer period (P ~ 350 s; A ~ 11 mma). Our NLTE model atmosphere analysis of the time-averaged optical spectra indicate that HS 0815+4243 has Teff = 33 700 K and log g=5.95, HS 2149+0847 has Teff = 35 600 K and log g = 5.9, and HS 2201+2610 has Teff = 29 300 K and log g= 5.4. This places the former two at the hot end and the latter at the cool end of the theoretical sdBV instability strip. Based on observations obtained at the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. Based on observations collected at the German-Spanish Astronomical Center, Calar Alto, operated by the Max-Plank-Institute für Astronomie Heidelberg jointly with the Spanish National Commission for Astronomy. Title: Photometric and Spectroscopic Modelling of Non-radial Oscillations in the sdB Star PG1605+072 Authors: Falter, S.; Heber, U.; Dreizler, S.; Cordes, O. Bibcode: 2001AGM....18.P101F Altcode: 2001AGAb...18R.185F We present the results of photometric and spectroscopic modelling of nonradial oscillations in subluminous B stars. Time-resolved synthetic spectra for a rotating star showing multi-mode non-radial pulsation are calculated. We use the program package BRUCE developed by R. Townsend (UCL, London) to compute the structure of the rotating and pulsating envelope. A code to construct the rotationally distorted synthetic spectra from these models has been developed by us. The equilibrium grid is distorted by one or more pulsation modes including temperature, velocity and geometric perturbations. We are able to model line profile variations in these stars as well as the photometric changes in different photometric filters. To test our modelling we have chosen the pulsating sdB stars: PG1605+072. which shows a great variety of pulsation modes (> 50). Furthermore it has the longest periods (main mode at P = 480 s) and the largest radial velocity amplitudes (up to 14 km/s). Simultaneous photometric and spectroscopic observations of this object recently obtained at Calar Alto Observatory are also presented. Title: PG 1605+072: First Application of BUSCA Authors: Cordes, O.; Reif, K.; Dreizler, S.; Heber, U.; Schuh, S. Bibcode: 2001AGM....18..P53C Altcode: 2001AGAb...18R.161C BUSCA (``Bonn University Simultaneous CAmera'') has now reached its final state. The instrument is now fully equipped with four 4 k×4 k 15 μm CCDs, one backside thinned device for the UV channel and 3 frontside devices for the other channels. After four successful observing runs at Calar Alto Observatory in 2000 and 2001 BUSCA will be a standard instrument at the 2.2m telescope beginning with the first semester 2002. During the commissioning procedures we were able to demonstrate the good optical quality of the system as well as the colour index stability during non photometric conditions. We found out that BUSCA reaches a stability of a factor of 100 better than the brightness fluctuations caused by clouds. As one of the first applications of BUSCA we observed the rapid variable star PG1605 +072. Belonging to the class of pulsating sdB (EC 14026) stars PG1605+072 has a dominant period of 480s which we are able to measure in the four primary BUSCA bands (UV, blue, green-yellow, near-infrared). Our relativ photometric data from this first simultaneous four colour observation are of excellent quality although the atmospheric conditions were highly variable. We expect to get new hints about the origin of the pulsating mechanisms from analysing the colour index light curves. Title: Stratified Non-LTE Model Atmospheres for Hot Hydrogen Rich White Dwarfs Authors: Schuh, Sonja L.; Dreizler, Stefan; Wolff, Burkhard Bibcode: 2001AGM....18S0916S Altcode: We present our recent work towards stratified non-LTE model atmospheres and applications thereof. The chemical stratification in our stellar atmosphere models is determined from the equilibrium between gravity and radiative levitation. The chemical composition is therefore no longer a free parameter but is determined from the fundamental atmospheric parameters, effective temperature and surface gravity, alone. Spectroscopic EUV data of hot DA white dwarfs are used as an observational basis to test the predictions of these chemically stratified, self-consistently constructed models. New values for the fundamental parameters are being derived for the sample stars and successfully interpreted within the framework of diffusion theory. For the first time, equilibrium abundance calculations are found to be in good agreement with observations for a large sample. Title: AcDc - A new Code to Calculate the Vertical Structure of Accretion Disks Authors: Nagel, T.; Werner, K.; Dreizler, S. Bibcode: 2001AGM....18..P47N Altcode: We present a new code to calculate the vertical structure of accretion disks in cataclysmic variables. The disk is divided into concentric rings, each ring is treated like an independent plane-parallel radiating slab. We first calculate a gray LTE model and then a NLTE model of the ring. Finally we integrate over all ring spectra to get the spectrum of the full disk. The system of hydrostatic and radiative equilibrium, atomic level populations and particle conservation is solved consistently with the radiative transfer. This allows to calculate detailed theoretical spectra of accretion disks. Comparison with observations will allow to derive radial temperature distribution, mass accretion rate, viscosity and chemical composition. We also plan to compare our vertical structures to those of hydrodynamic simulations in order to estimate the influence of a detailed radiation transport on the stratification. Title: High resolution Keck and NTT spectra of PG 1159 stars Authors: Köper, S.; Rauch, T.; Dreizler, S.; Heber, U.; Reid, I. N.; Werner, K. Bibcode: 2001ASPC..226...65K Altcode: 2001ewwd.work...65K No abstract at ADS Title: FUSE observations of the PG 1159-type Central Star K 1-16 Authors: Miksa, S.; Deetjen, J. L.; Dreizler, S.; Herwig, F.; Kruk, J. W.; Rauch, T.; Werner, K. Bibcode: 2001ASPC..226...60M Altcode: 2001ewwd.work...60M No abstract at ADS Title: Sphericity Effects in Metal-Line Blanketed NLTE Model Atmospheres Authors: Nagel, T.; Dreizler, S.; Werner, K. Bibcode: 2001ASPC..226...86N Altcode: 2001ewwd.work...86N No abstract at ADS Title: Rotation Velocities of White Dwarfs Authors: Karl, C.; Napiwotzki, R.; Heber, U.; Dreizler, S.; Koester, D.; Reid, I. N. Bibcode: 2001AGM....18S0918K Altcode: 2001AGAb...18...98K White dwarfs are the compact remnants of low and intermediate mass stars (M < 8Msolar). Due to the conservation of angular momentum white dwarfs should be very fast rotators, if a significant fraction of the angular momentum of the progenitor stars were preserved. The existence of sharp NLTE cores of the hydrogen Hα line in high resolution spectra (obtained at the Keck observatory) of DA white dwarfs allowed us to determine (projected) rotational velocities v sin i for white dwarfs. Among those of our targets lying close to the ZZ Ceti instability many show evidence for extra broadening similar to rotation, whereas stars at higher temperatures (and therefore younger ones) rotate more slowly or not at all. Our result based on a large sample is in accordance with previous results presented by Koester et al. (1998). We discuss possible explanations for this astonishing result. Title: Polarized Thermal Radiation from Neutron Star Atmospheres Authors: Deetjen, Jochen L.; Dreizler, Stefan; Werner, Klaus Bibcode: 2001AGM....18.P121D Altcode: We present model atmospheres appropriate for the spectroscopic analysis of the thermal spectra of old isolated neutron stars. The models consider the correct opacities from hydrogen exposed to magnetic fields in the range of 107 Gauss from Ruder et al. (1994). For the first time, these models account for deviations from LTE as well. Our synthetic spectra are calculated in two successive steps. At first a model atmosphere is calculated by the simultaneous solution of many thousands of radiation transfer equations under the constraints of hydrostatic and radiative equilibrium as well as statistical equilibrium for atomic level populations. The solution method is an Accelerated Lambda Iteration (ALI) technique (Werner & Dreizler, 1999). Thereby we neglect the magnetic field. In the second step the atmospheric structure is kept fix and and a synthetic spectrum is calculated by solving the full polarized radiation transfer equation (PRT). We are using the Stokes vector to describe the radiation field and apply the PRT version of Accelerated Lambda Iteration (ALI) technique (Takeda, 1991). References: Ruder H., Wunner G., Herold H., Geyer F., 1994, Atoms in Strong Magnetic Fields, A&A Library, 1st edition Takeda Y, 1991, PASJ 43, 719 Werner K., Dreizler S., 1999, Journal of Computational and Applied Math. 109, 65 Title: New Pulsating sdB Stars from the HS Survey Authors: Silvotti, R.; Solheim, J. -E.; Heber, U.; Østensen, R.; Dreizler, S.; Edelmann, H. Bibcode: 2001ASPC..226..177S Altcode: 2001ewwd.work..177S No abstract at ADS Title: Application of Stratified Non-LTE Model Atmospheres to Hot DA White Dwarfs Authors: Schuh, S.; Dreizler, S.; Wolff, B. Bibcode: 2001ASPC..226...79S Altcode: 2001ewwd.work...79S No abstract at ADS Title: Stratified Non-LTE Model Atmospheres for hot White Dwarfs Authors: Dreizler, S.; Schuh, S. Bibcode: 2001ASPC..226...69D Altcode: 2001ewwd.work...69D No abstract at ADS Title: sdO Stars Authors: Dreizler, S. Bibcode: 2000eaa..bookE5412D Altcode: Subdwarfs of spectral type O (sdO stars) are hot evolved stars with a lower luminosity than main sequence O stars. The sdO stars cover a wide range in the HERTZSPRUNG-RUSSELL DIAGRAM (HRD, see figure 1). At lower luminosities and temperatures they form the extension of the subdwarfs of spectral type B (sdB), bounded by the extreme blue extension of the Horizontal Branch (EHB) and the helium mai... Title: PG 1618+563B: A new bright pulsating sdB star Authors: Silvotti, R.; Solheim, J. -E.; Gonzalez Perez, J. M.; Heber, U.; Dreizler, S.; Edelmann, H.; Østensen, R.; Kotak, R. Bibcode: 2000A&A...359.1068S Altcode: The results of two runs of time-series photometry made at the Nordic Optical Telescope clearly show that the sdB star PG 1618+563B is a new member of the EC 14026 class of sdB pulsators. Its power spectrum shows a doublet of frequencies at about 6.95 and 7.18 mHz (P ~ 144 and 139 s respectively), which produce a modulation effect in the light curve with a beat period of about 1.2 hours. The amplitudes of the two signals are very low, not more than 2 mma. Thanks to its brightness (B=13.4), which makes PG 1618+563B one of the brightest objects of its class, we were able to observe the star also in different colours and measure its UBV pulsation amplitudes and phases. The comparison of these ``nonadiabatic observables'' with models may help the identification of the oscillation modes. The spectral analysis of the sdB star and the spectral classification of PG 1618+563A suggest that both stars form a wide visual binary ( ~ 2500 A.U. separation), at a distance of about 680 pc from the sun. Based on observations obtained at the Nordic Optical Telescope, operated on the island of La Palma jointly by Denmark, Finland, Iceland, Norway, and Sweden, in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias. And on observations obtained at the German-Spanish Astronomical Center, Calar Alto, operated by the Max-Planck-Institut für Astronomie Heidelberg jointly with the Spanish National Commission for Astronomy Title: NLTE Model Atmospheres for Extremely Hot Compact Stars Authors: Rauch, T.; Deetjen, J. L.; Dreizler, S.; Werner, K. Bibcode: 2000IAUS..195..423R Altcode: Present observational techniques provide stellar spectra with high resolution at a high signal-to-noise ratio over the complete wavelength range---from the far infrared to X-rays. The effects of Non-``Local Thermal Equilibrium'' (NLTE) are particularly important for hot stars, hence the use of reliable NLTE stellar model atmosphere fluxes is required for an adequate spectral analysis. State-of-the-art NLTE model atmospheres include metal-line blanketing of millions of lines of all elements from hydrogen up to the iron-group elements, and thus permit precise analyses of extremely hot compact stars, e.g., central stars of planetary nebulae, PG 1159 stars, white dwarfs, and neutron stars. Their careful spectroscopic study is of great interest in several branches of modern astrophysics, e.g., stellar and galactic evolution, and interstellar matter. Title: The discovery of photospheric nickel in the hot DO white dwarf REJ 0503-289 Authors: Barstow, M. A.; Dreizler, S.; Holberg, J. B.; Finley, D. S.; Werner, K.; Hubeny, I.; Sion, E. M. Bibcode: 2000MNRAS.314..109B Altcode: We present the first evidence for the direct detection of nickel in the photosphere of the hot DO white dwarf REJ 0503-289. While this element has been seen previously in the atmospheres of hot H-rich white dwarfs, this is one of the first similar discoveries in a He-rich object. Intriguingly, iron, which is observed to be more abundant than Ni in the hot DA stars, is not detected, the upper limit to its abundance (Fe/He=10-6) implying an Fe/Ni ratio a factor of 10 lower than seen in the H-rich objects (Ni/He=10-5 for REJ 0503-289). The abundances of nickel and various other elements heavier than He were determined from Goddard High Resolution Spectrograph spectra. We used two completely independent sets of non-local thermodynamic equilibrium model atmospheres, which both provide the same results. This not only reduces the possibility of systematic errors in our analysis, but is also an important consistency check for both model atmosphere codes. We have also developed a more objective method of determining Teff and logg, from the He lines in the optical spectrum, in the form of a formal fitting of the line profiles to a grid of model spectra, an analogue of the standard procedure utilizing the Balmer lines in DA white dwarfs. This gives the assigned uncertainties in Teff and logg a firm statistical basis and allows us to demonstrate that inclusion of elements heavier than H, He and C in the spectral calculations, exclusively considered in most published optical analyses, yields a systematic downward shift in the measured value of Teff. Title: NLTE Model Atmospheres for Central Stars of Planetary Nebulae Authors: Rauch, Thomas; Deetjen, Jochen L.; Dreizler, Stefan; Werner, Klaus Bibcode: 2000ASPC..199..337R Altcode: 2000apn..conf..337R; 1999astro.ph..9507R Present observational techniques provide stellar spectra with high resolution at a high signal-to-noise ratio over the complete wavelength range - from the far infrared to the X-ray. NLTE effects are particularly important for hot stars, hence the use of reliable NLTE stellar model atmosphere fluxes is required for an adequate spectral analysis. State-of-the-art NLTE model atmospheres include the metal-line blanketing of millions of lines of all elements from hydrogen up to the iron-group elements and thus permit precise analyses of extremely hot compact stars, e.g. central stars of planetary nebulae, PG 1159 stars, white dwarfs, and neutron stars. Their careful spectroscopic study is of great interest in several branches of modern astrophysics, e.g. stellar and galactic evolution, and interstellar matter. Title: CCD Photometry of Variable Subdwarfs and White Dwarfs at Calar Alto Observatory Authors: Schuh, Sonja; Dreizler, Stefan; Deetjen, Jochen L.; Heber, Uli; Geckeler, Ralf D. Bibcode: 2000BaltA...9..395S Altcode: 2000OAst....9..395S We report on our time-resolved photometry of subdwarfs and white dwarfs at the Calar Alto Observatory. Candidates are taken from a spectroscopically pre-selected sample obtained from the Hamburg Schmidt Survey. We also report on our experience during the WET run in April 1999 and introduce our revised CCD photometry reduction package TRIPP, as well as preliminary results. Title: PG 1618+563: A New Bright Pulsating sdB Star Authors: Silvotti, R.; Gonzalez Perez, J. M.; Solheim, J. -E.; Heber, U.; Dreizler, S.; Edelmann, H. Bibcode: 2000BaltA...9..205S Altcode: 2000OAst....9..205S Recent observations at the NOT telescope clearly show that PG 1618+563 is a new member of the EC14026 class of sdB pulsating stars (Kilkenny et al. 1997, O'Donoghue et al. 1999). The very good quality of the non-filtered data allows to detect an amplitude modulation effect with a beat period of about 1.2 hours, which is consistent with the presence in the temporal spectrum of two close frequencies at 6.95 and 7.14 mHz ( ~ 144 and 140 s). The amplitudes are very low: between 1 and 2 mma. Moreover, from UBV data we find amplitude (and phase) differences, that could be useful for mode identification. Title: Preliminary Results from XCOV 17: PG 1336-018 Authors: Reed, M. D.; Kilkenny, D.; Kawaler, S. D.; Mukadam, A.; Kleinman, S. J.; Nitta-Kleinman, A.; Provencal, J. L.; Watson, T.; Sullivan, D.; Sullivan, T.; Shobbrook, B.; Jiang, X. J.; Ashoka, B. N.; Seetha, S.; Leibowitz, E.; Ibbetson, P.; Mendelson, H.; Meistas, E. G.; Kalytis, R.; Alisauskas, D.; O'Donoghue, D.; Martinez, P.; van Wyk, F.; Stobie, R.; Marang, F.; Zola, S.; Krzesinski, J.; Ogloza, W.; Moskalik, P.; Silvotti, R.; Piccioni, A.; Vauclair, G.; Dolez, N.; Rene-Fremy, J.; Chevreton, M.; Ulla, A.; Dreizler, S.; Schuh, S.; Deetjen, J.; Solheim, J. E.; Perez, J.; Suarez, O.; Manteiga, M.; Burleigh, M.; Barstow, M.; Kepler, S. O.; Kanaan, A.; Giovannini, O.; Metcalfe, T.; Ostensen, R. Bibcode: 2000BaltA...9..183R Altcode: 2000OAst....9..183R We present a preliminary analysis of the data collected during the 1999/1 (XCOV17) Whole Earth Telescope (WET) campaign to observe the pulsating subdwarf B star PG 1336-018. Since PG 1336-018 is an HW Vir type eclipsing binary, our hope is to use the known orbital period, assume a tidally locked system, and search for rotationally split modes. To this end, we can already report some success. Title: The Amplitude Differences Between CCD and PMT Measurements Authors: Kanaan, A.; O'Donoghue, D.; Kleinman, S. J.; Krzesinski, J.; Koester, D.; Dreizler, S. Bibcode: 2000BaltA...9..387K Altcode: 2000OAst....9..387K Using model atmospheres, quantum efficiency and transmission curves, we compute expected values for amplitudes of DAV, DBV and DOV stellar models as measured through different detectors and/or filter combinations. We conclude that choosing the wrong detector may lead to amplitudes lower by 20 % than those measured by phototubes. The correct choice of CCD + filter may reduce this problem down to a difference of 6 %. Title: Trace elements and radiative levitation in hot helium-rich white dwarfs Authors: Dreizler, Stefan Bibcode: 2000fuse.prop.A013D Altcode: We propose to observe three helium-rich (DO) white dwarfs in order to determine their photospheric abundances of trace elements (e.g. C, N, O, H, Fe, Ni,...). FUSE spectroscopy is ideal for this purpose since the FUV allows to explore a large variety of line transitions of various elements which are not detectable in existing optical or UV spectra of the targets. The data will be analyzed with non-LTE metal line blanketed model atmospheres. The results will be compared to predictions from newly developed, self-consistent diffusion/radiative levitation calculations under non-LTE conditions. The observed metal abundances will serve as bench-marks for such kind of new calculations.

As a basis for this work we have obtained high-S/N optical spectra of almost all known DO white dwarfs within the last five years as well as HST GHRS spectra of selected DO white dwarfs. A comprehensive analysis of the atmospheric parameters is now available. For the present proposal we have selected three targets which -- together with calibration and PI targets-- represent the non-DA white dwarf cooling sequence from the hot end down to the DB gap. Title: Time-Resolved Spectroscopy of BPM 37093 and PG 1336-018 Authors: Dreizler, Stefan; Koester, Detlev; Heber, Uli Bibcode: 2000BaltA...9..113D Altcode: 2000OAst....9..113D We present time-resolved spectroscopy of two pulsating stars using VLT UT1. Primary aim is an identification of the pulsation modes from the wavelength dependency of the amplitudes. A mode identification is the prerequisite to make full use of the photometric data obtained for asteroseismologic studies. Title: Hubble Space Telescope spectroscopy of hot helium-rich white dwarfs: metal abundances along the cooling sequence Authors: Dreizler, S. Bibcode: 1999A&A...352..632D Altcode: Metal abundances are the indicators of the chemical evolution in white dwarfs, which is dominated by the element separation due to the strong gravitational field. A reliable analysis and interpretation requires high resolution and high signal-to-noise UV spectroscopy. For hot helium rich DO white dwarfs this is currently only feasible with the Hubble Space Telescope. In this paper I report on our HST spectroscopy of DO white dwarfs and describe our model atmospheres employed for the analysis. This includes an introduction to our new self-consistent, chemically stratified non-LTE model atmospheres, which take into account gravitational sedimentation and radiative levitation. The results of the analysis shows that DO white dwarfs can best be fitted with chemically homogeneous models, whereas stratified models show significant deviations. Several possible reasons for this unexpected result are discussed. At the current stage, weak mass loss is the most plausible explanation. Based on observations obtained with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555 Title: HST/STIS ultraviolet spectroscopy of the supersoft X-ray source RX J0439.8-6809 Authors: van Teeseling, A.; Gänsicke, B. T.; Beuermann, K.; Dreizler, S.; Rauch, T.; Reinsch, K. Bibcode: 1999A&A...351L..27V Altcode: 1999astro.ph.10330V We present ultraviolet observations of the supersoft X-ray source RX J0439.8-6809 obtained with the Hubble Space Telescope Imaging Spectrograph. The ultraviolet spectrum is a very blue continuum overlayed with interstellar absorption lines. The observed broad Lyalpha absorption line is consistent with an interstellar column density of neutral hydrogen N_HI=(4.0+/-1.0)*E20};cm{-2. The light curve obtained from the time-tagged dataset puts a 3sigma upper limit of 0.04 mag on the ultraviolet variability of RX J0439.8-6809 on time scales between 10 s and 35 min. The long-term X-ray light curve obtained from our three-year ROSAT HRI monitoring of RX J0439.8-6809 shows the source with a constant count rate, and implies that the temperature did not change more than a few 1000 K. If RX J0439.8-6809 is a massive extremely hot pre-white dwarf on the horizontal shell-burning track, opposed to the alternative possibility of a very compact double-degenerate supersoft X-ray binary, its constant temperature and luminosity are a challenge to stellar evolution theory. Interestingly, RX J0439-6809 is found close to the theoretical carbon-burning main-sequence. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. Title: The classical stellar atmosphere problem. Authors: Werner, K.; Dreizler, S. Bibcode: 1999JCoAM.109...65W Altcode: 1999astro.ph..6130W The authors introduce the classical stellar atmosphere problem and describe in detail its numerical solution. The problem consists of the solution of the radiation transfer equations under the constraints of hydrostatic, radiative and statistical equilibrium (non-LTE). They outline the basic idea of the accelerated lambda iteration (ALI) technique and statistical methods which finally allow the construction of non-LTE model atmospheres considering the influence of millions of metal absorption lines. Some applications of the new models are presented. Title: Analysis of ultraviolet and extreme-ultraviolet spectra of the DA white dwarf G 191-B2B using self-consistent diffusion models Authors: Dreizler, S.; Wolff, B. Bibcode: 1999A&A...348..189D Altcode: We present a multi-wavelength spectral analysis of the DA white dwarf G 191-B2B. The employed atmospheric models account for gravitational settling and radiative levitation, which are, for the first time, calculated self-consistently with the atmospheric structure. The resulting spectra can reproduce the complete EUVE spectrum and the ultraviolet lines of iron. Some restrictions regarding the UV lines of other elements (C, N, O, Ni), however, still remain. In contrast to homogeneous models, it is not necessary to introduce additional photospheric or interstellar absorbers to account for the high opacity at lambda <~ 230 Ä. Abundance profile changing mechanisms, like mass-loss or accretion, are also not needed. Based on observations made with the EUVE Sattelite and with the NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute. STScI is operated by the Association of Universities for Research in Astronomy, Inc. under NASA contract NAS 5-26555. Title: The iron abundance in hot central stars of planetary nebulae derived from IUE spectra Authors: Deetjen, J. L.; Dreizler, S.; Rauch, T.; Werner, K. Bibcode: 1999A&A...348..940D Altcode: 2000astro.ph..6338D We present the first attempt to determine the iron abundance in hot central stars of planetary nebulae. We perform an analysis with fully metal-line blanketed NLTE model atmospheres for a sample of ten stars (T_eff >~ 70 000 K) for which high-resolution UV spectra are available from the IUE archive. In all cases lines of Fe Vi or Fe Vii can be identified. As a general trend, the iron abundance appears to be subsolar by 0.5-1 dex, however, the S/N of the IUE spectra is not sufficient to exclude a solar abundance in any specific case. Improved spectroscopy by either FUSE or HST is necessary to verify the possibility of a general iron deficiency in central stars. The suspected deficiency may be the result of gravitational settling in the case of three high-gravity objects. For the other stars with low gravity and high luminosity dust fractionation during the previous AGB phase is a conceivable origin. Based on observations with the International Ultraviolet Explorer (IUE) satellite. Title: The photometric behaviour of the peculiar PG 1159 star HS 2324+3944 at high frequency resolution Authors: Silvotti, R.; Dreizler, S.; Handler, G.; Jiang, X. J. Bibcode: 1999A&A...342..745S Altcode: 1998astro.ph.11178S We present the results from 135 hours of nearly continuous time series photometry on the ``hybrid'' (H-rich) PG 1159 variable star HS 2324+3944, obtained in August-September 1997. The power spectrum of the data shows several frequencies (about 20 or more), concentrated in three narrow and very crowded regions near 475, 390 and 950 mu Hz in decreasing amplitude order. Most (if not all) of the peaks in the latter region are linear combinations of the high-amplitude frequencies between 455 and 500 mu Hz. If we divide the data set into two equal parts, the power spectra are different. This is probably due to a not sufficiently long (and therefore not completely resolved) light curve; nevertheless an alternative hypothesis of a single damped oscillator may not be completely ruled out. If we adopt the first hypothesis, the high concentration of peaks between 455 and 500 mu Hz suggests the presence of both l=1 and l=2 high-overtone nonradial g-modes. The insufficient frequency resolution of our data does not allow to obtain definite precision asteroseismology results. Nevertheless a spacing of the signals is observed, probably due to stellar rotation with a period of 2.3 days. If the signal spacing was due to the successive overtones, the period spacings would be equal to 18.8 (l=1) and 10.4 (l=2) s. Based on observations obtained at the McDonald, Loiano and Beijing Observatories and at the German-Spanish Astronomical Center, Calar Alto, operated by the Max-Planck-Institut für Astronomie Heidelberg jointly with the Spanish National Commission for Astronomy. Title: Iron abundance in hot central stars of planetary nebulae Authors: Deetjen, J. L.; Dreizler, S.; Rauch, T.; Werner, K. Bibcode: 1999AGAb...15..119D Altcode: 1999AGM....15..P64D We present the first attempt to determine the iron abundance in hot central stars of planetary nebulae. We perform an analysis with fully metal-line blanketed NLTE model atmospheres for a sample of ten stars (T_eff >~ 70 000 K) for which high-resolution UV spectra are available from the IUE archive. In all cases lines of Fe vi or Fe vii can be identified. As a general trend, the iron abundance appears to be subsolar by 0.5-1 dex, however, the S/N of the IUE spectra is not sufficient to exclude a solar abundance in any specific case. Improved spectroscopy by either FUSE or HST is necessary to verify the possibility of a general iron deficiency in central stars. The suspected deficiency may be the result of gravitational settling in the case of three high-gravity objects. For the other stars with low gravity and high luminosity dust fractionation during the previous AGB phase is a conceivable origin. Title: HST spectroscopy of hot hydrogen deficient white dwarfs Authors: Dreizler, S. Bibcode: 1999ASPC..169..499D Altcode: 1999ewwd.conf..499D No abstract at ADS Title: Iron and nickel abundances in hot hydrogen-rich central stars of planetary nebulae Authors: Deetjen, J. L.; Dreizler, S.; Rauch, T.; Werner, K. Bibcode: 1999ASPC..169..475D Altcode: 1999ewwd.conf..475D No abstract at ADS Title: Born-again AGB stars: Starting point of the H-deficient post-AGB evolutionary sequence? Authors: Werner, K.; Dreizler, S.; Rauch, T.; Koesterke, L.; Heber, U. Bibcode: 1999IAUS..191..493W Altcode: We discuss the origin of hot hydrogen-deficient post-AGB stars. Evidence is growing that the ``born-again AGB star scenario'' as a consequence of a late He shell flash cannot explain the diverse observations. Analyses of the stars and their associated planetary nebulae suggest that the H-deficiency is not formed during the second post-AGB phase but already while the star is still on the AGB. There are even hints that the H-deficiency can occur before the first departure from the AGB. Title: Sphericity effects in non-LTE model atmospheres for hot stars Authors: Nagel, T.; Dreizler, S.; Werner, K. Bibcode: 1999AGAb...15..104N Altcode: 1999AGM....15..P35N Spectral analyses of hot compact stars (white dwarfs, sdO stars, central stars of planetary nebulae) are usually performed with model atmospheres assuming plane-parallel geometry. This approximation becomes questionable in case of observational data with very high signal-to-noise where even tiny effects become visible or, because of their extended atmospheres, for objects close to the Eddington limit. As long as wind effects are negligible, static and spherically symmetric models can be used. We describe how our non-LTE model atmosphere code has been generalized to spherical geometry and present results from our first model calculations. This new implementation is used to study sphericity effects on atmospheric structure and line profiles which are compared to effects arising from non-LTE metal line blanketing. Title: EUVE observations of DA white dwarfs Authors: Wolff, B.; Koester, D.; Dreizler, S. Bibcode: 1999ASPC..169..524W Altcode: 1999ewwd.conf..524W No abstract at ADS Title: NLTE Model Atmospheres for Extremely Hot Compact Stars Authors: Rauch, Thomas; Deetjen, Jochen L.; Dreizler, Stefan; Werner, Klaus Bibcode: 1999AGAb...15..105R Altcode: 1999AGM....15..P36R Present observational techniques provide stellar spectra with high resolution at a high signal-to-noise ratio over the complete wavelength range - from the far infrared to the X-ray. NLTE effects are particularly important for hot stars, hence the use of relia ble NLTE stellar model atmosphere fluxes is required for an adequate spectral analysis. State-of-the-art NLTE model atmospheres include the metal-line blanketing of millions of lines of all elements from hydrogen up to the iron-group elements and thus permit precise analyses of extremely hot compact stars, e.g. central stars of planetary nebulae, PG 1159 stars, white dwarfs, and neutron stars. Their careful spectroscopic study is of great interest in several branches of modern astrophysics, e.g. stellar and galactic evolution, and interstellar mat ter. Title: Spectroscopy of Hot Hydrogen Deficient White Dwarfs Authors: Dreizler, Stefan Bibcode: 1999RvMA...12..255D Altcode: No abstract at ADS Title: Equilibrium Abundances in Hot White Dwarfs Authors: Schuh, Sonja; Dreizler, Stefan; Wolff, Burkhard Bibcode: 1999AGAb...15..105S Altcode: Metal abundances are the indicators of the chemical evolution in white dwarfs, which is dominated by the sedimentation of the heavier elements due to the strong gravitational field. A reliable analysis and interpretation requires high resolution and high signal-to-noise UV and EUV spectroscopy. It can only be performed in these wavelength ranges as the weak metal lines needed for the analysis do not show up in the optical regime. During previous work by Wolff et al. (A&A 329, 1045), the spectra of hot, hydrogen rich white dwarfs as detected by EUVE were analysed and effective temperatures, surface gravity and metallicities were determined using chemically homogeneous model atmospheres. We now present calculations of self-consistent, chemically stratified non-LTE model atmospheres which take into account gravitational sedimentation and radiative levitation. In the case of G191-B2B, these new, refined models are able to reproduce the EUVE observations to an unprecedented degree of accuracy (Dreizler et al., A&A 348, 189). This result is now to be checked for a larger sample of objects using UV spectra from IUE and HST as well as future FUSE spectra. Title: The stellar content of the Hamburg Quasar Survey Authors: Homeier, D.; Koester, D.; Jordan, S.; Hagen, H. -J.; Engels, S.; Heber, U.; Dreizler, S. Bibcode: 1999ASPC..169...37H Altcode: 1999ewwd.conf...37H No abstract at ADS Title: Results of the multi-site photometric campaign on HS 2324+3944 Authors: Silvotti, R.; Dreizler, S.; Handler, G.; Jiang, X. Bibcode: 1999ASPC..169..100S Altcode: 1999ewwd.conf..100S No abstract at ADS Title: Observations of Variable [pre-] White Dwarfs Authors: Dreizler, S.; Schuh, S.; Deetjen, J.; Heber, U.; Edelmann, H.; Koester, D. Bibcode: 1999AGAb...15..106D Altcode: Stellar seismology is an extremely valuable tool for a direct investigation of stellar structure and evolution. The usual observational approach is photometric monitoring of stars, yielding pulsation frequencies and amplitudes. The comparison of the observed modes with predicted ones are then used to probe the stellar structure. The typical separation of consecutive overtones in these stars are of the same order as the side bands in the Fourier spectrum produced by the periodic day interruption. Thus, in order to obtain light curves suitable for a detailed seismologic analysis, world wide coordinated observing campaigns are required (Whole Earth Telescope, WET). Using the Calar Alto 1.23m telescope, we participated in the last WET campaign, where the close binary PG 1336-018, a pulsating sdB and a very cool main sequence star, was observed. Using the same instrumentation, we also searched for new candidates of variable [pre-] white dwarfs. A seismologic analysis requires a reliable mode identification, namely the degree l denoting the number of node lines of the non-radial pulsation. In the case of many observed eigenmodes these can be identified by a comparison with theoretical predictions. When only very few modes are present this comparison is ambiguous and an alternative approach is required, i.e. an evaluation of wavelength dependent pulsation amplitudes as seen in time-resolved spectroscopy of two variable [pre-] white dwarfs performed with the VLT. Title: Search for rotation in white dwarfs Authors: Koester, D.; Dreizler, S.; Weidemann, V.; Allard, N. F. Bibcode: 1999ASPC..169..415K Altcode: 1999ewwd.conf..415K No abstract at ADS Title: FUV spectroscopy of DO and PG 1159 stars with ORFEUS Authors: Werner, K.; Dreizler, S.; Rauch, T.; Barnstedt, J.; Gölz, M.; Gringel, W.; Kappelmann, N.; Krämer, G.; Widmann, H.; Koesterke, L.; Haas, S.; Heber, U.; Appenzeller, I.; Grewing, M. Bibcode: 1999ASPC..169..511W Altcode: 1999ewwd.conf..511W No abstract at ADS Title: An analysis of DA white dwarfs from the Hamburg Quasar Survey Authors: Homeier, D.; Koester, D.; Hagen, H. -J.; Jordan, S.; Heber, U.; Engels, D.; Reimers, D.; Dreizler, S. Bibcode: 1998A&A...338..563H Altcode: Follow-up spectroscopy of several hundred hot stars detected by the Hamburg Quasar Survey (HQS) has been carried out between 1989 and 1996. We present the analysis of 80 DA white dwarfs using model atmospheres and theoretical cooling tracks to derive the atmospheric parameters T_eff and log g, masses and absolute magnitudes. The HQS turned out to be sensitive to the detection of hydrogen-rich white dwarfs in a wide temperature range, from 10 000 K upwards. Star counts within four HQS fields for magnitudes B<= 16fm 4 exceed those from the Palomar Green survey by about 50%. The more recent observation campaigns emphasized the detection of very hot degenerates, yielding a large fraction of DA stars with T_eff > 50 000 K compared to other surveys. The mean mass of our DA sample is M=0.61{M}_{\odot}, with three massive DA stars exceeding 1{M}_{\odot} and three DA stars with masses significantly below the assummed lower mass limit for single white dwarf evolution of 0.45{M}_{\odot}. Among the cool DA stars, thirteen are potential ZZ Ceti candidates because their effective temperatures lie close to the instability strip. Based on observations collected at the German-Spanish Astronomical Center (DSAZ), Calar Alto, operated by the Max-Plank-Institut für Astronomie Heidelberg jointly with the Spanish National Commission for Astronomy; with the International Ultraviolet Explorer satellite (IUE) collected at Villafranca, Spain, and with the ROSAT X-ray telescope. Title: Search for rotation in white dwarfs Authors: Koester, D.; Dreizler, S.; Weidemann, V.; Allard, N. F. Bibcode: 1998A&A...338..612K Altcode: We report high-resolution spectroscopic observations of the NLTE Hα core in 28 DA white dwarfs. From a comparison with theoretically broadened NLTE models projected rotation velocities can be determined. The majority of objects are found to be compatible with zero or very small rotation with typical upper limits for v sin i of 15 km/s, corresponding to periods of hours or longer. The implications for the loss of angular momentum during the evolution of the progenitors is discussed. Three new magnetic white dwarfs are detected with very small tangential fields in the range of 30 to 50 kG. In two more magnetic objects known before we found field strengths significantly larger than the mean longitudinal fields determined from the circular polarization. Very puzzling is the result for three ZZ Ceti stars in the sample, which all seem to have projected rotational velocities between 30 and 45 km/s, in conflict with asteroseismological results. Based on observations collected at the European Southern Observatory, La Silla, Chile (55.D-0459, 57.D-0631) Title: Spectral analysis of O(He)-type post-AGB stars Authors: Rauch, T.; Dreizler, S.; Wolff, B. Bibcode: 1998A&A...338..651R Altcode: We present an analysis of two recently discovered, very hot hydrogen-deficient post-AGB stars of spectral type O(He), namely HS 1522+6615 and HS 2209+8229, by means of state-of-the-art NLTE model atmospheres based on new optical, UV, and X-ray observations. In the spectra of HS 1522+6615 we discovered a variability of the \Ionw{O}{6}{5290} line complex on a time scale of few days. We also report on the discovery of a ring structure in the planetary nebula K 1-27 which has an O(He)-type central star. We discuss how the group of O(He) stars fits in our picture of hydrogen-deficient post-AGB stellar evolution. Based on observations obtained at the German-Spanish Astronomical Center, Calar Alto, operated by the Max-Planck-Institut für Astronomie Heidelberg jointly with the Spanish National Commission for Astronomy; collected at the European Southern Observatory, La Silla, Chile; on observations made with ROSAT, retrieved from the archive; and on observations made with the International Ultraviolet Explorer (IUE) and retrieved from the IUE Final Archive; this research has made use of the SIMBAD database, operated at CDS, Strasbourg, France Title: Spectral analyses of PG 1159 star: constraints on the GW Virginis pulsations from HST observations Authors: Dreizler, S.; Heber, U. Bibcode: 1998A&A...334..618D Altcode: We present the results of a quantitative analysis of UV and optical spectra of nine PG 0122+200ls, very hot hydrogen-deficient [pre-] white dwarfs, by means of line blanketed NLTE model atmospheres. Four programme stars constitute the GW Vir variables, a class of non-radial g-mode pulsators. Precise effective temperatures, carbon, nitrogen and oxygen abundances and spectroscopic masses are used to constrain the GW Vir pulsations. The blue edge of the instability strip is at 140 000 K (PG 1159-035). PG 0122+200 sets the red edge at 80 000 K, but is also one of the coolest PG 0122+200ls\ known, suggesting that the pulsations are stopped when the transformation of a PG 1159 star into a hot white dwarf occurs by gravitational settling of the metals. Four non-variables are found to lie inside the GW Vir instability strip indicating that an additional parameter determines whether a PG 1159 star pulsates. Abundances of C and O in the pulsating stars appear to be higher than in the non-variables in agreement with the theoretical prediction that the pulsations are driven by cyclic ionization of C and O. The outstanding discovery of our investigation, however, is a strong correlation between the nitrogen abundance and pulsations. All GW Vir stars are nitrogen rich, whereas no nitrogen can be detected in the non-variables except in PG 1144+005. We conjecture that this correlation provides a key for the understanding of the driving mechanism. Comparing their position in the T_eff-log g diagram to new evolutionary models we conclude that most programme stars are post-AGB stars of rather low mass (0.5 ... 0.65 M_sun) which have lost their entire hydrogen-rich envelope and part of their helium-rich envelope whereas we confirm HS 0704+6153 to be an AGB manquestar. The high nitrogen abundance in four stars is a tracer of mixing processes which have led to ingestion and burning of hydrogen during the final helium shell flash. Based on observations obtained a) with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555; b) at the German-Spanish Astronomical Center, Calar Alto, operated by the Max-Planck-Institut für Astronomie Heidelberg jointly with the Spanish National Commission for Astronomy; c) at the European Southern Observatory, La Silla, Chile; d) with the International Ultraviolet Explorer (IUE). Title: The Pulsating ``HYBRID'' PG 1159 Star HS 2324+3944: Past, Present and Future Authors: Handler, G.; Dreizler, S.; Silvotti, R.; Xiao-Jun, Jiang Bibcode: 1998BaltA...7..105H Altcode: 1998OAst....7..105H We review past efforts to unravel the nature of the light variations of the ``hybrid'' PG 1159 star HS 2324+3944 and present preliminary results of a recent multisite campaign devoted to this interesting object. From the on-line frequency analysis of our measurements, we can safely conclude that this star is a multimode pulsating variable. Some suggestions for further investigations are given. Title: On the inclination and binarity of the pulsating pre-white dwarf PG 2131+066 Authors: Paunzen, Ernst; Konig, Michael; Dreizler, Stefan Bibcode: 1998A&A...331..162P Altcode: We report on new spectroscopic data as well as recent results from a temporal analysis of PG 2131+066 WET time series, yielding a new interpretation of the binarity nature for PG 2131+066. The newly discovered Hα emission features, the estimated low inclination and the found 3.9h period, support the picture of a close binary system, composed of the nonradial oscillating white dwarf with a cool red dwarf companion. Since the spin and the orbital period are not yet synchronized and because PG 2131+066 has no X-ray counterpart, we classify it as a progenitor of a cataclysmic variable. Based on observations obtained at the German-Spanish Astronomical Center, Calar Alto, operated by the Max Planck Institut für Astronomie Heidelberg jointly with the Spanish National Commission for Astronomy. Title: HST Spectroscopy of PG 1159 Stars: the Boundary of the GW VIR Instability Strip Authors: Dreizler, S. Bibcode: 1998BaltA...7...71D Altcode: 1998OAst....7...71D Our recent analysis of PG 1159 stars, mainly based on the HST spectroscopy, is presented. The results allow several conclusions regarding the boundary of the GW Vir instability strip and the driving mechanism for these pulsations. Title: On the mass-loss of PG1159 stars Authors: Koesterke, L.; Dreizler, S.; Rauch, T. Bibcode: 1998A&A...330.1041K Altcode: The winds of the four PG1159 stars NGC7094, NGC246, K1-16 and RXJ2117.1+3412 are investigated by means of non-LTE models for spherically expanding atmospheres. Based on the results of recent plane-parallel non-LTE analyses, several individual models with various mass-loss rates are calculated. Synthetic profiles of the C Iv resonance line are compared to high resolution, high quality HST and IUE UV spectra in order to determine mass-loss rates of the stars and terminal velocities of their winds. Complex model atoms of hydrogen, helium, carbon and oxygen are taken into account. In contrast to previous studies we find from the C Iv line at 1550 Angstroms exceedingly high mass-loss rates of -7.6<=log(dot {M}/[M_sunyr(-1) ])<=-6.9 which are, in case of K1-16, only two times smaller than the mass-loss rates of [WC]-PG1159 stars. From the comparison with theoretical predictions of line strength and terminal wind velocity it is most likely that the theory of radiation driven winds is appropriate for the PG1159 stars. The results are discussed in the light of the evolutionary sequence [WCL]->[WCE]->[WC]-PG1159->PG1159\= rightarrowWD, which is suggested for hydrogen deficient post-AGB stars. Similarities between the winds of PG1159 stars and the exceptional strong winds of [WC]-type stars lead to the assumption that the theory of radiation driven winds might also apply for [WCE] stars. Changes of ionization degrees, which might enhance the mass-loss by multi-scattering processes, are found in the atmospheres of [WCE] stars but not in the atmospheres of PG1159 stars. Partly based on observations made with NASA/ESA Hubble Space Telescope, obtained from the data archive at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555; Partly based on observations obtained with the IUE satellite from VILSPA, Spain, jointly operated by the NASA, ESA, and PPARC. Title: HS0507+0434: a double DA degenerate with a ZZCeti component Authors: Jordan, S.; Koester, D.; Vauclair, G.; Dolez, N.; Heber, U.; Hagen, H. -J.; Reimers, D.; Chevreton, M.; Dreizler, S. Bibcode: 1998A&A...330..277J Altcode: HS0507+0434 and HS2240+1234 are two new common proper motion pairs of DA white dwarfs, discovered by the Hamburg Quasar Survey. Our model atmosphere analysis shows that HS0507+0434A has an effective temperature of 20000K and is remarkably young (tau_cool < 1Gyr) compared to the average cooling time of all known wide double degenerates (~ 3Gyr). The cooler B component of HS0507+0434 is particularly interesting; the determination of the atmospheric parameters is complicated by the strong dependence of the solution on the details of the treatment of convection. Only those parameterizations of mixing length theory are consistent with all observations (especially the magnitude difference between the components), which lead to an intermediate efficiency of the convective flux. In the standard version of the mixing length theory this corresponds to a mixing length parameter of l/H_p = 1.75 - 2.0, where H_p is the pressure scale height. This result does not depend on the model atmosphere code and is in agreement with previous studies of convection in DA white dwarfs; there are, however, slightly different formulations of the MLT in use, which achieve the same efficiency at different values of l/H. These versions are discussed and compared in the paper. The result of our analysis (T_eff=11900K, log g=8) places the B component into the ZZCeti instability strip, where DA white dwarfs are pulsating non-radially. Photometric observations have now confirmed that HS0507+0434 is variable and identified 3 or 4 fundamental g-modes in the Fourier spectrum. Based on observations collected at the German-Spanish Astronomical Center (DSAZ) at Calar Alto, Spain, at the European Southern Observatory, La Silla, Chile, with the International Ultraviolet Explorer Satellite, and at the Observatoire de Haute Provence (CNRS), France. Title: Iron and Nickel Abundances in DA White Dwarfs and SDO Stars Authors: Werner, K.; Dreizler, S.; Haas, S.; Heber, U. Bibcode: 1998ESASP.413..301W Altcode: 1998uabi.conf..301W No abstract at ADS Title: White Dwarfs in the Hamburg Quasar Survey Authors: Homeier, D.; Koester, D.; Hagen, H. -J.; Jordan, S.; Heber, U.; Engels, D.; Reimers, D.; Dreizler, S. Bibcode: 1998AGAb...14..148H Altcode: 1998AGM....14..P98H The spatial distribution and the luminosity function of white dwarfs provide important information on stellar evolution and the structure and age of the Galactic disk. A total of about 2 200 white dwarfs is known to date. The Hamburg Quasar Survey (HQS) has the capability to substantially enlarge this number and to provide an optically selected sample of white dwarfs not relying on EUV/X-ray emission. The HQS, covering 14 000 deg^2 of the northern sky, has produced objective prism spectra of several thousand stellar UV-excess sources. We expect to be able to identify 2 000-3 000 white dwarfs down to a limiting magnitude of B=17_{\cdot}m5 from this database. The spectra also allow a rough estimate of Teff by the Balmer line strengh of DA white dwarfs. Follow-up observations of hot star candidates in selected fields of the survey and comparisons with the catalogue of known white dwarfs have shown that DAs with temperatures down to, and below, the ZZ-Ceti instability strip (~ 11 000 K) are found. The number density of DA per deg^2 found within the magnitude range of the Palomar-Green survey (B <= 16_{\cdot}m4) was higher than estimated from that survey. The 80 DA white dwarfs discovered by the follow-up spectroscopy have been analyzed using LTE model atmospheres to determine Teff and \log g, from which the mass distribution, luminosities and photometric distances can be derived. Title: Photospheric metals in hot DA white dwarfs Authors: Wolff, B.; Koester, D.; Dreizler, S.; Haas, S. Bibcode: 1998A&A...329.1045W Altcode: Previous observations of the soft X-ray and EUV region with the Einstein, EXOSAT, and ROSAT satellites have indicated the presence of photospheric absorbers in most DA white dwarfs with {T_eff} ga 40000K. Several of these objects have now been observed with the Extreme Ultraviolet Explorer (EUVE). Since the detection of individual metal lines is rather difficult with EUVE spectra we chose the well studied DA G191-B2B as reference object for the analysis of other white dwarfs. In spectra obtained with the GHRS of the Hubble Space Telescope photospheric lines of nitrogen, silicon, iron, and nickel could be detected. With the abundances determined from these observations we were able to reproduce the EUVE spectrum of G191-B2B. The main source of EUV opacity turned out to be iron, followed by nickel. The analysis of both the EUV continuum and the hydrogen Balmer lines led to {T_eff} = 56000 +/- 2000K. For the analysis of other DA white dwarfs we used the same relative abundances as for G191-B2B but introduced a free scaling factor (``metallicity'') for the total amount of metals. From EUVE spectra we determined relative metallicities for 20 objects with {T_eff} ga 40000K. The main result is that all DAs with {T_eff} ga 50000K contain additional photospheric absorbers, whereas at lower temperatures all observations, with the exception of GD394, are compatible with pure hydrogen atmospheres. As in the case of G191-B2B, iron determines also the EUV opacity in the objects at {T_eff} ga 50000K. This is in agreement with radiative levitation theory which predicts the support of iron above this temperature. Based on observations with the HST and EUVE satellites, and on optical spectra obtained at the DSAZ Calar Alto Title: On the Red Edge of the GW Virginis Instability Strip Authors: Werner, K.; Dreizler, S.; Heber, U.; Rauch, T. Bibcode: 1998ASPC..135..130W Altcode: 1998hcsp.conf..130W GW Vir (alias PG1159-035) is the prototype of a spectroscopic class of extremely hot hydrogen-deficient (pre-) White Dwarfs. The prototype as well as a number of other PG1159 stars define the GW Vir (or DOV) instability strip in the HR diagram. Considerable effort has been made to confine the limits of this instability strip by both, pulsational theory (Kawaler and collaborators) as well as by spectroscopic analysis (Werner and collaborators). Our first analysis of the prototype (Werner, Heber, Hunger 1991 A&A 244, 437) revealed the peculiar surface abundances which entered as an essential ingredient into the pulsational analysis of Whole Earth Telescope (WET) observations (Kawaler & Bradley 1994, ApJ 427, 415). We succeeded in constraining the blue edge of the instability strip (Werner et al. 1996, IAU Coll. 155, p. 96). We now present non-LTE model atmosphere analyses of RcoolS (Teff < 100,000K) PG1159 stars based on latest UV spectra obtained with the Hubble Space Telescope, aiming at the red edge of the instability strip. Preliminary results indicate that the red edge is much less well defined and seems to depend rather sensitively on photospheric and stellar parameters. The analysis comprises one pulsator which was a target of a WET observation run and it will support the interpretation of asteroseismologic analyses. Title: Photospheric metals in hot DA white dwarfs. Authors: Wolff, B.; Koester, D.; Dreizler, S.; Haas, S. Bibcode: 1997AGAb...13..218W Altcode: No abstract at ADS Title: (Erratum) On the hot ends of the white dwarf spectral sequences: white dwarfs containing helium from the Hamburg-Schmidt survey. Authors: Heber, U.; Dreizler, S.; Hagen, H. -J. Bibcode: 1997A&A...319..363H Altcode: Erratum to Astron. Astrophys. 311, L17 (1996). Title: Spectral Analyses of PG 1159 Stars with Line-Blanketed Non-Lte Model Atmospheres Authors: Werner, K.; Dreizler, S.; Rauch, T.; Heber, U. Bibcode: 1997fbs..conf..227W Altcode: 1997LDP....22..227W No abstract at ADS Title: Analysis of hydrogen rich PG 1159 central stars of Planetary Nebulae Authors: Dreizler, S.; Werner, K.; Heber, U. Bibcode: 1997IAUS..180..103D Altcode: No abstract at ADS Title: NLTE analyses of PG 1159 stars: constraints for the structure and evolution of post-AGB stars. Authors: Dreizler, S.; Werner, K.; Rauch, T.; Heber, U.; Reid, I. N.; Koesterke, L. Bibcode: 1997IAUS..189..369D Altcode: 1998IAUS..189..369D The majority of all stars (Mi < 8Msun) end their lives as white dwarfs (WD). On the tip of the Asymptotic Giant Branch (AGB) the star ejects its outer layers which become a planetary nebula and the stellar core evolves rapidly towards very high effective temperatures (Teff > 100 kK). When the nuclear burning in the H or He shell ceases the star enters the WD cooling sequence. The evolution starting from the AGB is separated in a H-rich and a H-deficient sequence where the latter contributes with a number fraction of ≍20%. In this paper the authors describe their recent effort in the analysis of one group of these stars, the PG 1159 stars. Title: Abundance Patterns of Iron and Nickel in SDO Stellar Atmospheres Authors: Haas, Stefan; Heber, Ulrich; Dreizler, Stefan; Werner, Klaus Bibcode: 1997fbs..conf..177H Altcode: 1997LDP....22..177H No abstract at ADS Title: Ultraviolet Spectroscopy of Hot Compact Stars. Authors: Werner, K.; Dreizler, S.; Heber, U.; Kappelmann, N.; Kruk, J.; Rauch, T.; Wolff, B. Bibcode: 1997RvMA...10..219W Altcode: No abstract at ADS Title: On the fate of born-again red giants. Authors: Werner, K.; Dreizler, S.; Heber, U.; Rauch, T. Bibcode: 1997seas.conf..163W Altcode: 1997ase..work..163W Post-AGB stars which are burning hydrogen in a shell and hot white dwarfs may suffer a final helium shell flash. Subsequently the stellar envelope re-expands and the star becomes a "born-again" red giant. What is the consequence for the chemistry in the envelope? In particular, what surface abundances can be expected and how are they affected by mass loss during the second descent from the AGB? Iben and MacDonald (1995) provided the only appropriate theoretical calculation available up to now for this scenario. The authors present here the results of spectroscopic analyses from hot H-deficient stars, which they believe to have undergone a late helium flash. The surface abundance pattern strongly varies from star to star. An explanation of this variety demands extensive parameter studies in evolutionary calculations. Title: Trace Elements in White Dwarfs Authors: Koester, Detlev; Wolff, Burkhard; Jordan, Stefan; Dreizler, Stefan Bibcode: 1997fbs..conf..313K Altcode: 1997LDP....22..313K No abstract at ADS Title: New Spectral analyses of pre-white dwarfs Authors: Rauch, T.; Dreizler, S.; Werner, K. Bibcode: 1997ASSL..214..221R Altcode: 1997whdw.work..221R No abstract at ADS Title: Apparently Normal o- and B-Type Stars at High Galactic Latitudes? Authors: Heber, U.; Moehler, S.; Schmidt, J. H. K.; Dreizler, S.; Geffert, M.; Reid, I. N. Bibcode: 1997fbs..conf...87H Altcode: 1997LDP....22...87H No abstract at ADS Title: Non-LTE analyses of DO white dwarfs Authors: Dreizler, S.; Werner, K. Bibcode: 1997ASSL..214..213D Altcode: 1997whdw.work..213D No abstract at ADS Title: New results on PG 1159 stars and ultrahigh-excitation DO white dwarfs Authors: Werner, K.; Dreizler, S.; Heber, U.; Rauch, T. Bibcode: 1997ASSL..214..207W Altcode: 1997whdw.work..207W No abstract at ADS Title: Do White Dwarfs Authors: Dreizler, S.; Werner, K.; Heber, U.; Reid, N.; Hagen, Hans Bibcode: 1997fbs..conf..303D Altcode: 1997LDP....22..303D No abstract at ADS Title: New Results from the Stellar Component of the Hamburg Schmidt Survey: a Sample of SDO Stars Authors: Lemke, M.; Heber, U.; Napiwotzki, R.; Dreizler, S.; Engels, D. Bibcode: 1997fbs..conf..375L Altcode: 1997LDP....22..375L No abstract at ADS Title: The extreme-ultraviolet spectrum of the central star of the planetary nebula NGC 1360 Authors: Hoare, Melvin G.; Drake, Jeremy J.; Werner, Klaus; Dreizler, Stefan Bibcode: 1996MNRAS.283..830H Altcode: We have used the Extreme Ultraviolet Explorer (EUVE) to obtain the first EUV spectrum of the central star of a planetary nebula, that of NGC 1360. The photospheric spectrum shows continuum absorption edges due to O^4+ as well as absorption-line features. NLTE model atmospheres including line blanketing by iron-group elements can match the general level and shape of the spectrum, but are not capable of explaining all the observed features, precluding a detailed fit. Our solar abundance models require T_eff=110000K, logg=6.0 and N_H=8.5x10^19cm^-2. A new optical spectrum is presented and analysed with NLTE models. Stellar parameters in reasonable agreement with the EUV results are derived. It is found that many optical lines need to be considered, otherwise the best fits are not necessarily unique. This data set will provide a stern test for future NLTE models, which will need to include still more line blanketing before a totally satisfactory fit is obtained. Title: Spectral analysis of hot helium-rich white dwarfs. Authors: Dreizler, S.; Werner, K. Bibcode: 1996A&A...314..217D Altcode: We present a model atmosphere analysis of most known hot helium-rich white dwarfs of spectral type DO. The stars represent the non-DA white dwarf cooling sequence from the hot end (T_eff_=~120000K) down to the DB gap (T_eff_=~45000K). From medium resolution optical spectra, effective temperatures, surface gravities, and element abundances are determined by means of non-LTE model atmospheres. Compared to previous LTE analyses available for some of the program stars, higher effective temperatures are derived. The existence of the DB gap is confirmed. For the first time reliable surface gravities for a large sample of DO white dwarfs are determined. With the help of theoretical evolutionary tracks the DO masses are determined. We find a mean value of 0.59+/-0.08Msun_ which virtually coincides with the mean masses of the DA and DB white dwarfs. Hydrogen cannot be identified in any optical DO spectrum, which includes the former DOA prototype HZ21. Hence HD149499B remains the only DO white dwarf with a positive (FUV) detection of trace hydrogen in the photosphere. The number ratio of DA/non-DA white dwarfs significantly increases along the cooling sequence and thus corroborates the hydrogen float-up hypothesis as an explanation for the DB gap. From optical, IUE, and HST spectra metal abundances or upper limits could be derived for most DOs, allowing a comprehensive comparison with predictions from diffusion/radiative levitation calculations. A large scatter in metallicities is found, even among objects with similar parameters and no clear trend along the cooling sequence is detectable. This is severely at odds with theoretical predictions. The evolutionary link between DO white dwarfs, the PG1159 stars and DB white dwarfs is discussed, in particular considering the overlapping positions of DO and PG1159 stars in the HR diagram. Title: Confining the edges of the GW Vir instability strip. Authors: Werner, K.; Dreizler, S.; Heber, U.; Rauch, T. Bibcode: 1996AGAb...12..198W Altcode: No abstract at ADS Title: On the hot ends of the white dwarf spectral sequences: Hot white dwarfs containing helium from the Hamburg-Schmidt survey. Authors: Heber, U.; Dreizler, S.; Hagen, H. -J. Bibcode: 1996A&A...311L..17H Altcode: We report on the discovery of twelve very hot white dwarf stars containing helium by follow-up spectroscopy of candidates selected by the Hamburg-Schmidt survey. These stars belong to the sparsely populated spectral subclasses DAO, DO and PG1159 tracing the hottest ends of the white dwarf spectral sequences. Eight stars show helium dominated spectra (four DOs, two PG1159 stars and two very hot DO/sdO transition objects). Four stars have hydrogen dominated spectra (DAO), out of which one is a spectroscopic binary. Metal absorption lines are detected in one DO and one DAO star. The latter is unique and has to be classified as the first known DAOZ star. Spectral comparison indicates that all stars lie beyond the DB gap with T_eff_ exceeding 45000K. Evidence is given for T_eff_ as high as 100000K or more in some stars. With these new discoveries the Hamburg-Schmidt survey has increased the number of known DO and DAO white dwarfs and PG1159 stars by 55%, 30% and 40%, respectively, an important step towards deriving statistically meaningful samples of the hottest white dwarfs. Title: Iron and nickel abundances of subluminous O-stars. I. NLTE-model atmospheres with line blanketing by iron group elements. Authors: Haas, S.; Dreizler, S.; Heber, U.; Jeffery, S.; Werner, K. Bibcode: 1996A&A...311..669H Altcode: NLTE model atmospheres for hot evolved stars including line blanketing of all iron group elements were first constructed by Dreizler & Werner (1993). In this paper we improve computational details and check the adopted simplifications. We also present a systematic investigation of the consequences of iron group line blanketing on the atmospheric structure (temperature stratification and ionization equilibria of iron and nickel) and for various observational quantities in the case of hot sdO model atmospheres. The inclusion of a vast number of iron group lines yields a substantial flux blocking in the vicinity of the He{2} 228A edge. The resulting effects on the optical line profiles of hydrogen and helium lines are none the less marginal. The most pronounced differences occur in the cores of these lines, in particular of the He{2} 4686A line. The new models are applied to an abundance analysis of Fe{5}, Fe{6} and Ni{6} lines in the high resolution IUE spectrum of the hot sdO star BD+28 4211. An underabundance of iron by 1dex with respect to the sun is found, while nickel displays a solar abundance. The reduced n_Fe_/n_Ni_ ratio (~1dex compared to the solar value) is an important hint that radiative levitation may hinder the gravitational settling of these species. It is demonstrated that the Fe{5}/Fe{6} ionization equilibrium is a reliable indicator for T_eff_ consistent with results from the optical He{1}/He{2} ionization equilibrium routinely used for spectroscopic analyses. Title: The Origin of the Peculiar Hybrid PG 1159 Stars Authors: Dreizler, S. Bibcode: 1996hst..prop.6463D Altcode: 1996hst..prop.2874D The PG 1159 stars form a new class of hydrogen deficient prewhite dwarfs (PWD) representing the hottest stage of PWDevolution. Quantitative spectral analyses of most knownPG 1159 stars have been carried out by the proposers fromoptical, UV (IUE, HST) and EUV (EUVE) observations. It hasbeen shown that these stars have atmospheres dominated by Cand He. In the hottest stars also a significant amount of O ispresent. The proposed targets, HS2324+3944, NGC7094, and Abell43define a small group of peculiar PG 1159 stars. Unlikeall other PG 1159 stars hydrogen is detected in their spectra.Stellar parameters derived by the investigators from opticalspectra suggest that, as a consequence of a lower mass, theywent through a less drastic mass-loss phase than the ordinaryPG 1159 stars. In order to verify that hypothesis a moreprecise determination of the effective temperature isrequired. This is not possible from optical analyses alone. Wedemonstrate that a great improvement on the determination ofthe effective temperatures can be achieved by HST-GHRSspectra. The spectra will be analyzed with new highlysophisticated NLTE line blanketed model atmospheres, whichallow to include many elements up to the iron group self-consistently. A precise placement of HS2324+3944, NGC7094, and Abell43in the HR-diagram holds the key for understanding theevolutionary history of the PG 1159 class. Title: Discovery and analysis of a hydrogen-rich PG1159 star. Authors: Dreizler, S.; Werner, K.; Heber, U.; Engels, D. Bibcode: 1996A&A...309..820D Altcode: The discovery of a new peculiar PG1159 star by follow-up spectroscopy of candidates selected from objective-prism plates of the Hamburg Schmidt Survey is presented. From a NLTE model atmosphere analysis an effective temperature of 130000+/-10000K and a surface gravity of logg=6.2+/-0.2 are determined, which together with the high carbon abundance place HS2324+3944 in the region of low gravity PG1159 stars. The detection of hydrogen, however, makes HS2324+3944 unique amongst the PG1159 stars. While three central stars of Planetary Nebulae have spectra similar to HS2324+3944, hydrogen could not be detected up to now in any PG1159 star not associated with a nebula. The abundances of helium, carbon and nitrogen (C/He=0.3, N/He<2x10^-3^) are similar to that of "normal" PG1159 stars while the O abundance is found to be somewhat lower than "normal" (O/He=2-10x10^-3^). Title: High resolution UV spectroscopy of two hot (pre-) white dwarfs with the Hubble Space Telescope. KPD0005+5106 and RXJ2117+3412. Authors: Werner, K.; Dreizler, S.; Heber, U.; Rauch, T.; Fleming, T. A.; Sion, E. M.; Vauclair, G. Bibcode: 1996A&A...307..860W Altcode: High resolution UV spectra of KPD0005+5106 and RXJ2117+3412 have been obtained with the Goddard High Resolution Spectrograph aboard the Hubble Space Telescope. The data were subject to a non-LTE model atmosphere analysis. For KPD0005+5106, the hottest known helium-rich white dwarf, the C and N abundances as well as an upper limit for O have been determined (log(C/He)=-3, log(N/He)=-6, log(O/He)<-5.5, by number), improving results from previous studies. These abundances are severely at odds with diffusion/radiative forces theory. They are possible primordial relics of their ancestral progenitor in the post-AGB phase. Besides the photospheric lines with a velocity shift of +35km/s we find a distinct interstellar/circumstellar absorption line system shifted by -15km/s. Difficulties are encountered with line profile fits to the spectrum of RXJ2117+3412, an extremely hot hydrogen-deficient (PG1159-type) central star. Some of the strong C IV and O VI lines are too narrow to match the observations. Either the neglect of wind-effects in our models or the lack of reliable line broadening data may be responsible for this. A weak O V 1371A line is detected which suggests, that the effective temperature is higher than thought before (T_eff_=170000K). This means that RXJ2117+3412 is the hottest known PG1159 star together with H1504+65. Interstellar and photospheric line spectra are clearly separated, with shifts of -19 and +23km/s, respectively. Both stars exhibit a strong O VIII emission line near 2977A, which cannot be of photospheric origin but probably arises from shock fronts along a stellar wind. The line widths are of the order of 150km/s. In addition, KPD0005+5106 shows another, equally strong emission feature near 2982A which either stems from photospheric N V or from non-photospheric C V. Title: Spectral analysis of hot helium-rich white dwarfs Authors: Dreizler, S.; Werner, K. Bibcode: 1996ASPC...96..281D Altcode: 1996hds..conf..281D No abstract at ADS Title: Confining the Edges of the GW VIR Instability Strip Authors: Werner, Klaus; Dreizler, Stefan; Heber, Ulrich; Rauch, Thomas Bibcode: 1996aeu..conf..229W Altcode: 1996IAUCo.152..229W No abstract at ADS Title: Helium-rich stars from the HS, PG and KPD surveys Authors: Heber, U.; Dreizler, S.; Werner, K.; Engels, D.; Hagen, H. -J. Bibcode: 1996ASPC...96..241H Altcode: 1996hds..conf..241H No abstract at ADS Title: NLTE spectral analysis of helium-rich sdO stars from the southern HK survey Authors: Drilling, J. S.; Napiwotzki, R.; Dreizler, S.; Heber, U.; Beers, T. C. Bibcode: 1996ASPC...96..317D Altcode: 1996hds..conf..317D No abstract at ADS Title: A catalogue of hydrogen-deficient stars Authors: Jeffery, C. S.; Heber, U.; Hill, P. W.; Dreizler, S.; Drilling, J. S.; Lawson, W. A.; Leuenhagen, U.; Werner, K. Bibcode: 1996ASPC...96..471J Altcode: 1996hds..conf..471J No abstract at ADS Title: PG 1159 stars Authors: Werner, K.; Dreizler, S.; Heber, U.; Rauch, T. Bibcode: 1996ASPC...96..267W Altcode: 1996hds..conf..267W No abstract at ADS Title: Ultra-high excitation features in hot white dwarfs: A DAO and three DO stars discovered by the Hamburg-Schmidt survey. Authors: Dreizler, S.; Heber, U.; Napiwotzki, R.; Hagen, H. J. Bibcode: 1995A&A...303L..53D Altcode: We report on the discovery of four hot white dwarfs, one DAO (HS2115+1148) and three DO (HS0158+2335, HS 0727+6003 and HS 2027+0651). The spectra of these stars exhibit shallow metal absorption lines from ultrahighly excited ionization stages (C V, C VI/N VI, N VII/O VII, O VIII, Ne IX, Ne X) with ionization energies ranging from 392eV to 1362eV. We propose that they are formed in a stellar wind, explaining their asymmetric shape. However, the He II line spectra of the three DOs as well as the Balmer-line spectrum of the DAO are peculiar and cannot be fitted by static NLTE model atmospheres. These stars increase the number of hot degenerate stars showing this phenomenon to six, this is the first time it is observed in a hydrogen-rich star. Thus, these six stars might constitute a new spectral subclass of hot white dwarfs suffering mass-loss from a hot and fast wind. Title: Spectral analysis of the hot DO white dwarf PG1034+001. Authors: Werner, K.; Dreizler, S.; Wolff, B. Bibcode: 1995A&A...298..567W Altcode: We present a non-LTE model atmosphere analysis of the hot DO white dwarf PG1034+001. It is based on archival HST GHRS spectra, on new optical medium resolution spectra and pointed ROSAT PSPC observations. The effective temperature is higher than previously thought (T_eff_=100000K, Logg=7.5). We determined abundances of carbon, nitrogen, and oxygen which are roughly in agreement with earlier LTE results. We also determined the silicon abundance and, for the first time in a DO white dwarf, the abundance of iron on hand of newly identified Fe VI lines in the HST spectra. An upper abundance limit for nickel is derived. The results are discussed in the framework of diffusion theory. We derive a stellar mass of 0.59Msun_ and propose that PG1034+001 is a descendant from the hydrogen-deficient PG1159 stars. Title: Detection of QSO Ton S 180 by the EUVE satellite. Authors: Wisotzki, L.; Dreizler, S.; Engels, D.; Fink, H. -H.; Heber, U. Bibcode: 1995A&A...297L..55W Altcode: We report the detection of the bright QSO Ton S 180 by the Extreme Ultraviolet Explorer satellite during its all-sky survey. The measured count rate is 58cts/ksec, more than any other QSO or Sy-1 listed by the First EUVE Source Catalog. We have compiled previously unpublished optical, ultraviolet, and X-ray observations of this source, and construct the continuum spectral energy distribution. The soft X-ray range is well described by a single power law with spectral energy index α=-2.0. Although different ROSAT pointings show that the total X-ray counts have varied by a factor of 3, the shape of the spectrum has remained unchanged. The EUVE flux is fully compatible with the ROSAT survey measurement, confirming that the power law shape reaches well into the EUV regime. No additional soft X-ray or EUV excess could be found. The optical-UV continuum displays a strongly convex shape, with a turnover in νxfnu_ already below 10eV. The overall shape of the continuum suggests that more than a single emission component contributes to the big blue bump. Title: Analysis of the DO White Dwarf PG 1034+001: Solution of the He II 4686 Å Line Problem Authors: Werner, Klaus; Dreizler, Stefan; Wolff, Burkhard Bibcode: 1995LNP...443..204W Altcode: 1995whdw.conf..204W No abstract at ADS Title: Iron- and Nickel Abundances of sdO Stars Authors: Haas, Stefan; Dreizler, Stefan; Heber, Ulrich; Meier, Thomas; Werner, Klaus Bibcode: 1995LNP...443..243H Altcode: 1995whdw.conf..243H No abstract at ADS Title: Confining the Edges of the GW VIR Instability Strip Authors: Werner, K.; Rauch, T.; Dreizler, S.; Heber, U. Bibcode: 1995ASPC...83...96W Altcode: 1995aasp.conf...96W; 1995IAUCo.155...96W No abstract at ADS Title: Discovery of two hot DO white dwarfs exhibiting ultrahigh-excitation absorption lines. Authors: Werner, K.; Dreizler, S.; Heber, U.; Rauch, T.; Wisotzki, L.; Hagen, H. -J. Bibcode: 1995A&A...293L..75W Altcode: We report on the detection of two faint blue stars (HE0504-2408 and HS0713+3958) discovered by the Hamburg Schmidt surveys whose spectra are dominated by broad and shallow metal absorption lines from ultrahighly excited ionization stages (CV, CVI/NVI, NVII/OVII, OVIII, NeIX, NeX) with ionization energies ranging from 392eV to 1362eV. Detailed non-LTE modeling excludes a photospheric origin of these lines. Instead we propose that they are formed in a stellar wind, explaining their asymmetric shape. The underlying stellar source is probably a hot helium-rich white dwarf (Teff about 70000K) causing the observed HeII line spectrum with symmetric profiles. However, the HeII absorptions are relatively strong and cannot simply be reproduced by a model atmosphere for a DO white dwarf. Thus, these two stars might constitute a new spectral subclass of hot helium-rich white dwarfs exhibiting spectral signatures never observed before in any astrophysical object. Title: Triple-Alpha Burning Products on the Surface of Peculiar Post-AGB Stars Authors: Werner, K.; Dreizler, S.; Heber, U.; Rauch, T. Bibcode: 1995AIPC..327...45W Altcode: 1995nct3.conf...45W The so-called PG 1159 stars form a new spectroscopic class of extremely hot hydrogen-deficient post-AGB stars. Our spectral analyses with model atmospheres show that their chemical surface composition is dominated by carbon, helium, and oxygen. We suggest that these peculiar stars have suffered a late helium-shell flash which has caused the removal of the hydrogen-rich envelope and even most of the helium-rich intershell matter. The idea that the former helium-burning region is now exposed at the surface of the PG 1159 stars is supported by the recent detection of a very high amount of neon in some objects. The most extreme object is H1504+65 which is one of the brightest X-ray sources in the sky and the hottest star ever analyzed with model atmosphere techniques (Teff=170 000 K). The photosphere is devoid of hydrogen and helium and composed of oxygen and carbon by equal amounts! This means that we look at the naked core of the former Red Giant. This gives us the unique possibility to confine empirically the still uncertainty known 12C(α,γ)16O nuclear reaction rate. Title: Detection of Ultra-Hot Pre-White Dwarfs? Authors: Werner, Klaus; Rauch, Thomas; Dreizler, Stefan; Heber, Ulrich Bibcode: 1995LNP...443..171W Altcode: 1995whdw.conf..171W No abstract at ADS Title: The EUVE spectrum of the hot DA white dwarf PG 1234+482 Authors: Jordan, Stefan; Koester, Detlev; Finley, David; Werner, Klaus; Dreizler, Stefan Bibcode: 1995LNP...443..332J Altcode: 1995whdw.conf..332J We have analyzed the EUVE spectrum of PG 1234+482 with fully blanketed model atmospheres taking into account several million lines of heavy elements. Most of the spectral features in the short (SW) and medium (MW) wavelength spectrum can be identified with lines of iron, nickel and calcium ions. Title: PG 1159 Stars and Their Evolutionary Link to DO White Dwarfs Authors: Dreizler, Stefan; Werner, Klaus; Heber, Ulrich Bibcode: 1995LNP...443..160D Altcode: 1995whdw.conf..160D No abstract at ADS Title: Stratification of helium in the photospheres of the helium-weak stars HD 28843 and HD 49333. Authors: Farthmann, M.; Dreizler, S.; Heber, U.; Hunger, K. Bibcode: 1994A&A...291..919F Altcode: For four helium-weak and variable B stars phase-dependent high-resolution spectrograms have been obtained with the Echelec-spectrograph attached to the 1.5 m ESO telescope, with the aim of testing whether HeI 4471A will give evidence of chemical stratification within their photospheres. Of the four candidates, HR 3448=HD 74196 is a fast rotator (vsini=300km/s), however, no variability is detectable, while HR 1100=HD 22470 does not exhibit any helium line (posibly due to incomplete phase coverage). Only HR 1441=HD 28843 and HR 2509=HD 49333 are genuine helium variables. Profile analyses of HeI 4471, based on fully line blanketed model atmospheres which are adapted to the relevant helium-content show that HD 28843 can fully be explained by a cap model with two asymmetrically located helium caps of equal radii. For HD 49333 vertical stratification in addition has to be assumed in order to explain the excessively broad wings. This confirms earlier (preliminary) results by Groote et al. (see Hunger 1986). Vertical stratification is infered for both inside and outside the helium-caps of HD 49333. Title: On the nickel abundance in hot hydrogen-rich white dwarfs. Authors: Werner, K.; Dreizler, S. Bibcode: 1994A&A...286L..31W Altcode: We present a non-LTE iron and nickel abundance analysis of four hot hydrogen rich white dwarfs from high resolution IUE spectra. The investigation aims at the determination of the Ni/Fe ratio in order to investigate if radiative acceleration prevents gravitational settling of both elements. We succeeded in the first identification of nickel lines in white dwarfs. In fact we find enhanced Ni/Fe ratios (compared to the solar value) in the two extremely iron rich (for white dwarf standards) stars RE0623--377 and RE2214--2 The effect is slightly smaller in the other two objects considered (G191-B2B and Feige24). This is regarded as evidence that radiation pressure acting through the huge number of spectral lines is responsible for radiative levitation of iron and nickel. Title: A "cool" PG 1159 star discovered by the Hamburg Schmidt Survey: NLTE analysis of HS 0704+6153. Authors: Dreizler, S.; Werner, K.; Jordan, S.; Hagen, H. Bibcode: 1994A&A...286..463D Altcode: The discovery of a new PG 1159 star by follow-up spectroscopy of candidates selected from objective-prism plates of the Hamburg Schmidt Survey is presented. From a NLTE model atmosphere analysis an effective temperature of 65 000 K and a surface gravity of logg=7.0 is determined, which together with the extreme helium abundance (H/He<1 by number) place HS 0704+6153 in the region of hot DO white dwarfs. The high carbon and oxygen abundances (C/He=0.2, O/He~0.05 by number), however, are typical for PG 1159 stars. Its effective temperature is by far lower than that of any other PG 1159 star. HS 0704+6153 therefore is in the transition stage between the PG 1159 stars and the DO white dwarfs, it hence is an ideal object to study the gravitational settling of metals in helium-rich atmospheres. Title: PG 2120+062 : an apparently normal O-star at high galactic latitude. Authors: Moehler, S.; Heber, U.; Dreizler, S. Bibcode: 1994A&A...282L..29M Altcode: We report the spectroscopic identification of the faint blue star PG 2120+062 (V = 14.4 m) as an apparently normal O9 star. If massive, PG 2120+062 would be at a distance of 50 kpc and 25 kpc below the galactic plane. Teff = 38000 K, log g = 4.25 results from a nonlocal thermodynamic equilibrium (NLTE) model atmosphere analysis. PG 2120+062 could, however, also be a low mass post-AGB star at a distance of 5 kpc that mimics a normal O star spectroscopically. Variable H-alpha emission is interpreted as due to a circumstellar disk (Be star phenomenon) or a close companion star. In the latter case, the primary to secondary mass ratio would be very large Mp/Ms greater than 7) and PG 2120+062 could be the progenitor of a symbiotic star or a cataclysmic variable. Title: PG 1159 stars and their evolutionary link to DO white dwarfs. Authors: Dreizler, S.; Werner, K.; Heber, U. Bibcode: 1994AGAb...10...62D Altcode: No abstract at ADS Title: PG 2120+062: an apparently normal O-star at high galactic latitude. Authors: Moehler, S.; Heber, U.; Dreizler, S. Bibcode: 1994AGAb...10...34M Altcode: No abstract at ADS Title: Faint Blue Stars from the Hamburg Schmidt Survey Authors: Dreizler, Stefan; Heber, Uli; Jordan, S.; Engels, D. Bibcode: 1994hsgh.conf..228D Altcode: No abstract at ADS Title: On the Evolutionary Link Between the PG 1159 Stars and the DO White Dwarfs Authors: Dreizler, S. Bibcode: 1994iue..prop.4896D Altcode: No abstract at ADS Title: Quantitative Spectroscopy of the Very Hot Subluminous O-Stars: K648 PG1159-035, and KPD0005+5106 Authors: Heber, Ulrich; Dreizler, Stefan; Werner, Klaus Bibcode: 1994hsgh.conf..187H Altcode: No abstract at ADS Title: Detection of a possible new ultra-hot pre-white dwarf. Authors: Werner, K.; Dreizler, S.; Heber, U.; Rauch, T.; Wisotzki, L. Bibcode: 1994AGAb...10...58W Altcode: No abstract at ADS Title: Line blanketing by iron group elements in non-LTE model atmospheres of hot stars. Authors: Dreizler, S.; Werner, K. Bibcode: 1994ems..conf..147D Altcode: The authors report on their recent progress in modeling non-LTE atmospheres of O-stars including blanketing by lines from the iron group elements. The numerical method to account for the huge number of atomic levels and line transitions is presented. Results of exploratory model calculations examining the effects on the temperature structure, the hydrogen and helium line profiles and UV/EUV fluxes are discussed. Title: Quantitative Spectroscopy of K 648 --the PNN of Ps1 in the Globular Cluster M15 Authors: Heber, Ulrich; Dreizler, Stefan; Werner, Klaus Bibcode: 1993AcA....43..337H Altcode: We report preliminary results of a quantitative study of high resolution UV and optical spectra of K648 obtained with the Hubble Space Telescope and the Calar Alto 3.5 m telescope, respectively. Using state of the art NLTE model- atmospheres we determine atmospheric parameters and the abundances of hydrogen, helium and carbon. K648 is found to be helium- and carbon-rich when compared to solar composition. Title: Two New Extremely Iron-rich Hot DA White Dwarfs and the Nature of the EUV Opacity Authors: Holberg, J. B.; Barstow, M. A.; Buckley, D. A. H.; Chen, A.; Dreizler, S.; Marsh, M. C.; O'Donoghue, D.; Sion, E. M.; Tweedy, R. W.; Vauclair, G.; Werner, K. Bibcode: 1993ApJ...416..806H Altcode: We have obtained IUE echelle spectra of two bright extreme ultraviolet (EUV) sources discovered by the ROSAT wide field camera all-sky survey. These stars, RE 2214-492 and RE 0623-377, are previously uncataloged hot DA white dwarfs with respective apparent visual magnitudes of 11.71 and 12.09 and exhibit short-wavelength EUV cutoffs steeper than most other DAs. The IUE echelle spectra are rich in absorption lines due to a large number of Fe V and Fe VI features, in addition to the highly ionized C, N, O ions frequently seen in other hot DA white dwarfs. No He is observed in either star. Comparison of RE 2214-492 and RE 0623-377 with two well-studied hot DA white dwarfs, G191 B2B and Feige 24, indicates that these new stars are both significantly hotter and more metal-rich than G191 B2B and Feige 24. From optical and UV line profiles we find Teff = 63,500 K and 60,300 K for RE 2214-492 and RE 0623-377, respectively. From modeling of Fe V features in the echelle spectra we find corresponding Fe abundances of log [N(Fe)/ n(H)] = -4.25±0.25. The association of steep EUV cutoffs in these stars, and in G191 B2B and Feige 24, with the observed presence of Fe suggests that iron-group elements along with other heavy elements are responsible for much of the EUV opacity observed by ROSA T in the hottest DA stars. Title: Line blanketing by iron group elements in non-LTE model atmospheres for hot stars. Authors: Dreizler, S.; Werner, K. Bibcode: 1993A&A...278..199D Altcode: We present the first metal line blanketed non-Local Thermodynamic Equilibrium (LTE) model atmospheres for O stars which include 130,000 lines of the iron group elements scandium through nickel, a subset from Kurucz' (1991) line list, fully self-consistently. It is shown that even the treatment of the complete line list (greater than 106 lines) in NLTE models poses no longer any fundamental problem. The numerical solution of the metal line blanketing problem consists of an opacity sampling technique within the framework of the Accelerated Lambda Iteration method. Exploratory models with different parameters were successfully constructed, e.g. for hot subdwarfs and central stars of planetary nebulae as well as for white dwarfs. We discuss the blanketing effects of metal lines (1) onto the atmospheric stratification, (2) onto UV and EUV fluxes, (3) onto the emergent H and He line profiles, and (4) the potential of iron lines as sensitive temperature indicators. The models are used to interprete EUV observations of the white dwarf G191-B2B and UV spectra of the hot sdO star BD+28 deg 4211. Title: Metal Line Blanketed Non-LTE Model Atmospheres for Planetary Nebula Nuclei Authors: Werner, K.; Dreizler, S. Bibcode: 1993AcA....43..321W Altcode: We report on our recent progress in modeling non-LTE central star atmospheres including blanketing by lines from the iron group elements. It is found that the spectroscopic analysis of the hottest stars (Teff approx 90,000 K) based on hydrogen Balmer and HeII lines is hardly affected by metal opacities in the models. As a consequence, results from earlier analyses based on models composed of hydrogen and helium only remain essentially unchanged. Title: Spectral analysis of extremely helium rich subdwarfs O-stars. Authors: Dreizler, S. Bibcode: 1993A&A...273..212D Altcode: The NLTE analyses of four extremely helium rich sdO stars based on high resolution, high S/N CASPEC spectra are presented. Effective temperatures, gravities and the abundances of H, He, C, N, O, Ne, Mg, and Si have been deter- mined. It is found that LSIV+1O°9, LSS 1274, and UV 0832-01 have very similar parameters: Teff = 44500±1000 K, log g = 5.55±0.15. H is undetected in all programme stars resulting in a upper limit of nH/nHe ≤ 0.1. C, N, and Ne are enriched, while Mg and Si are solar and O is slightly depleted. Microturbulent velocity is found to be lower than to km/s. The positions of these stars in the (log Teff,log g) diagram indicate, that they are post-EHB (Extended Horizontal Branch) stars. Their atmospheric composition can be understood as a mixture of CNO and 3 - α processed material. UV 0904-02 is slightly hotter, Teff = 46500±1000 K, log g = 5.55±0.15, and is as well a post-EHB star. The atmosphere also displays a mixture of CNO and 3-α processed material, the primordial metallicity however, was possibly lower. Title: Line blanketing by iron group elements in non-LTE model atmospheres of hot stars Authors: Dreizler, Stefan; Werner, Klaus Bibcode: 1993SSRv...66..147D Altcode: We report on our recent progress in modeling non-LTE atmospheres of O-stars including blanketing by lines from the iron group elements. The numerical method to account for the huge number of atomic levels and line transitions is presented. Results of exploratory model calculations examining the effects on the temperature structure, the hydrogen and helium line profiles and UV/EUV fluxes are discussed. Title: Faint blue stars from the Hamburg Schmidt Survey. Authors: Dreizler, S.; Heber, U.; Jordan, S. Bibcode: 1993AGAb....9..152D Altcode: No abstract at ADS Title: Metal Line Blanketed Non-LTE Model Atmospheres for Central Stars of Planetary Nebulae Authors: Werner, K.; Dreizler, S. Bibcode: 1993IAUS..155...83W Altcode: No abstract at ADS Title: Line blanketing by iron group elements in non-LTE model atmospheres for hot stars. Authors: Haas, S.; Dreizler, S.; Werner, K. Bibcode: 1993AGAb....9..153H Altcode: No abstract at ADS Title: High resolution optical and UV spectroscopy of the central star of K648. Authors: Heber, U.; Dreizler, S.; Werner, K. Bibcode: 1993AGAb....9...70H Altcode: No abstract at ADS Title: Metal line blanketing in non-LTE model atmospheres Authors: Dreizler, S.; Werner, K. Bibcode: 1993ASIC..403..205D Altcode: 1993wdao.conf..205D No abstract at ADS Title: NLTE analysis of extremely helium rich subdwarf O stars Authors: Dreizler, S. Bibcode: 1993ASIC..403..287D Altcode: 1993wdao.conf..287D No abstract at ADS Title: High Resolution UV Spectroscopy of 3 Metal Weak LIned SdO Stars Authors: Dreizler, S. Bibcode: 1993iue..prop.4737D Altcode: No abstract at ADS Title: NLTE analysis of helium rich subdwarf O stars Authors: Dreizler, S. Bibcode: 1992LNP...401..270D Altcode: 1992aets.conf..270D No abstract at ADS Title: Iron line blanketing in NLTE model atmospheres for O stars: First results Authors: Dreizler, S.; Werner, K. Bibcode: 1992LNP...401..436D Altcode: 1992aets.conf..436D No abstract at ADS Title: Non-Lte Model Atmosphere Calculations with Approximate Lambda Operators Authors: Dreizler, S.; Werner, K. Bibcode: 1991ASIC..341..155D Altcode: 1991sabc.conf..155D No abstract at ADS Title: Non-LTE Sternatmosphärenmodelle für heliumreiche Sterne des Spektraltyps sd0 Title: Non-LTE Sternatmosphärenmodelle für heliumreiche Sterne des Spektraltyps sd0 Title: Non-LTE stellar atmosphere models for helium-rich stars of spectral type sd0; Authors: Dreizler, Stefan Bibcode: 1991PhDT.......156D Altcode: No abstract at ADS Title: Hot subluminous stars at high galactic latitudes. III. Non-LTE analysis of extremely helium rich sdO-stars. Authors: Dreizler, S.; Heber, U.; Werner, K.; Moehler, S.; de Boer, K. S. Bibcode: 1990A&A...235..234D Altcode: The visual spectra of 15 extremely helium rich subdwarf O-stars are analyzed. Effective temperatures and gravities are determined by means of a new grid of helium and hydrogen line-blanketed non-LTE model atmospheres calculated with the accelerated lambda iteration. Effective temperatures cluster around 45,000 K and 65,000 K. Gravities range from log g = 4.8 to log g = 6.0. Hydrogen is detected in 5 stars. Upper limits to the hydrogen content are derived for the others. From these spectroscopic results first conclusions about the evolutionary status of these stars can be drawn. The program stars probably evolve from the extended or blue horizontal branch. Mixing induced by thermal pulses might account for the helium enrichment. Title: NLTE model atmospheres for He-rich sdO-stars. Authors: Dreizler, S.; Heber, U.; Werner, K. Bibcode: 1990AGAb....5...16D Altcode: No abstract at ADS Title: Non-LTE model atmospheres for hot evolved stars. Authors: Werner, K.; Dreizler, S.; Heber, U.; Hunger, K.; Rauch, T. Bibcode: 1990nba..meet..379W Altcode: 1990taco.conf..379W During the last years the authors have developed a computer code to construct non-LTE model atmospheres for hot stars including line blanketing effects. The particular methods gave way to the computation of non-LTE model atmospheres which account for many more opacity sources than could be treated within the classical complete linearisation approach by Auer and Mihalas. With this code it became possible for the first time to calculate grids of realistic non-LTE line blanketed model atmospheres for subdwarf O-stars in a critical temperature range as well as for the extremely hot (100,000K to 150,000K) so-called PG1159 stars. Both groups of stars consist of objects being in advanced evolutionary stages representing immediate White Dwarf progenitors. The atmospheres of these stars are enriched or even dominated by nuclear processed material, namely either by helium (sdO stars) or also by carbon and oxygen (PG1159 stars). Title: NLTE-analysis of extremely helium-rich sd0 stars Authors: Dreizler, S.; Heber, U.; Werner, K.; de Boer, K. S.; Moehler, S. Bibcode: 1989AGAb....3...45D Altcode: No abstract at ADS Title: NLTE-analysis of extremely helium-rich sdO-stars. Authors: Dreizler, S.; Heber, U.; Werner, K.; de Boer, K. S.; Moehler, S. Bibcode: 1989AGAb....3...44D Altcode: No abstract at ADS Title: Spectroscopy of helium-rich subluminous O and B stars. Authors: Heber, U.; Dreizler, S.; de Boer, K. S.; Moehler, S.; Richtler, T. Bibcode: 1988AGAb....1...16H Altcode: No abstract at ADS