strassmeier

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Author name code: strassmeier
ADS astronomy entries on 2022-09-14
author:"Strassmeier, Klaus G."

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Title: The Great Dimming of Betelgeuse: A Surface Mass Ejection and
Its Consequences
Authors: Dupree, Andrea K.; Strassmeier, Klaus G.; Calderwood, Thomas;
Granzer, Thomas; Weber, Michael; Kravchenko, Kateryna; Matthews,
Lynn D.; Montargès, Miguel; Tappin, James; Thompson, William T.
2022ApJ...936...18D Altcode: 2022arXiv220801676D
The bright supergiant, Betelgeuse (Alpha Orionis, HD 39801), underwent
a historic optical dimming during 2020 January 27-February 13. Many
imaging and spectroscopic observations across the electromagnetic
spectrum were obtained prior to, during, and subsequent to this dimming
event. These observations of Betelgeuse reveal that a substantial
surface mass ejection (SME) occurred and moved out through the extended
atmosphere of the supergiant. A photospheric shock occurred in 2019
January-March, progressed through the extended atmosphere of the
star during the following 11 months and led to dust production in the
atmosphere. Resulting from the substantial mass outflow, the stellar
photosphere was left with lower temperatures and the chromosphere
with a lower density. The mass ejected could represent a significant
fraction of the total annual mass-loss rate from the star suggesting
that episodic mass-loss events can contribute an amount comparable to
that of the stellar wind. Following the SME, Betelgeuse was left with a
cooler average photosphere, an unusual short photometric oscillation,
reduced velocity excursions, and the disappearance of the ~400 day
pulsation in the optical and radial velocity for more than two years
following the Great Dimming.

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Title: The recurrent nova V3890 Sgr: a near-infrared and optical
study of the red giant component and its environment
Authors: Kaminsky, B.; Evans, A.; Pavlenko, Ya V.; Woodward, C. E.;
Banerjee, D. P. K.; Gehrz, R. D.; Walter, F.; Starrfield, S.; Ilyin,
I.; Strassmeier, K. G.; Wagner, R. M.
2022MNRAS.tmp.2296K Altcode: 2022arXiv220714721K
We present an analysis of the red giant component of the recurrent nova
V3890 Sgr, using data obtained before and after its 2019 eruption. Its
effective temperature is Teff = 3050 ±200 K for log g =
0.7, although there are modest changes in Teff. There is
an overabundance of both carbon (0.20 ± 0.05 dex) and sodium (1.0
± 0.3 dex) relative to their solar values, possibly the result of
ejecta from the 1990 nova eruption being entrained into the red giant
photosphere. We find 12C/13C =25 ± 2, a value
similar to that found in red giants in other recurrent novae. The
interpretation of the quiescent spectrum in the 5-38 μm region
requires the presence of photospheric SiO absorption and cool (~400
K) dust in the red giant environment. The spectrum in the region of
the Na I D lines is complex, and includes at least six interstellar
components, together with likely evidence for interaction between
ejecta from the 2019 eruption and material accumulated in the plane
of the binary. Three recurrent novae with giant secondaries have been
shown to have environments with different dust content, but photospheres
with similar 12C/13C ratios. The SiO fundamental
bands most likely have a photospheric origin in the all three stars.

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Title: The Origin of Weakened Magnetic Braking in Old Solar Analogs
Authors: Metcalfe, Travis S.; Finley, Adam J.; Kochukhov, Oleg; See,
Victor; Ayres, Thomas R.; Stassun, Keivan G.; van Saders, Jennifer L.;
Clark, Catherine A.; Godoy-Rivera, Diego; Ilyin, Ilya V.; Pinsonneault,
Marc H.; Strassmeier, Klaus G.; Petit, Pascal
2022ApJ...933L..17M Altcode: 2022arXiv220608540M
The rotation rates of main-sequence stars slow over time as they
gradually lose angular momentum to their magnetized stellar winds. The
rate of angular momentum loss depends on the strength and morphology
of the magnetic field, the mass-loss rate, and the stellar rotation
period, mass, and radius. Previous observations suggested a shift in
magnetic morphology between two F-type stars with similar rotation
rates but very different ages (88 Leo and ρ CrB). In this Letter, we
identify a comparable transition in an evolutionary sequence of solar
analogs with ages between 2-7 Gyr. We present new spectropolarimetry of
18 Sco and 16 Cyg A and B from the Large Binocular Telescope, and we
reanalyze previously published Zeeman Doppler images of HD 76151 and
18 Sco, providing additional constraints on the nature and timing of
this transition. We combine archival X-ray observations with updated
distances from Gaia to estimate mass-loss rates, and we adopt precise
stellar properties from asteroseismology and other sources. We then
calculate the wind braking torque for each star in the evolutionary
sequence, demonstrating that the rate of angular momentum loss drops
by more than an order of magnitude between the ages of HD 76151 and
18 Sco (2.6-3.7 Gyr) and continues to decrease modestly to the age
of 16 Cyg A and B (7 Gyr). We suggest that this magnetic transition
may represent a disruption of the global dynamo arising from weaker
differential rotation, and we outline plans to probe this phenomenon
in additional stars spanning a wide range of spectral types.

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Title: The Spectroscopic Evolution of V1674 Hercules: The Fastest
Nova Ever
Authors: Starrfield, Sumner; Woodward, Charles E.; Perron, Isabelle;
Wagner, R. Mark; Page, Kim; Strassmeier, Klaus; Ilyin, Ilya
2022AAS...24034604S Altcode:
V1674 Her (Nova Her 2021) was discovered in outburst on 2021 June 12
and reached a peak brightness of V ~ 6. It then declined extremely
rapidly falling 2 magnitudes in 1.2 days. It was followed at high
cadence by a slew of ground and space based observatories with numerous
publications ensuing. These observations found that in addition to the
fastest decline on record, it was an ONe type nova exhibiting strong
forbidden Ne emission lines, and it exhibited a 501 s oscillation
that suggested that the outburst occurred in an intermediate polar
system. Moreover, the ejection velocities were of the order of 6000
km/s. We have continued to monitor it as it returned to quiescence and
will present the optical spectra collected for this nova, plus any
new data at other wavelengths, that we obtain after the submission
of this abstract. Our optical data have been collected on 22 epochs
to date at spectral resolutions ranging from 1700 to 130,000 with
facilities of the MDM, MMT, and LBT observatories. Our latest spectrum,
obtained with the MDM 2.4-m Hiltner telescope and OSMOS spectrograph
(2022 March 27 UT), after it emerged from solar conjunction, show a
dramatic change in that the forbidden lines have disappeared and He II
4686 Ang is the strongest emission line in the spectrum superposed on
a blue continuum. We will discuss the implications of this change. We
are grateful to all the facilities for their support of observing time.

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Title: Nodal Precession and Tidal Evolution of KELT-9 b and WASP-33 b
Authors: Stephan, Alexander P.; Wang, Ji; Cauley, Paul W.; Gaudi,
B. Scott; Ilyin, Ilya; Johnson, Marshall; Strassmeier, Klaus
2022BAAS...54e4601S Altcode:
Hot Jupiters provide important insights into planetary formation,
migration, atmospheric composition, and star-planet tidal
interactions. Of special interest are Hot Jupiters with strongly
misaligned orbits to their host stars' spin axis, which generally
induces strong nodal precession of the planetary orbits, measurable via
the Doppler Tomography technique. Here we present new results for the
nodal precession of KELT-9 b, derived from new PEPSI/LBT observations
and archival data covering a time span of 7 years. We measure the
stellar gravitational quadrupole moment, J2, the stellar oblateness
and spin rate, and true spin-orbit misalignment to a high degree of
accuracy. We confirm the validity of our methodology by also analyzing
the previously studied WASP-33 system, using new PEPSI/LBT observations
and archival data covering a time span of 11 years. We conclude that
both KELT-9 b and WASP-33 b will cease to transit their host stars by
the end of the 21st century. Based on their tidal dynamics,
we estimate the expected remaining life spans of both planets as well
as speculate on their likely dynamical origins.

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Title: Nodal Precession and Tidal Evolution of KELT-9 b and WASP-33 b
Authors: Stephan, Alexander P.; Wang, Ji; Cauley, Paul W.; Gaudi,
B. Scott; Ilyin, Ilya; Johnson, Marshall; Strassmeier, Klaus
2022AAS...24041801S Altcode:
Hot Jupiters provide important insights into planetary formation,
migration, atmospheric composition, and star-planet tidal
interactions. Of special interest are Hot Jupiters with strongly
misaligned orbits to their host stars' spin axis, which generally
induces strong nodal precession of the planetary orbits, measurable via
the Doppler Tomography technique. Here we present new results for the
nodal precession of KELT-9 b, derived from new PEPSI/LBT observations
and archival data covering a time span of 5 years. We measure the
stellar gravitational quadrupole moment, J2, the stellar oblateness
and spin rate, and true spin-orbit misalignment to a high degree of
accuracy. We confirm the validity of our methodology by also analyzing
the previously studied WASP-33 system, using new PEPSI/LBT observations
and archival data covering a time span of 11 years. We conclude that
both KELT-9 b and WASP-33 b will cease to transit their host stars by
the end of the 21st century. Based on their tidal dynamics,
we estimate the expected remaining life spans of both planets as well
as speculate on their likely dynamical origins.

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Title: Variable and super-sonic winds in the atmosphere of an
ultra-hot giant planet
Authors: Pai Asnodkar, Anusha; Wang, Ji; Eastman, Jason; Cauley,
Paul; Gaudi, B. Scott; Ilyin, Ilya; Strassmeier, Klaus
2022BAAS...54e.188P Altcode:
Hot Jupiters (HJs) present an extreme case for exploring the
conditions that regulate planetary atmospheres because they experience
intense irradiation from their host stars that induces global-scale
winds. General circulation models (GCMs) of HJ atmospheres predict
day-to-nightside winds (winds flowing from the side of the planet
facing its host star to the side facing away from the star) and
equatorial jets (winds that entirely circulate around the planet)
with speeds on the order of a few km/s. We apply high-resolution
transmission spectroscopy using the PEPSI spectrograph on the Large
Binocular Telescope to empirically constrain supersonic ~10 km/s
day-to-nightside winds traced by Fe II features in the atmosphere of
KELT-9 b, an ultra-hot Jupiter (UHJ) that remains to-date the hottest
known planet. Reconciling our findings with archival HARPS-N datasets
suggests multi-epoch variability ~5-8 km/s over timescales between
weeks to years. We compare with the UHJ KELT-20 b to demonstrate the
exceptional nature of KELT-9 b's atmospheric dynamics. A qualitative
evaluation of our measured wind velocities and variability against
current UHJ GCMs reveals that KELT-9 b poses unique challenges for
validating giant planet atmospheric models.

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Title: Characterization of chromospheric activity based on
Sun‑as‑a‑star spectral and disk‑resolved activity indices
Authors: Dineva, Ekaterina; Pearson, Jeniveve; Ilyin, Ilya; Verma,
Meetu; Diercke, Andrea; Strassmeier, Klaus G.; Denker, Carsten
2022AN....34323996D Altcode: 2022arXiv220606076D
The strong chromospheric absorption lines Ca H &amp; K are tightly
connected to stellar surface magnetic fields. Only for the Sun, spectral
activity indices can be related to evolving magnetic features on the
solar disk. The Solar Disk-Integrated (SDI) telescope feeds the Potsdam
Echelle Polarimetric and Spectroscopic Instrument (PEPSI) of the Large
Binocular Telescope (LBT) at Mt. Graham International Observatory
(MGIO), Arizona, U.S.A. We present high-resolution, high-fidelity
spectra that were recorded on 184 &amp; 82 days in 2018 &amp; 2019 and
derive the Ca H &amp; K emission ratio, i.e., the S-index. In addition,
we compile excess brightness and area indices based on full-disk Ca
K line-core filtergrams of the Chromospheric Telescope (ChroTel) at
Observatorio del Teide, Tenerife, Spain and full-disk ultraviolet (UV)
1600~Å images of the Atmospheric Imaging Assembly (AIA) on board the
Solar Dynamics Observatory (SDO). Thus, Sun-as-a-star spectral indices
are related to their counterparts derived from resolved images of
the solar chromosphere. All indices display signatures of rotational
modulation, even during the very low magnetic activity in the minimum
of Solar Cycle 24. Bringing together different types of activity
indices has the potential to join disparate chromospheric datasets,
yielding a comprehensive description of chromospheric activity across
many solar cycles.

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Title: A Search for Temperature Inversion Agents in KELT-20b with
LBT/PEPSI
Authors: Johnson, Marshall C.; Wang, Ji; Pai Asnodkar, Anusha;
Strassmeier, Klaus; Ilyin, Ilya
2022BAAS...54e.028J Altcode:
The existence of temperature inversions in the atmospheres of hot
Jupiters has long been a controversial topic, but there is growing
evidence that at least some ultra hot Jupiters possess inverted
atmospheric profiles. In most cases, however, it is unclear what
chemical agents are responsible for the inversions. Most previous
searches for inversion agents have been through transmission
spectroscopy, but this method typically probes lower pressure levels
than those where inversion agents are expected to occur. Emission
spectroscopy, on the other hand, is more technically challenging
but directly probes the altitudes inhabited by inversion agents. We present a search for inversion agents in the ultra hot Jupiter
KELT-20b/MASCARA-2b using both emission and transmission spectroscopy
with the PEPSI high-resolution spectrograph on LBT. An atmospheric
inversion was recently detected on this planet by several authors using
the spectra of several different atomic and molecular species. We search
for inversion agents including TiO, VO, and FeH using cross-correlation
methodology. The use of both emission and transmission data allows us
to set stringent limits upon the presence of these species at multiple
levels in the atmosphere.

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Title: The PEPSI exoplanet transit survey (PETS) I: investigating
the presence of a silicate atmosphere on the super-earth 55 Cnc e
Authors: Keles, Engin; Mallonn, Matthias; Kitzmann, Daniel;
Poppenhaeger, Katja; Hoeijmakers, H. Jens; Ilyin, Ilya; Alexoudi,
Xanthippi; Carroll, Thorsten A.; Alvarado-Gomez, Julian; Ketzer, Laura;
Bonomo, Aldo S.; Borsa, Francesco; Gaudi, B. Scott; Henning, Thomas;
Malavolta, Luca; Molaverdikhani, Karan; Nascimbeni, Valerio; Patience,
Jennifer; Pino, Lorenzo; Scandariato, Gaetano; Schlawin, Everett;
Shkolnik, Evgenya; Sicilia, Daniela; Sozzetti, Alessandro; Foster,
Mary G.; Veillet, Christian; Wang, Ji; Yan, Fei; Strassmeier, Klaus G.
2022MNRAS.513.1544K Altcode: 2022MNRAS.tmp..838K; 2022arXiv220316856K
The study of exoplanets and especially their atmospheres can reveal
key insights on their evolution by identifying specific atmospheric
species. For such atmospheric investigations, high-resolution
transmission spectroscopy has shown great success, especially for
Jupiter-type planets. Towards the atmospheric characterization of
smaller planets, the super-Earth exoplanet 55 Cnc e is one of the
most promising terrestrial exoplanets studied to date. Here, we
present a high-resolution spectroscopic transit observation of this
planet, acquired with the PEPSI instrument at the Large Binocular
Telescope. Assuming the presence of Earth-like crust species on the
surface of 55 Cnc e, from which a possible silicate-vapor atmosphere
could have originated, we search in its transmission spectrum for
absorption of various atomic and ionized species such as Fe , Fe
+, Ca , Ca +, Mg, and K , among others. Not
finding absorption for any of the investigated species, we are able to
set absorption limits with a median value of 1.9 × RP. In
conclusion, we do not find evidence of a widely extended silicate
envelope on this super-Earth reaching several planetary radii.

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Title: Nodal Precession and Tidal Evolution of Two Hot Jupiters:
WASP-33 b and KELT-9 b
Authors: Stephan, Alexander P.; Wang, Ji; Cauley, P. Wilson; Gaudi,
B. Scott; Ilyin, Ilya; Johnson, Marshall C.; Strassmeier, Klaus G.
2022ApJ...931..111S Altcode: 2022arXiv220302546S
Hot Jupiters orbiting rapidly rotating stars on inclined orbits
undergo tidally induced nodal precession measurable over several
years of observations. The Hot Jupiters WASP-33 b and KELT-9 b are
particularly interesting targets because they are among the hottest
planets found to date, orbiting relatively massive stars. Here, we
analyze archival and new data that span 11 and 5 yr for WASP-33 b
and KELT-9 b, respectively, in order to model and improve upon their
tidal precession parameters. Our work confirms the nodal precession
for WASP-33 b and presents the first clear detection of the precession
of KELT-9 b. We determine that WASP-33 and KELT-9 have gravitational
quadrupole moments $({6.3}_{-0.8}^{+1.2})\times {10}^{-5}$ and
$({3.26}_{-0.80}^{+0.93})\times {10}^{-4}$ , respectively. We estimate
the planets' precession periods to be ${1460}_{-130}^{+170}$ yr and
${890}_{-140}^{+200}$ yr, respectively, and that they will cease
to transit their host stars around the years ${2090}_{-10}^{+17}$
CE and ${2074}_{-10}^{+12}$ CE, respectively. Additionally, we
investigate both planets' tidal and orbital evolution, suggesting that a
high-eccentricity tidal migration scenario is possible to produce both
system architectures and that they will most likely not be engulfed
by their hosts before the end of their main-sequence lifetimes.

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Title: An Aligned Orbit for the Young Planet V1298 Tau b
Authors: Johnson, Marshall C.; David, Trevor J.; Petigura, Erik A.;
Isaacson, Howard T.; Van Zandt, Judah; Ilyin, Ilya; Strassmeier, Klaus;
Mallonn, Matthias; Zhou, George; Mann, Andrew W.; Livingston, John H.;
Luger, Rodrigo; Dai, Fei; Weiss, Lauren M.; Močnik, Teo; Giacalone,
Steven; Hill, Michelle L.; Rice, Malena; Blunt, Sarah; Rubenzahl,
Ryan; Dalba, Paul A.; Esquerdo, Gilbert A.; Berlind, Perry; Calkins,
Michael L.; Foreman-Mackey, Daniel
2022AJ....163..247J Altcode: 2021arXiv211010707J
The alignment of planetary orbits with respect to the stellar rotation
preserves information on their dynamical histories. Measuring this
angle for young planets helps illuminate the mechanisms that create
misaligned orbits for older planets, as different processes could
operate over timescales ranging from a few megayears to a gigayear. We
present spectroscopic transit observations of the young exoplanet
V1298 Tau b; we update the age of V1298 Tau to be 28 ± 4 Myr
based on Gaia EDR3 measurements. We observed a partial transit with
Keck/HIRES and LBT/PEPSI, and detected the radial velocity anomaly
due to the Rossiter-McLaughlin effect. V1298 Tau b has a prograde,
well-aligned orbit, with $\lambda ={4}_{-10}^{+7}$ deg. By combining the
spectroscopically measured $v\sin {i}_{\star }$ and the photometrically
measured rotation period of the host star we also find that the orbit
is aligned in 3D, $\psi ={8}_{-7}^{+4}$ deg. Finally, we combine our
obliquity constraints with a previous measurement for the interior
planet V1298 Tau c to constrain the mutual inclination between the two
planets to be i mut = 0° ± 19°. This measurements adds to
the growing number of well-aligned planets at young ages, hinting that
misalignments may be generated over timescales of longer than tens
of megayears. The number of measurements, however, is still small,
and this population may not be representative of the older planets
that have been observed to date. We also present the derivation of the
relationship between i mut, λ, and i for the two planets.

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Title: The PEPSI-LBT Exoplanet Transit Survey (PETS). II. A Deep
Search for Thermal Inversion Agents in KELT-20 b/MASCARA-2 b with
Emission and Transmission Spectroscopy
Authors: Johnson, Marshall C.; Wang, Ji; Pai Asnodkar, Anusha; Bonomo,
Aldo S.; Gaudi, B. Scott; Henning, Thomas; Ilyin, Ilya; Keles, Engin;
Malavolta, Luca; Mallonn, Matthias; Molaverdikhani, Karan; Nascimbeni,
Valerio; Patience, Jennifer; Poppenhaeger, Katja; Scandariato, Gaetano;
Schlawin, Everett; Shkolnik, Evgenya; Sicilia, Daniela; Sozzetti,
Alessandro; Strassmeier, Klaus G.; Veillet, Christian; Yan, Fei
2022arXiv220512162J Altcode:
Recent observations have shown that the atmospheres of ultra hot
Jupiters (UHJs) commonly possess temperature inversions, where the
temperature increases with increasing altitude. Nonetheless, which
opacity sources are responsible for the presence of these inversions
remains largely observationally unconstrained. We used LBT/PEPSI
to observe the atmosphere of the UHJ KELT-20 b in both transmission
and emission in order to search for molecular agents which could be
responsible for the temperature inversion. We validate our methodology
by confirming a previous detection of Fe I in emission at $15.1\sigma$;
however, we are unable to reproduce published detections of Fe II,
Cr I, or Si I. We attribute the non-detection of Si I to the lack of
lines in our bandpass, but the non-detections of Fe II and Cr I are
puzzling due to our much higher signal-to-noise ratio than previous
works. Our search for the inversion agents TiO, VO, FeH, and CaH results
in non-detections. Using injection-recovery testing we set $4\sigma$
upper limits upon the volume mixing ratios for these constituents as
low as $\sim1\times10^{-10}$ for TiO. For TiO, VO, and CaH, our limits
are much lower than expectations from an equilibrium chemical model,
while FeH is lower than the expectations only from a super-Solar
metallicity model. We thus rule out TiO, VO, and CaH as the source of
the temperature inversion in KELT-20 b, while FeH is disfavored only
if KELT-20 b possesses a high-metallicity atmosphere.

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Title: VizieR Online Data Catalog: KELT-9 radial velocity with
LBT/PEPSI (Pai Asnodkar+, 2022)
Authors: Pai Asnodkar, A.; Wang, Ji; Gaudi, B. S.; Cauley, P. W.;
Eastman, J. D.; Ilyin, I.; Strassmeier, K.; Beatty, T.
2022yCat..51630040P Altcode:
We observed two transits of KELT-9 b with the high-resolution echelle
spectrograph Polarimetric and Spectroscopic Instrument (PEPSI) on the
Large Binocular Telescope (LBT) (two 8.4m mirrors, effective aperture
of 11.8m) in Arizona. PEPSI has a blue arm (nominally 3830-5440Å)
and a red arm (nominally 5440-9070Å) with six cross-dispersers for
full optical coverage. In this work, we use high-resolution data from
the blue arm taken with cross-disperser 3 (~4750-5430Å, R=50000)
exclusively because of negligible telluric contamination. In this
work, we apply the classical techniques used to analyze SB2s to the
KELT-9 system using observations from PEPSI spectrograph on LBT and
the HARPS-N spectrograph on the Telescopio Nazionale Galileo (TNG). We
utilize the original Tillinghast Reflector Echelle Spectrograph (TRES)
data (Gaudi+, 2017Natur.546..514G) as well as additional velocities
from higher-precision spectrographs. (1 data file).

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Title: Variable and Supersonic Winds in the Atmosphere of an Ultrahot
Giant Planet
Authors: Pai Asnodkar, Anusha; Wang, Ji; Eastman, Jason D.; Cauley,
P. Wilson; Gaudi, B. Scott; Ilyin, Ilya; Strassmeier, Klaus
2022AJ....163..155P Altcode: 2022arXiv220104154P
Hot Jupiters (HJs) receive intense irradiation from their stellar
hosts. The resulting extreme environments in their atmospheres
allow us to study the conditions that drive planetary atmospheric
dynamics, e.g., global-scale winds. General circulation models predict
day-to-nightside winds and equatorial jets with speeds of the order of
a few km s-1. To test these models, we apply high-resolution
transmission spectroscopy using the Potsdam Echelle Polarimetric and
Spectroscopic Instrument (PEPSI) spectrograph on the Large Binocular
Telescope to study the atmosphere of KELT-9 b, an ultrahot Jupiter and
currently the hottest known planet. We measure ~10 km s-1
day-to-nightside winds traced by Fe II features in the planet's
atmosphere. This is at odds with previous literature (including data
taken with PEPSI), which report no significant day-to-nightside winds
on KELT-9 b. We identify the cause of this discrepancy as due to an
inaccurate ephemeris for KELT-9 b in previous literature. We update
the ephemeris, which shifts the midtransit time by up to 10 minutes for
previous data sets, resulting in consistent detections of blueshifts in
all the data sets analyzed here. Furthermore, a comparison with archival
data sets from the High-accuracy Radial velocity Planet Searcher for
the Northern hemisphere suggests a temporal wind variability of ~5-8
km s-1 over timescales between weeks to years. Temporal
variability of atmospheric dynamics on HJs is a phenomenon anticipated
by certain general circulation models that has not been observed
over these timescales until now. However, such large variability as
we measure on KELT-9 b challenges general circulation models, which
predict much lower amplitudes of wind variability over timescales
between days to weeks.

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Title: KELT-9 as an Eclipsing Double-lined Spectroscopic Binary:
A Unique and Self-consistent Solution to the System
Authors: Pai Asnodkar, Anusha; Wang, Ji; Gaudi, B. Scott; Cauley,
P. Wilson; Eastman, Jason D.; Ilyin, Ilya; Strassmeier, Klaus;
Beatty, Thomas
2022AJ....163...40P Altcode: 2021arXiv211015275P
Transiting hot Jupiters present a unique opportunity to measure absolute
planetary masses due to the magnitude of their radial velocity signals
and known orbital inclination. Measuring planet mass is critical to
understanding atmospheric dynamics and escape under extreme stellar
irradiation. Here we present the ultrahot Jupiter system KELT-9 as
a double-lined spectroscopic binary. This allows us to directly and
empirically constrain the mass of the star and its planetary companion
without reference to any theoretical stellar evolutionary models
or empirical stellar scaling relations. Using data from the PEPSI,
HARPS-N, and TRES spectrographs across multiple epochs, we apply
least-squares deconvolution to measure out-of-transit stellar radial
velocities. With the PEPSI and HARPS-N data sets, we measure in-transit
planet radial velocities using transmission spectroscopy. By fitting
the circular orbital solution that captures these Keplerian motions,
we recover a planetary dynamical mass of 2.17 ± 0.56 M J
and stellar dynamical mass of 2.11 ± 0.78 M ⊙, both
of which agree with the discovery paper. Furthermore, we argue that
this system, as well as systems like it, are highly overconstrained,
providing multiple independent avenues for empirically cross-validating
model-independent solutions to the system parameters. We also discuss
the implications of this revised mass for studies of atmospheric escape.

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Title: Detection capability of ground-based meter-sized telescopes
for shallow exoplanet transits
Authors: Mallonn, M.; Poppenhaeger, K.; Granzer, T.; Weber, M.;
Strassmeier, K. G.
2022A&A...657A.102M Altcode: 2021arXiv211014344M
Meter-sized ground-based telescopes are frequently used today for the
follow-up of extrasolar planet candidates. While the transit signal
of a Jupiter-sized object can typically be detected to a high level
of confidence with small telescope apertures as well, the shallow
transit dips of planets with the size of Neptune and smaller are more
challenging to reveal. We employ new observational data to illustrate
the photometric follow-up capabilities of meter-sized telescopes for
shallow exoplanet transits. We describe in detail the capability of
distinguishing the photometric signal of an exoplanet transit from
an underlying trend in the light curve. The transit depths of the
six targets we observed, Kepler-94b, Kepler-63b, K2-100b, K2-138b,
K2-138c, and K2-138e, range from 3.9 ppt down to 0.3 ppt. For five
targets of this sample, we provide the first ground-based photometric
follow-up. The timing of three targets is precisely known from previous
observations, and the timing of the other three targets is uncertain
and we aim to constrain it. We detect or rule out the transit features
significantly in single observations for the targets that show transits
of 1.3 ppt or deeper. The shallower transit depths of two targets
of 0.6 and 0.8 ppt were detected tentatively in single light curves,
and were detected significantly by repeated observations. Only for the
target of the shallowest transit depth of 0.3 ppt were we unable to
draw a significant conclusion despite combining five individual light
curves. An injection-recovery test on our real data shows that we detect
transits of 1.3 ppt depth significantly in single light curves if the
transit is fully covered, including out-of-transit data toward both
sides, in some cases down to 0.7 ppt depth. For Kepler-94b, Kepler-63b,
and K2-100b, we were able to verify the ephemeris. In the case of
K2-138c with a 0.6 ppt deep transit, we were able to refine it, and in
the case of K2-138e, we ruled out the transit in the time interval of
more than ±1.5 σ of its current literature ephemeris. Reduced
light curves are only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/657/A102">http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/657/A102</A>
Based on data obtained with the STELLA robotic telescopes in
Tenerife, an AIP facility jointly operated by AIP and IAC.

---------------------------------------------------------
Title: Letter from the Editor 2022
Authors: Strassmeier, Klaus G.
2022AN....34328001S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: A detailed understanding of the rotation-activity relationship
using the 300 Myr old open cluster NGC 3532
Authors: Fritzewski, D. J.; Barnes, S. A.; James, D. J.; Järvinen,
S. P.; Strassmeier, K. G.
2021A&A...656A.103F Altcode: 2021arXiv211203302F
Context. The coeval stars of young open clusters provide insights
into the formation of the rotation-activity relationship that elude
studies of multi-age field populations. Aims: We measure
the chromospheric activity of cool stars in the 300 Myr old open
cluster NGC 3532 in concert with their rotation periods to study the
mass-dependent morphology of activity for this transitional coeval
population. Methods: Using multi-object spectra of the Ca II
infrared triplet region obtained with the AAOmega spectrograph at the
4 m Anglo-Australian Telescope, we measure the chromospheric emission
ratios RIRT' for 454 FGKM cluster members of NGC
3532. Results: The morphology of activity against colour appears
to be a near-mirror image of the cluster's rotational behaviour. In
particular, we identify a group of `desaturated transitional rotators'
that branches off from the main group of unsaturated FGK slow rotators,
and from which it is separated by an `activity gap'. The few desaturated
gap stars are identical to the ones in the rotational gap. Nevertheless,
the rotation-activity diagram is completely normal. In fact,
the relationship is so tight that it allows us to predict rotation
periods for many additional stars. We then precisely determine these
periods from our photometric light curves, allowing us to construct
an enhanced colour-period diagram that represents 66% of the members
in our sample. Our activity measurements show that all fast rotators
of near-solar mass (F-G type) have evolved to become slow rotators,
demonstrating that the absence of fast rotators in a colour-period
diagram is not a detection issue but an astrophysical fact. We also
identify a new population of low-activity stars among the early M
dwarfs, enabling us to populate the extended slow rotator sequence in
the colour-period diagram. Conclusions: The joint analysis of
chromospheric activity and photometric time series data thus enables
comprehensive insights into the evolution of the rotation and activity
of stars during the transitional phase between the Pleiades and Hyades
ages. Full Table 1 is only available at the CDS via anonymous ftp
to <A href="http://cdsarc.u-strasbg.fr/">cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/656/A103">http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/656/A103</A>
Based on data acquired through the Australian Astronomical
Observatory, under program S/2017A/02. Based on observations at
Cerro Tololo Inter-American Observatory, National Optical Astronomy
Observatory, under proposal 2008A-0476.

---------------------------------------------------------
Title: Rapid contraction of giant planets orbiting the
20-million-year-old star V1298 Tau
Authors: Suárez Mascareño, A.; Damasso, M.; Lodieu, N.; Sozzetti,
A.; Béjar, V. J. S.; Benatti, S.; Zapatero Osorio, M. R.; Micela, G.;
Rebolo, R.; Desidera, S.; Murgas, F.; Claudi, R.; González Hernández,
J. I.; Malavolta, L.; del Burgo, C.; D'Orazi, V.; Amado, P. J.;
Locci, D.; Tabernero, H. M.; Marzari, F.; Aguado, D. S.; Turrini,
D.; Cardona Guillén, C.; Toledo-Padrón, B.; Maggio, A.; Aceituno,
J.; Bauer, F. F.; Caballero, J. A.; Chinchilla, P.; Esparza-Borges,
E.; González-Álvarez, E.; Granzer, T.; Luque, R.; Martín, E. L.;
Nowak, G.; Oshagh, M.; Pallé, E.; Parviainen, H.; Quirrenbach, A.;
Reiners, A.; Ribas, I.; Strassmeier, K. G.; Weber, M.; Mallonn, M.
2022NatAs...6..232S Altcode: 2021NatAs...6..232S; 2021NatAs.tmp..252S; 2021arXiv211109193S;
2021NatAs.tmp..234S
Current theories of planetary evolution predict that infant giant
planets have large radii and very low densities before they slowly
contract to reach their final size after about several hundred
million years1,2. These theoretical expectations remain
untested so far as the detection and characterization of very young
planets is extremely challenging due to the intense stellar activity
of their host stars3,4. Only the recent discoveries of
young planetary transiting systems allow initial constraints to be
placed on evolutionary models5-7. With an estimated age
of 20 million years, V1298 Tau is one of the youngest solar-type
stars known to host transiting planets; it harbours a system
composed of four planets, two Neptune-sized, one Saturn-sized and
one Jupiter-sized8,9. Here we report a multi-instrument
radial velocity campaign of V1298 Tau, which allowed us to determine
the masses of two of the planets in the system. We find that the two
outermost giant planets, V1298 Tau b and e (0.64 ± 0.19 and 1.16 ±
0.30 Jupiter masses, respectively), seem to contradict our knowledge
of early-stages planetary evolution. According to models, they should
reach their mass-radius combination only hundreds of millions of years
after formation. This result suggests that giant planets can contract
much more quickly than usually assumed.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Searching transiting planets
around halo stars. I. (Kolecki+, 2021)
Authors: Kolecki, J. R.; Wang, J.; Johnson, J. A.; Zinn, J. C.; Ilyin,
I.; Strassmeier, K. G.
2021yCat..51620125K Altcode:
Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI)
spectrograph is located at the Large Binocular Telescope (LBT, 2x8.4m
on Mt. Graham, Arizona, USA). LBT PEPSI observations were made on 2019
March 25, May 15, June 23, and June 25, UT with 200μm fiber (R=130000
and 1.75" on sky) in two spectral regions 4800-5441Å and 6278-7419Å
(cross-dispersers (CD) 3 and 5) with 10-60minutes integration time
depending on the star brightness. (2 data files).

---------------------------------------------------------
Title: VizieR Online Data Catalog: NGC 3532 stars chromospheric
activity (Fritzewski+, 2021)
Authors: Fritzewski, D. J.; Barnes, S. A.; James, D. J.; Jarvinen,
S. P.; Strassmeier, K. G.
2021yCat..36560103F Altcode:
Measurements of chromospheric activity for cool star members of the open
cluster NGC 3532. In addition to the equivalent widths and chromospheric
emission ratios, the table contains photometric rotation periods for
258 stars. (1 data file).

---------------------------------------------------------
Title: The rapidly oscillating Ap star γ Equ: linear polarization
as an enhanced pulsation diagnostic?
Authors: Hubrig, S.; Järvinen, S. P.; Ilyin, I.; Strassmeier, K. G.;
Schöller, M.
2021MNRAS.508L..17H Altcode: 2021MNRAS.tmpL..86H; 2021arXiv210811272H
We present the first short time-scale observations of the rapidly
oscillating Ap (roAp) star γ Equ in linear polarized light obtained
with the Potsdam Echelle Polarimetric and Spectroscopic Instrument
installed at the Large Binocular Telescope. These observations are used
to search for pulsation variability in Stokes Q and U line profiles
belonging to different elements. The atmospheres of roAp stars are
significantly stratified with spectral lines of different elements
probing different atmospheric depths. roAp stars with strong magnetic
fields, such as γ Equ with a magnetic field modulus of 4 kG and a
pulsation period of 12.21 min, are of special interest because the
effect of the magnetic field on the structure of their atmospheres
can be studied with greatest detail and accuracy. Our results show
that we may detect changes in the transversal field component in Fe
I and rare earth element lines possessing large second-order Landé
factors. Such variability can be due to the impact of pulsation on
the transverse magnetic field, causing changes in the obliquity angles
of the magnetic force lines. Further studies of roAp stars in linear
polarized light and subsequent detailed modelling are necessary to
improve our understanding of the involved physics.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Transit events of 4 extrasolar
planets (Mallonn+, 2022)
Authors: Mallonn, M.; Poppenhaeger, K.; Granzer, T.; Weber, M.;
Strassmeier, K. G.
2021yCat..36570102M Altcode:
We obtained 19 photometric time series of transit events and employed
them to describe the detection capability of ground-based meter-sized
telescopes for shallow exoplanet transits on observational data. At
second, we verified or refined the orbital ephemeris of several
exoplanets. We present 19 differential photometry time series of
transit events of different extrasolar planets. (2 data files).

---------------------------------------------------------
Title: Searching For Transiting Planets Around Halo Stars. I. Sample
Selection and Validation
Authors: Kolecki, Jared R.; Wang, Ji; Johnson, Jennifer A.; Zinn,
Joel C.; Ilyin, Ilya; Strassmeier, Klaus G.
2021AJ....162..125K Altcode: 2021arXiv210613251K
By measuring the elemental abundances of a star, we can gain insight
into the composition of its initial gas cloud-the formation site
of the star and its planets. Planet formation requires metals, the
availability of which is determined by the elemental abundance. In
the case where metals are extremely deficient, planet formation can
be stifled. To investigate such a scenario requires a large sample of
metal-poor stars and a search for planets therein. This paper focuses on
the selection and validation of a halo star sample. We select ~17,000
metal-poor halo stars based on their Galactic kinematics, and confirm
their low metallicities ([Fe/H] &lt; -0.5), using spectroscopy from
the literature. Furthermore, we perform high-resolution spectroscopic
observations using LBT/PEPSI and conduct detailed metallicity ([Fe/H])
analyses on a sample of 13 previously-known halo stars that also
have hot kinematics. We can use the halo star sample presented here
to measure the frequency of planets and to test planet formation in
extremely metal-poor environments. The result of the planet search
and its implications will be presented and discussed in a companion
paper by Boley et al.

---------------------------------------------------------
Title: H-α Variability of V1298 Tau c
Authors: Schlawin, Everett; Ilyin, Ilya; Feinstein, Adina D.; Bean,
Jacob; Huang, Chenliang; Gao, Peter; Strassmeier, Klaus; Poppenhaeger,
Katja
2021RNAAS...5..195S Altcode: 2021arXiv210808851S
The 23 Myr system V1298 Tau hosts four transiting planets and is a
valuable laboratory for exploring the early stages of planet evolution
soon after formation of the star. We observe the innermost planet,
V1298 Tau c, during transit using LBT PEPSI to obtain high spectral
resolution characterization of escaping material near the H-α line. We
find no strong evidence for atmospheric material escaping at the orbital
velocity of the planet. Instead, we find a deep stellar feature that is
variable on the few percent level, similar to a previous observation
of the planet and can be explained by stellar activity. We attempted
to monitor the broadband optical transit with LBT MODS but do not
achieve the precision needed to characterize the atmosphere or improve
the ephemeris.

---------------------------------------------------------
Title: Rotation periods for cool stars in the open cluster NGC
3532. The transition from fast to slow rotation
Authors: Fritzewski, D. J.; Barnes, S. A.; James, D. J.; Strassmeier,
K. G.
2021A&A...652A..60F Altcode: 2021arXiv211203300F
Context. A very rich cluster intermediate in age between the Pleiades
(150 Myr) and the Hyades (600 Myr) is needed to probe the rotational
evolution, especially the transition between fast and slow rotation
that occurs between the two ages. Aims: We study the rich 300
Myr-old open cluster NGC 3532 to probe this important transition and
to provide constraints on angular momentum loss. Measuring the rotation
periods builds on our prior work of providing spectroscopic membership
information for the cluster, and it supports the chromospheric activity
measurements of cluster stars that we provide in a companion paper. Methods: Using 42 d-long photometric time series observations
obtained with the Yale 1 m telescope at CTIO, we measured rotation
periods for members of NGC 3532 and compared them with the predictions
of angular momentum evolution models. Results: We directly
measured 176 photometric rotation periods for the cluster members. An
additional 113 photometric rotation periods were identified using
activity information, described fully in the companion paper, resulting
in a total sample containing 279 rotation periods for FGKM stars in
NGC 3532. The colour-period diagram constructed from this rich data
set shows a well-populated and structured slow rotator sequence, and a
fast rotator sequence evolved beyond zero-age main sequence age whose
stars are in transition from fast to slow rotation. The slow rotator
sequence itself is split into slightly slower and faster rotators,
a feature we trace to photometric binary status. We also identify an
extended slow rotator sequence extending to P ∼ 32 d, apparently the
analogue of the one we previously identified in NGC 2516. We compare our
period distribution to rotational isochrones in colour-period space and
find that all considered models have certain shortcomings. Using more
detailed spin-down models, we evolve the rotation periods of the younger
NGC 2516 forward in time and find that the spindown of the models is
too aggressive with respect to the slow rotators. In contrast, stars on
the evolved fast rotator sequence are not spun down strongly enough by
these models. Our observations suggest a shorter crossing time for the
rotational gap, one we estimate to be ∼80 Myr for early-K dwarfs. Full Table 2 is only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr/">cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/652/A60">http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/652/A60</A>
Based on observations at Cerro Tololo Inter-American Observatory,
National Optical Astronomy Observatory under proposal 2008A-0476.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Rotation periods for NGC 3532
(Fritzewski+, 2021)
Authors: Fritzewski, D. J.; Barnes, S. A.; James, D. J.; Strassmeier,
K. G.
2021yCat..36520060F Altcode:
The table contains the rotation periods and photometric colours for
279 solar-like members of the open cluster NGC 3532. Each star is
cross-matched to Gaia DR2. The possible binarity status (from photometry
and astrometry) is given. (1 data file).

---------------------------------------------------------
Title: Further Optical Spectroscopic Observations of V1674 Herculis
Authors: Woodward, C. E.; Wagner, R. M.; Starrfield, S.; Kumar, V.;
Srivastava, M.; Banerjee, D. P. K.; Joshi, V.; IIyin, I.; Strassmeier,
K. G.; Evans, A.
2021ATel14723....1W Altcode:
We report optical spectroscopic observations of the very fast nova
V1674 Her (TCP J18573095+1653396) between 2021 June 13 to 15, obtained
at R = 1700 using the Blue Channel spectrograph (Schmidt et al. 1989,
PASP 101, 713) on the 6.5-m MMT, Mt. Hopkins, AZ, at high resolution
(R = 220 000) using PEPSI (Strassmeier et al. 2015, Aston.

---------------------------------------------------------
Title: Betelgeuse: An Iconic and Surprising Red Supergiant
Authors: Dupree, Andrea; Anugu, Narsireddy; Calderwood, Thomas; Cannon,
Emily; Granzer, Thomas; Kervella, Pierre; Kravchenko, Kateryna;
Matthews, Lynn D.; Montarges, Miguel; Quirrenbach, Andreas; Rau,
Gioia; Richards, Anita; Strassmeier, Klaus G.; Thompson, William T.;
Van Eck, Sophie; jorissen, alain
2021hst..prop16655D Altcode:
Multiple ultraviolet spectra of the nearby red supergiant, Betelgeuse,
using STIS will enable unique spatially resolved measures of
photospheric and chromospheric structure and mass inflows and
outflows. This follows the historic dimming of the star captured by
HST/STIS in 2019-2020, and will probe the unusual atmospheric structure
following the dimming event. An HST campaign of 2 cycles will be
complemented by multi-frequency photometry, spectroscopy, interferometry
and polarimetry at radio, infrared, and optical wavelengths in order
to map surface structures and their variability, and the extended outer
atmosphere over both the short (420-day) and long, secondary (2000-day)
periods of this supergiant. These observations, coupled with detailed
modeling and simulations. will probe the structure, dynamics, and mass
loss from Betelgeuse to provide crucial insights into the atmospheric
physics and wind-driving mechanisms of red supergiants.

---------------------------------------------------------
Title: A unicorn in monoceros: the 3 M⊙ dark companion
to the bright, nearby red giant V723 Mon is a non-interacting,
mass-gap black hole candidate
Authors: Jayasinghe, T.; Stanek, K. Z.; Thompson, Todd A.; Kochanek,
C. S.; Rowan, D. M.; Vallely, P. J.; Strassmeier, K. G.; Weber, M.;
Hinkle, J. T.; Hambsch, F. -J.; Martin, D. V.; Prieto, J. L.; Pessi,
T.; Huber, D.; Auchettl, K.; Lopez, L. A.; Ilyin, I.; Badenes, C.;
Howard, A. W.; Isaacson, H.; Murphy, S. J.
2021MNRAS.504.2577J Altcode: 2021arXiv210102212J
We report the discovery of the closest known black hole candidate as
a binary companion to V723 Mon. V723 Mon is a nearby ($d\sim 460\,
\rm pc$), bright (V ≃ 8.3 mag), evolved (Teff, giant
≃ 4440 K, and Lgiant ≃ 173 L⊙) red giant
in a high mass function, f(M) = 1.72 ± 0.01 M⊙, nearly
circular binary (P = 59.9 d, e ≃ 0). V723 Mon is a known variable
star, previously classified as an eclipsing binary, but its All-Sky
Automated Survey, Kilodegree Extremely Little Telescope, and Transiting
Exoplanet Survey Satellite light curves are those of a nearly edge-on
ellipsoidal variable. Detailed models of the light curves constrained
by the period, radial velocities, and stellar temperature give an
inclination of $87.0^{\circ ^{+1.7^\circ }}_{-1.4^\circ }$, a mass
ratio of q ≃ 0.33 ± 0.02, a companion mass of Mcomp =
3.04 ± 0.06 M⊙, a stellar radius of Rgiant
= 24.9 ± 0.7 R⊙, and a giant mass of Mgiant
= 1.00 ± 0.07 M⊙. We identify a likely non-stellar,
diffuse veiling component with contributions in the B and V band of
${\sim }63{{\ \rm per\ cent}}$ and ${\sim }24{{\ \rm per\ cent}}$,
respectively. The SED and the absence of continuum eclipses imply that
the companion mass must be dominated by a compact object. We do observe
eclipses of the Balmer lines when the dark companion passes behind
the giant, but their velocity spreads are low compared to observed
accretion discs. The X-ray luminosity of the system is $L_{\rm X}\simeq
7.6\times 10^{29}~\rm ergs~s^{-1}$, corresponding to L/Ledd
~ 10-9. The simplest explanation for the massive companion
is a single compact object, most likely a black hole in the 'mass gap'.

---------------------------------------------------------
Title: Space Photometry with Brite-Constellation
Authors: Weiss, Werner W.; Zwintz, Konstanze; Kuschnig, Rainer;
Handler, Gerald; Moffat, Anthony F. J.; Baade, Dietrich; Bowman,
Dominic M.; Granzer, Thomas; Kallinger, Thomas; Koudelka, Otto F.;
Lovekin, Catherine C.; Neiner, Coralie; Pablo, Herbert; Pigulski,
Andrzej; Popowicz, Adam; Ramiaramanantsoa, Tahina; Rucinski, Slavek
M.; Strassmeier, Klaus G.; Wade, Gregg A.
2021Univ....7..199W Altcode: 2021arXiv210612952W
BRITE-Constellation is devoted to high-precision optical photometric
monitoring of bright stars, distributed all over the Milky Way, in
red and/or blue passbands. Photometry from space avoids the turbulent
and absorbing terrestrial atmosphere and allows for very long and
continuous observing runs with high time resolution and thus provides
the data necessary for understanding various processes inside stars
(e.g., asteroseismology) and in their immediate environment. While
the first astronomical observations from space focused on the spectral
regions not accessible from the ground it soon became obvious around
1970 that avoiding the turbulent terrestrial atmosphere significantly
improved the accuracy of photometry and satellites explicitly
dedicated to high-quality photometry were launched. A perfect example
is BRITE-Constellation, which is the result of a very successful
cooperation between Austria, Canada and Poland. Research highlights
for targets distributed nearly over the entire HRD are presented,
but focus primarily on massive and hot stars.

---------------------------------------------------------
Title: Letter from the Editor
Authors: Strassmeier, Klaus G.
2021AN....342..606S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The Curious Case of Betelgeuse
Authors: Granzer, Thomas; Weber, Michael; Strassmeier, Klaus G.;
Dupree, Andrea
2021csss.confE..41G Altcode:
Since more than a decade, the AIP is monitoring (\alpha) Ori with
its robotic spectroscopic facility STELLA/SES in Teide observatory,
Tenerife along with its automated photoelectric telescope T7 in Fairborn
observatory, Az. Additionally, we got access with exclusive two-band
photometric data on Betelgeuse from the BRITE satellite consortium,
covering the last seven seasons. In late 2019, Betelgeuse showed
a rapid brightness decline, reaching an all-time low in Feb. 2020,
followed by a quick re-brightening. This poster shows radial velocity
data together with the photometry. The radial velocity follows the
photometry in general, but sometimes shows a time-shift, which was
particularly visible in the grand dimming event. Interesting is the
time-frequency analysis of the different data set: All three show
similar features at split-periods around the known P=420d.

---------------------------------------------------------
Title: Role of the impact parameter in exoplanet transmission
spectroscopy
Authors: Alexoudi, Xanthippi; Mallonn, Matthias; Keles, Engin;
Poppenhäger, Katja; Strassmeier, Klaus
2021csss.confE...9A Altcode:
Transmission spectroscopy is the widely used observational technique
that exploits the planetary transit events with aim to characterize
the exoplanetary atmospheres. While it already revealed atomic and
molecular absorption, haze layers and thick clouds in about two dozen
of objects, the literature presents some worthy mentioned discrepant
results on individual targets. An example of controversial results in
the literature is the case of HAT-P-12b, which I solved successfully
during my studies. Intriguingly, two independent investigations from
different groups, one with ground-based observations and one using the
Hubble Space Telescope (HST), concluded to contradicting transmission
spectra, interpreted from opaque clouds in the atmosphere to a Rayleigh
scattering slope. The optical slope in this case is affected by the
orbital parameters yielding to inconsistencies. I will present this
degeneracy investigated for the entire parameter space with aim to
ameliorate the quality of the scientific output.

---------------------------------------------------------
Title: Characterization of Chromospheric Activity Based on
Sun-as-a-star Spectral and Disk-resolved Observations
Authors: Dineva, Ekaterina; Pearson, Jeniveve; Verman, Meetu; Ilyin,
Ilya; Strassmeier, Klaus G.; Denker, Carsten
2021csss.confE.130D Altcode:
The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI)
is a state-of-the-art, thermally stabilized, fiber-fed, high-resolution
spectrograph for the Large Binocular Telescope (LBT) at Mt. Graham,
Arizona. It can be fed with sunlight from the Solar Disk-Integrated
(SDI) telescope. Synoptic solar observations with PEPSI/SDI produce
daily spectra with high signal-to-noise ratio, providing access to
unprecedented, quasi-continuous, long-term, disk-integrated spectra of
the Sun with high spectral and temporal resolution. The observed spectra
contain a multitude of photospheric and chromospheric spectral lines
in the wavelength range of 380 910 nm. Strong chromospheric absorption
lines, such as the Ca II H &amp; K lines, are powerful diagnostic
tools for solar activity studies, since they trace the variations
of the solar magnetic field. Derivation of activity indices, such
as the Ca II H &amp; K emission ratio S-index provides insight into
the chromospheric magnetic field and its variability over the solar
activity cycle. The well known relation between solar calcium indices
and UV flux variations motivates us to compute an excess brightness
indices from Ca II K full-disk images from of the Chromospheric
Telescope (ChroTel) at the Observatory del Teide on Tenerife, Spain
and UV data of the Solar Dynamics Observatory (SDO). We present a
set of indices representing magnetic activity at various heights in
the solar atmosphere. In the present work, we carefully compare the
indices computed from various datasets and discuss the differences in
terms of physical and observational properties.

---------------------------------------------------------
Title: HIRES, the High-resolution Spectrograph for the ELT
Authors: Marconi, A.; Abreu, M.; Adibekyan, V.; Aliverti, M.; Allende
Prieto, C.; Amado, P.; Amate, M.; Artigau, E.; Augusto, S.; Barros,
S.; Becerril, S.; Benneke, B.; Bergin, E.; Berio, P.; Bezawada,
N.; Boisse, I.; Bonfils, X.; Bouchy, F.; Broeg, C.; Cabral, A.;
Calvo-Ortega, R.; Canto Martins, B. L.; Chazelas, B.; Chiavassa,
A.; Christensen, L.; Cirami, R.; Coretti, I.; Covino, S.; Cresci,
G.; Cristiani, S.; Cunha Parro, V.; Cupani, G.; de Castro Leão,
I.; Renan de Medeiros, J.; Furlande Souza, M. A.; Di Marcantonio,
P.; Di Varano, I.; D'Odorico, V.; Doyon, R.; Drass, H.; Figueira,
P.; Belen Fragoso, A.; Uldall Fynbo, J. P.; Gallo, E.; Genoni,
M.; González Hernández, J.; Haehnelt, M.; Hlavacek-Larrondo, J.;
Hughes, I.; Huke, P.; Humphrey, A.; Kjeldsen, H.; Korn, A.; Kouach,
D.; Landoni, M.; Liske, J.; Lovis, C.; Lunney, D.; Maiolino, R.; Malo,
L.; Marquart, T.; Martins, C.; Mason, E.; Molaro, P.; Monnier, J.;
Monteiro, M.; Mordasini, C.; Morris, T.; Mucciarelli, A.; Murray,
G.; Niedzielski, A.; Nunes, N.; Oliva, E.; Origlia, L.; Pallé,
E.; Pariani, G.; Parr-Burman, P.; Peñate, J.; Pepe, F.; Pinna,
E.; Piskunov, N.; Rasilla Piñeiro, J. L.; Rebolo, R.; Rees, P.;
Reiners, A.; Riva, M.; Romano, D.; Rousseau, S.; Sanna, N.; Santos,
N.; Sarajlic, M.; Shen, T. -C.; Sortino, F.; Sosnowska, D.; Sousa,
S.; Stempels, E.; Strassmeier, K.; Tenegi, F.; Tozzi, A.; Udry,
S.; Valenziano, L.; Vanzi, L.; Weber, M.; Woche, M.; Xompero, M.;
Zackrisson, E.; Zapatero Osorio, M. R.
2021Msngr.182...27M Altcode: 2020arXiv201112317M
HIRES will be the high-resolution spectrograph at optical and
near-infrared (NIR) wavelengths for ESO's Extremely Large Telescope
(ELT). It will consist of three fibre-fed spectrographs providing a
wavelength coverage of 0.4-1.8 µm (with a goal of 0.35-1.8 µm) at a
spectral resolution of ~ 100 000. Fibre-feeding allows HIRES to have
several interchangeable observing modes, including a single-conjugate
adaptive optics (SCAO) module and a small diffraction-limited integral
field unit in the NIR. It will therefore be able to operate in both
seeing- and diffraction-limited modes. HIRES will address a wide range
of science cases spanning nearly all areas of research in astrophysics
and even fundamental physics. Some of the top science cases will be
the detection of biosignatures from exoplanet atmospheres, finding the
fingerprints of the first generation of stars (Pop III), tests on the
stability of Nature's fundamental couplings, and the direct detection
of the cosmic acceleration. The HIRES consortium is composed of more
than 30 institutes from 14 countries, forming a team of more than 200
scientists and engineers.

---------------------------------------------------------
Title: Time-resolved Rotational Velocities in the Upper Atmosphere
of WASP-33 b
Authors: Cauley, P. Wilson; Wang, Ji; Shkolnik, Evgenya L.; Ilyin,
Ilya; Strassmeier, Klaus G.; Redfield, Seth; Jensen, Adam G.
2021AJ....161..152C Altcode: 2020arXiv201002118C
While steady empirical progress has been made in understanding the
structure and composition of hot-planet atmospheres, direct measurements
of velocity signatures, including winds, rotation, and jets, have lagged
behind. Quantifying atmospheric dynamics of hot planets is critical for
a complete understanding of their atmospheres, and such measurements
may even illuminate other planetary properties, such as magnetic
field strengths. In this manuscript we present the first detection
of the Balmer lines Hα and Hβ in the atmosphere of the ultra-hot
Jupiter WASP-33 b. Using atmospheric models that include the effects
of atmospheric dynamics, we show that the shape of the average Balmer
line transmission spectrum is consistent with rotational velocities in
the planet's thermosphere of ${v}_{\mathrm{rot}}={10.1}_{-1.0}^{+0.8}$
km s-1. We also measure a low-significance day- to nightside
velocity shift of $-{4.6}_{-3.4}^{+3.4}$ km s-1 in the
transmission spectrum, which is naturally explained by a global
wind across the planet's terminator. In a separate analysis the
time-resolved velocity centroids of individual transmission spectra
show unambiguous evidence of rotation, with a best-fit velocity of
${10.0}_{-2.0}^{+2.4}$ km s-1, consistent with the value
of vrot derived from the shape of the average Balmer line
transmission spectrum. Our observations and analysis confirm the power
of time-resolved transmission spectra with a high signal-to-noise ratio
to measure the velocity structures in exoplanet atmospheres. The high
rotational and wind velocities we measure highlight the need for more
detailed 3D global climate simulations of the rarefied upper atmospheres
of ultra-hot gas giants. * Based on data acquired with PEPSI using
the Large Binocular Telescope (LBT). 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; Istituto Nazionale di
Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing
the Max-Planck Society, the Leibniz-Institute for Astrophysics Potsdam
(AIP), 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.

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Title: ELT-HIRES the High Resolution Spectrograph for the ELT:
status of the polarization ray tracing tool for the polarimetric unit
Authors: Di Varano, I.; Yuan, S.; Woche, M.; Strassmeier, K. G.;
Weber, M.
2020SPIE11451E..4GD Altcode:
ELT-HIRES (High Resolution Spectrograph for the Extremely Large
Telescope) is a multifold fiber-fed spectrograph planned for the Nasmyth
B focal station on ELT, covering a wavelength range between 0.4 and
1.8 μ. One of the most relevant science cases is represented by the
detection of life signature in the extrasolar atmospheres for Earth-like
planets. The polarimetric unit, feeding the UBVRI and the zYJH
spectrograph modules, will consist of two subassemblies: the main one,
aimed to be installed in the intermediate focus, will host the polarizer
(a double Wollaston calcite prism) and the retarder plates splitting
the optical beam into the four Stokes vector components; the other
will be located in one of the four dedicated arms of the Front End on
the Nasmyth platform, providing the atmospheric dispersion correction,
field stabilization and selection of the operating modes before the
fiber injection. At the conclusion of Phase A, we have presented this
as the optimal design solution fulfilling the top level requirement
of reaching a sensitivity of 10-5 S/I (S being equivalent to one of
the Stokes vectors), a condition achievable only if the polarizers are
installed in a rotationally symmetric focus. The current work, which can
be considered a continuation of two preceding papers, illustrates new
simulation results from the development of the polarization-ray-tracing
tool. We have included also the crystal anisotropic properties of the
polarizing components, analyzing the transmission loss that the light
beam encounters propagating through the optical train before entering
the fiber bundles in the different operating modes, bearing in mind
the polarimetric aberrations induced by the active compensation of
the primary mirror and the loads contributing as Zernike polynomials
of different orders, namely the telescope cross-talk.

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Title: BRITE photometry and STELLA spectroscopy of bright stars in
Auriga: Rotation, pulsation, orbits, and eclipses⋆
Authors: Strassmeier, K. G.; Granzer, T.; Weber, M.; Kuschnig, R.;
Pigulski, A.; Popowicz, A.; Moffat, A. F. J.; Wade, G. A.; Zwintz,
K.; Handler, G.
2020A&A...644A.104S Altcode: 2020arXiv201010092S
Context. Knowing rotational and pulsational periods across the
Hertzsprung-Russell diagram is of top priority for understanding stellar
activity as a function of time. Aims: We aim to determine
periods for bright stars in the Auriga field that are otherwise
not easily accessible for ground-based photometry. Methods:
Continuous photometry with up to three BRITE satellites was obtained
for 12 targets and subjected to a period search. Contemporaneous
high-resolution optical spectroscopy with STELLA was used to obtain
radial velocities through cross correlation with template spectra as
well as to determine astrophysical parameters through a comparison
with model spectra. Results: The Capella red light curve was
found to be constant over 176 days with a root mean square of 1 mmag,
but the blue light curve showed a period of 10.1 ± 0.6 d, which we
interpret to be the rotation period of the G0 component. From STELLA
we obtained an improved orbital solution based on 9600 spectra from
the previous 12.9 yr. We derive masses precise to ≈0.3% but 1%
smaller than previously published. The BRITE light curve of the F0
supergiant ɛ Aur suggests 152 d as its main pulsation period, while
the STELLA radial velocities reveal a clear 68 d period. An ingress
of an eclipse of the ζ Aur binary system was covered with BRITE
and a precise timing for its eclipse onset derived. A possible 70 d
period fits the proposed tidal-induced, nonradial pulsations of this
ellipsoidal K4 supergiant. η Aur is identified as a slowly pulsating B
(SPB) star with a main period of 1.29 d and is among the brightest SPB
stars discovered so far. The rotation period of the magnetic Ap star θ
Aur is detected from photometry and spectroscopy with a period of 3.6189
d and 3.6177 d, respectively, likely the same within the errors. The
radial velocities of this star show a striking non-sinusoidal shape
with a large amplitude of 7 km s-1. Photometric rotation
periods are also confirmed for the magnetic Ap star IQ Aur of 2.463 d
and for the solar-type star κ1 Cet of 9.065 d, and also
for the B7 HgMn giant β Tau of 2.74 d. Revised orbital solutions
are derived for the eclipsing SB2 binary β Aur, which replaces the
initial orbit dating from 1948 for the 27-year eclipsing SB1 ɛ Aur,
and for the RS CVn binary V711 Tau, for which a spot-corrected orbital
solution was achieved. The two stars ν Aur and ι Aur are found to be
long-term, low-amplitude RV and brightness variables, but provisional
orbital elements based on a period of 20 yr and an eccentricity of
0.7 could only be extracted for ν Aur. The variations of ι Aur are
due to oscillations with a period of ≈4 yr. The data used in
this paper are only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr/">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/644/A104">http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/644/A104</A>
Based on data obtained with the BRITE-Constellation satellite and
the STELLA robotic telescope in Tenerife. BRITE (BRIght Target Explorer)
Constellation was designed, built, launched, operated, and supported
by the Austrian Research Promotion Agency (FFG), the University of
Vienna, the Technical University of Graz, the University of Innsbruck,
the Canadian Space Agency (CSA), the University of Toronto Institute
for Aerospace Studies (UTIAS), the Foundation for Polish Science &amp;
Technology (FNiTP MNiSW), and National Science Centre (NCN).

---------------------------------------------------------
Title: Using raytracing to derive the expected performance of STELLA's
SES-VIS spectrograph
Authors: Weber, Michael; Strassmeier, Klaus G.; Woche, Manfred; Ilyin,
Ilya; Järvinen, Arto
2020SPIE11450E..1CW Altcode: 2020arXiv201208218W
The new visual STELLA echelle spectrograph (SES-VIS) is a new
instrument for the STELLA-II telescope at the Iza~na observatory on
Tenerife. Together with the original SES spectrograph - which will still
be used in the near IR - and a new H&amp;K-optimized spectrograph,
which is currently in the design phase, it will change the focus
of the spectroscopic observations at STELLA towards the follow up
of planetary candidates detected by upcoming surveys focusing on
bright targets (TESS, PLATO2). It is optimized for precise radial
velocity determination and long term stability. We have developed a
ZEMAX based software package to create simulated spectra, which are
then extracted using our new reduction package, which is based on the
PEPSI software package. The focus has been put on calibration spectra,
and the full range of available calibration sources (at field, Th-Ar,
and Fabry-Perot), which can be compared to actual commissioning data
once they are available. Furthermore we tested for the effect of changes
of the environmental parameters to the wavelength calibration precision.

---------------------------------------------------------
Title: On the binary orbit of Henry Draper one ( HD 1)
Authors: Strassmeier, Klaus G.; Weber, Michael
2020AN....341..983S Altcode: 2020arXiv201113330S
We present our final orbit for the late type spectroscopic binary
Henry Draper one (HD 1). area total of 553 spectra from 13 years of
observations are used with our robotic STELLA facility and its high
resolution echelle spectrograph SES. Its long term radial velocity
stability is ≈50 m s-1. A single radial velocity of HD 1
reached an rms residual of 63 m s-1, close to the expected
precision. Spectral lines of HD 1 are rotationally broadened with a v
sin i of 9.1 ± 0.1 km s-1. The overall spectrum appears
single lined and yielded an orbit with an eccentricity of 0.5056 ±
0.0005 and a semiamplitude of 4.44 km s-1. We constrain and
refine the orbital period based on the SES data alone to 2, 318.70
± 0.32 days, compared to 2, 317.8 ± 1.1 days when including the
older dataset published by DAO and Cambridge/Coravel. Owing to the
higher precision of the SES data, we base the orbit calculation only
on the STELLA/SES velocities so as to not degrade its solution. We
redetermine astrophysical parameters for HD 1 from spectrum synthesis
and, together with the new Gaia DR 2 parallax, suggest a higher
luminosity than published previously. We conclude that HD 1 is a
slightly metal deficient K0 III II giant 217 times more luminous than
the Sun. The secondary remains invisible at optical wavelengths. We
present evidence for the existence of a third component.

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Title: ELT-HIRES, the high resolution spectrograph for the ELT:
the Phase A study and the path to construction
Authors: Marconi, A.; Abreu, M.; Adibekyan, V.; Aliverti, M.; Allende
Prieto, C.; Amado, P.; Amate, M.; Artigau, E.; Augusto, S.; Barros, S.;
Becerril, S.; Benneke, B.; Bergin, E.; Berio, P.; Bezawada, N.; Boisse,
I.; Bonfils, X.; Bouchy, F.; Broeg, C.; Cabral, A.; Calvo-Ortega,
R.; Canto Martins, B. L.; Chazelas, B.; Chiavassa, A.; Christensen,
L.; Cirami, R.; Coretti, I.; Covino, S.; Cresci, G.; Cristiani, S.;
Cunha Parro, V.; Cupani, G.; D'Odorico, V.; de Castro Leão, I.;
de Medeiros, J. R.; de Souza, M.; Di Marcantonio, P.; Di Varano, I.;
Doyon, R.; Drass, H.; Figueira, P.; Fragoso, A.; Fynbo, J.; Gallo,
E.; Genoni, M.; González Hernández, J.; Gratton, R.; Haehnelt, M.;
Hansen, C.; Hlavacek-Larrondo, J.; Hughes, I.; Huke, P.; Humphrey,
A.; Kjeldsen, H.; Korn, A.; Kouach, D.; Landoni, M.; Liske, J.;
Lovis, C.; Lunney, D.; Maiolino, R.; Malo, L.; Marquart, T.; Martins,
C. J. A. P.; Maslowski, P.; Mason, E.; Micela, G.; Molaro, P.; Monnier,
J.; Monteiro, M.; Mordasini, C.; Morris, T.; Mucciarelli, A.; Murray,
G.; Niedzielski, A.; Niemczura, E.; Nisini, B.; Nunes, N.; Oliva,
E.; Origlia, L.; Pallé, E.; Pariani, G.; Parr-Burman, P.; Pasquini,
L.; Peñate, J.; Pepe, F.; Pietrzynski, G.; Pinna, E.; Piskunov,
N.; Pollo, A.; Rasilla, J.; Rebolo, R.; Rees, P.; Reiners, A.; Riva,
M.; Romano, D.; Rousseau, S.; Sanna, N.; Sarajlic, M.; Shen, T. -C.;
Sortino, F.; Sosnowska, D.; Sousa, S.; Stempels, E.; Strassmeier, K.;
Tenegi, F.; Tozzi, A.; Udry, S.; Valenziano, L.; Vanzi, L.; Weber,
M.; Woche, M.; Xompero, M.; Zackrisson, E.; Zapatero Osorio, M. R.
2020SPIE11447E..26M Altcode:
HIRES is the high-resolution spectrograph of the European Extremely
Large Telescope at optical and near-infrared wavelengths. It consists
of three fibre-fed spectrographs providing a wavelength coverage of
0.4-1.8 µm (goal 0.35-2.4 µm) at a spectral resolution of 100,000. The
fibre-feeding allows HIRES to have several, interchangeable observing
modes including a SCAO module and a small diffraction-limited IFU
in the NIR. Therefore, it will be able to operate both in seeing-
and diffraction-limited modes. Its modularity will ensure that HIRES
can be placed entirely on the Nasmyth platform, if enough mass and
volume is available, or part on the Nasmyth and part in the Coud`e
room. ELT-HIRES has a wide range of science cases spanning nearly all
areas of research in astrophysics and even fundamental physics. Among
the top science cases there are the detection of biosignatures from
exoplanet atmospheres, finding the fingerprints of the first generation
of stars (PopIII), tests on the stability of Nature's fundamental
couplings, and the direct detection of the cosmic acceleration. The
HIRES consortium is composed of more than 30 institutes from 14
countries, forming a team of more than 200 scientists and engineers.

---------------------------------------------------------
Title: Second generation spectroscopic instrumentation for the STELLA
robotic observatory
Authors: Weber, Michael; Woche, Manfred; Strassmeier, Klaus G.; Ilyin,
Ilya; Järvinen, Arto
2020SPIE11449E..0JW Altcode: 2020arXiv201208210W
The current STELLA Échelle spectrograph (SES), which records 390nm to
870nm in one shot at a spectral resolution of 55000, will be replaced
by a suite of specialized spectrographs in three spectral bands. The
UV will be covered by a newly designed H and K spectrograph covering
380nm to 470nm (SES-H and K), the visual band (470nm - 690 nm) will be
covered by SES-VIS, which is a vacuum-stabilized spectrograph designed
for high radial-velocity accuracy, and the NIR will be covered by the
current SES spectrograph from 690nm to 1050 nm. In order to improve
the UV transmission, and to accommodate three different fibre-feeds,
the prime focus corrector of the telescope will be refurbished,
leading to an optical system with the f/2 1200mm spherical primary,
a 4-lens collimator with 2" aperture, atmospheric dispersion corrector
(ADC), and two dichroic beam splitters, feeding 3 separate fibre feeds
for the three bands. The newly designed H and K spectrograph will be
an Échelle spectrograph, based on a R4-grating with 41.6 l/mm and
110mmx420mm, using a f/5 camera and the cross-disperser in double pass
(as in TRAFICOS, MIKE, KPF), using 21 spectral orders. The spectral
resolution of all three spectrographs will be comparable to the current
SES's 55000.

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Title: Mono-enriched stars and Galactic chemical evolution. Possible
biases in observations and theory
Authors: Hansen, C. J.; Koch, A.; Mashonkina, L.; Magg, M.; Bergemann,
M.; Sitnova, T.; Gallagher, A. J.; Ilyin, I.; Caffau, E.; Zhang,
H. W.; Strassmeier, K. G.; Klessen, R. S.
2020A&A...643A..49H Altcode: 2020arXiv200911876H
A long sought after goal using chemical abundance patterns derived
from metal-poor stars is to understand the chemical evolution
of the Galaxy and to pin down the nature of the first stars (Pop
III). Metal-poor, old, unevolved stars are excellent tracers as
they preserve the abundance pattern of the gas from which they were
born, and hence they are frequently targeted in chemical tagging
studies. Here, we use a sample of 14 metal-poor stars observed with the
high-resolution spectrograph called the Potsdam Echelle Polarimetric and
Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT)
to derive abundances of 32 elements (34 including upper limits). We
present well-sampled abundance patterns for all stars obtained using
local thermodynamic equilibrium (LTE) radiative transfer codes and
one-dimensional (1D) hydrostatic model atmospheres. However, it is
currently well-known that the assumptions of 1D and LTE may hide
several issues, thereby introducing biases in our interpretation
as to the nature of the first stars and the chemical evolution of
the Galaxy. Hence, we use non-LTE (NLTE) and correct the abundances
using three-dimensional model atmospheres to present a physically
more reliable pattern. In order to infer the nature of the first
stars, we compare unevolved, cool stars, which have been enriched
by a single event ("mono-enriched"), with a set of yield predictions
to pin down the mass and energy of the Pop III progenitor. To date,
only few bona fide second generation stars that are mono-enriched
are known. A simple χ2-fit may bias our inferred mass
and energy just as much as the simple 1D LTE abundance pattern, and
we therefore carried out our study with an improved fitting technique
considering dilution and mixing. Our sample presents Carbon Enhanced
Metal-Poor (CEMP) stars, some of which are promising bona fide second
generation (mono-enriched) stars. The unevolved, dwarf BD+09_2190
shows a mono-enriched signature which, combined with kinematical data,
indicates that it moves in the outer halo and likely has been accreted
onto the Milky Way early on. The Pop III progenitor was likely of
25.5 M⊙ and 0.6 foe (0.6 1051 erg) in LTE
and 19.2 M⊙ and 1.5 foe in NLTE, respectively. Finally,
we explore the predominant donor and formation site of the rapid
and slow neutron-capture elements. In BD-10_3742, we find an almost
clean r-process trace, as is represented in the star HD20, which is a
"metal-poor Sun benchmark" for the r-process, while TYC5481-00786-1 is
a promising CEMP-r/-s candidate that may be enriched by an asymptotic
giant branch star of an intermediate mass and metallicity. The
line list is only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/643/A49">http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/643/A49</A>
Based on data acquired with PEPSI using the Large Binocular
Telescope (LBT). The LBT is an international collaboration among
institutions in the United States, Italy, and Germany.

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Title: VizieR Online Data Catalog: Auriga bright stars BRITE phot. and
RV (Strassmeier+, 2020)
Authors: Strassmeier, K. G.; Granzer, T.; Weber, M.; Kuschnig, R.;
Pigulski, A.; Popowicz, A.; Moffat, A. F. J.; Wade, G. A.; Zwintz,
K.; Handler, G.
2020yCat..36440104S Altcode:
Continuous photometry with BRITE satellites BRITE-Toronto (BTr),
BRITE-Heweliusz (BHr), and BRITE-Lem (BLb) of 12 very bright stars in
BRITE fields 20-AurPer-I-2016 (9 stars), 21-CetEri-I-2016 (2 stars)
and one star at the edge of fields 31-Tau-I-2017 and 48-OriTau-II-2019
are presented. Contemporaneous high-resolution optical spectroscopy
(R=55000) with STELLA-SES was used to obtain radial velocities and to
determine astrophysical parameters. BTr and BHr are red sensitive,
filter passband comparable to Sloan r, while BLb is blue sensitive
(Geneva B). The Aur-Per field was observed from JD 2457640 to 2457822
(9th Sept., 2016 to 9th March 2017) with BTr and BLb, from the latter
only the first 35 days and the last 27 days were successful. In this
field, the following stars were observed (names in parenthesis): HD
34029 (alpha Aur), HD 40183 (beta Aur), HD 31964 (epsilon Aur), HD
32069 (zeta Aur), HD 32630 (eta Aur), HD 40312 (theta Aur), HD 39003
(nu Aur, only BTr), HD 31398 (iota Aur), and HD 34452 (IQ Aur). The
latter was observed only between JD 2457647 and 2457672. The Cet-Eri
field was observed with BHr from JD 2457668 to 2457757 (6th Oct., 2016
to 3rd Jan., 2017) with BHr only. In this field, HD 20630 (kappa1 Cet)
and HD 22468 (V711 Tau) were observed. Finally, HD 40183 (beta Tau)
was observed in two fields, with BLb from JD 2458030 (3rd Oct.,
2017) to 2458170 (20th Feb. 2018) and BTr from 2458155 (5th Feb.,
2018) to 2458179 (1st March, 2018) in field Tau, and again with Blb
from JD 2458749 (22nd Sept., 2019) to 2458871 (22nd Jan., 2020) in
field Ori-Tau. The BRITE data are obtained in different satellite
configurations and are provided by the BRITE consortium comprising HJD,
absolute magnitude plus ancillary data used for data decorrelation. For
analysis of the individual stars, data within an orbit, consisting
of up to 60 individual data points taken in immediate succession,
were 3-sigma clipped and then zero-point adjusted, see paper for
details. Provided in the data files are HJD and magnitude averages plus
an error estimate which is the sample standard deviation divided by the
square-root of the number of observations within an orbit (RMS). The
STELLA-SES spectroscopic data were obtained contemporaneously to the
BRITE data for nine stars, namely HD 34029, HD 31964, HD 40183, HD
32630, HD 40312, HD 39003, HD 31398, HD 20630, and HD 22468, usually
on a daily basis. The first two stars have been observed in extended
campaigns. Consequentially, for HD 34029, all observed epochs from JD
2454305 (24th July 2007) to 2458996 (26th May 2020) are listed, while
HD 31964 data spans from 2457228 (25th July 2015) to 2458242 (3rd May
2018). Barycentric radial velocities (RV) were determined from an
order-by-order cross correlation with a synthetic template spectrum. 60
echelle orders were used, the RV in the files is the weighted average,
the error is the RMS value. (3 data files).

---------------------------------------------------------
Title: VizieR Online Data Catalog: Linelist (Hansen+, 2020)
Authors: Hansen, C. J.; Koch, A.; Mashonkina, L.; Magg, M.; Bergemann,
M.; Sitnova, T.; Gallagher, A. J.; Ilyin, I.; Caffau, E.; Zhang,
H. W.; Strassmeier, K. G.; Klessen, R. S.
2020yCat..36430049H Altcode:
Linelist containing wavelength, element and ionisation degree (0 =
neutral, 1 = single ionised), excitation potential [eV], oscillator
strength (loggf), number of stars in the study in which the line
has been detected (limits indicated by &lt;), and finally, hyperfine
structure of oscillator strength indicated by HFS. (1 data file).

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Title: Probing the atmosphere of HD189733b with the Na I and K I lines
Authors: Keles, E.; Kitzmann, D.; Mallonn, M.; Alexoudi, X.; Fossati,
L.; Pino, L.; Seidel, J. V.; Carroll, T. A.; Steffen, M.; Ilyin, I.;
Poppenhäger, K.; Strassmeier, K. G.; von Essen, C.; Nascimbeni, V.;
Turner, J. D.
2020MNRAS.498.1023K Altcode: 2020MNRAS.tmp.2443K; 2020arXiv200804044K
High spectral resolution transmission spectroscopy is a powerful tool to
characterize exoplanet atmospheres. Especially for hot Jupiters, this
technique is highly relevant, due to their high-altitude absorption,
e.g. from resonant sodium (Na I) and potassium (K I) lines. We resolve
the atmospheric K I absorption on HD189733b with the aim to compare
the resolved K I line and previously obtained high-resolution Na
I-D line observations with synthetic transmission spectra. The line
profiles suggest atmospheric processes leading to a line broadening of
the order of ∼10 km/s for the Na I-D lines and only a few km/s for
the K I line. The investigation hints that either the atmosphere of
HD189733b lacks a significant amount of K I or the alkali lines probe
different atmospheric regions with different temperature, which could
explain the differences we see in the resolved absorption lines.

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Title: On the Chemical Abundance of HR 8799 and the Planet c
Authors: Wang, Ji; Wang, Jason J.; Ma, Bo; Chilcote, Jeffrey; Ertel,
Steve; Guyon, Olivier; Ilyin, Ilya; Jovanovic, Nemanja; Kalas, Paul;
Lozi, Julien; Macintosh, Bruce; Strassmeier, Klaus G.; Stone, Jordan
2020AJ....160..150W Altcode: 2020arXiv200702810W
Comparing chemical abundances of a planet and the host star reveals
the origin and formation pathway of the planet. Stellar abundance is
measured with high-resolution spectroscopy. Planet abundance, on the
other hand, is usually inferred from low-resolution data. For directly
imaged exoplanets, the data are available from a slew of high-contrast
imaging/spectroscopy instruments. Here, we study the chemical abundance
of HR 8799 and its planet c. We measure stellar abundance using
LBT/PEPSI (R = 120,000) and archival HARPS data: stellar [C/H], [O/H],
and C/O are 0.11 ± 0.12, 0.12 ± 0.14, and ${0.54}_{-0.09}^{+0.12}$ ,
all consistent with solar values. We conduct atmospheric retrieval using
newly obtained Subaru/CHARIS data together with archival Gemini/GPI and
Keck/OSIRIS data. We model the planet spectrum with petitRADTRANS and
conduct retrieval using PyMultiNest. Retrieved planetary abundance can
vary by ∼0.5 dex, from sub-stellar to stellar C and O abundances. The
variation depends on whether strong priors are chosen to ensure a
reasonable planet mass. Moreover, comparison with previous works
also reveals inconsistency in abundance measurements. We discuss
potential issues that can cause the inconsistency, e.g., systematics
in individual data sets and different assumptions in the physics and
chemistry in retrieval. We conclude that no robust retrieval can be
obtained unless the issues are fully resolved.

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Title: The rotation period distribution of the rich Pleiades-age
southern open cluster NGC 2516. Existence of a representative zero-age
main sequence distribution
Authors: Fritzewski, D. J.; Barnes, S. A.; James, D. J.; Strassmeier,
K. G.
2020A&A...641A..51F Altcode: 2021arXiv211203299F
 Aims: We wish to measure the cool star rotation period
distribution for the Pleiades-age rich open cluster NGC 2516 and
use it to determine whether cluster-to-cluster variations exist in
otherwise identical open clusters. Methods: We obtained 42
d-long time-series CCD photometry of NGC 2516 in the V and Ic
filters using the Yale 1 m telescope at CTIO and performed a number of
related analyses, including PSF-based time-series photometry. Our data
are complemented with additional information from several photometric
datasets, literature radial velocities, and Gaia DR2 astrometry. All
available data are used to construct an integrated membership list
for NGC 2516, containing 844 stars in our ≈1° field of view. Results: We derived 308 rotation periods for late-F to mid-M
cluster members from our photometry. We identified an additional
247 periodic M dwarf stars from a prior study as cluster members,
and used these to construct a 555-star rotation period distribution
for NGC 2516. The colour-period diagram (in multiple colours) has
almost no outliers and exhibits the anticipated triangular shape,
with a diagonal slow rotator sequence that is preferentially occupied
by the warmer stars along with a flat fast rotator sequence that is
preferentially populated by the cooler cluster members. We also find a
group of extremely slowly rotating M dwarfs (10 d ≲ Prot
≲ 23 d), forming a branch in the colour-period diagram which we call
the "extended slow rotator sequence". This, and other features of the
rotational distribution can also be found in the Pleiades, making the
colour-period diagrams of the two clusters nearly indistinguishable. A
comparison with the well-studied (and similarly aged) open cluster
M 35 indicates that the cluster's rotational distribution is also
similarly indistinguishable from that of NGC 2516. Those for the open
clusters M 50 and Blanco 1 are similar, but data issues for those
clusters make the comparisons somewhat more ambiguous. Nevertheless,
we demonstrate the existence of a representative zero-age main sequence
rotational distribution and provide a simple colour-independent way
to represent it. We perform a detailed comparison of the NGC 2516
rotation period data with a number of recent rotational evolution
models. Using X-ray data from the literature, we also construct the
first rotation-activity diagram for solar-type stars in NGC 2516,
one that we find is essentially indistinguishable from those for
the Pleiades and Blanco 1. Conclusions: The two clusters
NGC 2516 and Pleiades can be considered twins in terms of stellar
rotation and related properties (and M 35, M 50, and Blanco 1 are
similar), suggesting that otherwise identical open clusters also have
intrinsically similar cool star rotation and activity distributions. Full Tables 3 and 4 are only available at the CDS via anonymous ftp to
<A href="http://cdsarc.u-strasbg.fr/">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/641/A51">http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/641/A51</A>
Based on observations at Cerro Tololo Inter-American Observatory,
National Optical Astronomy Observatory under proposal 2008A-0476.

---------------------------------------------------------
Title: Spatially Resolved Ultraviolet Spectroscopy of the Great
Dimming of Betelgeuse
Authors: Dupree, Andrea K.; Strassmeier, Klaus G.; Matthews, Lynn
D.; Uitenbroek, Han; Calderwood, Thomas; Granzer, Thomas; Guinan,
Edward F.; Leike, Reimar; Montargès, Miguel; Richards, Anita M. S.;
Wasatonic, Richard; Weber, Michael
2020ApJ...899...68D Altcode: 2020arXiv200804945D
The bright supergiant Betelgeuse (Alpha Orionis, HD 39801) experienced
a visual dimming during 2019 December and the first quarter of
2020, reaching an historic minimum 2020 February 7-13. During 2019
September-November, prior to the optical dimming event, the photosphere
was expanding. At the same time, spatially resolved ultraviolet spectra
using the Hubble Space Telescope/Space Telescope Imaging Spectrograph
revealed a substantial increase in the ultraviolet spectrum and Mg II
line emission from the chromosphere over the southern hemisphere of the
star. Moreover, the temperature and electron density inferred from the
spectrum and C II diagnostics also increased in this hemisphere. These
changes happened prior to the Great Dimming Event. Variations in the
Mg II k-line profiles suggest material moved outwards in response to
the passage of a pulse or acoustic shock from 2019 September through
November. It appears that this extraordinary outflow of material from
the star, likely initiated by convective photospheric elements, was
enhanced by the coincidence with the outward motions in this phase of
the ∼400 day pulsation cycle. These ultraviolet observations appear
to provide the connecting link between the known large convective cells
in the photosphere and the mass ejection event that cooled to form
the dust cloud in the southern hemisphere imaged in 2019 December, and
led to the exceptional optical dimming of Betelgeuse in 2020 February.

---------------------------------------------------------
Title: Role of the impact parameter in exoplanet transmission
spectroscopy
Authors: Alexoudi, X.; Mallonn, M.; Keles, E.; Poppenhäger, K.;
von Essen, C.; Strassmeier, K. G.
2020A&A...640A.134A Altcode: 2020arXiv200707716A
Context. Transmission spectroscopy is a promising tool for the
atmospheric characterization of transiting exoplanets. Because the
planetary signal is faint, discrepancies have been reported regarding
individual targets. Aims: We investigate the dependence of the
estimated transmission spectrum on deviations of the orbital parameters
of the star-planet system that are due to the limb-darkening effects of
the host star. We describe how the uncertainty on the orbital parameters
translates into an uncertainty on the planetary spectral slope. 
Methods: We created synthetic transit light curves in seven different
wavelength bands, from the near-ultraviolet to the near-infrared, and
fit them with transit models parameterized by fixed deviating values
of the impact parameter b. First, we performed a qualitative study to
illustrate the effect by presenting the changes in the transmission
spectrum slope with different deviations of b. Then, we quantified these
variations by creating an error envelope (for centrally transiting,
off-center, and grazing systems) based on a derived typical uncertainty
on b from the literature. Finally, we compared the variations in the
transmission spectra for different spectral types of host stars. 
Results: Our simulations show a wavelength-dependent offset that is more
pronounced at the blue wavelengths where the limb-darkening effect is
stronger. This offset introduces a slope in the planetary transmission
spectrum that becomes steeper with increasing b values. Variations
of b by positive or negative values within its uncertainty interval
introduce positive or negative slopes, thus the formation of an error
envelope. The amplitude from blue optical to near-infrared wavelength
for a typical uncertainty on b corresponds to one atmospheric pressure
scale height and more. This impact parameter degeneracy is confirmed for
different host types; K stars present prominently steeper slopes, while
M stars indicate features at the blue wavelengths. Conclusions:
We demonstrate that transmission spectra can be hard to interpret,
basically because of the limitations in defining a precise impact
parameter value for a transiting exoplanet. This consequently limits
a characterization of its atmosphere.

---------------------------------------------------------
Title: VizieR Online Data Catalog: NGC 2516 membership list
(Fritzewski+, 2020)
Authors: Fritzewski, D. J.; Barnes, S. A.; James, D. J.; Strassmeier,
K. G.
2020yCat..36410051F Altcode:
Table 2 lists radial velocity variable stars in NGC 2516 which can
be considered radial velocity binaries. Their radial velocities were
acquired from various sources in the literature (see references of Table
2). Table 3 includes our members of NGC 2516 upon which we based
the analysis of the rotation periods. The data are exclusively taken
from the literature and the membership is based on photometry, radial
velocities, parallax, and proper motions. Table 4 includes rotation
periods measured from our photometric time-series campaign between 19
February 2008 and 01 April 2008 at the CTIO Yale 1m telescope. This
table lists additional periods by Irwin et al. (2007MNRAS.377..741I,
Cat. J/MNRAS/377/741) and related activity properties. (3 data
files).

---------------------------------------------------------
Title: The STIX Aspect System (SAS): The Optical Aspect System of
the Spectrometer/Telescope for Imaging X-Rays (STIX) on Solar Orbiter
Authors: Warmuth, A.; Önel, H.; Mann, G.; Rendtel, J.; Strassmeier,
K. G.; Denker, C.; Hurford, G. J.; Krucker, S.; Anderson, J.;
Bauer, S. -M.; Bittner, W.; Dionies, F.; Paschke, J.; Plüschke,
D.; Sablowski, D. P.; Schuller, F.; Senthamizh Pavai, V.; Woche, M.;
Casadei, D.; Kögl, S.; Arnold, N. G.; Gröbelbauer, H. -P.; Schori,
D.; Wiehl, H. J.; Csillaghy, A.; Grimm, O.; Orleanski, P.; Skup,
K. R.; Bujwan, W.; Rutkowski, K.; Ber, K.
2020SoPh..295...90W Altcode:
The Spectrometer/Telescope for Imaging X-rays (STIX) is a remote
sensing instrument on Solar Orbiter that observes the hard X-ray
bremsstrahlung emission of solar flares. This paper describes the
STIX Aspect System (SAS), a subunit that measures the pointing of
STIX relative to the Sun with a precision of ±4″, which
is required to accurately localize the reconstructed X-ray images on
the Sun. The operating principle of the SAS is based on an optical
lens that images the Sun onto a plate that is perforated by small
apertures arranged in a cross-shaped configuration of four radial
arms. The light passing through the apertures of each arm is detected
by a photodiode. Variations of spacecraft pointing and of distance
from the Sun cause the solar image to move over different apertures,
leading to a modulation of the measured lightcurves. These signals are
used by ground analysis to calculate the locations of the solar limb,
and hence the pointing of the telescope.

---------------------------------------------------------
Title: 16th Potsdam Thinkshop: The rotation periods of cool stars:
Measurements, uses, connections and prospects
Authors: Barnes, S. A.; Steffen, M.; Strassmeier, K. G.
2020AN....341..485B Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Improving spectroscopic lithium abundances. Fitting functions
for 3D non-LTE corrections in FGK stars of different metallicity
Authors: Mott, A.; Steffen, M.; Caffau, E.; Strassmeier, K. G.
2020A&A...638A..58M Altcode: 2020arXiv200410803M
Context. Accurate spectroscopic lithium abundances are essential in
addressing a variety of open questions, such as the origin of a uniform
lithium content in the atmospheres of metal-poor stars (Spite plateau)
or the existence of a correlation between the properties of extrasolar
planetary systems and the lithium abundance in the atmosphere of
their host stars. Aims: We have developed a tool that allows
the user to improve the accuracy of standard lithium abundance
determinations based on 1D model atmospheres and the assumption of
local thermodynamic equilibrium (LTE) by applying corrections that
account for hydrodynamic (3D) and non-LTE (NLTE) effects in FGK stars
of different metallicity. Methods: Based on a grid of CO5BOLD
3D models and associated 1D hydrostatic atmospheres, we computed
three libraries of synthetic spectra of the lithium λ 670.8 nm line
for a wide range of lithium abundances, accounting for detailed line
formation in 3D NLTE, 1D NLTE, and 1D LTE, respectively. The resulting
curves-of-growth were then used to derive 3D NLTE and 1D NLTE lithium
abundance corrections. Results: For all metallicities, the
largest corrections are found at the coolest effective temperature,
Teff = 5000 K. They are mostly positive, up to + 0.2 dex,
for the weakest lines (lithium abundance A(Li)1DLTE = 1.0),
whereas they become more negative towards lower metallicities, where
they can reach - 0.4 dex for the strongest lines (A(Li)1DLTE
= 3.0) at [Fe/H] = - 2.0. We demonstrate that 3D and NLTE effects are
small for metal-poor stars on the Spite plateau, leading to errors of at
most ± 0.05 dex if ignored. We present analytical functions evaluating
the 3D NLTE and 1D NLTE corrections as a function of Teff
[5000…6500 K], log g [3.5…4.5], and LTE lithium abundance A(Li)
[1.0…3.0] for a fixed grid of metallicities [Fe/H] [ - 3.0…0.0]. In
addition, we also provide analytical fitting functions for directly
converting a given lithium abundance into an equivalent width, or vice
versa, a given equivalent width (EW) into a lithium abundance. For
convenience, a Python script is made available that evaluates all
fitting functions for given Teff, log g, [Fe/H], and A(Li)
or EW. Conclusions: By means of the fitting functions developed
in this work, the results of complex 3D and NLTE calculations are
made readily accessible and quickly applicable to large samples of
stars across a wide range of metallicities. Improving the accuracy
of spectroscopic lithium abundance determinations will contribute to
a better understanding of the open questions related to the lithium
content in metal-poor and solar-like stellar atmospheres.

---------------------------------------------------------
Title: Focus on Betelgeuse
Authors: Dupree, Andrea; Chiavassa, Andrea; Freytag, Bernd; Harper,
Graham M.; Kervella, Pierre; Lebre, Agnes; Montarges, Miguel; Ohnaka,
Keiichi; Quirrenbach, Andreas; Richards, Anita; Schmitt, Henrique R.;
Strassmeier, Klaus G.; Uitenbroek, Han; Wheeler, J. Craig; Wittkowski,
Markus; Matthews, Lynn D.
2020hst..prop16216D Altcode:
Multiple ultraviolet spectra of the nearby red supergiant, Betelgeuse,
using STIS will enable spatially resolved measures of chromospheric
structure and mass inflows and outflows. An HST campaign of 3 cycles
will be complemented by multi-frequency photometry, spectroscopy,
interferometry, and polarimetry at radio, infrared, and optical
wavelengths in order to map surface structures and their variability,
and the extended outer atmosphere over both the short (400-day)
and long secondary (2000-day) periods of this supergiant. These
observations, coupled with detailed modeling and simulations, will
probe the structure, the dynamics, and the mass loss from Betelgeuse in
unprecedented detail and provide crucial insights into the atmospheric
physics and wind-driving mechanisms of red supergiants.

---------------------------------------------------------
Title: Lithium in T Coronae Borealis
Authors: Woodward, C. E.; Pavlenko, Ya. V.; Evans, A.; Wagner, R. M.;
IIyin, I.; Strassmeier, K. G.; Starrfield, S.; Munari, U.
2020AJ....159..231W Altcode:
T Coronae Borealis is a recurrent, symbiotic nova system
currently in quiescence between its periodic ≍80 yr cycle of
eruptions. Observations during inter-outburst epochs provide an
opportunity to study properties of the accretion disk and the M red
giant. Here we present new irradiated (blackbody veiling) models,
incorporating modern molecular opacities and line lists, of spectra
derived from high-resolution (22,000 ≲ R ≲ 120,000) optical echelle
observations obtained at two epochs, one prior to and one post the 2015
rebrightening event at similar spectroscopic system phase. We find a
lithium abundance in the secondary at both epochs to be comparable. The
non-irradiated (classical) model atmospheres yield a lithium abundance,
A(Li) = 1.3 ± 0.1. The irradiated model (veiled) atmospheres, which are
likely a better representation of the system in which the white dwarf
and accretion disk illuminate the red giant, give A(Li) = 2.4 ± 0.1.

---------------------------------------------------------
Title: No Consistent Atmospheric Absorption Detected for the Ultra-hot
Jupiter WASP-189 b
Authors: Cauley, P. Wilson; Shkolnik, Evgenya L.; Ilyin, Ilya;
Strassmeier, Klaus G.; Redfield, Seth; Jensen, Adam
2020RNAAS...4...53C Altcode: 2020arXiv200406859C
We observed a partial transit of the ultra-hot Jupiter WASP-189 b with
PEPSI on the LBT. We detect a highly variable transit signal in multiple
atomic transitions, including H-alpha, Fe I, and Mg I. The signal
is not consistent with a transiting planetary atmosphere. We suggest
instead that the in-transit signal is due to an inhomogeneous stellar
surface. Our observations demonstrate the lack of a highly extended
atmosphere in common optical atomic tracers. Although WASP-189 is very
bright, atmospheric characterization of the planet will be difficult
due to the small transit depth and apparently compact atmosphere.

---------------------------------------------------------
Title: Monitoring solar activity with PEPSI
Authors: Dineva, Ekaterina; Denker, Carsten; Strassmeier, Klaus G.;
Ilyin, Ilya; Pevtsov, Alexei A.
2020IAUGA..30..351D Altcode:
Synoptic Sun-as-a-star observations are carried out with the Potsdam
Echelle Polarimetric and Spectroscopic Instrument (PEPSI), which
receives light from the Solar Disk-Integration (SDI) telescope. Daily
spectra are produced with a high signal-to-noise ratio, providing access
to unprecedented quasi-continuous, long-term, disk-integrated spectra
of the Sun with high spectral and temporal resolution. We developed
tools to monitor and study solar activity on different time-scales
ranging from daily changes, over periods related to solar rotation,
to annual and decadal trends. Strong chromospheric absorption lines,
such as the Ca ii H &amp; K λ3934 &amp; 3968 Å lines, are powerful
diagnostic tools for solar activity studies, since they trace the
variations of the solar magnetic field. Other lines, such as Hα λ6563
Å line and the near-infrared (NIR) Ca ii λ8542 Å line, provide
additional information on the physical properties in this highly
complex and dynamic atmospheric layer. Currently, we work on a data
pipeline for extraction, calibration, and analysis of the PEPSI/SDI
data. We compare the SDI data with daily spectra from the Integrated
Sunlight Spectrometer (ISS), which is part of the Synoptic Long-Term
Investigation of the Sun (SOLIS) facility operated by the U.S. National
Solar Observatory (NSO). This facilitates cross-calibration and
validation of the SDI data.

---------------------------------------------------------
Title: High-resolution spectroscopy and spectropolarimetry of the
total lunar eclipse January 2019
Authors: Strassmeier, K. G.; Ilyin, I.; Keles, E.; Mallonn, M.;
Järvinen, A.; Weber, M.; Mackebrandt, F.; Hill, J. M.
2020A&A...635A.156S Altcode: 2020arXiv200208690S
Context. Observations of the Earthshine off the Moon allow for the
unique opportunity to measure the large-scale Earth atmosphere. Another
opportunity is realized during a total lunar eclipse which, if
seen from the Moon, is like a transit of the Earth in front of the
Sun. Aims: We thus aim at transmission spectroscopy of an
Earth transit by tracing the solar spectrum during the total lunar
eclipse of January 21, 2019. Methods: Time series spectra of
the Tycho crater were taken with the Potsdam Echelle Polarimetric and
Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope in
its polarimetric mode in Stokes IQUV at a spectral resolution of 130
000 (0.06 Å). In particular, the spectra cover the red parts of the
optical spectrum between 7419-9067 Å. The spectrograph's exposure meter
was used to obtain a light curve of the lunar eclipse. Results:
The brightness of the Moon dimmed by 10.m75 during umbral
eclipse. We found both branches of the O2 A-band almost
completely saturated as well as a strong increase of H2O
absorption during totality. A pseudo O2 emission feature
remained at a wavelength of 7618 Å, but it is actually only a residual
from different P-branch and R-branch absorptions. It nevertheless
traces the eclipse. The deep penumbral spectra show significant excess
absorption from the Na I 5890-Å doublet, the Ca II infrared triplet
around 8600 Å, and the K I line at 7699 Å in addition to several
hyper-fine-structure lines of Mn I and even from Ba II. The detections
of the latter two elements are likely due to an untypical solar
center-to-limb effect rather than Earth's atmosphere. The absorption in
Ca II and K I remained visible throughout umbral eclipse. Our radial
velocities trace a wavelength dependent Rossiter-McLaughlin effect of
the Earth eclipsing the Sun as seen from the Tycho crater and thereby
confirm earlier observations. A small continuum polarization of the
O2 A-band of 0.12% during umbral eclipse was detected at
6.3σ. No line polarization of the O2 A-band, or any other
spectral-line feature, is detected outside nor inside eclipse. It
places an upper limit of ≈0.2% on the degree of line polarization
during transmission through Earth's atmosphere and magnetosphere. All 1D spectra are only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/635/A156">http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/635/A156</A>
Based on data acquired with the Potsdam Echelle Polarimetric and
Spectroscopic Instrument (PEPSI) using the Large Binocular Telescope
(LBT) in Arizona.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Total lunar eclipse January 2019
spectra (Strassmeier+, 2020)
Authors: Strassmeier, K. G.; Ilyin, I.; Keles, E.; Mallonn, M.;
Jaervinen, A.; Weber, M.; Mackebrandt, F.; Hill, J. M.
2020yCat..36350156S Altcode:
All observations were obtained with PEPSI (Strassmeier et al.,
2015AN....336..324S) at the 28.4m LBT (Hill et al., 2012, Proc. SPIE,
8444-1) in Arizona. Observations of the Moon commenced between
UT 3:25 and 7:41 on January 21, 2019. Maximum of the total eclipse
was at UT 5:12. (3 data files).

---------------------------------------------------------
Title: Sun-as-a-star observations of the 2017 August 21 solar eclipse
Authors: Dineva, Ekaterina; Denker, Carsten; Verma, Meetu; Strassmeier,
Klaus G.; Ilyin, Ilya; Milic, Ivan
2020IAUS..354..473D Altcode:
The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI)
is a state-of-the-art, thermally stabilized, fiber-fed, high-resolution
spectrograph for the Large Binocular Telescope (LBT) at Mt. Graham,
Arizona. During daytime the instrument is fed with sunlight from the
10-millimeter aperture, fully automated, binocular Solar Disk-Integrated
(SDI) telescope. The observed Sun-as-a-star spectra contain a multitude
of photospheric and chromospheric spectral lines in the wavelength
ranges 4200-4800 Å and 5300-6300 Å. One of the advantages of PEPSI
is that solar spectra are recorded in the exactly same manner as
nighttime targets. Thus, solar and stellar spectra can be directly
compared. PEPSI/SDI recorded 116 Sun-as-a-star spectra during the
2017 August 21 solar eclipse. The observed maximum obscuration was
61.6%. The spectra were taken with a spectral resolution of ≈ 250000
and an exposure time of 0.3 s. The high-spectral resolution facilitates
detecting subtle changes in the spectra while the Moon passes the solar
disk. Sun-as-a-star spectra are affected by changing contributions due
to limb darkening and solar differential rotation, and to a lesser
extend by supergranular velocity pattern and the presence of active
regions on the solar surface. The goal of this study is to investigate
the temporal evolution of the chromospheric Na D doublet during the
eclipse and to compare observations with synthetic line profiles
computed with the state-of-the-art Bifrost code.

---------------------------------------------------------
Title: LBT/PEPSI Spectropolarimetry of a Magnetic Topology Shift in
Old Solar-type Stars
Authors: Metcalfe, T. S.; Kochukhov, O.; Ilyin, I.; Strassmeier, K.;
Godoy Rivera, D.; Pinsonneault, M.
2020AAS...23513105M Altcode:
Solar-type stars are born with relatively rapid rotation and strong
magnetic fields. Through a process known as magnetic braking, the
rotation slows over time as stellar winds gradually remove angular
momentum from the system. The rate of angular momentum loss depends
sensitively on the magnetic topology, with the dipole field exerting
the largest torque on the star. Recent observations suggest that the
efficiency of magnetic braking may decrease dramatically in stars
near the middle of their main-sequence lifetimes. One hypothesis to
explain this reduction in efficiency is a shift in magnetic topology
from predominantly larger to smaller spatial scales. We aim to test
this hypothesis with spectropolarimetric measurements of two stars
that sample chromospheric activity levels above and below the proposed
magnetic transition. As predicted, the more active star (HD 100180)
exhibits a significant Stokes profile due to a non-axisymmetric
large-scale magnetic field, while the less active star (HD 143761)
shows no significant signal. We identify analogs of the two stars
among a sample of well-characterized Kepler targets, and we predict
that the asteroseismic age of HD 143761 from future TESS observations
will substantially exceed the age expected from gyrochronology. We
conclude that a shift in magnetic topology is likely to be responsible
for the loss of magnetic braking in middle-aged stars, which appears
to coincide with the shutdown of their global dynamos.

---------------------------------------------------------
Title: Cycle times of early M dwarf stars: mean field models versus
observations
Authors: Küker, Manfred; Rüdiger, Günther; Oláh, Katalin;
Strassmeier, Klaus G.
2020IAUS..354..116K Altcode: 2019arXiv191113094K
Observations of early-type M stars suggest that there are two
characteristic cycle times, one of order one year for fast rotators
(Prot &lt; 1 day) and another of order four years for slower
rotators. For a sample of fast-rotating stars, the equator-to-pole
differences of the rotation rates up to 0.03 rad d-1 are also known
from Kepler data. These findings are well-reproduced by mean field
models. These models predict amplitudes of the meridional flow,
from which the travel time from pole to equator at the base of the
convection zone of early-type M stars can be calculated. As these
travel times always exceed the observed cycle times, our findings do
not support the flux transport dynamo.

---------------------------------------------------------
Title: Letter from the Editor
Authors: Strassmeier, Klaus G.
2020AN....341....9S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: LBT/PEPSI Spectropolarimetry of a Magnetic Morphology Shift
in Old Solar-type Stars
Authors: Metcalfe, T. S.; Kochukhov, O.; Ilyin, I. V.; Strassmeier,
K. G.; Godoy-Rivera, D.; Pinsonneault, M. H.
2019ApJ...887L..38M Altcode: 2019arXiv191201186M
Solar-type stars are born with relatively rapid rotation and strong
magnetic fields. Through a process known as magnetic braking, the
rotation slows over time as stellar winds gradually remove angular
momentum from the system. The rate of angular momentum loss depends
sensitively on the magnetic morphology, with the dipole field exerting
the largest torque on the star. Recent observations suggest that the
efficiency of magnetic braking may decrease dramatically in stars
near the middle of their main-sequence lifetimes. One hypothesis to
explain this reduction in efficiency is a shift in magnetic morphology
from predominantly larger to smaller spatial scales. We aim to test
this hypothesis with spectropolarimetric measurements of two stars
that sample chromospheric activity levels on opposite sides of the
proposed magnetic transition. As predicted, the more active star (HD
100180) exhibits a significant circular polarization signature due to
a nonaxisymmetric large-scale magnetic field, while the less active
star (HD 143761) shows no significant signal. We identify analogs of
the two stars among a sample of well-characterized Kepler targets,
and we predict that the asteroseismic age of HD 143761 from future
Transiting Exoplanet Survey Satellite observations will substantially
exceed the age expected from gyrochronology. We conclude that a shift in
magnetic morphology likely contributes to the loss of magnetic braking
in middle-aged stars, which appears to coincide with the shutdown of
their global dynamos. 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 Board of Regents; Istituto 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.

---------------------------------------------------------
Title: The potassium absorption on HD189733b and HD209458b
Authors: Keles, Engin; Mallonn, Matthias; von Essen, Carolina;
Carroll, Thorsten A.; Alexoudi, Xanthippi; Pino, Lorenzo; Ilyin,
Ilya; Poppenhäger, Katja; Kitzmann, Daniel; Nascimbeni, Valerio;
Turner, Jake D.; Strassmeier, Klaus G.
2019MNRAS.489L..37K Altcode: 2019arXiv190904884K; 2019MNRAS.tmpL.124K
In this work, we investigate the potassium excess absorption around
7699 Å of the exoplanets HD189733b and HD209458b. For this purpose,
we used high-spectral resolution transit observations acquired with
the 2 × 8.4 m Large Binocular Telescope (LBT) and the Potsdam Echelle
Polarimetric and Spectroscopic Instrument (PEPSI). For a bandwidth
of 0.8 Å, we present a detection &gt;7σ with an absorption level of
0.18 per cent for HD189733b. Applying the same analysis to HD209458b,
we can set 3σ upper limit of 0.09 per cent, even though we do not
detect a K-excess absorption. The investigation suggests that the K
feature is less present in the atmosphere of HD209458b than in the
one of HD189733b. This comparison confirms previous claims that the
atmospheres of these two planets must have fundamentally different
properties.

---------------------------------------------------------
Title: Antisolar differential rotation of slowly rotating cool stars
Authors: Rüdiger, G.; Küker, M.; Käpylä, P. J.; Strassmeier, K. G.
2019A&A...630A.109R Altcode: 2019arXiv190204172R
Rotating stellar convection transports angular momentum towards
the equator, generating the characteristic equatorial acceleration
of the solar rotation while the radial flux of angular momentum is
always inwards. New numerical box simulations for the meridional
cross-correlation ⟨uθuϕ⟩, however, reveal
the angular momentum transport towards the poles for slow rotation
and towards the equator for fast rotation. The explanation is that for
slow rotation a negative radial gradient of the angular velocity always
appears, which in combination with a so-far neglected rotation-induced
off-diagonal eddy viscosity term ν⊥ provides
"antisolar rotation" laws with a decelerated equator. Similarly,
the simulations provided positive values for the rotation-induced
correlation ⟨uruθ⟩, which is relevant for
the resulting latitudinal temperature profiles (cool or warm poles)
for slow rotation and negative values for fast rotation. Observations
of the differential rotation of slowly rotating stars will therefore
lead to a better understanding of the actual stress-strain relation,
the heat transport, and the underlying model of the rotating convection.

---------------------------------------------------------
Title: Project BMK10k: Zeiss Ballistische Messkammer with a 10k ×
10k CCD for ground-based PLATO support
Authors: Strassmeier, Klaus G.; Granzer, Thomas; Weingrill, Jörg;
Woche, Manfred; Bittner, Wilbert; Bauer, Svend-Marian; Paschke, Jens;
Chini, Rolf
2019AN....340..712S Altcode:
Ballistische Messkammer with 10k CCD's (BMK10k) central goal is
supporting the upcoming PLAnetary Transits and Oscillation of
stars (PLATO) mission by reducing its number of false positives
(planet-compatible transit candidates but not planets at the
end). For Kepler, the number of false positives had been estimated
to still be about 10%. Understanding the PLATO false alarm rate is
not as straightforward, and preparatory data from the ground will
dramatically improve the target selection and minimize the number
of false positives. We aim to identify the target contamination
for every PLATO target and initially provide well-sampled light
curves of all detectable contaminants in the long-duration southern
PLATO field. Thereby, it will be possible to identify background
eclipsing binaries and rotating spotted stars with periods between
1 hr and 100 days down to 17-18th mag. This will be achieved with a
dedicated robotic telescope with one of the world's largest CCDs with
the smallest pixels, enabling a field of view of 52.5 square degrees
with a sampling of 2.5″/pix. Auxiliary science is also foreseen and
will focus on the period-mass relation of Ptolemy's cluster (M7). In
this paper, we describe the entire telescope system and show initial
commissioning data.

---------------------------------------------------------
Title: Focus on Betelgeuse
Authors: Dupree, Andrea; Chiavassa, Andrea; Freytag, Bernd; Harper,
Graham M.; Kervella, Pierre; Lebre, Agnes; Montarges, Miguel; Ohnaka,
Keiichi; Quirrenbach, Andreas; Richards, Anita; Schmitt, Henrique R.;
Strassmeier, Klaus G.; Uitenbroek, Han; Wheeler, J. Craig; Wittkowski,
Markus; Matthews, Lynn D.
2019hst..prop15873D Altcode:
Multiple ultraviolet spectra of the nearby red supergiant, Betelgeuse,
using STIS will enable spatially resolved measures of chromospheric
structure and mass inflows and outflows. An HST campaign of 3 cycles
will be complemented by multi-frequency photometry, spectroscopy,
interferometry, and polarimetry at radio, infrared, and optical
wavelengths in order to map surface structures and their variability,
and the extended outer atmosphere over both the short (400-day)
and long secondary (2000-day) periods of this supergiant. These
observations, coupled with detailed modeling and simulations, will
probe the structure, the dynamics, and the mass loss from Betelgeuse in
unprecedented detail and provide crucial insights into the atmospheric
physics and wind-driving mechanisms of red supergiants.

---------------------------------------------------------
Title: Warm and cool starspots with opposite polarities. A
high-resolution Zeeman-Doppler-Imaging study of II Pegasi with PEPSI
Authors: Strassmeier, K. G.; Carroll, T. A.; Ilyin, I. V.
2019A&A...625A..27S Altcode: 2019arXiv190211201S
 Aims: We present a temperature and a magnetic-field surface
map of the K2 subgiant of the active binary II Peg. Employed are
high resolution Stokes IV spectra obtained with the new Potsdam
Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the
Large Binocular Telescope (LBT). Methods: Fourteen average
line profiles are inverted using our iMap code. We have employed
an iterative regularization scheme without the need of a penalty
function and incorporate a physical 3D description of the surface field
vector. The spectral resolution of our data is 130 000 which converts
to 20 resolution elements across the disk of II Peg. Results: Our
main result is that the temperature features on II Peg closely correlate
with its magnetic field topology. We find a warm spot (350 K warmer with
respect to the effective temperature) of positive polarity and radial
field density of 1.1 kG coexisting with a cool spot (780 K cooler) of
negative polarity of 2 kG. Several other cool features are reconstructed
containing both polarities and with (radial) field densities of up to 2
kG. The largest cool spot is reconstructed with a temperature contrast
of 550 K, an area of almost 10% of the visible hemisphere, and with a
multipolar magnetic morphology. A meridional and an azimuthal component
of the field of up to ±500 G is detected in two surface regions
between spots with strong radial fields but different polarities. A
force-free magnetic-field extrapolation suggests that the different
polarities of cool spots and the positive polarity of warm spots are
physically related through a system of coronal loops of typical height
of ≈2 R⋆. While the Hα line core and its red-side wing
exhibit variations throughout all rotational phases, a major increase
of blue-shifted Hα emission was seen for the phases when the warm spot
is approaching the stellar central meridian indicating high-velocity
mass motion within its loop. Conclusions: Active stars such as
II Peg can show coexisting cool and warm spots on the surface that
we interpret resulting from two different formation mechanisms. We
explain the warm spots due to photospheric heating by a shock front
from a siphon-type flow between regions of different polarities while
the majority of the cool spots is likely formed due to the expected
convective suppression like on the Sun. The reduced LBT spectra
(FITS files) are only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/625/A27">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/625/A27</A>Based
on data acquired with PEPSI using the Large Binocular Telescope
(LBT). The LBT is an international collaboration among institutions
in the United States, Italy, and Germany.

---------------------------------------------------------
Title: Spectropolarimetric Observations of an Arch Filament System
with GREGOR
Authors: Balthasar, H.; Gömöry, P.; González Manrique, S. J.;
Kuckein, C.; Kučera, A.; Schwartz, P.; Berkefeld, T.; Collados, M.;
Denker, C.; Feller, A.; Hofmann, A.; Schlichenmaier, R.; Schmidt,
D.; Schmidt, W.; Sigwarth, M.; Sobotka, M.; Solanki, S. K.; Soltau,
D.; Staude, J.; Strassmeier, K. G.; von der Lühe, O.
2019ASPC..526..217B Altcode: 2018arXiv180401789B
We observed an arch filament system (AFS) in a sunspot group with the
GREGOR Infrared Spectrograph attached to the GREGOR solar telescope. The
AFS was located between the leading sunspot of negative polarity and
several pores of positive polarity forming the following part of the
sunspot group. We recorded five spectro-polarimetric scans of this
region. The spectral range included the spectral lines Si I 1082.7
nm, He I 1083.0 nm, and Ca I 1083.9 nm. In this work we concentrate
on the silicon line which is formed in the upper photosphere. The
line profiles are inverted with the code 'Stokes Inversion based
on Response functions' to obtain the magnetic field vector. The
line-of-sight velocities are determined independently with a Fourier
phase method. Maximum velocities are found close to the ends of AFS
fibrils. These maximum values amount to 2.4 km s-1 next
to the pores and to 4 km s-1 at the sunspot side. Between
the following pores, we encounter an area of negative polarity that
is decreasing during the five scans. We interpret this by new emerging
positive flux in this area canceling out the negative flux. In summary,
our findings confirm the scenario that rising magnetic flux tubes
cause the AFS.

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Title: Photospheric Magnetic Fields of the Trailing Sunspots in
Active Region NOAA 12396
Authors: Verma, M.; Balthasar, H.; Denker, C.; Böhm, F.; Fischer,
C. E.; Kuckein, C.; González Manrique, S. J.; Sobotka, M.; Bello
González, N.; Diercke, A.; Berkefeld, T.; Collados, M.; Feller, A.;
Hofmann, A.; Lagg, A.; Nicklas, H.; Orozco Suárez, D.; Pastor Yabar,
A.; Rezaei, R.; Schlichenmaier, R.; Schmidt, D.; Schmidt, W.; Sigwarth,
M.; Solanki, S. K.; Soltau, D.; Staude, J.; Strassmeier, K.; Volkmer,
R.; von der Lühe, O.; Waldmann, T.
2019ASPC..526..291V Altcode: 2018arXiv180507752V
The solar magnetic field is responsible for all aspects of solar
activity. Sunspots are the main manifestation of the ensuing solar
activity. Combining high-resolution and synoptic observations has
the ambition to provide a comprehensive description of the sunspot
growth and decay processes. Active region NOAA 12396 emerged on 2015
August 3 and was observed three days later with the 1.5-meter GREGOR
solar telescope on 2015 August 6. High-resolution spectropolarimetric
data from the GREGOR Infrared Spectrograph (GRIS) are obtained in the
photospheric lines Si I λ1082.7 nm and Ca I λ1083.9 nm, together
with the chromospheric He I λ1083.0 nm triplet. These near-infrared
spectropolarimetric observations were complemented by synoptic
line-of-sight magnetograms and continuum images of the Helioseismic
and Magnetic Imager (HMI) and EUV images of the Atmospheric Imaging
Assembly (AIA) on board the Solar Dynamics Observatory (SDO).

---------------------------------------------------------
Title: Stars and exoplanets in Stokes IQUV: a decadal opportunity
for HIRES at the ELT
Authors: Strassmeier, Klaus G.
2019arXiv190405075S Altcode:
We proposed that the European ELT will be equipped with an
ultra-high-precision polarimetric light feed as part of its high
resolution optical and near-IR spectrograph HIRES. Such a feed is unique
among the new ELTs and only possible in a rotationally symmetric focus
of the telescope. The ELT's f/4.4 intermediate focus near M4 could
provide such a capability with a polarimetric sensitivity of down to
10^(-5) for the brightest targets. Among the new science steps forward
with HIRES-Pol at the 39m ELT would be the full characterization
of solar-like stellar magnetospheres by means of Zeeman-Doppler
Imaging. In particular for planet-hosting stars it could constrain
the habitability of a planet based on its particle-emission geometry
from the host star. Besides, any stellar linear-polarization spectrum
is new territory for astrophysics and I refresh reasons why this can
be also important for exoplanet atmospheres.

---------------------------------------------------------
Title: Surface magnetic activity of the fast-rotating G5 giant IN
Comae, central star of the faint planetary nebula LoTr 5
Authors: Kővári, Zs.; Strassmeier, K. G.; Oláh, K.; Kriskovics,
L.; Vida, K.; Carroll, T. A.; Granzer, T.; Ilyin, I.; Jurcsik, J.;
Kővári, E.; Weber, M.
2019A&A...624A..83K Altcode: 2019arXiv190209460K
Context. On the asymptotic giant branch, low to intermediate mass stars
blow away their outer envelopes, forming planetary nebulae. Dynamic
interaction between the planetary nebula and its central progenitor
is poorly understood. The interaction is even more complex when the
central object is a binary star with a magnetically active component,
as is the case for the target in this paper. Aims: We aim to
quantify the stellar surface activity of the cool binary component
of IN Com and aim to explain its origin. In general, we need a better
understanding of how central binary stars in planetary nebulae evolve
and how this evolution could develop such magnetically active stars
as IN Com. Methods: We present a time series of 13 consecutive
Doppler images covering six months in 2017 that we used to measure the
surface differential rotation with a cross-correlation method. Hitherto
unpublished high-precision photometric data from 1989 to 2017 are
presented. We applied Fourier-transformation-based frequency analysis
to both photometry and spectra. Very high resolution (R ≈ 200 000)
spectra were used to update IN Com's astrophysical parameters by
means of spectral synthesis. Results: Our time-series Doppler
images show cool and warm spots coexisting with an average surface
temperature contrast of -1000 K and +300 K with respect to the effective
temperature. Approximately 8% of the stellar surface is covered with
cool spots and ∼3% with warm spots. A consistent cool polar spot is
seen in all images. The average lifetime of the cool spots is not much
more than a few stellar rotations (one month), while the warm spots
appear to live longer (three months) and are mostly confined to high
latitudes. We found anti-solar surface differential rotation with a
shear coefficient of α = -0.026 ± 0.005 suggesting an equatorial
rotation period of 5.973 ± 0.008 d. We reconfirm the 5.9 day rotation
period of the cool star from photometry, radial velocities, and Hα
line-profile variations. A long-term V-brightness variation with a
likely period of 7.2 yr is also found. It appears in phase with the
orbital radial velocity of the binary system in the sense that it is
brightest at highest velocity and faintest at lowest velocity, that
is, at the two phases of quadrature. We redetermine [Ba/Fe], [Y/Fe],
and [Sr/Fe] ratios and confirm the overabundance of these s-process
elements in the atmosphere of IN Com. Based on data obtained with
the STELLA robotic observatory in Tenerife, an AIP facility jointly
operated by AIP and the Instituto de Astrofisica de Canarias, and on
data acquired with PEPSI using the Vatican Advanced Technology Telescope
(VATT) jointly operated by AIP and the Vatican Observatory.

---------------------------------------------------------
Title: Low albedos of hot to ultra-hot Jupiters in the optical to
near-infrared transition regime
Authors: Mallonn, M.; Köhler, J.; Alexoudi, X.; von Essen, C.;
Granzer, T.; Poppenhaeger, K.; Strassmeier, K. G.
2019A&A...624A..62M Altcode: 2019arXiv190207944M
The depth of a secondary eclipse contains information of both the
thermally emitted light component of a hot Jupiter and the reflected
light component. If the day side atmosphere of the planet is assumed
to be isothermal, it is possible to disentangle both. In this work,
we analyzed 11 eclipse light curves of the hot Jupiter HAT-P-32 b
obtained at 0.89 μm in the z' band. We obtained a null detection
for the eclipse depth with state-of-the-art precision, -0.01 ± 0.10
ppt. We confirm previous studies showing that a non-inverted atmosphere
model is in disagreement to the measured emission spectrum of HAT-P-32
b. We derive an upper limit on the reflected light component, and
thus, on the planetary geometric albedo Ag. The 97.5%
confidence upper limit is Ag &lt; 0.2. This is the first
albedo constraint for HAT-P-32 b, and the first z' band albedo value
for any exoplanet. This finding disfavors the influence of large-sized
silicate condensates on the planetary day side. We inferred z' band
geometric albedo limits from published eclipse measurements also for
the ultra-hot Jupiters WASP-12 b, WASP-19 b, WASP-103 b, and WASP-121
b, applying the same method. These values consistently point to a low
reflectivity in the optical to near-infrared transition regime for
hot to ultra-hot Jupiters. Based on data obtained with the STELLA
robotic telescopes in Tenerife, an AIP facility jointly operated by AIP
and IAC.Lightcurves are only available at the CDS via anonymous ftp to
<A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/624/A62">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/624/A62</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: II Pegasi spectra with PEPSI
(Strassmeier+, 2019)
Authors: Strassmeier, K. G.; Carroll, T. A.; Ilyin, I. V.
2019yCat..36250027S Altcode:
The polarimetric observations in this paper were obtained with PEPSI at
the 2x8.4m LBT in Arizona. We employed both polarimeters in the LBT's
two symmetric straight-through Gregorian foci. (2 data files).

---------------------------------------------------------
Title: Carbon 12C/13C isotope ratio of α
Aurigae revised
Authors: Sablowski, Daniel P.; Järvinen, Silva; Ilyin, Ilya;
Strassmeier, Klaus G.
2019A&A...622L..11S Altcode: 2019arXiv190201133S
Context. Capella (α Aur) is one of the few binaries in the sky
with two cool giant stars. With spectral types of G8III and G0III,
the two components appear at different but distinct stages in their
evolution. The G0 secondary star is a Hertzsprung-gap giant, and the G8
primary star is thought to be a clump giant. Aims: We present a
new measure of the carbon 12C/13C isotope ratio
of the primary component of Capella using high-resolution R ≈ 250 000
spectra obtained with the Potsdam Echelle Polarimetric and Spectroscopic
Instrument (PEPSI) with both the Vatican Advanced Technology Telescope
(VATT) and the Large Binocular Telescope (LBT). Methods:
Signal-to-noise ratios of up to 2 700 were obtained by averaging nightly
spectra. These average spectra were used to disentangle the two binary
components. The isotope ratio was derived with the use of spectrum
synthesis from the CN lines at 8004 Å. Results: We found that
the 12C/13C ratio of the primary component of
Capella is 17.8 ± 1.9. Our measurement precision is now primarily
limited by the spectral-line data and by the grid-step size of the
model atmospheres rather than the data. The separated spectrum of the
secondary component does not show distinguishable 12CN and
13CN lines because of its vsini and higher temperature. Conclusions: Our new 12C/13C value is
significantly lower than the previous value of 27 ± 4 but now agrees
better with the recent model prediction of 18.8-20.7.

---------------------------------------------------------
Title: Flares in open clusters with K2 . I. M 45 (Pleiades), M 44
(Praesepe), and M 67
Authors: Ilin, Ekaterina; Schmidt, Sarah J.; Davenport, James R. A.;
Strassmeier, Klaus G.
2019A&A...622A.133I Altcode: 2018arXiv181206725I
Context. The presence and strength of a stellar magnetic field and
activity is rooted in a star's fundamental parameters such as mass
and age. Can flares serve as an accurate stellar "clock"? Aims:
To explore if we can quantify an activity-age relation in the form of
a flaring-age relation, we measured trends in the flaring rates and
energies for stars with different masses and ages. Methods: We
investigated the time-domain photometry provided by Kepler's follow-up
mission K2 and searched for flares in three solar metallicity open
clusters with well-known ages, M 45 (0.125 Gyr), M 44 (0.63 Gyr), and
M 67 (4.3 Gyr). We updated and employed the automated flare finding
and analysis pipeline Appaloosa, originally designed for Kepler. We
introduced a synthetic flare injection and recovery sub-routine to
ascribe detection and energy recovery rates for flares in a broad energy
range for each light curve. Results: We collect a sample of 1761
stars, mostly late-K to mid-M dwarfs and found 751 flare candidates with
energies ranging from 4 × 1032 erg to 6 × 1034
erg, of which 596 belong to M 45, 155 to M 44, and none to M 67. We find
that flaring activity depends both on Teff, and age. But
all flare frequency distributions have similar slopes with α ≈
2.0-2.4, supporting a universal flare generation process. We discuss
implications for the physical conditions under which flares occur, and
how the sample's metallicity and multiplicity affect our results. The detected flare indices, the stellar parameters for M 44 and M 45,
and a copy of Table 4 are available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr/">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/622/A133">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/622/A133</A>.
We also published all flares we validated, and stellar parameters used
for M 44 and M 45 in the same location.

---------------------------------------------------------
Title: Spectroscopic membership for the populous 300 Myr-old open
cluster NGC 3532
Authors: Fritzewski, D. J.; Barnes, S. A.; James, D. J.; Geller,
A. M.; Meibom, S.; Strassmeier, K. G.
2019A&A...622A.110F Altcode: 2019arXiv190104507F
Context. NGC 3532 is an extremely rich open cluster embedded in
the Galactic disc, hitherto lacking a comprehensive, documented
membership list. Aims: We provide membership probabilities
from new radial velocity observations of solar-type and low-mass
stars in NGC 3532, in part as a prelude to a subsequent study of
stellar rotation in the cluster. Methods: Using extant
optical and infra-red photometry we constructed a preliminary
photometric membership catalogue, consisting of 2230 dwarf and
turn-off stars. We selected 1060 of these for observation with the
AAOmega spectrograph at the 3.9 m-Anglo-Australian Telescope and 391
stars for observations with the Hydra-South spectrograph at the 4 m
Victor Blanco Telescope, obtaining spectroscopic observations over a
decade for 145 stars. We measured radial velocities for our targets
through cross-correlation with model spectra and standard stars, and
supplemented them with radial velocities for 433 additional stars
from the literature. We also measured log g, Teff, and
[Fe/H] from the AAOmega spectra. Results: The radial velocity
distribution emerging from the observations is centred at 5.43 ±
0.04 km s-1 and has a width (standard deviation) of 1.46
km s-1. Together with proper motions from Gaia DR2 we find
660 exclusive members, of which five are likely binary members. The
members are distributed across the whole cluster sequence, from
giant stars to M dwarfs, making NGC 3532 one of the richest Galactic
open clusters known to date, on par with the Pleiades. From further
spectroscopic analysis of 153 dwarf members we find the metallicity to
be marginally sub-solar, with [Fe/H] = -0.07 ± 0.10. We confirm the
extremely low reddening of the cluster, EB - V = 0.034 ±
0.012 mag, despite its location near the Galactic plane. Exploiting
trigonometric parallax measurements from Gaia DR2 we find a distance
of 48435-30 pc [(m - M)0 = 8.42 ±
0.14 mag]. Based on the membership we provide an empirical cluster
sequence in multiple photometric passbands. A comparison of the
photometry of the measured cluster members with several recent model
isochrones enables us to confirm the 300 Myr cluster age. However,
all of the models evince departures from the cluster sequence in
particular regions, especially in the lower mass range. Full
Tables 1, 3 and 4 are only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr/">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/622/A110">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/622/A110</A>Based
on data acquired through the Australian Astronomical Observatory, under
program S/2017A/02.Based on observations at Cerro Tololo Inter-American
Observatory, National Optical Astronomy Observatory under proposals
2008A-0476, 2008A-0512, 2008B-0248, 2010A-0281, 2010B-0492, and
2011B-0322.

---------------------------------------------------------
Title: VizieR Online Data Catalog: HAT-P-32b differential photometry
time series (Mallonn+, 2019)
Authors: Mallonn, M.; Koehler, J.; Alexoudi, X.; von Essen, C.;
Granzer, T.; Poppenhaeger, K.; Strassmeier, K. G.
2019yCat..36240062M Altcode:
11 differential photometry time series of secondary eclipse events of
the hot Jupiter extrasolar planet HAT-P-32b. Filter: Sloan z' band. (1 data file).

---------------------------------------------------------
Title: Ephemeris refinement of 21 hot Jupiter exoplanets with high
timing uncertainties
Authors: Mallonn, M.; von Essen, C.; Herrero, E.; Alexoudi, X.;
Granzer, T.; Sosa, M.; Strassmeier, K. G.; Bakos, G.; Bayliss, D.;
Brahm, R.; Bretton, M.; Campos, F.; Carone, L.; Colón, K. D.; Dale,
H. A.; Dragomir, D.; Espinoza, N.; Evans, P.; Garcia, F.; Gu, S. -H.;
Guerra, P.; Jongen, Y.; Jordán, A.; Kang, W.; Keles, E.; Kim, T.;
Lendl, M.; Molina, D.; Salisbury, M.; Scaggiante, F.; Shporer, A.;
Siverd, R.; Sokov, E.; Sokova, I.; Wünsche, A.
2019A&A...622A..81M Altcode: 2018arXiv181205882M
Transit events of extrasolar planets offer a wealth of information
for planetary characterization. However, for many known targets, the
uncertainty of their predicted transit windows prohibits an accurate
scheduling of follow-up observations. In this work, we refine the
ephemerides of 21 hot Jupiter exoplanets with the largest timing
uncertainties. We collected 120 professional and amateur transit light
curves of the targets of interest, observed with a range of telescopes
of 0.3 m-2.2 m, and analyzed them along with the timing information of
the planets discovery papers. In the case of WASP-117b, we measured
a timing deviation compared to the known ephemeris of about 3.5 h,
and for HAT-P-29b and HAT-P-31b the deviation amounted to about 2 h
and more. For all targets, the new ephemeris predicts transit timings
with uncertainties of less than 6 min in the year 2018 and less than
13 min until 2025. Thus, our results allow for an accurate scheduling
of follow-up observations in the next decade. Observational
lightcurves are only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr/">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/622/A81">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/622/A81</A>

---------------------------------------------------------
Title: Cycle period, differential rotation, and meridional flow for
early M dwarf stars
Authors: Küker, M.; Rüdiger, G.; Olah, K.; Strassmeier, K. G.
2019A&A...622A..40K Altcode: 2018arXiv180402925K
Recent observations suggest the existence of two characteristic cycle
times for early-type M stars dependent on the rotation period. They
are of order one year for fast rotators (Prot &lt; 1
day) and of order four years for slower rotators. Additionally,
the equator-to-pole differences of the rotation rates with δΩ
up to 0.03 rad d-1 are known from Kepler data for the
fast-rotating stars. These values are well-reproduced by the theory
of large-scale flows in rotating convection zones on the basis of
the Λ effect. The resulting amplitudes um of the bottom
value of the meridional circulation allows for the calculation of the
travel time from pole to equator at the base of the convection zone of
early-type M stars. These travel times strongly increase with rotation
period and they always exceed the observed cycle periods. Therefore,
the operation of an advection-dominated dynamo in early M dwarfs,
where the travel time must always be shorter than the cycle period,
is not confirmed by our model nor the data. Based partly on data
obtained with the STELLA robotic telescope in Tenerife, an AIP facility
jointly operated by AIP and IAC.

---------------------------------------------------------
Title: Atmospheric Dynamics and the Variable Transit of KELT-9 b
Authors: Cauley, P. Wilson; Shkolnik, Evgenya L.; Ilyin, Ilya;
Strassmeier, Klaus G.; Redfield, Seth; Jensen, Adam
2019AJ....157...69C Altcode: 2018arXiv181005776C
We present a spectrally and temporally resolved detection of the optical
Mg I triplet at 7.8σ in the extended atmosphere of the ultra-hot
Jupiter KELT-9 b, adding to the list of detected metal species in
the hottest gas giant currently known. Constraints are placed on
the density and radial extent of the excited hydrogen envelope using
simultaneous observations of Hα and Hβ under the assumption of a
spherically symmetric atmosphere. We find that planetary rotational
broadening of {v}rot}={8.2}-0.7+0.6 km
s-1 is necessary to reproduce the Balmer line transmission
profile shapes, where the model including rotation is strongly
preferred over the non-rotating model using a Bayesian information
criterion comparison. The time series of both metal line and hydrogen
absorption show remarkable structure, suggesting that the atmosphere
observed during this transit is dynamic rather than static. We
detect a relative emission feature near the end of the transit
which exhibits a P-Cygni-like shape, evidence of material moving
at ≈50-100 km s-1 away from the planet. We hypothesize
that the in-transit variability and subsequent P-Cygni-like profiles
are due to a flaring event that caused the atmosphere to expand,
resulting in unbound material being accelerated to high speeds by
stellar radiation pressure. Further spectroscopic transit observations
will help establish the frequency of such events. Based on data
acquired with PEPSI using the Large Binocular Telescope (LBT). 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;
Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft,
Germany, representing the Max-Planck Society, the Leibniz-Institute for
Astrophysics Potsdam (AIP), 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.

---------------------------------------------------------
Title: VizieR Online Data Catalog: 15 hot Jupiter exoplanets light
curves (Mallonn+, 2019)
Authors: Mallonn, M.; von Essen, C.; Herrero, E.; Alexoudi, X.;
Granzer, T.; Sosa, M.; Strassmeier, K. G.; Bakos, G.; Bayliss, D.;
Brahm, R.; Bretton, M.; Campos, F.; Carone, L.; Colon, K. D.; Dale,
H. A.; Dragomir, D.; Espinoza, N.; Evans, P.; Garcia, F.; Gu, S. -H.;
Guerra, P.; Jongen, Y.; Jordan, A.; Kang, W.; Keles, E.; Kim, T.;
Lendl, M.; Molina, D.; Salisbury, M.; Scaggiante, F.; Shporer, A.;
Siverd, R.; Sokov, E.; Sokova, I.; Wuensche, A.
2019yCat..36220081M Altcode:
We obtained 35 photometric time series of transit events and employed
them together with 85 publically available data sets to refine the
orbital ephemeris of 21 hot Jupiter exoplanets. We present 35
differential photometry time series of transit events of different
extrasolar planets. (2 data files).

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Title: Mapping EK Draconis with PEPSI. Possible evidence for starspot
penumbrae
Authors: Järvinen, S. P.; Strassmeier, K. G.; Carroll, T. A.; Ilyin,
I.; Weber, M.
2018A&A...620A.162J Altcode: 2018arXiv181203675J
 Aims: We present the first temperature surface map of EK
Dra from very-high-resolution spectra obtained with the Potsdam
Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the
Large Binocular Telescope. Methods: Changes in spectral line
profiles are inverted to a stellar surface temperature map using our
iMap code. The long-term photometric record is employed to compare our
map with previously published maps. Results: Four cool spots were
reconstructed, but no polar spot was seen. The temperature difference
to the photosphere of the spots is between 990 and 280 K. Two spots
are reconstructed with a typical solar morphology with an umbra and a
penumbra. For the one isolated and relatively round spot (spot A), we
determine an umbral temperature of 990 K and a penumbral temperature of
180 K below photospheric temperature. The umbra to photosphere intensity
ratio of EK Dra is approximately only half of that of a comparison
sunspot. A test inversion from degraded line profiles showed that the
higher spectral resolution of PEPSI reconstructs the surface with a
temperature difference that is on average 10% higher than before and
with smaller surface areas by 10-20%. PEPSI is therefore better suited
to detecting and characterising temperature inhomogeneities. With ten
more years of photometry, we also refine the spot cycle period of EK
Dra to 8.9 ± 0.2 yr with a continuing long-term fading trend. 
Conclusions: The temperature morphology of spot A so far appears to
show the best evidence for the existence of a solar-like penumbra for
a starspot. We emphasise that it is more the non-capture of the true
umbral contrast rather than the detection of the weak penumbra that is
the limiting factor. The relatively small line broadening of EK Dra,
together with the only moderately high spectral resolutions previously
available, appear to be the main contributors to the lower-than-expected
spot contrasts when comparing to the Sun. Based on data acquired
with PEPSI using the Large Binocular Telescope (LBT).

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Title: Deciphering the atmosphere of HAT-P-12b: solving discrepant
results
Authors: Alexoudi, X.; Mallonn, M.; von Essen, C.; Turner, J. D.;
Keles, E.; Southworth, J.; Mancini, L.; Ciceri, S.; Granzer, T.;
Denker, C.; Dineva, E.; Strassmeier, K. G.
2018A&A...620A.142A Altcode: 2018arXiv181002172A
Context. Two independent investigations of the atmosphere of the
hot Jupiter HAT-P-12b by two different groups resulted in discrepant
solutions. Using broad-band photometry from the ground, one study found
a flat and featureless transmission spectrum that was interpreted as
gray absorption by dense cloud coverage. The second study made use of
Hubble Space Telescope (HST) observations and found Rayleigh scattering
at optical wavelengths caused by haze. Aims: The main purpose
of this work is to determine the source of this inconsistency and
provide feedback to prevent similar discrepancies in future analyses of
other exoplanetary atmospheres. Methods: We studied the observed
discrepancy via two methods. With further broad-band observations in the
optical wavelength regions, we strengthened the previous measurements in
precision, and with a homogeneous reanalysis of the published data, we
were able to assess the systematic errors and the independent analyses
of the two different groups. Results: Repeating the analysis
steps of both works, we found that deviating values for the orbital
parameters are the reason for the aforementioned discrepancy. Our
work showed a degeneracy of the planetary spectral slope with these
parameters. In a homogeneous reanalysis of all data, the two literature
data sets and the new observations converge to a consistent transmission
spectrum, showing a low-amplitude spectral slope and a tentative
detection of potassium absorption. The transit light curves
of HAT-P-12b are only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/620/A142">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/620/A142</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: M45, M44 and M67 flare stars
(Ilin+, 2019)
Authors: Ilin, E.; Schmidt, S. J.; Davenport, J. R. A.; Strassmeier,
K. G.
2018yCat..36220133I Altcode:
Using K2SC de-trended Kepler/K2 LCs we investigated the flaring activity
of three solar metallicity OCs, the ZAMS cluster M 45, intermediate age
M 44 and solar age M 67, a total of more than 250 years of cumulative
observation time at 30-min cadence from 1761 targets, mostly late-K
and early- to mid-M dwarfs. Pan-STARRS and 2MASS multiband photometry
yielded Teff and radii of individual stars, using solar metallicity
standards (Pickles, 1998PASP..110..863P), computed by Covey et
al. (2007, Cat. J/AJ/134/2398), and colour-temperature relations from
Pecaut &amp; Mamajek (2013, Cat. J/ApJS/208/9). From these we derived
quiescent luminosities and the Kepler band energies of flares detected
by the flare finding and analysis pipeline Appaloosa (Davenport 2016,
Cat. J/ApJ/829/23). (3 data files).

---------------------------------------------------------
Title: VizieR Online Data Catalog: Spectroscopic membership for NGC
3532 (Fritzewski+, 2019)
Authors: Fritzewski, D. J.; Barnes, S. A.; James, D. J.; Geller,
A. M.; Meibom, S.; Strassmeier, K. G.
2018yCat..36220110F Altcode:
The radial velocities were measured from spectroscopic observations with
the Hydra-South spectrograph at the Victor Blanco Telescope at CTIO and
the AAOmega on the Anglo-Australian Telescope at AAO. The observations
at CTIO were carried out from February 2008 to March 2010 on 15 nights
and at AAO we observed on 10 and 11 March 2017. (4 data files).

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Title: 3D non-LTE corrections for Li abundance and
6Li/7Li isotopic ratio in solar-type
stars. I. Application to HD 207129 and HD 95456
Authors: Harutyunyan, G.; Steffen, M.; Mott, A.; Caffau, E.; Israelian,
G.; González Hernández, J. I.; Strassmeier, K. G.
2018A&A...618A..16H Altcode: 2018arXiv180704089H
Context. Convective motions in solar-type stellar atmospheres
induce Doppler shifts that affect the strengths and shapes of
spectral absorption lines and create slightly asymmetric line
profiles. One-dimensional (1D) local thermodynamic equilibrium
(LTE) studies of elemental abundances are not able to reproduce this
phenomenon, which becomes particularly important when modeling the
impact of isotopic fine structure, like the subtle depression created by
the 6Li isotope on the red wing of the Li I resonance doublet
line. Aims: The purpose of this work is to provide corrections
for the lithium abundance, A(Li), and the 6Li/7Li
isotopic ratio that can easily be applied to correct 1D LTE lithium
abundances in G and F dwarf stars of approximately solar mass and
metallicity for three-dimensional (3D) and non-LTE (NLTE) effects. Methods: The corrections for A(Li) and 6Li/7Li
are computed using grids of 3D NLTE and 1D LTE synthetic lithium
line profiles, generated from 3D hydro-dynamical CO5BOLD
and 1D hydrostatic model atmospheres, respectively. For comparative
purposes, all calculations are performed for three different line
lists representing the Li I λ670.8 nm spectral region. The 3D NLTE
corrections are then approximated by analytical expressions as a
function of the stellar parameters (Teff, log ℊ, [Fe/H],
ν sin i, A(Li), 6Li/7Li). These are applied to
adjust the 1D LTE isotopic lithium abundances in two solar-type stars,
<ASTROBJ>HD 207129</ASTROBJ> and <ASTROBJ>HD 95456</ASTROBJ>, for
which high-quality HARPS observations are available. Results:
The derived 3D NLTE corrections range between -0.01 and +0.11 dex for
A(Li), and between -4.9 and -0.4% for 6Li/7Li,
depending on the adopted stellar parameters. We confirm that the
inferred 6Li abundance depends critically on the strength of
the Si I 670.8025 nm line. Our findings show a general consistency with
recent works on lithium abundance corrections. After the application of
such corrections, we do not find a significant amount of 6Li
in any of the two target stars. Conclusions: In the case of
6Li/7Li, our corrections are always negative,
showing that 1D LTE analysis can significantly overestimate the
presence of 6Li (up to 4.9% points) in the atmospheres
of solar-like dwarf stars. These results emphasize the importance
of reliable 3D model atmospheres combined with NLTE line formation
for deriving precise isotopic lithium abundances. Although 3D NLTE
spectral synthesis implies an extensive computational effort,
the results can be made accessible with parametric tools like
the ones presented in this work. The table with the 3D NLTE
corrections is only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/618/A16">http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/618/A16</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: HAT-P-12b 2016-2017 light curve
(Alexoudi+, 2018)
Authors: Alexoudi, X.; Mallonn, M.; von Essen, C.; Turner, J. D.;
Keles, E.; Southworth, J.; Mancini, L.; Ciceri, S.; Granzer, T.;
Denker, C.; Dineva, E.; Strassmeier, K. G.
2018yCat..36200142A Altcode:
Photometric observations of the transiting exoplanet HAT-P-12b in
2016-2017 with different ground-based facilities. These observations
made use of the 1.2m STELLA robotic telescope (5 transits at Sloan g'),
the 3.5m Telescopio Nazionale Galileo (TNG) on Roque de los Muchachos
Observatory (1 transit at Johnson B), the 1.23m (two transits at
Johnson B) and 2.2m (1 transit at Johnson B) telescopes of Calar Alto
Observatory and the 3.5m (1 transit at Johnson B) Astrophysics Research
Consortium (ARC) telescope from the Apache Point Observatory. (2
data files).

---------------------------------------------------------
Title: VizieR Online Data Catalog: A(Li) and 6Li/7Li 3D NLTE
corrections (Harutyunyan+, 2018)
Authors: Harutyunyan, G.; Steffen, M.; Mott, A.; Caffau, E.; Israelian,
G.; Gonzalez Hernandez, J. I.; Strassmeier, K. G.
2018yCat..36180016H Altcode:
A grid of 3D non-LTE (NLTE) corrections for the lithium abundance,
A(Li), and the 6Li/7Li isotopic ratio are
presented. These corrections can be easily applied to correct 1D
LTE lithium abundances in G and F dwarf stars of approximately
solar mass and metallicity for 3D and NLTE effects. The stellar
parameters defining the grid are effective temperatures, Teff (5900,
6300 and 6500K), surface gravity, logg (4.0 and 4.5), metallicity,
[Fe/H] (-1.0, -0.5, 0.0, +0.5), 1D LTE lithium abundance, A(Li)
(1.5, 2.0, 2.5), 1D LTE 6Li/7Li isotopic ratio
(0, 5 and 10%), as well as projected rotational velocity, vsini (0,
2, 4 and 6km/s). Based on this table, a web page calculator was
created that allows to compute the 3D NLTE corrections of A(Li)
and 6Li/7Li ratio for a given combination of stellar parameters
(https://pages.aip.de/li67nlte3d/). (1 data file).

---------------------------------------------------------
Title: Exploring flaring activity as an age indicator using open
cluster data
Authors: Ilin, Ekaterina; Schmidt, Sarah J.; Davenport, James R. A.;
Strassmeier, Klaus G.
2018csss.confE...1I Altcode:
The presence and strength of stellar magnetic activity is rooted in
a star's fundamental parameters such as mass and age. Age-resolved
investigations of chromospheric activity indicators, and large scale
magnetic field observations suggest that one can access an individual
star's age via its magnetic activity. Can flares, magnetically
driven energetic outbursts of energy on the surfaces of stars, serve
as an accurate stellar clock" then? For a star with given mass, the
probability to encounter a flare scales as a power law with its total
released energy. If there is an activity-age relation in the form of a
flaring-age relation we expect the observed flaring rates and energies
to vary significantly in these objects. Thus, the slope and intercept
of the power law fit to the flare frequency distribution would be a
function of both mass and age. The Kepler mission provides the means
to test this hypothesis - high precision time domain photometry of
thousands of stars in more than 10 open clusters spanning a wide range
of ages. Using Kepler's K2 Campaigns 4 and 5 we explore the possibility
to calibrate such a clock on the example of three open clusters: M67
(4.3 Gyr), M44 (0.63 Gyr) and the Pleiades (0.125 Gyr), and present
first results.

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Title: GANS: a nighttime spectrograph for the GREGOR solar telescope
Authors: Järvinen, Arto S.; Weber, M.; Strassmeier, K. G.; Granzer,
T.; Woche, M.; Bauer, S. -M.; Bittner, W.; Weingrill, J.; Sablowski,
D. P.
2018SPIE10702E..6LJ Altcode:
GREGOR at night spectrograph (GANS) is a high-resolution
thermally-stabilised vacuum-enclosed fixed-format fiber-fed Echelle
spectrograph. GANS will be installed starting 2018 alongside the daytime
instrumentation in the building of the 1,5m Gregor Solar Telescope at
the Observatorio del Teide at Izan∼a, Tenerife. Specified resolving
power is R 55k with wavelength coverage from 470 to 680 nm in single
shot on 2k 2k CCD with 3", 50μm fiber on sky, and with space between
orders for simultaneous calibration light in the form of a Fabry-Perot
Etalon or a Laser-comb spectrum. The end-to-end simulated radial
velocity precision performance estimate is 2 ms-1. The main
observing project of GANS will be the ground-based follow-up survey of
TESS and PLATO2.0 exoplanet candidates. GANS will observe its targets
in autonomous operation without human intervention using the normally
human-operated day-time observatory. Limited operations will begin in
first half of 2019 with first science-light planned for summer 2019.

---------------------------------------------------------
Title: Want a PEPSI? Performance status of the recently commissioned
high-resolution spectrograph and polarimeter for the 2x8.4m Large
Binocular Telescope
Authors: Strassmeier, Klaus G.; Ilyin, I.; Weber, M.; Järvinen,
A.; Woche, M.; Järvinen, S.; Sablowski, D.; Mallonn, M.; Keles, E.;
Carroll, T.; Johnson, M. C.; Bender, C.; Wagner, R. M.; Veillet, C.
2018SPIE10702E..12S Altcode:
PEPSI is the new fiber-fed and stabilized "Potsdam Echelle Polarimetric
and Spectroscopic Instrument" for the Large Binocular Telescope
(LBT). It covers the entire optical wavelength range from 384 to 913
nm in three exposures at resolutions of either R=λ/▵λ=50,000,
130,000 or 250,000. The R=130,000 mode can also be used with two
dual-beam Stokes IQUV polarimeters. The 50,000-mode with its 12-pix
sampling per resolution element is our "bad seeing" or "faint-object"
mode. A robotic solar-disk-integration (SDI) telescope feeds solar
light to PEPSI during day time and a 450-m fiber feed from the 1.8m
VATT can be used when the LBT is busy otherwise. CCD characterization
and a removal procedure for the spatial fixed-pattern noise were the
main tasks left from the commissioning phase. Several SDI spectral
time series with up to 300 individual spectra per day recovered the
well-known solar 5-minute oscillation at a peak of 3 mHz (5.5min) with
a disk-integrated radial-velocity amplitude of only 47 cm/s. Spectral
atlases for 50 bright benchmark stars including the Sun were recently
released to the scientific community, among them the ancient planet-
system host Kepler-444. These data combine PEPSI's high spectral
resolution of R=250,000 with signal-to-noise ratio (S/N) of many
hundreds to even thousands covering the entire optical to near-infrared
wavelength range from 384 to 913 nm. Other early science cases were
exoplanet transits including TRAPPIST-1, a spectrum of Boyajian's
star that revealed strong and structured but stable ISM Na D lines, a
spectrum of Oph allowing a redetermination of the ISM Li line doublet,
and a first Doppler image of the young solar analog EK Dra that revealed
starspots with solar-like penumbrae.

---------------------------------------------------------
Title: ELT-HIRES the high resolution spectrograph for the ELT:
optical design studies for the polarimetric unit
Authors: Woche, M.; Di Varano, I.; Strassmeier, K. G.; Weber, M.;
Laux, U.; Riva, M.
2018SPIE10706E..53W Altcode:
We present the optical design of the ELT polarimeter in the context of
the Phase-A study for HIRES. It is well known that in order to reduce
the instrumental polarization and cross-talk, the optimal position for
a polarimeter along the optical path of a telescope is the rotationally
symmetric focus. In the particular case of ELT this is represented by
the intermediate focus (IF) below M4 which is not directly accessible
and needs therefore a reimaging to a safety distance of at least
500 mm. The design of a transfer optics unit for such location is
challenging due to the constraint of having an allowed vignetting area
of maximum 5 arc min. We focus in our paper on two optical design
solutions. The first one is deploying a double Cassegrain system to
reimage the IF, which includes the polarization optics and feeds the
other ELT mirrors, redirecting the ordinary and extraordinary beams to
the front end module (FE) onto the Nasmyth focus. This module comprises
components for sky derotation, atmospheric dispersion correction (ADC),
wavelength splitting in two bands (UBVRI, zYJH), field stabilization
and conversion to f/20, dispatching the light into two pairs of fiber
bundles to feed the HIRES spectrograph. The other solution considers a
fiber based compact IF module, using a Schwarzschild Collimator with
Foster prism, ADC and beam splitters for the two spectral bands. The
two polarized beams are sent by pupil imaging through four separate
long fibers to the fiber link module of the spectrograph. There we
convert the output fiber f ratio from f/2.5 to f/20.

---------------------------------------------------------
Title: ELT-HIRES the high resolution spectrograph for the ELT:
phase-A design of its polarimetric unit
Authors: Di Varano, I.; Woche, M.; Strassmeier, K. G.; Ilyin, I.;
Weber, M.; Yuan, S.; Covino, S.; Di Marcantonio, P.; Landoni, M.;
Genoni, M.; Riva, M.; Marconi, A.
2018SPIE10706E..1YD Altcode:
The Phase A study for the high-resolution spectrograph for the
Extremely Large Telescope (ELT-HIRES) has been concluded in late
2017. We present the main outcome for a polarimetric light feed from
the intermediate focus (IF) and a Nasmyth focus of the telescope. We
conclude that the use of the IF is mandatory for high-precision
spectropolarimetry. Among the description of the product tree, we
present phase-A level opto-mechanical designs of the subunits, describe
the observational and calibration modes, the PSF error budget, and the
preliminary FEM structural and earthquake analysis. An update on the
development of a ray tracing polarimetric simulator to estimate the
instrumental polarization including both the telescope mirrors and the
optical elements of the polarimeter is reported. Trade-off strategies
and ongoing solutions in view of the Phase B are outlined too.

---------------------------------------------------------
Title: Radial velocity accuracy prediction of the GREGOR at night
spectrograph based on simulated spectra
Authors: Weber, Michael; Strassmeier, Klaus G.; Woche, Manfred; Ilyin,
Ilya; Järvinen, Arto
2018SPIE10705E..1EW Altcode:
The Gregor At Night Spectrograph (GANS) is a new instrument currently
being built for the GREGOR solar telescope at Iza na observatory
on Tenerife. Its primary science case will be the follow up of
planetary candidates detected by upcoming surveys focussing on
bright targets (TESS, PLATO2). Therefore it will be optimised for
precise radial velocity determination and long term stability. We
have developed a ZEMAX based software package to create simulated
spectra, which are reduced using standard IRAF tasks. We used a solar
model spectrum to determine the influence of S/N ratio, wavelength
coverage, pixel sampling and telluric lines on the extracted radial
velocities. Furthermore we derived the effect of an asymmetric
spectrograph illumination on the measured radial velocity.

---------------------------------------------------------
Title: ELT-HIRES, the high resolution spectrograph for the ELT:
results from the Phase A study
Authors: Marconi, A.; Allende Prieto, C.; Amado, P. J.; Amate, M.;
Augusto, S. R.; Becerril, S.; Bezawada, N.; Boisse, I.; Bouchy,
F.; Cabral, A.; Chazelas, B.; Cirami, R.; Coretti, I.; Cristiani,
S.; Cupani, G.; de Castro Leão, I.; de Medeiros, J. R.; de Souza,
M. A. F.; Di Marcantonio, P.; Di Varano, I.; D'Odorico, V.; Drass, H.;
Figueira, P.; Fragoso, A. B.; Fynbo, J. P. U.; Genoni, M.; González
Hernández, J. I.; Haehnelt, M.; Hughes, I.; Huke, P.; Kjeldsen,
H.; Korn, A. J.; Landoni, M.; Liske, J.; Lovis, C.; Maiolino, R.;
Marquart, T.; Martins, C. J. A. P.; Mason, E.; Monteiro, M. A.; Morris,
T.; Murray, G.; Niedzielski, A.; Oliva, E.; Origlia, L.; Pallé, E.;
Parr-Burman, P.; Parro, V. C.; Pepe, F.; Piskunov, N.; Rasilla, J. L.;
Rees, P.; Rebolo, R.; Riva, M.; Rousseau, S.; Sanna, N.; Santos, N. C.;
Shen, T. -C.; Sortino, F.; Sosnowska, D.; Sousa, S.; Stempels, E.;
Strassmeier, K.; Tenegi, F.; Tozzi, A.; Udry, S.; Valenziano, L.;
Vanzi, L.; Weber, M.; Woche, M.; Xompero, M.; Zackrisson, E.
2018SPIE10702E..1YM Altcode:
We present the results from the phase A study of ELT-HIRES, an
optical-infrared High Resolution Spectrograph for ELT, which has just
been completed by a consortium of 30 institutes from 12 countries
forming a team of about 200 scientists and engineers. The top science
cases of ELT-HIRES will be the detection of life signatures from
exoplanet atmospheres, tests on the stability of Nature's fundamental
couplings, the direct detection of the cosmic acceleration. However,
the science requirements of these science cases enable many other
groundbreaking science cases. The baseline design, which allows
to fulfil the top science cases, consists in a modular fiber- fed
cross-dispersed echelle spectrograph with two ultra-stable spectral
arms providing a simultaneous spectral range of 0.4-1.8 μm at a
spectral resolution of 100,000. The fiber-feeding allows ELT-HIRES to
have several, interchangeable observing modes including a SCAO module
and a small diffraction-limited IFU.

---------------------------------------------------------
Title: A study of white pupil configurations for high-resolution
échelle spectrographs
Authors: Sablowski, D. P.; Woche, M.; Weber, M.; Järvinen, A.;
Strassmeier, K. G.
2018SPIE10706E..6FS Altcode:
White pupil arrangements using parabolic off-axis mirrors are commonly
used by instrument designers of high-resolution spectrographs. Their
advantage is a non-chromatic, spherical free collimation, an
intermediate focus providing the possibility for stray light
apertures, and the compression of the beam diameter using a second,
a transfer, collimator. However, these arrangements suffer from
off-axis aberrations in the field. Many configurations create the
intermediate focus, after double-passing the primary collimator,
in the vicinity of the spectrograph input. This makes it necessary
to introduce small angles at the main collimator, further increasing
off-axis aberrations. Furthermore, image curvature is high and requires
toroidal surfaces to be added near the spectrograph focus in front of
the CCD. In high-precision radial velocity measurements, it is of great
importance to properly model the spectrographs transfer function in
order to derive exact line positions. Therefore, clean and very well
defined spots, even when working near the sampling limit, which can
simply be represented by gaussians will benefit such measurements. This
point is usually considered less by instrument designers. We have
studied several possible off-axis mirror arrangements for white pupil
spectrographs and discuss our results here. We focus on the image
quality generated by the mirrors, on-axis as well as in the field. We
come to the conclusion that a fairly uncommon arrangement provides
best performance in the sense of image quality and focus accessibility.

---------------------------------------------------------
Title: GJ 1214: Rotation period, starspots, and uncertainty on the
optical slope of the transmission spectrum
Authors: Mallonn, M.; Herrero, E.; Juvan, I. G.; von Essen, C.;
Rosich, A.; Ribas, I.; Granzer, T.; Alexoudi, X.; Strassmeier, K. G.
2018A&A...614A..35M Altcode: 2018arXiv180305677M
 Aims: Brightness inhomogeneities in the stellar photosphere
(dark spots or bright regions) affect the measurements of the planetary
transmission spectrum. To investigate the star spots of the M dwarf
GJ 1214, we conducted a multicolor photometric monitoring from 2012 to
2016. Methods: The time-series photometry was analyzed with the
light curve inversion tool StarSim. Using the derived stellar surface
properties from the light curve inversion, we modeled the impact of
the star spots when unocculted by the transiting planet. We compared
the photometric variability of GJ 1214 to published results of mid-
to late M dwarfs from the MEarth sample. Results: The measured
variability shows a periodicity of 125 ± 5 days, which we interpret
as the signature of the stellar rotation period. This value overrules
previous suggestions of a significantly shorter stellar rotation
period. A light curve inversion of the monitoring data yields an
estimation of the flux dimming of a permanent spot filling factor not
contributing to the photometric variability, a temperature contrast
of the spots of 370 K and persistent active longitudes. The derived
surface maps over all five seasons were used to estimate the influence
of the star spots on the transmission spectrum of the planet from
400 to 2000 nm. The monitoring data presented here do not support a
recent interpretation of a measured transmission spectrum of GJ 1214b
as to be caused by bright regions in the stellar photosphere. Instead,
we list arguments as to why the effect of dark spots likely dominated
over bright regions in the period of our monitoring. Furthermore,
our photometry proves an increase in variability over at least four
years, indicative for a cyclic activity behavior. The age of GJ 1214
is likely between 6 and 10 Gyr. Conclusions: The long-term
photometry allows for a correction of unocculted spots. For an active
star such as GJ 1214, there remains a degeneracy between occulted
spots and the transit parameters used to build the transmission
spectrum. This degeneracy can only be broken by high-precision transit
photometry resolving the spot crossing signature in the transit light
curve. Based on data obtained with the STELLA robotic telescopes
in Tenerife, an AIP facility jointly operated by AIP and IAC.The
photometry tables are only available at the CDS via anonymous ftp to
<A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(<A href="http://130.79.128.5">http://130.79.128.5</A>) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/614/A35">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/614/A35</A>

---------------------------------------------------------
Title: PEPSI deep spectra. III. Chemical analysis of the ancient
planet-host star Kepler-444
Authors: Mack, C. E.; Strassmeier, K. G.; Ilyin, I.; Schuler, S. C.;
Spada, F.; Barnes, S. A.
2018A&A...612A..46M Altcode: 2017arXiv171206986M
Context. With the Large Binocular Telescope (LBT), we obtained
a spectrum with PEPSI, its new optical high-resolution échelle
spectrograph. The spectrum has very high resolution and a high
signal-to-noise (S/N) and is of the K0V host Kepler-444, which is
known to host five sub-Earth-sized rocky planets. The spectrum has
a resolution of R ≈ 250 000, a continuous wavelength coverage from
4230 Å to 9120 Å, and an S/N between 150-550:1 (blue to red). Aim. We
performed a detailed chemical analysis to determine the photospheric
abundances of 18 chemical elements. These were used to place constraints
on the bulk composition of the five rocky planets. Methods: Our
spectral analysis employs the equivalent-width method for most of our
spectral lines, but we used spectral synthesis to fit a small number
of lines that required special care. In both cases, we derived our
abundances using the MOOG spectral analysis package and Kurucz model
atmospheres. Results: We find no correlation between elemental
abundance and condensation temperature among the refractory elements
(TC &gt; 950 K). In addition, using our spectroscopic stellar
parameters and isochrone fitting, we find an age of 10 ± 1.5 Gyr,
which is consistent with the asteroseismic age of 11 ± 1 Gyr. Finally,
from the photospheric abundances of Mg, Si, and Fe, we estimate that the
typical Fe-core mass fraction for the rocky planets in the Kepler-444
system is approximately 24%. Conclusions: If our estimate of
the Fe-core mass fraction is confirmed by more detailed modeling of
the disk chemistry and simulations of planet formation and evolution
in the Kepler-444 system, then this would suggest that rocky planets in
more metal-poor and α-enhanced systems may tend to be less dense than
their counterparts of comparable size in more metal-rich systems. Based on data acquired with PEPSI using the Large Binocular Telescope
(LBT). 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;
Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft,
Germany, representing the Max-Planck Society, the Leibniz-Institute for
Astrophysics Potsdam (AIP), 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.

---------------------------------------------------------
Title: PEPSI deep spectra. II. Gaia benchmark stars and other M-K
standards
Authors: Strassmeier, K. G.; Ilyin, I.; Weber, M.
2018A&A...612A..45S Altcode: 2017arXiv171206967S
Context. High-resolution échelle spectra confine many essential stellar
parameters once the data reach a quality appropriate to constrain the
various physical processes that form these spectra. Aim. We provide
a homogeneous library of high-resolution, high-S/N spectra for 48
bright AFGKM stars, some of them approaching the quality of solar-flux
spectra. Our sample includes the northern Gaia benchmark stars, some
solar analogs, and some other bright Morgan-Keenan (M-K) spectral
standards. Methods: Well-exposed deep spectra were created by
average-combining individual exposures. The data-reduction process
relies on adaptive selection of parameters by using statistical
inference and robust estimators. We employed spectrum synthesis
techniques and statistics tools in order to characterize the spectra and
give a first quick look at some of the science cases possible. 
Results: With an average spectral resolution of R ≈ 220 000 (1.36
km s-1), a continuous wavelength coverage from 383 nm to
912 nm, and S/N of between 70:1 for the faintest star in the extreme
blue and 6000:1 for the brightest star in the red, these spectra are
now made public for further data mining and analysis. Preliminary
results include new stellar parameters for 70 Vir and α Tau, the
detection of the rare-earth element dysprosium and the heavy elements
uranium, thorium and neodymium in several RGB stars, and the use of
the 12C to 13C isotope ratio for age-related
determinations. We also found Arcturus to exhibit few-percent Ca II
H&amp;K and Hα residual profile changes with respect to the KPNO atlas
taken in 1999. Based on data acquired with PEPSI using the Large
Binocular Telescope (LBT) and the Vatican Advanced Technology Telescope
(VATT). 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;
Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft,
Germany, representing the Max-Planck Society, the Leibniz-Institute for
Astrophysics Potsdam (AIP), 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.

---------------------------------------------------------
Title: PEPSI deep spectra. I. The Sun-as-a-star
Authors: Strassmeier, K. G.; Ilyin, I.; Steffen, M.
2018A&A...612A..44S Altcode: 2017arXiv171206960S
Context. Full-disk solar flux spectra can be directly compared to
stellar spectra and thereby serve as our most important reference
source for, for example stellar chemical abundances, magnetic activity
phenomena, radial-velocity signatures or global pulsations. Aim. As part
of the first Potsdam Echelle Polarimetric and Spectroscopic Instrument
(PEPSI) key-science project, we aim to provide well-exposed and
average-combined (viz. deep) high-resolution spectra of representative
stellar targets. Such deep spectra contain an overwhelming amount
of information, typically much more than what could be analyzed and
discussed within a single publication. Therefore, these spectra will
be made available in form of (electronic) atlases. The first star in
this series of papers is our Sun. It also acts as a system-performance
cornerstone. Methods: The Sun was monitored with PEPSI at the
Large Binocular Telescope (LBT). Instead of the LBT we used a small
robotic solar disk integration (SDI) telescope. The deep spectra
in this paper are the results of combining up to ≈100 consecutive
exposures per wavelength setting and are compared with other solar
flux atlases. Results: Our software for the optimal data
extraction and reduction of PEPSI spectra is described and verified
with the solar data. Three deep solar flux spectra with a spectral
resolution of up to 270 000, a continuous wavelength coverage from
383 nm to 914 nm, and a photon signal to noise ratio (S/N) of between
2000-8000:1 depending on wavelength are presented. Additionally,
a time-series of 996 high-cadence spectra in one cross disperser
is used to search for intrinsic solar modulations. The wavelength
calibration based on Th-Ar exposures and simultaneous Fabry-Pérot
combs enables an absolute wavelength solution within 10 m s-1
(rms) with respect to the HARPS laser-comb solar atlas and a relative
rms of 1.2 m s-1 for one day. For science demonstration,
we redetermined the disk-average solar Li abundance to 1.09 ±
0.04 dex on the basis of 3D NLTE model atmospheres. We detected
disk-averaged p-mode RV oscillations with a full amplitude of
47 cm s-1 at 5.5 min. Conclusions: Comparisons
with two solar FTS atlases, as well as with the HARPS solar atlas,
validate the PEPSI data product. Now, PEPSI/SDI solar-flux spectra
are being taken with a sampling of one deep spectrum per day, and
are supposed to continue a full magnetic cycle of the Sun. Based
on data acquired with PEPSI fed by the solar disk integration (SDI)
telescope operated by AIP at the Large Binocular Telescope Observatory
(LBTO). 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 Board of Regents;
Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft,
Germany, representing the Max-Planck Society, The Leibniz Institute for
Astrophysics Potsdam (AIP), 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.

---------------------------------------------------------
Title: Tracking of an electron beam through the solar corona with
LOFAR
Authors: Mann, G.; Breitling, F.; Vocks, C.; Aurass, H.; Steinmetz,
M.; Strassmeier, K. G.; Bisi, M. M.; Fallows, R. A.; Gallagher, P.;
Kerdraon, A.; Mackinnon, A.; Magdalenic, J.; Rucker, H.; Anderson,
J.; Asgekar, A.; Avruch, I. M.; Bell, M. E.; Bentum, M. J.; Bernardi,
G.; Best, P.; Bîrzan, L.; Bonafede, A.; Broderick, J. W.; Brüggen,
M.; Butcher, H. R.; Ciardi, B.; Corstanje, A.; de Gasperin, F.;
de Geus, E.; Deller, A.; Duscha, S.; Eislöffel, J.; Engels, D.;
Falcke, H.; Fender, R.; Ferrari, C.; Frieswijk, W.; Garrett, M. A.;
Grießmeier, J.; Gunst, A. W.; van Haarlem, M.; Hassall, T. E.;
Heald, G.; Hessels, J. W. T.; Hoeft, M.; Hörandel, J.; Horneffer,
A.; Juette, E.; Karastergiou, A.; Klijn, W. F. A.; Kondratiev, V. I.;
Kramer, M.; Kuniyoshi, M.; Kuper, G.; Maat, P.; Markoff, S.; McFadden,
R.; McKay-Bukowski, D.; McKean, J. P.; Mulcahy, D. D.; Munk, H.;
Nelles, A.; Norden, M. J.; Orru, E.; Paas, H.; Pandey-Pommier, M.;
Pandey, V. N.; Pizzo, R.; Polatidis, A. G.; Rafferty, D.; Reich,
W.; Röttgering, H.; Scaife, A. M. M.; Schwarz, D. J.; Serylak,
M.; Sluman, J.; Smirnov, O.; Stappers, B. W.; Tagger, M.; Tang, Y.;
Tasse, C.; ter Veen, S.; Thoudam, S.; Toribio, M. C.; Vermeulen, R.;
van Weeren, R. J.; Wise, M. W.; Wucknitz, O.; Yatawatta, S.; Zarka,
P.; Zensus, J. A.
2018A&A...611A..57M Altcode:
The Sun's activity leads to bursts of radio emission, among other
phenomena. An example is type-III radio bursts. They occur frequently
and appear as short-lived structures rapidly drifting from high to low
frequencies in dynamic radio spectra. They are usually interpreted as
signatures of beams of energetic electrons propagating along coronal
magnetic field lines. Here we present novel interferometric LOFAR (LOw
Frequency ARray) observations of three solar type-III radio bursts
and their reverse bursts with high spectral, spatial, and temporal
resolution. They are consistent with a propagation of the radio sources
along the coronal magnetic field lines with nonuniform speed. Hence,
the type-III radio bursts cannot be generated by a monoenergetic
electron beam, but by an ensemble of energetic electrons with a spread
distribution in velocity and energy. Additionally, the density profile
along the propagation path is derived in the corona. It agrees well
with three-fold coronal density model by (1961, ApJ, 133, 983).

---------------------------------------------------------
Title: VizieR Online Data Catalog: Differential photometry of GJ1214
(Mallonn+, 2018)
Authors: Mallonn, M.; Herrero, E.; Juvan, I. G.; von Essen, C.;
Rosich, A.; Ribas, I.; Granzer, T.; Alexoudi, X.; Strassmeier, K. G.
2018yCat..36140035M Altcode:
The photometric monitoring data of GJ1214 have been observed with
STELLA/WiFSIP over five observing seasons. In the first season 2012,
the broad band filters V and I have been used. In the seasons 2013 to
2016, the filters B and V have been used. (1 data file).

---------------------------------------------------------
Title: KELT-21b: A Hot Jupiter Transiting the Rapidly Rotating
Metal-poor Late-A Primary of a Likely Hierarchical Triple System
Authors: Johnson, Marshall C.; Rodriguez, Joseph E.; Zhou, George;
Gonzales, Erica J.; Cargile, Phillip A.; Crepp, Justin R.; Penev,
Kaloyan; Stassun, Keivan G.; Gaudi, B. Scott; Colón, Knicole D.;
Stevens, Daniel J.; Strassmeier, Klaus G.; Ilyin, Ilya; Collins, Karen
A.; Kielkopf, John F.; Oberst, Thomas E.; Maritch, Luke; Reed, Phillip
A.; Gregorio, Joao; Bozza, Valerio; Calchi Novati, Sebastiano; D'Ago,
Giuseppe; Scarpetta, Gaetano; Zambelli, Roberto; Latham, David W.;
Bieryla, Allyson; Cochran, William D.; Endl, Michael; Tayar, Jamie;
Serenelli, Aldo; Silva Aguirre, Victor; Clarke, Seth P.; Martinez,
Maria; Spencer, Michelle; Trump, Jason; Joner, Michael D.; Bugg, Adam
G.; Hintz, Eric G.; Stephens, Denise C.; Arredondo, Anicia; Benzaid,
Anissa; Yazdi, Sormeh; McLeod, Kim K.; Jensen, Eric L. N.; Hancock,
Daniel A.; Sorber, Rebecca L.; Kasper, David H.; Jang-Condell, Hannah;
Beatty, Thomas G.; Carroll, Thorsten; Eastman, Jason; James, David;
Kuhn, Rudolf B.; Labadie-Bartz, Jonathan; Lund, Michael B.; Mallonn,
Matthias; Pepper, Joshua; Siverd, Robert J.; Yao, Xinyu; Cohen,
David H.; Curtis, Ivan A.; DePoy, D. L.; Fulton, Benjamin J.; Penny,
Matthew T.; Relles, Howard; Stockdale, Christopher; Tan, Thiam-Guan;
Villanueva, Steven, Jr.
2018AJ....155..100J Altcode: 2017arXiv171203241J
We present the discovery of KELT-21b, a hot Jupiter transiting
the V = 10.5 A8V star HD 332124. The planet has an orbital
period of P = 3.6127647 ± 0.0000033 days and a radius of
{1.586}-0.040+0.039 {R}{{J}}. We
set an upper limit on the planetary mass of {M}P&lt; 3.91
{M}{{J}} at 3σ confidence. We confirmed the planetary
nature of the transiting companion using this mass limit and Doppler
tomographic observations to verify that the companion transits HD
332124. These data also demonstrate that the planetary orbit is
well-aligned with the stellar spin, with a sky-projected spin-orbit
misalignment of λ =-{5.6}-1.9+1.7\circ . The
star has {T}{eff}={7598}-84+81 K,
{M}* ={1.458}-0.028+0.029 {M}⊙
, {R}* =1.638 +/- 0.034 {R}⊙ , and v\sin
{I}* =146 km s-1, the highest projected rotation
velocity of any star known to host a transiting hot Jupiter. The
star also appears to be somewhat metal poor and α-enhanced, with
[{Fe}/{{H}}]=-{0.405}-0.033+0.032 and [α/Fe] =
0.145 ± 0.053 these abundances are unusual, but not extraordinary, for
a young star with thin-disk kinematics like KELT-21. High-resolution
imaging observations revealed the presence of a pair of stellar
companions to KELT-21, located at a separation of 1.″2 and with a
combined contrast of {{Δ }}{K}S=6.39+/- 0.06 with respect
to the primary. Although these companions are most likely physically
associated with KELT-21, we cannot confirm this with our current
data. If associated, the candidate companions KELT-21 B and C would
each have masses of ∼0.12 {M}⊙ , a projected mutual
separation of ∼20 au, and a projected separation of ∼500 au from
KELT-21. KELT-21b may be one of only a handful of known transiting
planets in hierarchical triple stellar systems.

---------------------------------------------------------
Title: Letter from the Editor
Authors: Strassmeier, Klaus G.
2018AN....339....9S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The First Post-Kepler Brightness Dips of KIC 8462852
Authors: Boyajian, Tabetha. S.; Alonso, Roi; Ammerman, Alex; Armstrong,
David; Asensio Ramos, A.; Barkaoui, K.; Beatty, Thomas G.; Benkhaldoun,
Z.; Benni, Paul; Bentley, Rory O.; Berdyugin, Andrei; Berdyugina,
Svetlana; Bergeron, Serge; Bieryla, Allyson; Blain, Michaela G.;
Capetillo Blanco, Alicia; Bodman, Eva H. L.; Boucher, Anne; Bradley,
Mark; Brincat, Stephen M.; Brink, Thomas G.; Briol, John; Brown,
David J. A.; Budaj, J.; Burdanov, A.; Cale, B.; Aznar Carbo, Miguel;
Castillo García, R.; Clark, Wendy J.; Clayton, Geoffrey C.; Clem,
James L.; Coker, Phillip H.; Cook, Evan M.; Copperwheat, Chris M.;
Curtis, J. L.; Cutri, R. M.; Cseh, B.; Cynamon, C. H.; Daniels, Alex
J.; Davenport, James R. A.; Deeg, Hans J.; De Lorenzo, Roberto; de
Jaeger, Thomas; Desrosiers, Jean-Bruno; Dolan, John; Dowhos, D. J.;
Dubois, Franky; Durkee, R.; Dvorak, Shawn; Easley, Lynn; Edwards, N.;
Ellis, Tyler G.; Erdelyi, Emery; Ertel, Steve; Farfán, Rafael. G.;
Farihi, J.; Filippenko, Alexei V.; Foxell, Emma; Gandolfi, Davide;
Garcia, Faustino; Giddens, F.; Gillon, M.; González-Carballo,
Juan-Luis; González-Fernández, C.; González Hernández, J. I.;
Graham, Keith A.; Greene, Kenton A.; Gregorio, J.; Hallakoun, Na'ama;
Hanyecz, Ottó; Harp, G. R.; Henry, Gregory W.; Herrero, E.; Hildbold,
Caleb F.; Hinzel, D.; Holgado, G.; Ignácz, Bernadett; Ilyin, Ilya;
Ivanov, Valentin D.; Jehin, E.; Jermak, Helen E.; Johnston, Steve;
Kafka, S.; Kalup, Csilla; Kardasis, Emmanuel; Kaspi, Shai; Kennedy,
Grant M.; Kiefer, F.; Kielty, C. L.; Kessler, Dennis; Kiiskinen,
H.; Killestein, T. L.; King, Ronald A.; Kollar, V.; Korhonen, H.;
Kotnik, C.; Könyves-Tóth, Réka; Kriskovics, Levente; Krumm, Nathan;
Krushinsky, Vadim; Kundra, E.; Lachapelle, Francois-Rene; LaCourse,
D.; Lake, P.; Lam, Kristine; Lamb, Gavin P.; Lane, Dave; Lau, Marie
Wingyee; Lewin, Pablo; Lintott, Chris; Lisse, Carey; Logie, Ludwig;
Longeard, Nicolas; Lopez Villanueva, M.; Whit Ludington, E.; Mainzer,
A.; Malo, Lison; Maloney, Chris; Mann, A.; Mantero, A.; Marengo,
Massimo; Marchant, Jon; Martínez González, M. J.; Masiero, Joseph R.;
Mauerhan, Jon C.; McCormac, James; McNeely, Aaron; Meng, Huan Y. A.;
Miller, Mike; Molnar, Lawrence A.; Morales, J. C.; Morris, Brett M.;
Muterspaugh, Matthew W.; Nespral, David; Nugent, C. R.; Nugent,
Katherine M.; Odasso, A.; O'Keeffe, Derek; Oksanen, A.; O'Meara,
John M.; Ordasi, András; Osborn, Hugh; Ott, John J.; Parks, J. R.;
Rodriguez Perez, Diego; Petriew, Vance; Pickard, R.; Pál, András;
Plavchan, P.; Pollacco, Don; Pozo Nuñez, F.; Pozuelos, F. J.; Rau,
Steve; Redfield, Seth; Relles, Howard; Ribas, Ignasi; Richards, Jon;
Saario, Joonas L. O.; Safron, Emily J.; Sallai, J. Martin; Sárneczky,
Krisztián; Schaefer, Bradley E.; Schumer, Clea F.; Schwartzendruber,
Madison; Siegel, Michael H.; Siemion, Andrew P. V.; Simmons, Brooke D.;
Simon, Joshua D.; Simón-Díaz, S.; Sitko, Michael L.; Socas-Navarro,
Hector; Sódor, Á.; Starkey, Donn; Steele, Iain A.; Stone, Geoff;
Strassmeier, Klaus G.; Street, R. A.; Sullivan, Tricia; Suomela, J.;
Swift, J. J.; Szabó, Gyula M.; Szabó, Róbert; Szakáts, Róbert;
Szalai, Tamás; Tanner, Angelle M.; Toledo-Padrón, B.; Tordai, Tamás;
Triaud, Amaury H. M. J.; Turner, Jake D.; Ulowetz, Joseph H.; Urbanik,
Marian; Vanaverbeke, Siegfried; Vanderburg, Andrew; Vida, Krisztián;
Vietje, Brad P.; Vinkó, József; von Braun, K.; Waagen, Elizabeth
O.; Walsh, Dan; Watson, Christopher A.; Weir, R. C.; Wenzel, Klaus;
Westendorp Plaza, C.; Williamson, Michael W.; Wright, Jason T.; Wyatt,
M. C.; Zheng, WeiKang; Zsidi, Gabriella
2018ApJ...853L...8B Altcode: 2018arXiv180100732B
We present a photometric detection of the first brightness dips of
the unique variable star KIC 8462852 since the end of the Kepler space
mission in 2013 May. Our regular photometric surveillance started in
2015 October, and a sequence of dipping began in 2017 May continuing
on through the end of 2017, when the star was no longer visible from
Earth. We distinguish four main 1%-2.5% dips, named “Elsie,”
“Celeste,” “Skara Brae,” and “Angkor,” which persist
on timescales from several days to weeks. Our main results so far
are as follows: (i) there are no apparent changes of the stellar
spectrum or polarization during the dips and (ii) the multiband
photometry of the dips shows differential reddening favoring non-gray
extinction. Therefore, our data are inconsistent with dip models that
invoke optically thick material, but rather they are in-line with
predictions for an occulter consisting primarily of ordinary dust,
where much of the material must be optically thin with a size scale
≪1 μm, and may also be consistent with models invoking variations
intrinsic to the stellar photosphere. Notably, our data do not place
constraints on the color of the longer-term “secular” dimming,
which may be caused by independent processes, or probe different
regimes of a single process.

---------------------------------------------------------
Title: High Resolution Optical Spectroscopy of the Classical Nova
V5668 Sgr Showing the Presence of Lithium
Authors: Wagner, R. Mark; Woodward, Charles E.; Starrfield, Sumner;
Ilyin, Ilya; Strassmeier, Klaus
2018AAS...23135810W Altcode:
The classical nova (CN) V5668 Sgr was discovered on 2015 March 15.634
and initial optical spectra implied it was an Fe II-class CN. We
obtained high resolution optical spectroscopy on 30 nights between 2015
April 3 and 2016 June 5 with the 2 x 8.4 m Large Binocular Telescope
(LBT) and the 1.8 m Vatican Advanced Technology Telescope (VATT) using
the Potsdam Echelle Polarimetric Spectroscopic Instrument (PEPSI). The
spectra cover all or part of the 3830-9065 Å spectral region at a
spectral resolution of up to 270,000 (1 km/s); the highest resolution
currently available on any 8-10 m class telescope. The early spectra
are dominated by emission lines of the Balmer and Paschen series of
hydrogen, Fe II, Ca II, and Na I with P Cyg-type line profiles as
well as emission lines of [O I]. Numerous interstellar lines and bands
are readily apparent at high spectral resolution. The permitted line
profiles show complex and dramatic variations in the multi-component
P Cyg-type line profiles with time. We detect a weak blue-shifted
absorption line at a velocity consistent with Li I 6708 Å when compared
with the line profiles of Hβ, Fe II 5169 Å, and Na I D. This line
is present in spectra obtained on 7 of 8 consecutive nights up to day
21 of the outburst; but absent on day 42 when it is evident that the
ionization of the ejecta has significantly increased. The equivalent
width of the line converted to a column density, and the resulting
mass fraction, imply a significant enrichment of 7Li
in the ejecta. 7Li is produced by the decay of unstable
7Be created during the thermonuclear runaway. The discovery
of the resonance lines of 7Be II in the optical spectra
of the recent CNe V339 Del, V2944 Oph, and V5668 Sgr by Tajitsu et
al. (2016) and its subsequent decay to 7Li (half life of 53
days) suggests a significant enrichment of 7Li in the Galaxy
from CNe is possible. Our observations of the Li I 6708 Å line in the
early optical spectra of V5668 Sgr mark the second direct detection of
Li in a CN following the detection of Li I in the early optical spectra
of V1369 Cen by Izzo et al. (2015). SS acknowledges partial support
from NSF and NASA grants to ASU. CEW acknowledges support from NASA.

---------------------------------------------------------
Title: Transmission spectroscopy of the hot Jupiter TrES-3 b:
Disproof of an overly large Rayleigh-like feature
Authors: Mackebrandt, F.; Mallonn, M.; Ohlert, J. M.; Granzer, T.;
Lalitha, S.; García Muñoz, A.; Gibson, N. P.; Lee, J. W.; Sozzetti,
A.; Turner, J. D.; Vaňko, M.; Strassmeier, K. G.
2017A&A...608A..26M Altcode: 2017arXiv170906124M
Context. Transit events of extrasolar planets offer the opportunity
to study the composition of their atmospheres. Previous work on
transmission spectroscopy of the close-in gas giant (TrES)-3 b
revealed an increase in absorption towards blue wavelengths of very
large amplitude in terms of atmospheric pressure scale heights,
too large to be explained by Rayleigh-scattering in the planetary
atmosphere. Aims: We present a follow-up study of the optical
transmission spectrum of the hot Jupiter TrES-3 b to investigate the
strong increase in opacity towards short wavelengths found by a previous
study. Furthermore, we aim to estimate the effect of stellar spots on
the transmission spectrum. Methods: This work uses previously
published long slit spectroscopy transit data of the Gran Telescopio
Canarias (GTC) and published broad band observations as well as new
observations in different bands from the near-UV to the near-IR, for
a homogeneous transit light curve analysis. Additionally, a long-term
photometric monitoring of the TrES-3 host star was performed. 
Results: Our newly analysed GTC spectroscopic transit observations show
a slope of much lower amplitude than previous studies. We conclude
from our results the previously reported increasing signal towards
short wavelengths is not intrinsic to the TrES-3 system. Furthermore,
the broad band spectrum favours a flat spectrum. Long-term photometric
monitoring rules out a significant modification of the transmission
spectrum by unocculted star spots. Based on (1) data obtained
with the STELLA robotic telescopes in Tenerife, an AIP facility
jointly operated by AIP and IAC, (2) observations collected at the
German-Spanish Astronomical Center, Calar Alto, jointly operated by
the Max-Planck-Institut für Astronomie Heidelberg and the Instituto
de Astrofísica de Andalucía (CSIC) and (3) observations made with
the Italian Telescopio Nazionale Galileo (TNG) operated on the island
of La Palma by the Fundación Galileo Galilei of the INAF (Istituto
Nazionale di Astrofisica) at the Spanish Observatorio del Roque de los
Muchachos of the Instituto de Astrofisica de Canarias.Newly observed
photometric data from Sects. 2.2 and 2.3 and tables of the lightcurves
are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr
(<A href="http://130.79.128.5">http://130.79.128.5</A>) or via <A
href="http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/608/A26">http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/608/A26</A>

---------------------------------------------------------
Title: Contemporaneous Imaging Comparisons of the Spotted Giant σ
Geminorum Using Interferometric, Spectroscopic, and Photometric Data
Authors: Roettenbacher, Rachael M.; Monnier, John D.; Korhonen,
Heidi; Harmon, Robert O.; Baron, Fabien; Hackman, Thomas; Henry,
Gregory W.; Schaefer, Gail H.; Strassmeier, Klaus G.; Weber, Michael;
ten Brummelaar, Theo A.
2017ApJ...849..120R Altcode: 2017arXiv170910109R
Nearby active stars with relatively rapid rotation and large
starspot structures offer the opportunity to compare interferometric,
spectroscopic, and photometric imaging techniques. In this paper,
we image a spotted star with three different methods for the first
time. The giant primary star of the RS Canum Venaticorum binary
σ Geminorum (σ Gem) was imaged for two epochs of interferometric,
high-resolution spectroscopic, and photometric observations. The light
curves from the reconstructions show good agreement with the observed
light curves, supported by the longitudinally consistent spot features
on the different maps. However, there is strong disagreement in the
spot latitudes across the methods.

---------------------------------------------------------
Title: Rotation-differential rotation relationships for late-type
single and binary stars from Doppler imaging
Authors: Kővári, Zs.; Oláh, K.; Kriskovics, L.; Vida, K.;
Forgács-Dajka, E.; Strassmeier, K. G.
2017AN....338..903K Altcode: 2017arXiv170909001K
From our sample of spotted late-type stars showing surface differential
rotation, we find that the relationship between the rotation period
and the surface shear coefficient α = ΔΩ/Ωeq is
significantly different for single stars compared to members in close
binaries. Single stars follow a general trend that α increases with
the rotation period. However, differential rotation of stars in close
binary systems shows much weaker dependence on the rotation, if any,
suggesting that in such systems, tidal forces operate as a controlling
mechanism of differential rotation.

---------------------------------------------------------
Title: 3D simulations of rising magnetic flux tubes in a compressible
rotating interior: The effect of magnetic tension
Authors: Fournier, Y.; Arlt, R.; Ziegler, U.; Strassmeier, K. G.
2017A&A...607A...1F Altcode: 2017arXiv170706781F
Context. Long-term variability in solar cycles represents a challenging
constraint for theoretical models. Mean-field Babcock-Leighton dynamos
that consider non-instantaneous rising flux tubes have been shown
to exhibit long-term variability in their magnetic cycle. However a
relation that parameterizes the rise-time of non-axisymmetric magnetic
flux tubes in terms of stellar parameters is still missing. Aims:
We aim to find a general parameterization of the rise-time of magnetic
flux tubes for solar-like stars. Methods: By considering the
influence of magnetic tension on the rise of non-axisymmetric flux
tubes, we predict the existence of a control parameter referred
as Γα1α2. This parameter is
a measure of the balance between rotational effects and magnetic
effects (buoyancy and tension) acting on the magnetic flux tube. We
carry out two series of numerical experiments (one for axisymmetric
rise and one for non-axisymmetric rise) and demonstrate that
Γα1α2 indeed controls the rise-time
of magnetic flux tubes. Results: We find that the rise-time
follows a power law of Γα1α2 with
an exponent that depends on the azimuthal wavenumber of the magnetic
flux loop. Conclusions: Compressibility does not impact the
rise of magnetic flux tubes, while non-axisymmetry does. In the case
of non-axisymmetric rise, the tension force modifies the force balance
acting on the magnetic flux tube. We identified the three independent
parameters required to predict the rise-time of magnetic flux tubes,
that is, the stellar rotation rate, the magnetic flux density of the
flux tube, and its azimuthal wavenumber. We combined these into one
single relation that is valid for any solar-like star. We suggest using
this generalized relation to constrain the rise-time of magnetic flux
tubes in Babcock-Leighton dynamo models.

---------------------------------------------------------
Title: Antisolar differential rotation with surface lithium enrichment
on the single K-giant V1192 Orionis
Authors: Kővári, Zs.; Strassmeier, K. G.; Carroll, T. A.; Oláh,
K.; Kriskovics, L.; Kővári, E.; Kovács, O.; Vida, K.; Granzer,
T.; Weber, M.
2017A&A...606A..42K Altcode: 2017arXiv170801577K
Context. Stars with about 1-2 solar masses at the red giant branch
(RGB) represent an intriguing period of stellar evolution, I.e. when
the convective envelope interacts with the fast-rotating core. During
these mixing episodes freshly synthesized lithium can come up to
the stellar surface along with high angular momentum material. This
high angular momentum may alter the surface rotation pattern. 
Aims: The single rapidly rotating K-giant V1192 Ori is revisited
to determine its surface differential rotation, lithium abundance,
and basic stellar properties such as a precise rotation period. The
aim is to independently verify the antisolar differential rotation
of the star and possibly find a connection to the surface lithium
abundance. Methods: We applied time-series Doppler imaging to a
new multi-epoch data set. Altogether we reconstructed 11 Doppler images
from spectroscopic data collected with the STELLA robotic telescope
between 2007-2016. We used our inversion code iMap to reconstruct all
stellar surface maps. We extracted the differential rotation from
these images by tracing systematic spot migration as a function of
stellar latitude from consecutive image cross-correlations. 
Results: The position of V1192 Ori in the Hertzsprung-Russell diagram
suggests that the star is in the helium core-burning phase just leaving
the RGB bump. We measure A(Li)NLTE = 1.27, I.e. a value
close to the anticipated transition value of 1.5 from Li-normal to
Li-rich giants. Doppler images reveal extended dark areas arranged
quasi-evenly along an equatorial belt. No cool polar spot is found
during the investigated epoch. Spot displacements clearly suggest
antisolar surface differential rotation with α = - 0.11 ± 0.02 shear
coefficient. Conclusions: The surface Li enrichment and the
peculiar surface rotation pattern may indicate a common origin. Based on data obtained with the STELLA robotic observatory in
Tenerife, an AIP facility jointly operated by AIP and IAC.

---------------------------------------------------------
Title: Flows along arch filaments observed in the GRIS `very fast
spectroscopic mode'
Authors: González Manrique, S. J.; Denker, C.; Kuckein, C.; Pastor
Yabar, A.; Collados, M.; Verma, M.; Balthasar, H.; Diercke, A.;
Fischer, C. E.; Gömöry, P.; Bello González, N.; Schlichenmaier,
R.; Cubas Armas, M.; Berkefeld, T.; Feller, A.; Hoch, S.; Hofmann,
A.; Lagg, A.; Nicklas, H.; Orozco Suárez, D.; Schmidt, D.; Schmidt,
W.; Sigwarth, M.; Sobotka, M.; Solanki, S. K.; Soltau, D.; Staude,
J.; Strassmeier, K. G.; Volkmer, R.; von der Lühe, O.; Waldmann, T.
2017IAUS..327...28G Altcode: 2017arXiv170102206G
A new generation of solar instruments provides improved spectral,
spatial, and temporal resolution, thus facilitating a better
understanding of dynamic processes on the Sun. High-resolution
observations often reveal multiple-component spectral line profiles,
e.g., in the near-infrared He i 10830 Å triplet, which provides
information about the chromospheric velocity and magnetic fine
structure. We observed an emerging flux region, including two small
pores and an arch filament system, on 2015 April 17 with the `very
fast spectroscopic mode' of the GREGOR Infrared Spectrograph (GRIS)
situated at the 1.5-meter GREGOR solar telescope at Observatorio del
Teide, Tenerife, Spain. We discuss this method of obtaining fast (one
per minute) spectral scans of the solar surface and its potential to
follow dynamic processes on the Sun. We demonstrate the performance
of the `very fast spectroscopic mode' by tracking chromospheric
high-velocity features in the arch filament system.

---------------------------------------------------------
Title: VizieR Online Data Catalog: TrES-3b UBVIz' light curves
(Mackebrandt+, 2017)
Authors: Mackebrandt, F.; Mallonn, M.; Ohlert, J. M.; Granzer, T.;
Lalitha, S.; Garcia Munoz, A.; Gibson, N. P.; Lee, J. W.; Sozzetti,
A.; Turner, J. D.; Vanko, M.; Strassmeier, K. G.
2017yCat..36080026M Altcode:
We observed transits of the hot Jupiter TrES-3b in Johnson U, B,
V, I and Sloan z'. Telescopes are named according to the paper. We monitored the exoplanet host star TrES-3 with STELLA/WiFSIP in
2016 over the course of four months from March 7 to July 10, 2016. We
observed in two filters, Johnson B and Johnson V, in blocks of three
exposures each. (4 data files).

---------------------------------------------------------
Title: Lithium abundance and 6Li/7Li ratio in
the active giant HD 123351. I. A comparative analysis of 3D and 1D
NLTE line-profile fits
Authors: Mott, A.; Steffen, M.; Caffau, E.; Spada, F.; Strassmeier,
K. G.
2017A&A...604A..44M Altcode: 2017arXiv170406460M
Context. Current three-dimensional (3D) hydrodynamical model
atmospheres together with detailed spectrum synthesis, accounting
for departures from local thermodynamic equilibrium (LTE), permit
to derive reliable atomic and isotopic chemical abundances from
high-resolution stellar spectra. Not much is known about the presence
of the fragile 6Li isotope in evolved solar-metallicity red
giant branch (RGB) stars, not to mention its production in magnetically
active targets like HD 123351. Aims: A detailed spectroscopic
investigation of the lithium resonance doublet in HD 123351 in terms
of both abundance and isotopic ratio is presented. From fits of
the observed spectrum, taken at the Canada-France-Hawaii telescope,
with synthetic line profiles based on 1D and 3D model atmospheres,
we seek to estimate the abundance of the 6Li isotope and
to place constraints on its origin. Methods: We derive the
lithium abundance A(Li) and the 6Li/7Li isotopic
ratio by fitting different synthetic spectra to the Li-line region
of a high-resolution CFHT spectrum (R = 120 000, S/N = 400). The
synthetic spectra are computed with four different line lists,
using in parallel 3D hydrodynamical CO5BOLD and 1D LHD
model atmospheres and treating the line formation of the lithium
components in non-LTE (NLTE). The fitting procedure is repeated with
different assumptions and wavelength ranges to obtain a reasonable
estimate of the involved uncertainties. Results: We find A(Li)
= 1.69 ± 0.11 dex and 6Li/7Li = 8.0 ± 4.4%
in 3D-NLTE, using the line list of Meléndez et al. (2012, A&amp;A,
543, A29), updated with new atomic data for V I, which results in
the best fit of the lithium line profile of HD 123351. Two other line
lists lead to similar results but with inferior fit qualities. 
Conclusions: Our 2σ detection of the 6Li isotope is the
result of a careful statistical analysis and the visual inspection
of each achieved fit. Since the presence of a significant amount of
6Li in the atmosphere of a cool evolved star is not expected
in the framework of standard stellar evolution theory, non-standard,
external lithium production mechanisms, possibly related to stellar
activity or a recent accretion of rocky material, need to be invoked
to explain the detection of 6Li in HD 123351.

---------------------------------------------------------
Title: PLATO as it is : A legacy mission for Galactic archaeology
Authors: Miglio, A.; Chiappini, C.; Mosser, B.; Davies, G. R.;
Freeman, K.; Girardi, L.; Jofré, P.; Kawata, D.; Rendle, B. M.;
Valentini, M.; Casagrande, L.; Chaplin, W. J.; Gilmore, G.; Hawkins,
K.; Holl, B.; Appourchaux, T.; Belkacem, K.; Bossini, D.; Brogaard,
K.; Goupil, M. -J.; Montalbán, J.; Noels, A.; Anders, F.; Rodrigues,
T.; Piotto, G.; Pollacco, D.; Rauer, H.; Prieto, C. Allende; Avelino,
P. P.; Babusiaux, C.; Barban, C.; Barbuy, B.; Basu, S.; Baudin, F.;
Benomar, O.; Bienaymé, O.; Binney, J.; Bland-Hawthorn, J.; Bressan,
A.; Cacciari, C.; Campante, T. L.; Cassisi, S.; Christensen-Dalsgaard,
J.; Combes, F.; Creevey, O.; Cunha, M. S.; Jong, R. S.; Laverny, P.;
Degl'Innocenti, S.; Deheuvels, S.; Depagne, É.; Ridder, J.; Matteo,
P. Di; Mauro, M. P. Di; Dupret, M. -A.; Eggenberger, P.; Elsworth,
Y.; Famaey, B.; Feltzing, S.; García, R. A.; Gerhard, O.; Gibson,
B. K.; Gizon, L.; Haywood, M.; Handberg, R.; Heiter, U.; Hekker,
S.; Huber, D.; Ibata, R.; Katz, D.; Kawaler, S. D.; Kjeldsen, H.;
Kurtz, D. W.; Lagarde, N.; Lebreton, Y.; Lund, M. N.; Majewski, S. R.;
Marigo, P.; Martig, M.; Mathur, S.; Minchev, I.; Morel, T.; Ortolani,
S.; Pinsonneault, M. H.; Plez, B.; Moroni, P. G. Prada; Pricopi, D.;
Recio-Blanco, A.; Reylé, C.; Robin, A.; Roxburgh, I. W.; Salaris,
M.; Santiago, B. X.; Schiavon, R.; Serenelli, A.; Sharma, S.; Aguirre,
V. Silva; Soubiran, C.; Steinmetz, M.; Stello, D.; Strassmeier, K. G.;
Ventura, P.; Ventura, R.; Walton, N. A.; Worley, C. C.
2017AN....338..644M Altcode: 2017arXiv170603778M
Deciphering the assembly history of the Milky Way is a formidable
task, which becomes possible only if one can produce high-resolution
chrono-chemo-kinematical maps of the Galaxy. Data from large-scale
astrometric and spectroscopic surveys will soon provide us with a
well-defined view of the current chemo-kinematical structure of the
Milky Way, but will only enable a blurred view on the temporal sequence
that led to the present-day Galaxy. As demonstrated by the (ongoing)
exploitation of data from the pioneering photometric missions CoRoT,
Kepler, and K2, asteroseismology provides the way forward: solar-like
oscillating giants are excellent evolutionary clocks thanks to the
availability of seismic constraints on their mass and to the tight
age-initial-mass relation they adhere to. In this paper we identify
five key outstanding questions relating to the formation and evolution
of the Milky Way that will need precise and accurate ages for large
samples of stars to be addressed, and we identify the requirements
in terms of number of targets and the precision on the stellar
properties that are needed to tackle such questions. By quantifying
the asteroseismic yields expected from PLATO for red-giant stars, we
demonstrate that these requirements are within the capabilities of the
current instrument design, provided that observations are sufficiently
long to identify the evolutionary state and allow robust and precise
determination of acoustic-mode frequencies. This will allow us to
harvest data of sufficient quality to reach a 10% precision in age. This
is a fundamental pre-requisite to then reach the more ambitious goal
of a similar level of accuracy, which will only be possible if we
have to hand a careful appraisal of systematic uncertainties on age
deriving from our limited understanding of stellar physics, a goal
which conveniently falls within the main aims of PLATO's core science.

---------------------------------------------------------
Title: Surface magnetism of cool stars
Authors: Kochukhov, O.; Petit, P.; Strassmeier, K. G.; Carroll, T. A.;
Fares, R.; Folsom, C. P.; Jeffers, S. V.; Korhonen, H.; Monnier,
J. D.; Morin, J.; Rosén, L.; Roettenbacher, R. M.; Shulyak, D.
2017AN....338..428K Altcode: 2016arXiv161203388K
Magnetic fields are essential ingredients of many physical processes in
the interiors and envelopes of cool stars. Yet their direct detection
and characterization is notoriously difficult, requiring high-quality
observations and advanced analysis techniques. Significant progress has
been recently achieved by several types of direct magnetic field studies
on the surfaces of cool, active stars. In particular, complementary
techniques of field topology mapping with polarization data and
total magnetic flux measurements from intensity spectra have been
systematically applied to different classes of active stars, leading
to interesting and occasionally controversial results. In this paper,
we summarize the current status of direct magnetic field studies of cool
stars and investigations of surface inhomogeneities caused by the field,
based on the material presented at the Cool Stars 19 splinter session.

---------------------------------------------------------
Title: 3D non-LTE corrections for the 6Li/7Li
isotopic ratio in solar-type stars
Authors: Harutyunyan, G.; Steffen, M.; Mott, A.; Caffau, E.; Israelian,
G.; González Hernández, J. I.; Strassmeier, K. G.
2017MmSAI..88...61H Altcode:
Doppler shifts induced by convective motions in stellar atmospheres
affect the shape of spectral absorption lines and create slightly
asymmetric line profiles. It is important to take this effect into
account in modeling the subtle depression created by the 6Li
isotope which lies on the red wing of the Li I 670.8 nm resonance
doublet line, since convective motions in stellar atmospheres can mimic
a presence of 6Li when intrinsically symmetric theoretical
line profiles are presumed for the analysis of the 7Li
doublet \citep{cayrel2007}. Based on CO5BOLD hydrodynamical model
atmospheres, we compute 3D non-local thermodynamic equilibrium
(NLTE) corrections for the 6Li/7Li isotopic
ratio by using a grid of 3D NLTE and 1D LTE synthetic spectra. These
corrections must be added to the results of the 1D LTE analysis to
correct them for the combined 3D non-LTE effects. As one would expect,
the resulting corrections are always negative and they range between
0 and -5 %, depending on effective temperature, surface gravity, and
metallicity. For each metallicity we derive an analytic expression
approximating the 3D NLTE corrections as a function of effective
temperature, surface gravity and projected rotational velocity.

---------------------------------------------------------
Title: Letter from the Editor
Authors: Strassmeier, Klaus G.
2017AN....338....7S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: CoRoT photometry and STELLA spectroscopy of an eccentric,
eclipsing, and spotted HgMn binary with sub-synchronized rotation
Authors: Strassmeier, K. G.; Granzer, T.; Mallonn, M.; Weber, M.;
Weingrill, J.
2017A&A...597A..55S Altcode: 2016A&A...597A..55S
Context. We report the discovery and analysis of very narrow transits
in the eccentric spectroscopic binary HSS 348 (IC 4756). Aims:
The aim is to characterize the full HSS 348 system. Methods:
We obtained high-precision CoRoT photometry over two long runs and
multi-epoch high-resolution échelle spectroscopy and imaging with
STELLA. Standard radial-velocity extraction, spectrum synthesis, Fourier
analysis, and light-curve inversions are applied to the data. 
Results: HSS 348 is found to be an eccentric (e = 0.18) double-lined
spectroscopic binary with a period of 12.47 d in which at least the
primary component is a peculiar B star of the HgMn class. The orbital
elements are such that the system undergoes a grazing eclipse with the
primary in front but no secondary eclipse. The out-of-eclipse light
variations show four nearly equidistant but unequal minima stable
in shape and amplitude throughout our observations. Their individual
photometric periods are all harmonics of the same fundamental period
which happens to agree with the transit period to within the errors. We
interpret the fundamental period to be the rotation period of at least
one if not both stars due to surface inhomogeneities. Due to the
non-zero eccentricity of the orbit the two components are rotating
sub-synchronously. Conclusions: It appears that HSS 348 is
not a member of the IC 4756 cluster but a background B8+B8.5 binary
system. Its sharp eclipses every 12.47 days just mimic a small-body
transit but are in reality the grazing eclipses of a B-star binary
and thus a classical false positive. The system seems to be pre-main
sequence with the primary possibly just arrived on the ZAMS. The
light curve with four unequal minima can be explained with four cool
spots of different size equidistantly positioned in longitude. Our
data do not allow to uniquely assign the spots to either of the two
stars. The CoRoT space mission, launched on 2006 December 27,
has been developed and is operated by CNES, with the contribution of
Austria, Belgium, Brazil, ESA (RSSD and Science Programme), Germany
and Spain. Partly based on data obtained with the STELLA robotic
observatory in Tenerife, an AIP facility jointly operated by AIP and
IAC.The final data sets are only available at the CDS via anonymous ftp
to <A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(<A href="http://130.79.128.5">http://130.79.128.5</A>) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/597/A55">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/597/A55</A>

---------------------------------------------------------
Title: Short-term evolution and coexistence of spots, plages and
flare activity on LQ Hydrae
Authors: Flores Soriano, M.; Strassmeier, K. G.
2017A&A...597A.101F Altcode: 2016arXiv161005067F
 Aims: We aim to study the short-term evolution of the
chromospheric and photospheric activity of the young, single K2 dwarf
LQ Hya. Methods: Four months of quasi-simultaneous spectroscopic
and photometric observations were used to study the variations of the
photometric light curve, the evolution of the chromospheric activity
from the Hα and Hβ lines, and the distribution of cool spots from
Doppler maps. Results: During our observations one side of
the star was more active than the other. The equivalent width of the
Hα line from the least active hemisphere increased from ≈0.7 Å
at the beginning of the observation to 1.0 Å at the end. The basal
emission of the most active hemisphere remained roughly constant
at EWHαt1.0 Å. Intense flare activity was observed
during the first twenty days, where at least four different events
were detected. The line asymmetries of the Hα line suggest that one
of the flares could have produced a mass ejection with a maximum
projected speed of 70kms-1. The rotational modulation
of the V-band photometry showed clear anti-correlation with the
chromospheric activity. The difference in brightness between the
opposite hemispheres decreased from 0.m16 to 0.m09
in two months. Three spots gradually moving apart from each other
are dominating the photospheric Doppler maps. The comparison between
the maps and the Hα line as the star rotates reveals the spatial
coexistence of chromospheric Hα emission and photospheric spots. 
Conclusions: Our results indicate that the active regions of LQ Hya can
live for at least four months. The detected changes in the photometric
light curve and the spectroscopic Doppler images seem to be more a
consequence of the spatial redistribution of the active regions rather
than due to changes in their strength. Only one of the active regions
shows significant changes in its chromospheric emission. Based
on data obtained with the STELLA robotic telescope in Tenerife, an
AIP facility jointly operated by AIP and IAC, and the Vienna-Potsdam
Automatic Photoelectric Telescopes at Fairborn Observatory in Arizona,
operated by AIP.

---------------------------------------------------------
Title: Lithium in the active sub-giant HD123351. A quantitative
analysis with 3D and 1D model atmospheres using different observed
spectra
Authors: Mott, A.; Steffen, M.; Caffau, E.; Strassmeier, K. G.
2017MmSAI..88...68M Altcode:
Current 3D hydrodynamical model atmosphere simulations together with
non-LTE spectrum synthesis calculations permit to determine reliable
atomic and in particular isotopic chemical abundances. Although this
approach is computationally time demanding, it became feasible in
studying lithium in stellar spectra. In the literature not much is
known about the presence of the more fragile {6Li} isotope
in evolved metal-rich objects. In this case the analysis is complicated
by the lack of a suitable list of atomic and molecular lines in the
spectral region of the lithium resonance line at 670.8 nm. Here we
present a spectroscopic comparative analysis of the Li doublet region
of HD 123351, an active sub-giant star of solar metallicity. We fit
the Li profile in three observed spectra characterized by different
qualities: two very-high resolution spectra (Gecko@CFHT, R=120 000,
SNR=400 and PEPSI@LBT, R=150 000, SNR=663) and a high-resolution
SOPHIE@OHP spectrum (R=40 000, SNR=300). We adopt a set of model
atmospheres, both 3D and 1D, having different stellar parameters
(T_{eff} and log g). The 3D models are taken from the CIFIST grid of
COBOLD model atmospheres and departures from LTE are considered for
the lithium components. For the blends other than the lithium in this
wavelength region we adopt the linelist of \citet{melendez12}. We find
consistent results for all three observations and an overall good fit
with the selected list of atomic and molecular lines, indicating a
high {6Li} content. The presence of {6Li}
is not expected in cool stellar atmospheres. Its detection is of
crucial importance for understanding mixing processes in stars and
external lithium production mechanisms, possibly related to stellar
activity or planetray accretion of {6Li}-rich material.

---------------------------------------------------------
Title: Slipping reconnection in a solar flare observed in high
resolution with the GREGOR solar telescope
Authors: Sobotka, M.; Dudík, J.; Denker, C.; Balthasar, H.; Jurčák,
J.; Liu, W.; Berkefeld, T.; Collados Vera, M.; Feller, A.; Hofmann,
A.; Kneer, F.; Kuckein, C.; Lagg, A.; Louis, R. E.; von der Lühe, O.;
Nicklas, H.; Schlichenmaier, R.; Schmidt, D.; Schmidt, W.; Sigwarth,
M.; Solanki, S. K.; Soltau, D.; Staude, J.; Strassmeier, K. G.;
Volkmer, R.; Waldmann, T.
2016A&A...596A...1S Altcode: 2016arXiv160500464S
A small flare ribbon above a sunspot umbra in active region 12205 was
observed on November 7, 2014, at 12:00 UT in the blue imaging channel
of the 1.5 m GREGOR telescope, using a 1 Å Ca II H interference
filter. Context observations from the Atmospheric Imaging Assembly
(AIA) onboard the Solar Dynamics Observatory (SDO), the Solar Optical
Telescope (SOT) onboard Hinode, and the Interface Region Imaging
Spectrograph (IRIS) show that this ribbon is part of a larger one
that extends through the neighboring positive polarities and also
participates in several other flares within the active region. We
reconstructed a time series of 140 s of Ca II H images by means of the
multiframe blind deconvolution method, which resulted in spatial and
temporal resolutions of 0.1″ and 1 s. Light curves and horizontal
velocities of small-scale bright knots in the observed flare ribbon
were measured. Some knots are stationary, but three move along the
ribbon with speeds of 7-11 km s-1. Two of them move in the
opposite direction and exhibit highly correlated intensity changes,
which provides evidence of a slipping reconnection at small spatial
scales. Movies associated to Figs. 1 and 2 are available at <A
href="http://www.aanda.org/10.1051/0004-6361/201527966/olm">http://www.aanda.org</A>

---------------------------------------------------------
Title: Broad-band spectrophotometry of HAT-P-32 b: search for a
scattering signature in the planetary spectrum
Authors: Mallonn, M.; Bernt, I.; Herrero, E.; Hoyer, S.; Kirk,
J.; Wheatley, P. J.; Seeliger, M.; Mackebrandt, F.; von Essen, C.;
Strassmeier, K. G.; Granzer, T.; Künstler, A.; Dhillon, V. S.; Marsh,
T. R.; Gaitan, J.
2016MNRAS.463..604M Altcode: 2016arXiv160802346M; 2016MNRAS.tmp.1124M
Multicolour broad-band transit observations offer the opportunity to
characterize the atmosphere of an extrasolar planet with small- to
medium-sized telescopes. One of the most favourable targets is the hot
Jupiter HAT-P-32 b. We combined 21 new transit observations of this
planet with 36 previously published light curves for a homogeneous
analysis of the broad-band transmission spectrum from the Sloan u'
band to the Sloan z' band. Our results rule out cloud-free planetary
atmosphere models of solar metallicity. Furthermore, a discrepancy
at reddest wavelengths to previously published results makes a recent
tentative detection of a scattering feature less likely. Instead, the
available spectral measurements of HAT-P-32 b favour a completely flat
spectrum from the near-UV to the near-IR. A plausible interpretation
is a thick cloud cover at high altitudes.

---------------------------------------------------------
Title: Deep probing of the photospheric sunspot penumbra: no evidence
of field-free gaps
Authors: Borrero, J. M.; Asensio Ramos, A.; Collados, M.;
Schlichenmaier, R.; Balthasar, H.; Franz, M.; Rezaei, R.; Kiess, C.;
Orozco Suárez, D.; Pastor Yabar, A.; Berkefeld, T.; von der Lühe,
O.; Schmidt, D.; Schmidt, W.; Sigwarth, M.; Soltau, D.; Volkmer, R.;
Waldmann, T.; Denker, C.; Hofmann, A.; Staude, J.; Strassmeier, K. G.;
Feller, A.; Lagg, A.; Solanki, S. K.; Sobotka, M.; Nicklas, H.
2016A&A...596A...2B Altcode: 2016arXiv160708165B
Context. Some models for the topology of the magnetic field in
sunspot penumbrae predict regions free of magnetic fields or with
only dynamically weak fields in the deep photosphere. Aims:
We aim to confirm or refute the existence of weak-field regions in
the deepest photospheric layers of the penumbra. Methods:
We investigated the magnetic field at log τ5 = 0 is
by inverting spectropolarimetric data of two different sunspots
located very close to disk center with a spatial resolution of
approximately 0.4-0.45”. The data have been recorded using the GRIS
instrument attached to the 1.5-m solar telescope GREGOR at the El
Teide observatory. The data include three Fe I lines around 1565 nm,
whose sensitivity to the magnetic field peaks half a pressure scale
height deeper than the sensitivity of the widely used Fe I spectral
line pair at 630 nm. Before the inversion, the data were corrected
for the effects of scattered light using a deconvolution method with
several point spread functions. Results: At log τ5
= 0 we find no evidence of regions with dynamically weak (B&lt;
500 Gauss) magnetic fields in sunspot penumbrae. This result is much
more reliable than previous investigations made on Fe I lines at 630
nm. Moreover, the result is independent of the number of nodes employed
in the inversion, is independent of the point spread function used to
deconvolve the data, and does not depend on the amount of stray light
(I.e., wide-angle scattered light) considered.

---------------------------------------------------------
Title: Spectropolarimetric observations of an arch filament system
with the GREGOR solar telescope
Authors: Balthasar, H.; Gömöry, P.; González Manrique, S. J.;
Kuckein, C.; Kavka, J.; Kučera, A.; Schwartz, P.; Vašková, R.;
Berkefeld, T.; Collados Vera, M.; Denker, C.; Feller, A.; Hofmann,
A.; Lagg, A.; Nicklas, H.; Orozco Suárez, D.; Pastor Yabar, A.;
Rezaei, R.; Schlichenmaier, R.; Schmidt, D.; Schmidt, W.; Sigwarth,
M.; Sobotka, M.; Solanki, S. K.; Soltau, D.; Staude, J.; Strassmeier,
K. G.; Volkmer, R.; von der Lühe, O.; Waldmann, T.
2016AN....337.1050B Altcode: 2016arXiv160901514B
Arch filament systems occur in active sunspot groups, where a fibril
structure connects areas of opposite magnetic polarity, in contrast to
active region filaments that follow the polarity inversion line. We
used the GREGOR Infrared Spectrograph (GRIS) to obtain the full
Stokes vector in the spectral lines Si I λ1082.7 nm, He I λ1083.0
nm, and Ca I λ1083.9 nm. We focus on the near-infrared calcium line
to investigate the photospheric magnetic field and velocities, and
use the line core intensities and velocities of the helium line to
study the chromospheric plasma. The individual fibrils of the arch
filament system connect the sunspot with patches of magnetic polarity
opposite to that of the spot. These patches do not necessarily coincide
with pores, where the magnetic field is strongest. Instead, areas are
preferred not far from the polarity inversion line. These areas exhibit
photospheric downflows of moderate velocity, but significantly higher
downflows of up to 30 km s-1 in the chromospheric helium
line. Our findings can be explained with new emerging flux where the
matter flows downward along the field lines of rising flux tubes,
in agreement with earlier results.

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Title: Magnetic fields of opposite polarity in sunspot penumbrae
Authors: Franz, M.; Collados, M.; Bethge, C.; Schlichenmaier, R.;
Borrero, J. M.; Schmidt, W.; Lagg, A.; Solanki, S. K.; Berkefeld,
T.; Kiess, C.; Rezaei, R.; Schmidt, D.; Sigwarth, M.; Soltau, D.;
Volkmer, R.; von der Luhe, O.; Waldmann, T.; Orozco, D.; Pastor Yabar,
A.; Denker, C.; Balthasar, H.; Staude, J.; Hofmann, A.; Strassmeier,
K.; Feller, A.; Nicklas, H.; Kneer, F.; Sobotka, M.
2016A&A...596A...4F Altcode: 2016arXiv160800513F
Context. A significant part of the penumbral magnetic field returns
below the surface in the very deep photosphere. For lines in the
visible, a large portion of this return field can only be detected
indirectly by studying its imprints on strongly asymmetric and
three-lobed Stokes V profiles. Infrared lines probe a narrow layer
in the very deep photosphere, providing the possibility of directly
measuring the orientation of magnetic fields close to the solar
surface. Aims: We study the topology of the penumbral magnetic
field in the lower photosphere, focusing on regions where it returns
below the surface. Methods: We analyzed 71 spectropolarimetric
datasets from Hinode and from the GREGOR infrared spectrograph. We
inferred the quality and polarimetric accuracy of the infrared data
after applying several reduction steps. Techniques of spectral
inversion and forward synthesis were used to test the detection
algorithm. We compared the morphology and the fractional penumbral
area covered by reversed-polarity and three-lobed Stokes V profiles for
sunspots at disk center. We determined the amount of reversed-polarity
and three-lobed Stokes V profiles in visible and infrared data of
sunspots at various heliocentric angles. From the results, we computed
center-to-limb variation curves, which were interpreted in the context
of existing penumbral models. Results: Observations in visible
and near-infrared spectral lines yield a significant difference in the
penumbral area covered by magnetic fields of opposite polarity. In
the infrared, the number of reversed-polarity Stokes V profiles is
smaller by a factor of two than in the visible. For three-lobed Stokes
V profiles the numbers differ by up to an order of magnitude.

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Title: Horizontal flow fields in and around a small active region. The
transition period between flux emergence and decay
Authors: Verma, M.; Denker, C.; Balthasar, H.; Kuckein, C.; González
Manrique, S. J.; Sobotka, M.; Bello González, N.; Hoch, S.; Diercke,
A.; Kummerow, P.; Berkefeld, T.; Collados, M.; Feller, A.; Hofmann,
A.; Kneer, F.; Lagg, A.; Löhner-Böttcher, J.; Nicklas, H.; Pastor
Yabar, A.; Schlichenmaier, R.; Schmidt, D.; Schmidt, W.; Schubert,
M.; Sigwarth, M.; Solanki, S. K.; Soltau, D.; Staude, J.; Strassmeier,
K. G.; Volkmer, R.; von der Lühe, O.; Waldmann, T.
2016A&A...596A...3V Altcode: 2016arXiv160507462V
Context. The solar magnetic field is responsible for all aspects
of solar activity. Thus, emergence of magnetic flux at the surface
is the first manifestation of the ensuing solar activity. 
Aims: Combining high-resolution and synoptic observations aims to
provide a comprehensive description of flux emergence at photospheric
level and of the growth process that eventually leads to a mature
active region. Methods: The small active region NOAA 12118
emerged on 2014 July 17 and was observed one day later with the 1.5-m
GREGOR solar telescope on 2014 July 18. High-resolution time-series
of blue continuum and G-band images acquired in the blue imaging
channel (BIC) of the GREGOR Fabry-Pérot Interferometer (GFPI) were
complemented by synoptic line-of-sight magnetograms and continuum
images obtained with the Helioseismic and Magnetic Imager (HMI) onboard
the Solar Dynamics Observatory (SDO). Horizontal proper motions and
horizontal plasma velocities were computed with local correlation
tracking (LCT) and the differential affine velocity estimator (DAVE),
respectively. Morphological image processing was employed to measure
the photometric and magnetic area, magnetic flux, and the separation
profile of the emerging flux region during its evolution. 
Results: The computed growth rates for photometric area, magnetic
area, and magnetic flux are about twice as high as the respective
decay rates. The space-time diagram using HMI magnetograms of five days
provides a comprehensive view of growth and decay. It traces a leaf-like
structure, which is determined by the initial separation of the two
polarities, a rapid expansion phase, a time when the spread stalls,
and a period when the region slowly shrinks again. The separation
rate of 0.26 km s-1 is highest in the initial stage, and
it decreases when the separation comes to a halt. Horizontal plasma
velocities computed at four evolutionary stages indicate a changing
pattern of inflows. In LCT maps we find persistent flow patterns such
as outward motions in the outer part of the two major pores, a diverging
feature near the trailing pore marking the site of upwelling plasma and
flux emergence, and low velocities in the interior of dark pores. We
detected many elongated rapidly expanding granules between the two
major polarities, with dimensions twice as large as the normal granules.

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Title: Upper chromospheric magnetic field of a sunspot penumbra:
observations of fine structure
Authors: Joshi, J.; Lagg, A.; Solanki, S. K.; Feller, A.; Collados,
M.; Orozco Suárez, D.; Schlichenmaier, R.; Franz, M.; Balthasar,
H.; Denker, C.; Berkefeld, T.; Hofmann, A.; Kiess, C.; Nicklas, H.;
Pastor Yabar, A.; Rezaei, R.; Schmidt, D.; Schmidt, W.; Sobotka, M.;
Soltau, D.; Staude, J.; Strassmeier, K. G.; Volkmer, R.; von der Lühe,
O.; Waldmann, T.
2016A&A...596A...8J Altcode: 2016arXiv160801988J
 Aims: The fine-structure of the magnetic field in a sunspot
penumbra in the upper chromosphere is to be explored and compared
to that in the photosphere. Methods: Spectropolarimetric
observations with high spatial resolution were recorded with the 1.5-m
GREGOR telescope using the GREGOR Infrared Spectrograph (GRIS). The
observed spectral domain includes the upper chromospheric Hei triplet
at 10 830 Å and the photospheric Sii 10 827.1 Å and Cai 10 833.4 Å
spectral lines. The upper chromospheric magnetic field is obtained
by inverting the Hei triplet assuming a Milne-Eddington-type model
atmosphere. A height-dependent inversion was applied to the Sii 10
827.1 Å and Cai 10 833.4 Å lines to obtain the photospheric magnetic
field. Results: We find that the inclination of the magnetic
field varies in the azimuthal direction in the photosphere and in the
upper chromosphere. The chromospheric variations coincide remarkably
well with the variations in the inclination of the photospheric field
and resemble the well-known spine and interspine structure in the
photospheric layers of penumbrae. The typical peak-to-peak variations
in the inclination of the magnetic field in the upper chromosphere
are found to be 10°-15°, which is roughly half the variation in
the photosphere. In contrast, the magnetic field strength of the
observed penumbra does not vary on small spatial scales in the upper
chromosphere. Conclusions: Thanks to the high spatial resolution
of the observations that is possible with the GREGOR telescope at 1.08
microns, we find that the prominent small-scale fluctuations in the
magnetic field inclination, which are a salient part of the property
of sunspot penumbral photospheres, also persist in the chromosphere,
although at somewhat reduced amplitudes. Such a complex magnetic
configuration may facilitate penumbral chromospheric dynamic phenomena,
such as penumbral micro-jets or transient bright dots.

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Title: Active region fine structure observed at 0.08 arcsec resolution
Authors: Schlichenmaier, R.; von der Lühe, O.; Hoch, S.; Soltau, D.;
Berkefeld, T.; Schmidt, D.; Schmidt, W.; Denker, C.; Balthasar, H.;
Hofmann, A.; Strassmeier, K. G.; Staude, J.; Feller, A.; Lagg, A.;
Solanki, S. K.; Collados, M.; Sigwarth, M.; Volkmer, R.; Waldmann,
T.; Kneer, F.; Nicklas, H.; Sobotka, M.
2016A&A...596A...7S Altcode: 2016arXiv160707094S
Context. The various mechanisms of magneto-convective energy transport
determine the structure of sunspots and active regions. 
Aims: We characterise the appearance of light bridges and other
fine-structure details and elaborate on their magneto-convective
nature. Methods: We present speckle-reconstructed images taken
with the broad-band imager (BBI) at the 1.5 m GREGOR telescope in the
486 nm and 589 nm bands. We estimate the spatial resolution from the
noise characteristics of the image bursts and obtain 0.08″ at 589
nm. We describe structure details in individual best images as well
as the temporal evolution of selected features. Results: We
find branched dark lanes extending along thin (≈1″) light bridges
in sunspots at various heliocentric angles. In thick (≳ 2″) light
bridges the branches are disconnected from the central lane and have a Y
shape with a bright grain toward the umbra. The images reveal that light
bridges exist on varying intensity levels and that their small-scale
features evolve on timescales of minutes. Faint light bridges show
dark lanes outlined by the surrounding bright features. Dark lanes are
very common and are also found in the boundary of pores. They have a
characteristic width of 0.1″ or smaller. Intergranular dark lanes of
that width are seen in active region granulation. Conclusions: We
interpret our images in the context of magneto-convective simulations
and findings: while central dark lanes in thin light bridges are
elevated and associated with a density increase above upflows, the dark
lane branches correspond to locations of downflows and are depressed
relative to the adjacent bright plasma. Thick light bridges with central
dark lanes show no projection effect. They have a flat elevated plateau
that falls off steeply at the umbral boundary. There, Y-shaped filaments
form as they do in the inner penumbra. This indicates the presence of
inclined magnetic fields, meaning that the umbral magnetic field is
wrapped around the convective light bridge.

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Title: Probing deep photospheric layers of the quiet Sun with high
magnetic sensitivity
Authors: Lagg, A.; Solanki, S. K.; Doerr, H. -P.; Martínez González,
M. J.; Riethmüller, T.; Collados Vera, M.; Schlichenmaier, R.;
Orozco Suárez, D.; Franz, M.; Feller, A.; Kuckein, C.; Schmidt, W.;
Asensio Ramos, A.; Pastor Yabar, A.; von der Lühe, O.; Denker, C.;
Balthasar, H.; Volkmer, R.; Staude, J.; Hofmann, A.; Strassmeier,
K.; Kneer, F.; Waldmann, T.; Borrero, J. M.; Sobotka, M.; Verma, M.;
Louis, R. E.; Rezaei, R.; Soltau, D.; Berkefeld, T.; Sigwarth, M.;
Schmidt, D.; Kiess, C.; Nicklas, H.
2016A&A...596A...6L Altcode: 2016arXiv160506324L
Context. Investigations of the magnetism of the quiet Sun are hindered
by extremely weak polarization signals in Fraunhofer spectral
lines. Photon noise, straylight, and the systematically different
sensitivity of the Zeeman effect to longitudinal and transversal
magnetic fields result in controversial results in terms of the strength
and angular distribution of the magnetic field vector. Aims:
The information content of Stokes measurements close to the diffraction
limit of the 1.5 m GREGOR telescope is analyzed. We took the effects of
spatial straylight and photon noise into account. Methods: Highly
sensitive full Stokes measurements of a quiet-Sun region at disk center
in the deep photospheric Fe I lines in the 1.56 μm region were obtained
with the infrared spectropolarimeter GRIS at the GREGOR telescope. Noise
statistics and Stokes V asymmetries were analyzed and compared to a
similar data set of the Hinode spectropolarimeter (SOT/SP). Simple
diagnostics based directly on the shape and strength of the profiles
were applied to the GRIS data. We made use of the magnetic line ratio
technique, which was tested against realistic magneto-hydrodynamic
simulations (MURaM). Results: About 80% of the GRIS spectra
of a very quiet solar region show polarimetric signals above a 3σ
level. Area and amplitude asymmetries agree well with small-scale
surface dynamo-magneto hydrodynamic simulations. The magnetic line ratio
analysis reveals ubiquitous magnetic regions in the ten to hundred Gauss
range with some concentrations of kilo-Gauss fields. Conclusions:
The GRIS spectropolarimetric data at a spatial resolution of ≈0.̋4
are so far unique in the combination of high spatial resolution scans
and high magnetic field sensitivity. Nevertheless, the unavoidable
effect of spatial straylight and the resulting dilution of the weak
Stokes profiles means that inversion techniques still bear a high risk
of misinterpretating the data.

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Title: Flow and magnetic field properties in the trailing sunspots
of active region NOAA 12396
Authors: Verma, M.; Denker, C.; Böhm, F.; Balthasar, H.; Fischer,
C. E.; Kuckein, C.; Bello González, N.; Berkefeld, T.; Collados,
M.; Diercke, A.; Feller, A.; González Manrique, S. J.; Hofmann, A.;
Lagg, A.; Nicklas, H.; Orozco Suárez, D.; Pator Yabar, A.; Rezaei,
R.; Schlichenmaier, R.; Schmidt, D.; Schmidt, W.; Sigwarth, M.;
Sobotka, M.; Solanki, S. K.; Soltau, D.; Staude, J.; Strassmeier,
K. G.; Volkmer, R.; von der Lühe, O.; Waldmann, T.
2016AN....337.1090V Altcode:
Improved measurements of the photospheric and chromospheric
three-dimensional magnetic and flow fields are crucial for a precise
determination of the origin and evolution of active regions. We present
an illustrative sample of multi-instrument data acquired during a
two-week coordinated observing campaign in August 2015 involving,
among others, the GREGOR solar telescope (imaging and near-infrared
spectroscopy) and the space missions Solar Dynamics Observatory (SDO)
and Interface Region Imaging Spectrograph (IRIS). The observations
focused on the trailing part of active region NOAA 12396 with complex
polarity inversion lines and strong intrusions of opposite polarity
flux. The GREGOR Infrared Spectrograph (GRIS) provided Stokes IQUV
spectral profiles in the photospheric Si I λ1082.7 nm line, the
chromospheric He I λ1083.0 nm triplet, and the photospheric Ca I
λ1083.9 nm line. Carefully calibrated GRIS scans of the active region
provided maps of Doppler velocity and magnetic field at different
atmospheric heights. We compare quick-look maps with those obtained
with the “Stokes Inversions based on Response functions” (SIR)
code, which furnishes deeper insight into the magnetic properties
of the region. We find supporting evidence that newly emerging flux
and intruding opposite polarity flux are hampering the formation
of penumbrae, i.e., a penumbra fully surrounding a sunspot is only
expected after cessation of flux emergence in proximity to the sunspots.

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Title: VizieR Online Data Catalog: Corot photometry of TYC 455-791-1
(Strassmeier+, 2017)
Authors: Strassmeier, K. G.; Granzer, T.; Mallonn, M.; Weber, M.;
Weingrill, J.
2016yCat..35970055S Altcode:
From the original CoRoT white-light flux obtained on two consecutive
runs, we filter out obvious outliers from the SAA (south Atlantic
Anomaly). The third column are the remaining CoRoT data points. The
two data set were merged using individual zero-points of 716386.54e-
for the first data set and 721882.56e- for the second data set,
respectively. The magnitudes thus calculates are in column four. The
last column is the combined model of the transit plus a 12th order
Fourier-series fit to the out-of-transit data. (1 data file).

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Title: Three-dimensional structure of a sunspot light bridge
Authors: Felipe, T.; Collados, M.; Khomenko, E.; Kuckein, C.; Asensio
Ramos, A.; Balthasar, H.; Berkefeld, T.; Denker, C.; Feller, A.;
Franz, M.; Hofmann, A.; Joshi, J.; Kiess, C.; Lagg, A.; Nicklas, H.;
Orozco Suárez, D.; Pastor Yabar, A.; Rezaei, R.; Schlichenmaier,
R.; Schmidt, D.; Schmidt, W.; Sigwarth, M.; Sobotka, M.; Solanki,
S. K.; Soltau, D.; Staude, J.; Strassmeier, K. G.; Volkmer, R.;
von der Lühe, O.; Waldmann, T.
2016A&A...596A..59F Altcode: 2016arXiv161104803F
Context. Active regions are the most prominent manifestations of solar
magnetic fields; their generation and dissipation are fundamental
problems in solar physics. Light bridges are commonly present during
sunspot decay, but a comprehensive picture of their role in the
removal of the photospheric magnetic field is still lacking. 
Aims: We study the three-dimensional configuration of a sunspot,
and in particular, its light bridge, during one of the last stages of
its decay. Methods: We present the magnetic and thermodynamical
stratification inferred from full Stokes inversions of the photospheric
Si I 10 827 Å and Ca I 10 839 Å lines obtained with the GREGOR
Infrared Spectrograph of the GREGOR telescope at the Observatorio del
Teide, Tenerife, Spain. The analysis is complemented by a study of
continuum images covering the disk passage of the active region, which
are provided by the Helioseismic and Magnetic Imager on board the Solar
Dynamics Observatory. Results: The sunspot shows a light bridge
with penumbral continuum intensity that separates the central umbra from
a smaller umbra. We find that in this region the magnetic field lines
form a canopy with lower magnetic field strength in the inner part. The
photospheric light bridge is dominated by gas pressure (high-β),
as opposed to the surrounding umbra, where the magnetic pressure
is higher. A convective flow is observed in the light bridge. This
flow is able to bend the magnetic field lines and to produce field
reversals. The field lines merge above the light bridge and become
as vertical and strong as in the surrounding umbra. We conclude that
this occurs because two highly magnetized regions approach each other
during the sunspot evolution. Movies associated to Figs. 2 and 13
are available at <A href="http://www.aanda.org">http://www.aanda.org</A>

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Title: Inference of magnetic fields in the very quiet Sun
Authors: Martínez González, M. J.; Pastor Yabar, A.; Lagg, A.;
Asensio Ramos, A.; Collados, M.; Solanki, S. K.; Balthasar, H.;
Berkefeld, T.; Denker, C.; Doerr, H. P.; Feller, A.; Franz, M.;
González Manrique, S. J.; Hofmann, A.; Kneer, F.; Kuckein, C.;
Louis, R.; von der Lühe, O.; Nicklas, H.; Orozco, D.; Rezaei, R.;
Schlichenmaier, R.; Schmidt, D.; Schmidt, W.; Sigwarth, M.; Sobotka,
M.; Soltau, D.; Staude, J.; Strassmeier, K. G.; Verma, M.; Waldman,
T.; Volkmer, R.
2016A&A...596A...5M Altcode: 2018arXiv180410089M
Context. Over the past 20 yr, the quietest areas of the solar surface
have revealed a weak but extremely dynamic magnetism occurring
at small scales (&lt;500 km), which may provide an important
contribution to the dynamics and energetics of the outer layers of
the atmosphere. Understanding this magnetism requires the inference
of physical quantities from high-sensitivity spectro-polarimetric
data with high spatio-temporal resolution. Aims: We present
high-precision spectro-polarimetric data with high spatial resolution
(0.4”) of the very quiet Sun at 1.56 μm obtained with the GREGOR
telescope to shed some light on this complex magnetism. Methods:
We used inversion techniques in two main approaches. First, we assumed
that the observed profiles can be reproduced with a constant magnetic
field atmosphere embedded in a field-free medium. Second, we assumed
that the resolution element has a substructure with either two constant
magnetic atmospheres or a single magnetic atmosphere with gradients of
the physical quantities along the optical depth, both coexisting with
a global stray-light component. Results: Half of our observed
quiet-Sun region is better explained by magnetic substructure within
the resolution element. However, we cannot distinguish whether this
substructure comes from gradients of the physical parameters along the
line of sight or from horizontal gradients (across the surface). In
these pixels, a model with two magnetic components is preferred, and
we find two distinct magnetic field populations. The population with
the larger filling factor has very weak ( 150 G) horizontal fields
similar to those obtained in previous works. We demonstrate that the
field vector of this population is not constrained by the observations,
given the spatial resolution and polarimetric accuracy of our data. The
topology of the other component with the smaller filling factor is
constrained by the observations for field strengths above 250 G:
we infer hG fields with inclinations and azimuth values compatible
with an isotropic distribution. The filling factors are typically
below 30%. We also find that the flux of the two polarities is not
balanced. From the other half of the observed quiet-Sun area 50% are
two-lobed Stokes V profiles, meaning that 23% of the field of view
can be adequately explained with a single constant magnetic field
embedded in a non-magnetic atmosphere. The magnetic field vector and
filling factor are reliable inferred in only 50% based on the regular
profiles. Therefore, 12% of the field of view harbour hG fields with
filling factors typically below 30%. At our present spatial resolution,
70% of the pixels apparently are non-magnetised.

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Title: Fitting peculiar spectral profiles in He I 10830Å absorption
features
Authors: González Manrique, S. J.; Kuckein, C.; Pastor Yabar, A.;
Collados, M.; Denker, C.; Fischer, C. E.; Gömöry, P.; Diercke, A.;
Bello González, N.; Schlichenmaier, R.; Balthasar, H.; Berkefeld, T.;
Feller, A.; Hoch, S.; Hofmann, A.; Kneer, F.; Lagg, A.; Nicklas, H.;
Orozco Suárez, D.; Schmidt, D.; Schmidt, W.; Sigwarth, M.; Sobotka,
M.; Solanki, S. K.; Soltau, D.; Staude, J.; Strassmeier, K. G.; Verma,
M.; Volkmer, R.; von der Lühe, O.; Waldmann, T.
2016AN....337.1057G Altcode: 2016arXiv160300679G
The new generation of solar instruments provides better
spectral, spatial, and temporal resolution for a better
understanding of the physical processes that take place on the
Sun. Multiple-component profiles are more commonly observed with these
instruments. Particularly, the He I 10830 Å triplet presents such
peculiar spectral profiles, which give information on the velocity
and magnetic fine structure of the upper chromosphere. The purpose
of this investigation is to describe a technique to efficiently fit
the two blended components of the He I 10830 Å triplet, which are
commonly observed when two atmospheric components are located within
the same resolution element. The observations used in this study were
taken on 2015 April 17 with the very fast spectroscopic mode of the
GREGOR Infrared Spectrograph (GRIS) attached to the 1.5-m GREGOR solar
telescope, located at the Observatorio del Teide, Tenerife, Spain. We
apply a double-Lorentzian fitting technique using Levenberg-Marquardt
least-squares minimization. This technique is very simple and much
faster than inversion codes. Line-of-sight Doppler velocities can
be inferred for a whole map of pixels within just a few minutes. Our
results show sub- and supersonic downflow velocities of up to 32 km
s-1 for the fast component in the vicinity of footpoints of
filamentary structures. The slow component presents velocities close
to rest.

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Title: Time-series Doppler images and surface differential rotation
of the effectively single, rapidly rotating K-giant KU Pegasi
Authors: Kővári, Zs.; Künstler, A.; Strassmeier, K. G.; Carroll,
T. A.; Weber, M.; Kriskovics, L.; Oláh, K.; Vida, K.; Granzer, T.
2016A&A...596A..53K Altcode: 2016arXiv160900196K
Context. According to most stellar dynamo theories, differential
rotation (DR) plays a crucial role in the generation of toroidal
magnetic fields. Numerical models predict surface differential rotation
to be anti-solar for rapidly rotating giant stars, I.e. their surface
angular velocity could increase with stellar latitude. However, surface
differential rotation has been derived only for a handful of individual
giant stars to date. Aims: The spotted surface of the K-giant
KU Pegasi is investigated in order to detect its time evolution and to
quantify the surface differential rotation. Methods: We present
11 Doppler images from spectroscopic data collected with the robotic
telescope STELLA between 2006 and 2011. All maps are obtained with the
surface reconstruction code iMap. Differential rotation is extracted
from these images by detecting systematic (latitude-dependent) spot
displacements. We apply a cross-correlation technique to find the
best differential rotation law. Results: The surface of KU Peg
shows cool spots at all latitudes and one persistent warm spot at high
latitude. A small cool polar spot exists for most but not all of the
epochs. Re-identification of spots in at least two consecutive maps is
mostly possible only at middle and high latitudes and thus restricts
the differential-rotation determination mainly to these latitudes. Our
cross-correlation analysis reveals solar-like differential rotation
with a surface shear of α = + 0.040 ± 0.006, I.e., approximately
five times weaker than on the Sun. We also derive a more accurate and
consistent set of stellar parameters for KU Peg including a small Li
abundance of ten times less than solar. Based on data obtained
with the STELLA robotic observatory in Tenerife, an AIP facility
jointly operated by AIP and IAC.

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Title: Time-series Doppler imaging of the red giant HD 208472. Active
longitudes and differential rotation
Authors: Özdarcan, O.; Carroll, T. A.; Künstler, A.; Strassmeier,
K. G.; Evren, S.; Weber, M.; Granzer, T.
2016A&A...593A.123O Altcode: 2016arXiv160706841O
Context. HD 208472 is among the most active RS CVn binaries with
cool starspots. Decade-long photometry has shown that the spots
seem to change their longitudinal appearance with a period of
about six years, coherent with brightness variations. 
Aims: Our aim is to spatially resolve the stellar surface of
<ASTROBJ>HD 208472</ASTROBJ> and relate the photometric results to
the true longitudinal and latitudinal spot appearance. Furthermore,
we investigate the surface differential rotation pattern of the
star. Methods: We employed three years of high-resolution
spectroscopic data with a high signal-to-noise ratio (S/N) from
the STELLA robotic observatory and determined new and more precise
stellar physical parameters. Precalculated synthetic spectra were fit
to each of these spectra, and we provide new spot-corrected orbital
elements. A sample of 34 absorption lines per spectrum was used to
calculate mean line profiles with a S/N of several hundred. A total
of 13 temperature Doppler images were reconstructed from these line
profiles with the inversion code iMap. Differential rotation was
investigated by cross-correlating successive Doppler images in each
observing season. Results: Spots on HD 208472 are distributed
preferably at high latitudes and less frequently around mid-to-low
latitudes. No polar-cap like structure is seen at any epoch. We observed
a flip-flop event between 2009 and 2010, manifested as a flip of the
spot activity from phase 0.0 to phase 0.5, while the overall brightness
of the star continued to increase and reached an all-time maximum
in 2014. Cross-correlation of successive Doppler images suggests
a solar-like differential rotation that is ≈15 times weaker than
that of the Sun. Based on data obtained with the STELLA robotic
telescope in Tenerife, an AIP facility jointly operated by AIP and IAC,
and the Potsdam Automatic Photoelectric Telescopes (APT) in Arizona,
jointly operated by AIP and Fairborn Observatory.Radial velocity
measurements are only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/593/A123">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/593/A123</A>

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Title: EELT-HIRES the high-resolution spectrograph for the E-ELT
Authors: Marconi, A.; Di Marcantonio, P.; D'Odorico, V.; Cristiani,
S.; Maiolino, R.; Oliva, E.; Origlia, L.; Riva, M.; Valenziano, L.;
Zerbi, F. M.; Abreu, M.; Adibekyan, V.; Allende Prieto, C.; Amado,
P. J.; Benz, W.; Boisse, I.; Bonfils, X.; Bouchy, F.; Buchhave,
L.; Buscher, D.; Cabral, A.; Canto Martins, B. L.; Chiavassa, A.;
Coelho, J.; Christensen, L. B.; Delgado-Mena, E.; de Medeiros, J. R.;
Di Varano, I.; Figueira, P.; Fisher, M.; Fynbo, J. P. U.; Glasse,
A. C. H.; Haehnelt, M.; Haniff, C.; Hansen, C. J.; Hatzes, A.; Huke,
P.; Korn, A. J.; Leão, I. C.; Liske, J.; Lovis, C.; Maslowski,
P.; Matute, I.; McCracken, R. A.; Martins, C. J. A. P.; Monteiro,
M. J. P. F. G.; Morris, S.; Morris, T.; Nicklas, H.; Niedzielski, A.;
Nunes, N. J.; Palle, E.; Parr-Burman, P. M.; Parro, V.; Parry, I.;
Pepe, F.; Piskunov, N.; Queloz, D.; Quirrenbach, A.; Rebolo Lopez,
R.; Reiners, A.; Reid, D. T.; Santos, N.; Seifert, W.; Sousa, S.;
Stempels, H. C.; Strassmeier, K.; Sun, X.; Udry, S.; Vanzi, L.;
Vestergaard, M.; Weber, M.; Zackrisson, E.
2016SPIE.9908E..23M Altcode: 2016arXiv160900497M
The first generation of E-ELT instruments will include an optic-infrared
High Resolution Spectrograph, conventionally indicated as EELT-HIRES,
which will be capable of providing unique breakthroughs in the fields
of exoplanets, star and planet formation, physics and evolution of
stars and galaxies, cosmology and fundamental physics. A 2-year long
phase A study for EELT-HIRES has just started and will be performed
by a consortium composed of institutes and organisations from Brazil,
Chile, Denmark, France, Germany, Italy, Poland, Portugal, Spain, Sweden,
Switzerland and United Kingdom. In this paper we describe the science
goals and the preliminary technical concept for EELT-HIRES which will
be developed during the phase A, as well as its planned development
and consortium organisation during the study.

---------------------------------------------------------
Title: Anti-solar differential rotation on the active sub-giant
HU Virginis
Authors: Harutyunyan, G.; Strassmeier, K. G.; Künstler, A.; Carroll,
T. A.; Weber, M.
2016A&A...592A.117H Altcode: 2016arXiv160605497H
Context. Measuring surface differential rotation (DR) on different
types of stars is important when characterizing the underlying stellar
dynamo. It has been suggested that anti-solar DR laws can occur when
strong meridional flows exist. Aims: We aim to investigate
the differential surface rotation on the primary star of the RS CVn
binary, HU Vir, by tracking its starspot distribution as a function of
time. We also aim to recompute and update the values for several system
parameters of the triple system HU Vir (close and wide orbits). 
Methods: Time-series high-resolution spectroscopy for four continuous
months was obtained with the 1.2-m robotic STELLA telescope. Nine
consecutive Doppler images were reconstructed from these data, using
our line-profile inversion code iMap. An image cross-correlation
method was applied to derive the surface differential-rotation law
for HU Vir. New orbital elements for the close and the wide orbits
were computed using our new STELLA radial velocities (RVs) combined
with the RV data available in the literature. Photometric observations
were performed with the Amadeus Automatic Photoelectric Telescope (APT),
providing contemporaneous Johnson-Cousins V and I data for approximately
20 yrs. This data was used to determine the stellar rotation period
and the active longitudes. Results: We confirm anti-solar DR
with a surface shear parameter α of -0.029 ± 0.005 and -0.026 ±
0.009, using single-term and double-term differential rotation laws,
respectively. These values are in good agreement with previously claimed
results. The best fit is achieved assuming a solar-like double-term
law with a lap time of ≈400 d. Our orbital solutions result in a
period of 10.387678 ± 0.000003 days for the close orbit and 2726 ±
7 d (≈7.5 yr) for the wide orbit. A Lomb-Scarge (L-S) periodogram of
the pre-whitened V-band data reveals a strong single peak providing a
rotation period of 10.391 ± 0.008 d, well synchronized to the short
orbit. Based on data obtained with the STELLA robotic observatory
in Tenerife, an AIP facility jointly operated by AIP and IAC.The tables
with the STELLA radial velocity data set and the APT photometric data
set are available only in electronic form at the CDS via anonymous ftp
to <A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(<A href="http://130.79.128.5">http://130.79.128.5</A>) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A117">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/592/A117</A>

---------------------------------------------------------
Title: Thermal control modeling approach for GRAPE (GRAntecan
PolarimEter)
Authors: Di Varano, I.; Woche, M.; Strassmeier, K. G.
2016SPIE.9911E..15D Altcode:
GRAPE is the polarimeter planned to be installed on the main Cassegrain
focus of GTC (Gran Telescopio Canarias), having an equivalent entrance
pupil of 10.4 m, located at the Observatorio del Roque de los Muchachos
(ORM) , in La Palma, Canary Islands. It's meant to deliver full Stokes
(IQUV) polarimetry covering the spectral range 0.420-1.6 μ, in order
to feed the HORS instrument (High Optical Resolution Spectrograph),
mounted on the Nasmyth platform, which has a FWHM resolving power
of about 25,000 (5 pixel) designed for the wavelength range of
380-800 nm. Two calcite blocks and a BK-7 prism arranged in a Foster
configuration are splitting the Ø12.5mm collimated beam into the
ordinary and extraordinary components. The entire subunit from the
Foster prisms down to the input fibers is rotated by steps of 45
degrees in order to retrieve Q, U components. By inserting a quarter
wave retarder plate before the entrance to the Foster unit circular
polarization is measured too. The current paper consist of two main
parts: at first CFD simulations are introduced, which have been run
compliant to the specifications derived by the environmental conditions
and the transient thermal gradients taking into account the presence of
the electronic cabinets installed, which are triggering the boundary
conditions for the outer structure of the instrument; then a thermal
control model is proposed based on heat exchangers to stabilize the
inner temperature when compensation via passive insulation is not
enough. The tools that have been adopted to reach for such goal are
Ansys Multiphysics, in particular CFX package and Python scripts.

---------------------------------------------------------
Title: HIRES the high-resolution spectrograph for the E-ELT:
dynamics and control of the repositioning mechanism for the E-ELT
HIRES polarimeter
Authors: Di Varano, I.; Strassmeier, K. G.; Woche, M.
2016SPIE.9908E..9LD Altcode:
A full Stokes dual channel polarimeter for the E-ELT HIRES spectrograph
has been envisioned for the intermediate focus f/4.4, operating
within a spectral range of 0.4-1.6 μ. It will feed the EELT- HIRES
instrument located on the Nasmyth platform via two pairs of dedicated
fibers: one fibre pair optimized for the BVRI, the other one optimized
for the JH band or any other feasible combination. The instrument
must be retractable within a workspace in fulfillment with the ESO
requirements on the allocated volume and the dynamic response of the AO
tower. For such purpose a swinging arm has been designed with a rotation
provided by 5 revolute joints and a jackscrew. Moreover repeatability in
repositioning has to be guaranteed by a parallel manipulator, performing
an alignment procedure mainly along 5 axes. Dynamics and control
criteria with a feed forward chain to compensate for vibration forces
and feedback chain for tracking procedure are hereafter presented.

---------------------------------------------------------
Title: PEPSI-feed: linking PEPSI to the Vatican Advanced Technology
Telescope using a 450m long fibre
Authors: Sablowski, D. P.; Weber, M.; Woche, M.; Ilyin, I.; Järvinen,
A.; Strassmeier, K. G.; Gabor, P.
2016SPIE.9912E..5HS Altcode:
Limited observing time at large telescopes equipped with the most
powerful spectrographs makes it almost impossible to gain long and
well-sampled time-series observations. Ditto, high-time-resolution
observations of bright targets with high signal-to-noise are rare. By
pulling an optical fibre of 450m length from the Vatican Advanced
Technology Telescope (VATT) to the Large Binocular Telescope (LBT) to
connect the Potsdam Echelle Polarimetric and Spectroscopic Instrument
(PEPSI) to the VATT, allows for ultra-high resolution time-series
measurements of bright targets. This article presents the fibre-link in
detail from the technical point-of-view, demonstrates its performance
from first observations, and sketches current applications.

---------------------------------------------------------
Title: VizieR Online Data Catalog: STELLA-SES Radial Velocities of
HD 208472 (Ozdarcan+, 2016)
Authors: Ozdarcan, O.; Carroll, T. A.; Kunstler, A.; Strassmeier,
K. G.; Evren, S.; Weber, M.; Granzer, T.
2016yCat..35930123O Altcode:
Precise radial velocity measurement of HD 208472 based on 229 high
resolution Stella Echelle Spectrograph (SES) spectra obtained at
STELLA robotic observatory on Tenerife, Spain from March 22, 2009 to
July 20, 2011 are presented. High precision radial velocities allow
one to trace spot jitter effect on measured radial velocities via
residuals from spectroscopic orbit solution. In case of HD 208472,
removing spot jitter effect from measured velocities, precision on
calculated orbital parameters were improved by factor of 4 without
changing the actual value of parameters. (1 data file).

---------------------------------------------------------
Title: VizieR Online Data Catalog: HU Vir radial velocities and VI
light curves (Harutyunyan+, 2016)
Authors: Harutyunyan, G.; Strassmeier, K. G.; Kuenstler, A.; Carroll,
T. A.; Weber, M.
2016yCat..35920117H Altcode:
We present two tables with the new STELLA radial velocity data
set and the APT Johnson-Cousins V and I photometric data set
for HU Virginis. RVs from STELLA-SES spectra were derived from an
order-by-order cross correlation with a synthetic template spectrum
and then averaged. The photometric measurements were always made
differentially with respect to HD 106270 and HD 106332 as a comparison
and check star, respectively. (2 data files).

---------------------------------------------------------
Title: An integrated thermo-structural model to design a polarimeter
for the GTC
Authors: Di Varano, I.; Strassmeier, K. G.; Woche, M.; Laux, U.
2016SPIE10012E..08D Altcode:
The GTC (Gran Telescopio Canarias), with an equivalent aperture of 10.4
m, effective focal length of 169.9 m, located at the Observatorio del
Roque de los Muchachos , in La Palma, Canary Islands, will host on its
Cassegrain focus the GRAPE polarimeter (GRAntecan PolarimEter). At
such focus the plate scale is 1.21 arcsec/mm and the unvignetted
FOV 8 arcmin. The instrument will provide full Stokes polarimetry
in the spectral range 380-1500 nm, feeding simultaneously up to
two spectrographs. At the moment an interface to HORS (High Optical
Resolution Spectrograph) is being defined, located on the Nasmyth
platform, it has a FWHM resolving power of about 25,000 (5 pixel) within
a spectral range of 400-680 nm. The rotator and instrumental flanges
for the Cassegrain focus are currently under definition. Hereafter I
present the state of art of the mechanical design of the polarimeter,
whose strategy is based on an integrated model of Zemax design into
ANSYS FEM static and dynamic analyses with thermal loads applied, in
order to retrieve tip-tilt, decentering errors and other significant
parameters to be looped back to the Zemax model. In such a way it
is possible to compare and refine the results achieved through the
tolerance analysis.

---------------------------------------------------------
Title: Multi-resolution waveguide image slicer for the PEPSI
instrument
Authors: Beckert, Erik; Strassmeier, Klaus G.; Woche, Manfred;
Harnisch, Gerd; Hornaff, Marcel; Weber, Michael; Barnes, Stuart
2016SPIE.9912E..5OB Altcode:
A waveguide image slicer with resolutions up to 270.000 (planned:
300.000) for the fiber fed PEPSI echelle spectrograph at the LBT and
single waveguide thicknesses of down to 70 μm has been manufactured and
tested. The waveguides were macroscopically prepared, stacked up to an
order of seven and thinned back to square stack cross sections. A high
filling ratio was achieved by realizing homogenous adhesive gaps of 3.6
μm, using index matching adhesives for TIR within the waveguides. The
image slicer stacks are used in immersion mode and are miniaturized
to enable implementation in a set of 2x8. The overall efficiency is
between 92 % and 96 %.

---------------------------------------------------------
Title: STELLA: 10 years of robotic observations on Tenerife
Authors: Weber, Michael; Granzer, Thomas; Strassmeier, Klaus G.
2016SPIE.9910E..0NW Altcode:
STELLA is a robotic observatory on Tenerife housing two 1.2m
robotic telescopes. One telescope is fibre-feeding a high-resolution
(R=55,000) échelle spectrograph (SES), while the other telescope
is equipped with a visible wide- field (FOV=22' x 22') imaging
instrument (WiFSIP). Robotic observations started mid 2006, and
the primary scientific driver is monitoring of stellar-activity
related phenomena. The STELLA Control System (SCS) software package
was originally tailored to the STELLA roll-off style building and
high-resolution spectroscopy, but was extended over the years to support
the wide-field imager, an off-axis guider for the imager, separate
acquisition telescopes, classical domes, and targets-of-opportunity. The
SCS allows for unattended, off-line operation of the observatory,
targets can be uploaded at any time and are selected based on
merit-functions in real-time (dispatch scheduling). We report on the
current status of the observatory and the current capabilities of
the SCS.

---------------------------------------------------------
Title: STELLA Meets RAVE: Calibrating Low-Resolution Ca II IRT Fluxes
Authors: Järvinen, Silva P.; Kordopatis, Georges; Strassmeier,
Klaus G.; Steinmetz, Matthias
2016csss.confE..65J Altcode:
Within the RAVE (the Radial Velocity Experument) survey in total
574,630low-resolution spectra of 483,330 stars covering the Ca II
IRT has beenobtained. With our selection criteria, out of those stars
about 10% arelate-type dwarfs. We have selected these dwarfs from the
database,converted the measured 1-Åcore equivalent widths into the
fluxes, andobtained follow up high-resolution spectra of selected
targets as well asspectra of MK standard stars using SES (STELLA
échelle spectrograph) atSTELLA (STELLar Activity) telescope. With a
single exposure, we cover allwavelengths from Ca H&amp;K to IRT and can
therefore relate IRT fluxes withthose of other activity indicators, such
as Hα. Furthermore, we canplace these fluxes in relation to observable
astrophysical parameters,such as global metallicity and temperature.

---------------------------------------------------------
Title: Rotation Periods for Cool Stars in the 4 Gyr old Open
Cluster M67, The Solar-Stellar Connection, and the Applicability of
Gyrochronology to at least Solar Age
Authors: Barnes, Sydney A.; Weingrill, Joerg; Fritzewski, Dario;
Strassmeier, Klaus G.; Platais, Imants
2016ApJ...823...16B Altcode: 2016arXiv160309179B
We report rotation periods for 20 cool (FGK) main sequence member
stars of the 4 Gyr-old open cluster M67 (=NGC 2682), obtained by
analyzing data from Campaign 5 of the K2 mission with the Kepler Space
Telescope. The rotation periods delineate a sequence in the color-period
diagram (CPD) of increasing period with redder color. This sequence
represents a cross-section at the cluster age of the surface P = P(t,
M), suggested in prior work to extend to at least solar age. The current
Sun is located marginally (approximately 1σ) above M67 in the CPD,
as its relative age leads us to expect, and lies on the P = P(t, M)
surface to within measurement precision. We therefore conclude that
the solar rotation rate is normal as compared with cluster stars,
a fact that strengthens the solar-stellar connection. The agreement
between the M67 rotation period measurements and prior predictions
further implies that rotation periods, especially when coupled
with appropriate supporting work such as spectroscopy, can provide
reliable ages via gyrochronology for other similar FGK dwarfs from the
early main sequence to solar age and likely until the main sequence
turnoff. The M67 rotators have a rotational age of 4.2 Gyr with a
standard deviation of 0.7 Gyr, implying that similar field stars can
be age-dated to precisions of ∼17%. The rotational age of the M67
cluster as a whole is therefore 4.2 Gyr, but with a lower (averaged)
uncertainty of 0.2 Gyr.

---------------------------------------------------------
Title: Transmission spectroscopy of HAT-P-32b with the LBT:
confirmation of clouds/hazes in the planetary atmosphere
Authors: Mallonn, M.; Strassmeier, K. G.
2016A&A...590A.100M Altcode: 2016arXiv160309136M
 Aims: Spectroscopic observations of a transit event of an
extrasolar planet offer the opportunity to study the composition of
the planetary atmosphere. This can be done with comparably little
telescope time using a low-resolution multi-object spectrograph at a
large aperture telescope. We observed a transit of the inflated hot
Jupiter HAT-P-32b with the Multi-Object Double Spectrograph at the
Large Binocular Telescope to characterize its atmosphere from 3300
to 10 000 Å. Methods: A time series of target and reference
star spectra was binned in two broad-band wavelength channels, from
which differential transit light curves were constructed. These
broad-band light curves were used to confirm previous transit
parameter determinations. To derive the planetary transmission
spectrum with a resolution of R ~ 60, we created a chromatic set of
62 narrow-band light curves. The spectrum was corrected for the third
light of a nearby M star. Additionally, we undertook a photometric
monitoring campaign of the host star to correct for the influence
of starspots. Results: The transmission spectrum of HAT-P-32b
shows no pressure-broadened absorption features from Na and K, which
is interpreted by the presence of clouds or hazes in the planetary
atmosphere. This result is in agreement with previous studies on the
same planet. The presence of TiO in gas phase could be ruled out. We
find a 2.8σ indication of increased absorption in the line core of
potassium (K I 7699 Å). No narrow absorption features of Na and Hα
were detected. Furthermore, tentative indications were found for a
slope of increasing opacity toward blue wavelengths from the near-IR
to the near-UV with an amplitude of two scale heights. If confirmed
by follow-up observations, it can be explained by aerosols either
causing Mie scattering or causing Rayleigh scattering with an aerosol
- gas scale height ratio below unity. The host star was found to be
photometrically stable within the measurement precision. Based
on observations made with the Large Binocular Telescope (LBT) and the
STELLA robotic telescopes. The LBT is an international collaboration
among institutions in the United States, Italy and Germany. LBT
Corporation partners are: LBT Beteiligungsgesellschaft, Germany,
representing the Leibniz Institute for Astrophysics Potsdam (AIP),
the Max-Planck Society, and Heidelberg University; The University of
Arizona on behalf of the Arizona Board of Regents; Istituto Nazionale
di Astrofisica, Italy; The Ohio State University, and The Research
Corporation, on behalf of The University of Notre Dame, University of
Minnesota and University of Virginia. STELLA is an AIP facility jointly
operated by AIP and Instituto de Astrofísica de Canarias (IAC).Tables
of the lightcurves are only available at the CDS via anonymous ftp to
<A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(<A href="http://130.79.128.5">http://130.79.128.5</A>) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/590/A100">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/590/A100</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: Transmission spectroscopy of
HAT-P-32b (Mallonn+, 2016)
Authors: Mallonn, M.; Strassmeier, K. G.
2016yCat..35900100M Altcode:
A set of 62 simultaneous photometric light curves from 3300 to
10000Å of a transit event of HAT-P-32b. The wavelength range
of each light curve is ~100Å in average. The light curves cover
about one hour pre-transit, the transit event, and about 1 hour
post-transit. Observations have been taken with MODS at LBT in
multi-object mode. Light curves are given in differential magnitudes. (2 data files).

---------------------------------------------------------
Title: Flows in and around Active Region NOAA12118 Observed with
the GREGOR Solar Telescope and SDO/HMI
Authors: Verma, M.; Denker, C.; Balthasar, H.; Kuckein, C.; González
Manrique, S. J.; Sobotka, M.; Bello González, N.; Hoch, S.; Diercke,
A.; Kummerow, P.; Berkefeld, T.; Collados, M.; Feller, A.; Hofmann,
A.; Kneer, F.; Lagg, A.; Löhner-Böttcher, J.; Nicklas, H.; Pastor
Yabar, A.; Schlichenmaier, R.; Schmidt, D.; Schmidt, W.; Schubert,
M.; Sigwarth, M.; Solanki, S. K.; Soltau, D.; Staude, J.; Strassmeier,
K.; Volkmer, R.; von der Lühe, O.; Waldmann, T.
2016ASPC..504...29V Altcode: 2016arXiv160301109V
Accurate measurements of magnetic and velocity fields in and around
solar active regions are key to unlocking the mysteries of the
formation and the decay of sunspots. High spatial resolution images
and spectral sequences with a high cadence obtained with the GREGOR
solar telescope give us an opportunity to scrutinize 3-D flow fields
with local correlation tracking and imaging spectroscopy. We present
GREGOR early science data acquired in 2014 July - August with the GREGOR
Fabry-Pérot Interferometer and the Blue Imaging Channel. Time-series
of blue continuum (λ 450.6 nm) images of the small active region
NOAA 12118 were restored with the speckle masking technique to derive
horizontal proper motions and to track the evolution of morphological
changes. In addition, high-resolution observations are discussed in
the context of synoptic data from the Solar Dynamics Observatory.

---------------------------------------------------------
Title: Triennial Report (2012-2015): the Legacy Issue
Authors: Pollard, Karen; Jeffery, Simon; Handler, Gerald; Catelan,
Márcio; Eyer, Laurent; Hekker, Saskia; Kolenberg, Katrien; Mkrtichian,
David; Kepler, S. O.; Stello, Dennis; Strassmeier, Klaus; Uytterhoeven,
Katrien
2016IAUTA..29..413P Altcode:
The study of variable stars has played a central role in astronomy
for over 400 years, and more so in the present than at any time
in history. Stars, especially variable stars, are astrophysical
laboratories for understanding physical processes in the universe. Stars
represent the fundamental components of stellar systems, galaxies and
the universe.

---------------------------------------------------------
Title: Comparing modal noise and FRD of circular and non-circular
cross-section fibres
Authors: Sablowski, D. P.; Plüschke, D.; Weber, M.; Strassmeier,
K. G.; Järvinen, A.
2016AN....337..216S Altcode: 2015arXiv151109281S
Modal noise is a common source of noise introduced to the
measurements by optical fibres and is particularly important for
fibre-fed spectroscopic instruments, especially for high-resolution
measurements. This noise source can limit the signal-to-noise ratio and
jeopardize photon-noise limited data. The subject of the present work
is to compare measurements of modal noise and focal-ratio degradation
(FRD) for several commonly used fibres. We study the influence of a
simple mechanical scrambling method (excenter) on both FRD and modal
noise. Measurements are performed with circular and octagonal fibres
from Polymicro Technology (FBP-Series) with diameters of 100, 200, and
300 μm and for square and rectangular fibres from CeramOptec, among
others. FRD measurements for the same sample of fibres are performed
as a function of wavelength. Furthermore, we replaced the circular
fibre of the STELLA-échelle-spectrograph (SES) in Tenerife with an
octagonal and found a SNR increase by a factor of 1.6 at 678 nm. It is
shown in the laboratory that an excenter with a large amplitude and
low frequency will not influence the FRD but will reduce modal noise
rather effectively by up to 180%.

---------------------------------------------------------
Title: FK Comae Berenices, King of Spin: The COCOA-PUFS Project
Authors: Ayres, Thomas R.; Kashyap, V.; Saar, S.; Huenemoerder,
D.; Korhonen, H.; Drake, J. J.; Testa, P.; Cohen, O.; Garraffo, C.;
Granzer, T.; Strassmeier, K.
2016ApJS..223....5A Altcode: 2016arXiv160103305A
COCOA-PUFS is an energy-diverse, time-domain study of the ultra-fast
spinning, heavily spotted, yellow giant FK Comae Berenices (FK Com:
HD117555; G4 III). This single star is thought to be a recent
binary merger, and is exceptionally active by measure of its
intense ultraviolet (UV) and X-ray emissions, and proclivity to
flare. COCOA-PUFS was carried out with the Hubble Space Telescope
in the UV (1200-3000 Å), using mainly its high-performance Cosmic
Origins Spectrograph, but also high precision Space Telescope Imaging
Spectrograph; Chandra X-ray Observatory in the soft X-rays (0.5-10 keV),
utilizing its High-Energy Transmission Grating Spectrometer; together
with supporting photometry and spectropolarimetry in the visible
from the ground. This is an introductory report on the project. FK Com
displayed variability on a wide range of timescales over all wavelengths
during the week-long main campaign, including a large X-ray flare;
“super-rotational broadening” of the far-ultraviolet “hot
lines” (e.g., Si IV 1393 Å 8 × 104 K) together with
chromospheric Mg II 2800 Å and C II 1335 Å (1-3 × 104
K); large Doppler swings suggestive of bright regions alternately on
advancing and retreating limbs of the star; and substantial redshifts
of the epoch-average emission profiles. These behaviors paint a picture
of a highly extended, dynamic, hot (∼10 MK) coronal magnetosphere
around the star, threaded by cooler structures perhaps analogous to
solar prominences and replenished continually by surface activity
and flares. Suppression of angular momentum loss by the confining
magnetosphere could temporarily postpone the inevitable stellar
spindown, thereby lengthening this highly volatile stage of coronal
evolution. COordinated Campaign of Observations and Analysis,
Photosphere to Upper Atmosphere, of a Fast-rotating Star.

---------------------------------------------------------
Title: The LEECH Exoplanet Imaging Survey: Orbit and Component Masses
of the Intermediate-Age, Late-Type Binary NO UMa
Authors: Schlieder, Joshua E.; Skemer, Andrew J.; Maire, Anne-Lise;
Desidera, Silvano; Hinz, Philip; Skrutskie, Michael F.; Leisenring,
Jarron; Bailey, Vanessa; Defrère, Denis; Esposito, Simone;
Strassmeier, Klaus G.; Weber, Michael; Biller, Beth A.; Bonnefoy,
Mickaël; Buenzli, Esther; Close, Laird M.; Crepp, Justin R.; Eisner,
Josh A.; Hofmann, Karl-Heinz; Henning, Thomas; Morzinski, Katie M.;
Schertl, Dieter; Weigelt, Gerd; Woodward, Charles E.
2016ApJ...818....1S Altcode: 2015arXiv151003813S
We present high-resolution Large Binocular Telescope LBTI/LMIRcam images
of the spectroscopic and astrometric binary NO UMa obtained as part of
the LBT Interferometer Exozodi Exoplanet Common Hunt exoplanet imaging
survey. Our H-, Ks-, and L‧-band observations resolve
the system at angular separations &lt;0.″09. The components exhibit
significant orbital motion over a span of ∼7 months. We combine our
imaging data with archival images, published speckle interferometry
measurements, and existing spectroscopic velocity data to solve the
full orbital solution and estimate component masses. The masses of
the K2.0 ± 0.5 primary and K6.5 ± 0.5 secondary are 0.83 ± 0.02
M⊙ and 0.64 ± 0.02 M⊙, respectively. We also
derive a system distance of d = 25.87 ± 0.02 pc and revise the Galactic
kinematics of NO UMa. Our revised Galactic kinematics confirm NO UMa as
a nuclear member of the ∼500 Myr old Ursa Major moving group, and it
is thus a mass and age benchmark. We compare the masses of the NO UMa
binary components to those predicted by five sets of stellar evolution
models at the age of the Ursa Major group. We find excellent agreement
between our measured masses and model predictions with little systematic
scatter between the models. NO UMa joins the short list of nearby,
bright, late-type binaries having known ages and fully characterized
orbits. Based on data obtained with the STELLA robotic telescope
in Tenerife, an AIP facility jointly operated by AIP and IAC.

---------------------------------------------------------
Title: Optical Spectroscopy of the Classical Novae V339 Del (2013)
and V5668 Sgr (2015 No. 2)
Authors: Wagner, R. Mark; Woodward, Charles E.; Starrfield, Sumner;
Ilyin, Ilya; Strassmeier, Klaus G.; Page, Kim; Osborne, Julian P.;
Beardmore, Andrew P.
2016AAS...22723910W Altcode:
We report the results of optical spectroscopy of the gamma-ray classical
novae V339 Del (2013) and V5668 Sgr (PNV J18365700-2855420/Nova Sgr
2015 No. 2) supplemented by UV and X-ray observations obtained with
Swift. Our spectra were obtained with the Steward Observatory Bok 2.3
m telescope (+B&amp;C), the MDM 2.4 m Hiltner telescope (+OSMOS), the
6.5 m MMT (+BlueChannel), and the 2 x 8.4 m Large Binocular Telescope
(+MODS1 and PEPSI) between 2013 August and 2015 September. The PEPSI
spectra cover all or part of the 384-907 nm spectral region at a
resolution of up to 270,000 (1 km/s). This is the highest resolution
available on any 8-10 m class telescope. V339 Del was discovered on
2015 August 14.58 by Itagaki at V about 6.8. This nova reached a peak
magnitude of about 4.3 making it one of the brightest novae of this
century. Because of its exceptional brightness it has been observed at a
variety of wavelengths and by a host of observatories both on the ground
and in space. V5668 Sgr was discovered on 2015 March 15.634 by Seach
at a magnitude of 6.0. It subsequently reached a maximum brightness
of about 4.0 in late March. High resolution PEPSI spectra obtained in
early April show dramatic variations in the multi-component P Cygni-type
line profiles. V5668 Sgr was observed to form dust in June thereafter
fading to about 13th magnitude. Our recent observations show that it
has now evolved into the nebular phase. SS acknowledges partial support
from NSF and NASA grants to ASU. CEW acknowledges support from NASA.

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Title: Scientific problems addressed by the Spektr-UV space project
(world space Observatory—Ultraviolet)
Authors: Boyarchuk, A. A.; Shustov, B. M.; Savanov, I. S.; Sachkov,
M. E.; Bisikalo, D. V.; Mashonkina, L. I.; Wiebe, D. Z.; Shematovich,
V. I.; Shchekinov, Yu. A.; Ryabchikova, T. A.; Chugai, N. N.; Ivanov,
P. B.; Voshchinnikov, N. V.; Gomez de Castro, A. I.; Lamzin, S. A.;
Piskunov, N.; Ayres, T.; Strassmeier, K. G.; Jeffrey, S.; Zwintz,
S. K.; Shulyak, D.; Gérard, J. -C.; Hubert, B.; Fossati, L.; Lammer,
H.; Werner, K.; Zhilkin, A. G.; Kaigorodov, P. V.; Sichevskii, S. G.;
Ustamuich, S.; Kanev, E. N.; Kil'pio, E. Yu.
2016ARep...60....1B Altcode:
The article presents a review of scientific problems and methods of
ultraviolet astronomy, focusing on perspective scientific problems
(directions) whose solution requires UV space observatories. These
include reionization and the history of star formation in the Universe,
searches for dark baryonic matter, physical and chemical processes
in the interstellar medium and protoplanetary disks, the physics of
accretion and outflows in astrophysical objects, from Active Galactic
Nuclei to close binary stars, stellar activity (for both low-mass and
high-mass stars), and processes occurring in the atmospheres of both
planets in the solar system and exoplanets. Technological progress
in UV astronomy achieved in recent years is also considered. The
well advanced, international, Russian-led Spektr-UV (World Space
Observatory—Ultraviolet) project is described in more detail. This
project is directed at creating a major space observatory operational
in the ultraviolet (115-310 nm). This observatory will provide an
effective, and possibly the only, powerful means of observing in this
spectral range over the next ten years, and will be an powerful tool
for resolving many topical scientific problems.

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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.
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 <A
href="http://www.aanda.org/10.1051/0004-6361/201526202/olm">http://www.aanda.org</A>

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Title: Chemical composition of a sample of bright solar-metallicity
stars
Authors: Caffau, E.; Mott, A.; Steffen, M.; Bonifacio, P.; Strassmeier,
K. G.; Gallagher, A.; Faraggiana, R.; Sbordone, L.
2015AN....336..968C Altcode: 2015arXiv151004269C
We present a detailed analysis of seven young stars observed with the
spectrograph SOPHIE at the Observatoire de Haute-Provence for which the
chemical composition was incomplete or absent in the literature. For
five stars, we derived the stellar parameters and chemical compositions
using our automatic pipeline optimized for F, G, and K stars, while
for the other two stars with high rotational velocity, we derived the
stellar parameters by using other information (parallax), and performed
a line-by-line analysis. Chromospheric emission-line fluxes from Ca
II are obtained for all targets. The stellar parameters we derive are
generally in good agreement with what is available in the literature. We
provide a chemical analysis of two of the stars for the first time. The
star HIP 80124 shows a strong Li feature at 670.8 nm implying a high
lithium abundance. Its chemical pattern is not consistent with it
being a solar sibling, as has been suggested. Data obtained at
Observatoire de Haute Provence, with the SOPHIE spectrograph.

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Title: The LOFAR Solar Imaging Pipeline and the LOFAR Solar Data
Center
Authors: Breitling, F.; Mann, G.; Vocks, C.; Steinmetz, M.;
Strassmeier, K. G.
2015A&C....13...99B Altcode: 2016arXiv160305990B
LOFAR is a new and sensitive radio interferometer that can be used for
dynamic high-resolution imaging spectroscopy at low radio frequencies
from 10 to 90 and 110 to 250 MHz. Here we describe its usage for
observations of the Sun and in particular of solar radio bursts. We
also describe the processing, archiving and accessing of solar LOFAR
data, which is accomplished via the LOFAR Solar Imaging Pipeline and
the LOFAR Solar Data Center.

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Title: A color-period diagram for the open cluster M 48 (NGC 2548),
and its rotational age
Authors: Barnes, Sydney A.; Weingrill, Joerg; Granzer, Thomas; Spada,
Federico; Strassmeier, Klaus G.
2015A&A...583A..73B Altcode: 2015arXiv151100554B
Rotation periods are increasingly being used to derive ages for cool
single field stars. Such ages are based on an empirical understanding
of how cool stars spin down, acquired by constructing color-period
diagrams (CPDs) for a series of open clusters. Our main aims here
are to construct a CPD for M 48, to compare this with other clusters
of similar age to check for consistency, and to derive a rotational
age for M 48 using gyrochronology. We monitored M 48 photometrically
for over 2 months with AIP's STELLA I 1.2 m telescope and the WiFSIP
4K imager in Tenerife. Light curves with 3 mmag precision for bright
(V ~ 14 mag) stars were produced and then analysed to provide rotation
periods. A cluster CPD has then been constructed. We report 62 rotation
periods for cool stars in M 48. The CPD displays a clear slow/I-sequence
of rotating stars, similar to those seen in the 625 Myr-old Hyades and
590 Myr-old Praesepe clusters, and below both, confirming that M 48 is
younger. A similar comparison with the 250 Myr-old M 34 cluster shows
that M 48 is older and does not possess any fast/C-sequence G or early
K stars like those in M 34, although relatively fast rotators do seem
to be present among the late-K and M stars. A more detailed comparison
of the CPD with rotational evolution models shows that the cluster
stars have a mean age of 450 Myr, and its (rotating) stars can be
individually dated to ± 117 Myr (26%). Much of this uncertainty stems
from intrinsic astrophysical spread in initial periods, and almost all
stars are consistent with a single age of 450 Myr. The gyro-age of M 48
as a whole is 450 ± 50 Myr, in agreement with the previously determined
isochrone age of 400 ± 100 Myr. Based on data obtained with the
STELLA robotic telescopes in Tenerife, an AIP facility jointly operated
by AIP and IAC; this paper presents results for the STELLA Open Cluster
Survey (SOCS).Appendices A and B are available in electronic form at <A
href="http://www.aanda.org/10.1051/0004-6361/201526129/olm">http://www.aanda.org</A>The
cluster photometry table is only available at the CDS via anonymous ftp
to <A href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/583/A73">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/583/A73</A>

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Title: Broad-band spectrophotometry of the hot Jupiter HAT-P-12b
from the near-UV to the near-IR
Authors: Mallonn, M.; Nascimbeni, V.; Weingrill, J.; von Essen,
C.; Strassmeier, K. G.; Piotto, G.; Pagano, I.; Scandariato, G.;
Csizmadia, Sz.; Herrero, E.; Sada, P. V.; Dhillon, V. S.; Marsh,
T. R.; Künstler, A.; Bernt, I.; Granzer, T.
2015A&A...583A.138M Altcode: 2015arXiv150905272M
Context. The detection of trends or gradients in the transmission
spectrum of extrasolar planets is possible with observations at very low
spectral resolution. Transit measurements of sufficient accuracy using
selected broad-band filters allow for an initial characterization of
the atmosphere of the planet. Aims: We want to investigate the
atmosphere of the hot Jupiter HAT-P-12b for an increased absorption at
the very blue wavelength regions caused by scattering. Furthermore,
we aim for a refinement of the transit parameters and the orbital
ephemeris. Methods: We obtained time series photometry of 20
transit events and analyzed them homogeneously, along with eight light
curves obtained from the literature. In total, the light curves span a
range from 0.35 to 1.25 microns. During two observing seasons over four
months each, we monitored the host star to constrain the potential
influence of starspots on the derived transit parameters. 
Results: We rule out the presence of a Rayleigh slope extending over
the entire optical wavelength range, a flat spectrum is favored for
HAT-P-12b with respect to a cloud-free atmosphere model spectrum. A
potential cause of such gray absorption is the presence of a cloud
layer at the probed latitudes. Furthermore, in this work we refine the
transit parameters, the ephemeris and perform a TTV analysis in which
we found no indication for an unseen companion. The host star showed a
mild non-periodic variability of up to 1%. However, no stellar rotation
period could be detected to high confidence.

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Title: Line Profile Variations of Solar Analog Stars: Chromospheric
Indexes vs. Li Abundance. The Host Star Search.
Authors: Amazo-Gómez, E. M.; Harutyunyan, G.; Alvarado-Gómez, J. D.;
Strassmeier, K. G.; Weber, M.; Carroll, T. A.
2015IAUS..305..340A Altcode:
PolarBase contains stellar spectropolarimetric data collected with
the NARVAL &amp; ESPaDOnS instruments (Petit et al. 2014). Their
respective spectral resolutions are 65 000 and 68 000, in
spectropolarimetric mode. As the first part of this work, we use the
NARVAL spectropolarimetric repositories. We selected spectra from a
sample of cool stars with effective Temperature (T eff)
ranging between 4900 to 6000 K. This sample contains stellar
systems with and without reported exoplanets. We exploit the full
wavelength range from 380 to 900 nm in order to obtain chromospheric
indexes such as the Ca ii H&amp;K S-Index, and a Ca ii IRT and Hα
index. We calibrated our measurements using the Mount Wilson S-Index
values. Furthermore, we employ lithium (Li) abundance measurements
from the literature (Gonzalez et al. 2010; Delgado Mena et al. 2014;
Israelian et al. 2004), investigating in this way a possible correlation
between the chromospheric activity measurements and the Li abundance
in 32 selected cool stars.

---------------------------------------------------------
Title: VizieR Online Data Catalog: BR light curves of GJ1214b
(Nascimbeni+, 2015)
Authors: Nascimbeni, V.; Mallonn, M.; Scandariato, G.; Pagano, I.;
Piotto, G.; Micela, G.; Messina, S.; Leto, G.; Strassmeier, K. G.;
Bisogni, S.; Speziali, R.
2015yCat..35790113N Altcode:
We observed two complete transits of GJ1214b during the nights of
March 29 and May 17, 2012 with the LBC camera mounted at the double
8.4m Large Binocular Telescope (LBT). We mounted a Bessel B and Bessel
R filter on the blue and red channel, respectively. (4 data files).

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Title: Antisolar-type surface differential rotation of the K1-giant
sigma Geminorum
Authors: Kovari, Zsolt; Künstler, Andreas; Vida, Krisztián;
Kriskovics, Levente; Carroll, Thorsten; Strassmeier, Klaus
2015IAUGA..2242132K Altcode:
Spot migration pattern is analysed to derive surface differential
rotation on the active K1-giant component of the long-period RS CVn-type
binary system σ Gem. From a set of high-resolution spectra taken with
STELLA-I SES in 2006/07, three subsequent Doppler images were obtained
using our advanced surface reconstruction code iMap. The time-evolution
of the spotted surface suggests antisolar-type differential rotation
with α of -0.04 shear parameter, in quite an agreement with preceding
results.

---------------------------------------------------------
Title: Transmission spectroscopy of the inflated exo-Saturn HAT-P-19b
Authors: Mallonn, M.; von Essen, C.; Weingrill, J.; Strassmeier,
K. G.; Ribas, I.; Carroll, T. A.; Herrero, E.; Granzer, T.; Claret,
A.; Schwope, A.
2015A&A...580A..60M Altcode: 2015arXiv150605685M
Context. Transiting highly inflated giant planets offer the
possibility of characterizing their atmospheres. A fraction of the
starlight passes through the high-altitude layers of the planetary
atmosphere during transit. The resulting absorption is expected to
be wavelength dependent for cloud-free atmospheres with an amplitude
of up to 10-3 of the stellar flux, while a high-altitude
cloud deck would cause a gray opacity. Aims: We observed
the Saturn-mass and Jupiter-sized exoplanet HAT-P-19b to refine its
transit parameters and ephemeris as well as to shed first light on
its transmission spectrum. We monitored the host star over one year
to quantify its flux variability and to correct the transmission
spectrum for a slope caused by starspots. Methods: A transit
of HAT-P-19b was observed spectroscopically with OSIRIS at the Gran
Telescopio Canarias in January 2012. The spectra of the target and the
comparison star covered the wavelength range from 5600 to 7600 Å. One
high-precision differential light curve was created by integrating
the entire spectral flux. This white-light curve was used to derive
absolute transit parameters. Furthermore, a set of light curves over
wavelength was formed by a flux integration in 41 wavelength channels
of 50 Å width. We analyzed these spectral light curves for chromatic
variations of transit depth. Results: The transit fit of the
combined white-light curve yields a refined value of the planet-to-star
radius ratio of 0.1390 ± 0.0012 and an inclination of 88.89 ± 0.32
deg. After a re-analysis of published data, we refine the orbital
period to 4.0087844 ± 0.0000015 days. We obtain a flat transmission
spectrum without significant additional absorption at any wavelength
or any slope. However, our accuracy is not sufficient to significantly
rule out the presence of a pressure-broadened sodium feature. Our
photometric monitoring campaign allowed for an estimate of the stellar
rotation period of 35.5 ± 2.5 days and an improved age estimate
of 5.5+ 1.8-1.3 Gyr by gyrochronology. The
calculated correction of the transit depth for unocculted spots on
the visible hemisphere was found to be well within the derived 1σ
uncertainty of the white-light curve and the spectral data points of
the transmission spectrum. Based on observations made with the
Gran Telescopio Canarias (GTC), installed in the Spanish Observatorio
del Roque de los Muchachos of the Instituto de Astrofisica de Canarias,
in the island of La Palma, as well as on data obtained with the STELLA
robotic telescope in Tenerife, an AIP facility jointly operated by
AIP and IAC.Tables 1 and 3 are available in electronic form at <A
href="http://www.aanda.org/10.1051/0004-6361/201423778/olm">http://www.aanda.org</A>

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Title: Stellar rotation, binarity, and lithium in the open cluster
IC 4756
Authors: Strassmeier, K. G.; Weingrill, J.; Granzer, T.; Bihain, G.;
Weber, M.; Barnes, S. A.
2015A&A...580A..66S Altcode: 2015arXiv150305676S
Context. An important aspect in the evolutionary scenario of cool
stars is their rotation and the rotationally induced magnetic activity
and interior mixing. Stars in open clusters are particularly useful
tracers for these aspects because of their known ages. Aims:
We aim to characterize the open cluster IC 4756 and measure stellar
rotation periods and surface differential rotation for a sample
of its member stars. Methods: Thirty-seven cluster stars
were observed continuously with the CoRoT satellite for 78 days in
2010. Follow-up high-resolution spectroscopy of the CoRoT targets and
deep Strömgren uvbyβ and Hα photometry of the entire cluster were
obtained with our robotic STELLA facility and its echelle spectrograph
and wide-field imager, respectively. Results: We determined
high-precision photometric periods for 27 of the 37 CoRoT targets and
found values between 0.155 and 11.4 days. Twenty of these are rotation
periods. Twelve targets are spectroscopic binaries of which 11 were
previously unknown; orbits are given for six of them. Six targets
were found that show evidence of differential rotation with ΔΩ/Ω in
the range 0.04-0.15. Five stars are non-radially pulsating stars with
fundamental periods of below 1 d, two stars are semi-contact binaries,
and one target is a micro-flaring star that also shows rotational
modulation. Nine stars in total were not considered members because
of much redder color(s) and deviant radial velocities with respect to
the cluster mean. Hα photometry indicates that the cluster ensemble
does not contain magnetically over-active stars. The cluster average
metallicity is -0.08 ± 0.06 (rms) and its logarithmic lithium abundance
for 12 G-dwarf stars is 2.39 ± 0.17 (rms). Conclusions: The
cluster is 890 ± 70 Myrs old with an average turn-off mass of 1.8
M⊙ and a solar or slightly subsolar metallicity. The
distance modulus is 8m.02 and the average reddening E(b -
y) = 0m.16.. The cluster is masked by a very inhomogeneous
foreground and background dust distribution and our survey covered 38%
of the cluster. The average lithium abundance and the rotation periods
in the range 1.7 to 11.4 d are consistent with the cluster age. The CoRoT space mission has been developed and is operated by CNES,
with the contribution of Austria, Belgium, Brazil, ESA (RSSD and Science
Programme), Germany and Spain. Partly based on data obtained with the
STELLA robotic observatory in Tenerife, an AIP facility jointly operated
by AIP and IAC.Appendices are available in electronic form at <A
href="http://www.aanda.org/10.1051/0004-6361/201525756/olm">http://www.aanda.org</A>

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Title: Large Binocular Telescope view of the atmosphere of GJ1214b
Authors: Nascimbeni, V.; Mallonn, M.; Scandariato, G.; Pagano, I.;
Piotto, G.; Micela, G.; Messina, S.; Leto, G.; Strassmeier, K. G.;
Bisogni, S.; Speziali, R.
2015A&A...579A.113N Altcode: 2015arXiv150501488N
The atmospheric composition and vertical structure of the super-Earth
GJ1214b has been a subject of debate since its discovery in
2009. Recent studies have indicated that high-altitude clouds might
mask the lower layers. However, some data points that were gathered
at different times and facilities do not fit this picture, probably
because of a combination of stellar activity and systematic errors. We
observed two transits of GJ1214b with the Large Binocular Camera, the
dual-channel camera at the Large Binocular Telescope. For the first
time, we simultaneously measured the relative planetary radius k =
Rp/R⋆ at blue and red optical wavelengths
(B + R), thus constraining the Rayleigh scattering on GJ1214b after
correcting for stellar activity effects. To the same purpose, a
long-term photometric follow-up of the host star was carried out with
WiFSIP at STELLA, revealing a rotational period that is significantly
longer than previously reported. Our new unbiased estimates of k yield
a flat transmission spectrum extending to shorter wavelengths, thus
confirming the cloudy atmosphere scenario for GJ1214b. Based on
data acquired using the Large Binocular Telescope (LBT). 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; Istituto Nazionale
di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany,
representing the Max-Planck Society, the Astrophysical Institute
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. Partly based
on STELLA WiFSIP data (Strassmeier et al. 2004).The data of the
light curves are only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/579/A113">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/579/A113</A>

---------------------------------------------------------
Title: Spot evolution on the red giant star XX Triangulum. A
starspot-decay analysis based on time-series Doppler imaging
Authors: Künstler, A.; Carroll, T. A.; Strassmeier, K. G.
2015A&A...578A.101K Altcode: 2015arXiv150402270K
Context. Solar spots appear to decay linearly proportional to
their size. The decay rate of solar spots is directly related to
magnetic diffusivity, which itself is a key quantity for the length
of a magnetic-activity cycle. Is a linear spot decay also seen on
other stars, and is this in agreement with the large range of solar
and stellar activity cycle lengths? Aims: We investigate the
evolution of starspots on the rapidly-rotating (Prot≈24
d) K0 giant XX Tri, using consecutive time-series Doppler images. Our
aim is to obtain a well-sampled movie of the stellar surface over
many years, and thereby detect and quantify a starspot decay law
for further comparison with the Sun. Methods: We obtained
continuous high-resolution and phase-resolved spectroscopy with the
1.2-m robotic STELLA telescope on Tenerife over six years, and these
observations are ongoing. For each observing season, we obtained
between 5 to 7 independent Doppler images, one per stellar rotation,
making up a total of 36 maps. All images were reconstructed with our
line-profile inversion code iMap. A wavelet analysis was implemented
for denoising the line profiles. To quantify starspot area decay and
growth, we match the observed images with simplified spot models based
on a Monte Carlo approach. Results: It is shown that the surface
of XX Tri is covered with large high-latitude and even polar spots and
with occasional small equatorial spots. Just over the course of six
years, we see a systematically changing spot distribution with various
timescales and morphology, such as spot fragmentation and spot merging
as well as spot decay and formation. An average linear decay of D =
-0.022 ± 0.002 SH/day is inferred. We found evidence of an active
longitude in phase toward the (unseen) companion star. Furthermore,
we detect a weak solar-like differential rotation with a surface shear
of α = 0.016 ± 0.003. From the decay rate, we determine a turbulent
diffusivity of ηT = (6.3 ± 0.5) × 1014
cm2/s and predict a magnetic activity cycle of ≈26 ±
6 yr. Finally, we present a short movie of the spatially resolved
surface of XX Tri. Based on data obtained with the STELLA
robotic telescopes in Tenerife, an AIP facility jointly operated with
IAC.Appendices and the movie are available in electronic form at <A
href="http://www.aanda.org/10.1051/0004-6361/201525687/olm">http://www.aanda.org</A>

---------------------------------------------------------
Title: PEPSI: The high-resolution échelle spectrograph and
polarimeter for the Large Binocular Telescope
Authors: Strassmeier, K. G.; Ilyin, I.; Järvinen, A.; Weber, M.;
Woche, M.; Barnes, S. I.; Bauer, S. -M.; Beckert, E.; Bittner, W.;
Bredthauer, R.; Carroll, T. A.; Denker, C.; Dionies, F.; DiVarano,
I.; Döscher, D.; Fechner, T.; Feuerstein, D.; Granzer, T.; Hahn,
T.; Harnisch, G.; Hofmann, A.; Lesser, M.; Paschke, J.; Pankratow,
S.; Plank, V.; Plüschke, D.; Popow, E.; Sablowski, D.
2015AN....336..324S Altcode: 2015arXiv150506492S
PEPSI is the bench-mounted, two-arm, fibre-fed and stabilized Potsdam
Echelle Polarimetric and Spectroscopic Instrument for the 2×8.4 m
Large Binocular Telescope (LBT). Three spectral resolutions of either
43 000, 120 000 or 270 000 can cover the entire optical/red wavelength
range from 383 to 907 nm in three exposures. Two 10.3k×10.3k CCDs with
9-μm pixels and peak quantum efficiencies of 94-96 % record a total of
92 échelle orders. We introduce a new variant of a wave-guide image
slicer with 3, 5, and 7 slices and peak efficiencies between 92-96
%. A total of six cross dispersers cover the six wavelength settings
of the spectrograph, two of them always simultaneously. These are made
of a VPH-grating sandwiched by two prisms. The peak efficiency of the
system, including the telescope, is 15 % at 650 nm, and still 11 %
and 10 % at 390 nm and 900 nm, respectively. In combination with
the 110 m2 light-collecting capability of the LBT, we
expect a limiting magnitude of ≈ 20th mag in V in the low-resolution
mode. The R = 120 000 mode can also be used with two, dual-beam Stokes
IQUV polarimeters. The 270 000-mode is made possible with the 7-slice
image slicer and a 100-μm fibre through a projected sky aperture of
0.74 arcsec, comparable to the median seeing of the LBT site. The 43
000-mode with 12-pixel sampling per resolution element is our bad
seeing or faint-object mode. Any of the three resolution modes can
either be used with sky fibers for simultaneous sky exposures or with
light from a stabilized Fabry-Pérot étalon for ultra-precise radial
velocities. CCD-image processing is performed with the dedicated
data-reduction and analysis package PEPSI-S4S. Its full error
propagation through all image-processing steps allows an adaptive
selection of parameters by using statistical inferences and robust
estimators. A solar feed makes use of PEPSI during day time and a 500-m
feed from the 1.8 m VATT can be used when the LBT is busy otherwise. In
this paper, we present the basic instrument design, its realization,
and its characteristics. Some pre-commissioning first-light spectra
shall demonstrate the basic functionality.

---------------------------------------------------------
Title: Magnetic field measurements of ɛ Eridani from Zeeman
broadening
Authors: Lehmann, L. T.; Künstler, A.; Carroll, T. A.; Strassmeier,
K. G.
2015AN....336..258L Altcode: 2015arXiv150306662L
We present new magnetic field measurements of the K2
main-sequence star ɛ Eri based on principal components analysis
(PCA) line-profile reconstructions. The aim of this paper is to
quantify the surface-averaged magnetic field and search for possible
variations. A total of 338 optical échelle spectra from our robotic
telescope facility STELLA with a spectral resolution of 55 000 were
available for analysis. This time-series was used to search for the
small line-profile variations due to a surface magnetic field with
the help of a PCA. Evidence for a spatial and temporal inhomogeneous
magnetic field distribution is presented. The mean, surface averaged,
magnetic field strength was found to be &lt; B &gt; = 186 ± 47 G in
good agreement with previous Zeeman-broadening measurements. Clear
short-term variations of the surface averaged magnetic field of up to
few tens Gauss were detected together with evidence for a three-year
cycle in the surface-averaged magnetic field of ɛ Eri. Based on
data obtained with the STELLA robotic telescopes in Tenerife, an AIP
facility jointly operated with IAC.

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Title: Chromospheric activity and lithium line variations in the
spectra of the spotted star LQ Hydrae
Authors: Flores Soriano, M.; Strassmeier, K. G.; Weber, M.
2015A&A...575A..57F Altcode:
Context. Although the relationship between lithium abundance in stars
and their magnetic activity is commonly accepted, it is still unclear
how the different phenomena related to it can increase the amount of Li,
reduce its depletion, or be a source of bias for the measurements. Aims: We study the rotational modulation of chromospheric and
photospheric parameters of the young, active, single K2 dwarf LQ
Hya and their connection with the variability of the Li i 6708 Å
line. Methods: A total of 199 high-resolution STELLA spectra
and quasi-simultaneous photometry were used to compute effective
temperature, gravity, and chromospheric activity indicators such as
Hα and Hβ emission, Balmer decrement, and chromospheric electron
density, as a function of the rotational phase. The variation of the
Li i 6708 Å line was characterized in terms of equivalent width,
abundance, and of 6Li/7Li isotopic ratio in the
form of line shifts. Results: Photospheric and chromospheric
parameters show clear rotational modulation. Effective temperatures
and continuum variations reveal a higher concentration of cool spots
on the side of the star on which we also detect stronger chromospheric
activity. Increased electron densities and the modulation of the He i
D3 line suggest that the source of this activity can be a
combination of plages and repeated low-intensity flares. The Li line
and other temperature-sensitive lines are clearly enhanced by the spots
located on the most active side of the star. Li abundances calculated
taking into account the temperature variations simultaneously show,
although with high dispersion, a small overabundance of this element
that correlates well with the surface magnetic activity. In addition,
the Li line center is more intensely redshifted than in the other
hemisphere, which might be interpreted as a weak enrichment of
6Li. Based on data obtained with the STELLA robotic
telescope in Tenerife, an AIP facility jointly operated by AIP and IAC,
and the Vienna-Potsdam Automatic Photoelectric Telescopes at Fairborn
Observatory in Arizona, operated by AIP.The numerical results of the
spectral analysis are only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/575/A57">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/575/A57</A>

---------------------------------------------------------
Title: Driving magnetic activity: differential rotation, flow
structures, and surface patterns
Authors: Strassmeier, Klaus G.
2015HiA....16...94S Altcode:
The interplay between stellar rotation and turbulent flows is a major
ingredient for vertical angular momentum transport in stellar convection
zone. Combined with the centrifugal force and the buoyancy force due to
pole-equator temperature gradients one can expect a large-scale flow
structure that is usually referred to as differential rotation and
meridional flows. I review such observations for stars other than the
Sun, mostly for stars significantly more active, and ask the question
whether such observations can constrain the dynamo process.

---------------------------------------------------------
Title: Evidence for enhanced mixing on the super-meteoritic Li-rich
red giant HD 233517
Authors: Strassmeier, K. G.; Carroll, T. A.; Weber, M.; Granzer, T.
2015A&A...574A..31S Altcode:
Context. HD 233517 is among the most Li-rich stars in the sky. It is
a rapidly rotating, single K giant thought to be on its first ascent
on the red giant branch. The star has also the highest known infrared
excess among any of the known first-ascent giants. Aims: We
revisit the physical parameters of the system and aim to map its surface
temperature distribution. Methods: New time-series photometry
and high-resolution spectroscopy were obtained with our robotic
facilities STELLA and Amadeus Automatic Photoelectric Telescope (APT)
in 2007-2011. Inverse line-profile modelling is performed on a total
of 167 échelle spectra and six Doppler images are presented. 
Results: Light and radial-velocity variations suggest a stellar rotation
period of 47.6±0.3 d. The atmospheric parameters agree with previous
studies and verify a super-meteoritic log 7Li abundance
of 4.29±0.10 with undetected 6Li, while the metals are
generally deficient by -0.4 dex with respect to the Sun. We determine a
lower than normal isotopic carbon ratio of 12C/13C
= 9+4-2. Our Doppler images indicate warm and cool
spots with an average temperature contrast of just ±65 K with respect
to the effective temperature. Doppler maps from Li i 670.78 reveal
practically identical surface morphology, with a higher average contrast
of ±160 K and errors that are five times larger. Reconstructions
with simultaneously 1617 and 3007 spectral lines showed both a signal
degradation with respect to our 56-line final image. An error analysis
indicates an average temperature error per surface pixel of just ±4
K. Conclusions: HD 233517 appears to be an old (≈10-Gyr)
single 0.95-M⊙ giant currently undergoing mild mass
loss in the form of a wind. The cool and warm photospheric features
are interpreted to be merely locations of suppressed and enhanced
convection, respectively, probably intermingled by a yet undetected
weak magnetic field. The low carbon-isotope ratio is indicative of extra
mixing rather than of an engulfing event. We tentatively conclude that
HD 233517 operates an enhanced non-axisymmetric mixing process that
leads to an inhomogeneous super-granulation pattern on the surface
in form of large cool and warm features. Based on data obtained
with the STELLA robotic telescope in Tenerife, an AIP facility jointly
operated by AIP and IAC, and the Vienna-Potsdam Automatic Photoelectric
Telescopes at Fairborn Observatory in Arizona, operated by AIP.

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Title: Doppler images and the underlying dynamo. The case of AF
Leporis
Authors: Järvinen, S. P.; Arlt, R.; Hackman, T.; Marsden, S. C.;
Küker, M.; Ilyin, I. V.; Berdyugina, S. V.; Strassmeier, K. G.;
Waite, I. A.
2015A&A...574A..25J Altcode: 2014arXiv1412.2892J
Context. The (Zeeman-)Doppler imaging studies of solar-type stars very
often reveal large high-latitude spots. This also includes F stars that
possess relatively shallow convection zones, indicating that the dynamo
operating in these stars differs from the solar dynamo. Aims:
We aim to determine whether mean-field dynamo models of late-F type
dwarf stars can reproduce the surface features recovered in Doppler
maps. In particular, we wish to test whether the models can reproduce
the high-latitude spots observed on some F dwarfs. Methods:
The photometric inversions and the surface temperature maps of AF Lep
were obtained using the Occamian-approach inversion technique. Low
signal-to-noise spectroscopic data were improved by applying the
least-squares deconvolution method. The locations of strong magnetic
flux in the stellar tachocline as well as the surface fields obtained
from mean-field dynamo solutions were compared with the observed
surface temperature maps. Results: The photometric record of
AF Lep reveals both long- and short-term variability. However, the
current data set is too short for cycle-length estimates. From the
photometry, we have determined the rotation period of the star to be
0.9660 ± 0.0023 days. The surface temperature maps show a dominant,
but evolving, high-latitude (around +65°) spot. Detailed study of
the photometry reveals that sometimes the spot coverage varies only
marginally over a long time, and at other times it varies rapidly. Of
a suite of dynamo models, the model with a radiative interior rotating
as fast as the convection zone at the equator delivered the highest
compatibility with the obtained Doppler images. Partially
based on observations made with the Nordic Optical Telescope,
operated by the Nordic Optical Telescope Scientific Association at
the Observatorio del Roque de los Muchachos, La Palma, Spain, of
the Instituto de Astrofísica de Canarias.Based partly on STELLA SES
data.Tables 1-3 and Figs. 7-14 are available in electronic form at <A
href="http://www.aanda.org/10.1051/0004-6361/201424229/olm">http://www.aanda.org</A>

---------------------------------------------------------
Title: Editorial
Authors: Strassmeier, Klaus G.
2015AN....336....4S Altcode:
Not Available.

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Title: VizieR Online Data Catalog: LQ Hya activity and Li variations
(Flores Soriano+, 2015)
Authors: Flores Soriano, M.; Strassmeier, K. G.; Weber, M.
2015yCat..35750057F Altcode: 2015yCat..35759057F
We preset in these two tables the observing log and the numerical
results of the spectral analysis of LQ Hya. They are a tabular version
of the results shown in the figures of the paper. (2 data files).

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Title: Antisolar differential rotation of the K1-giant σ Geminorum
revisited
Authors: Kővári, Zs.; Kriskovics, L.; Künstler, A.; Carroll, T. A.;
Strassmeier, K. G.; Vida, K.; Oláh, K.; Bartus, J.; Weber, M.
2015A&A...573A..98K Altcode: 2014arXiv1411.1774K
Context. Surface differential rotation and other global surface flows on
magnetically active stars are among the observable manifestations of the
underlying stellar dynamo. Therefore, these types of observations are
important for stellar dynamo theory and useful constraints for solar
dynamo studies as well. Aims: We revisit the active K1-giant
component of the long-period RS CVn-type binary system σ Gem and its
global surface flow pattern. Methods: We refine the differential
rotation law from recovering the spot migration pattern. We apply a
detailed cross-correlation technique to a unique set of 34 time-series
Doppler images recovered using data from 1996-97. By increasing the
number of the available cross-correlation function maps, we expect
a more robust determination of the differential surface rotation
law. In addition, we present a new time-series Doppler imaging study
of σ Gem using our advanced surface reconstruction code iMap for
a data set collected in 2006-07. Results: Results from the
reprocessed cross-correlation study confirm that the star performs
antisolar-type differential rotation with a surface shear α of -
0.04 ± 0.01, i.e., almost a factor of two larger compared to the
previously claimed value. We also confirm the evidence of a global
poleward spot migration, with an average velocity of 0.21 ± 0.03 km
s-1, in accordance with theoretical predictions. From the
new observations, we obtain three subsequent Doppler images. The time
evolution of these images confirms the antisolar-type differential
rotation of the same amount.

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Title: Magnitude-range brightness variations of overactive K giants
Authors: Oláh, K.; Moór, A.; Kővári, Zs.; Granzer, T.; Strassmeier,
K. G.; Kriskovics, L.; Vida, K.
2014A&A...572A..94O Altcode: 2014arXiv1409.6515O
Context. Decades-long, phase-resolved photometry of overactive
spotted cool stars has revealed that their long-term peak-to-peak
light variations can be as large as one magnitude. Such brightness
variations are too large to be solely explained by rotational
modulation and/or a cyclic, or pseudo-cyclic, waxing and waning
of surface spots and faculae as we see in the Sun. Aims:
We study three representative, overactive spotted K giants (IL Hya,
XX Tri, and DM UMa) known to exhibit V-band light variations between
0.m65-1.m05. Our aim is to find the origin of
their large brightness variation. Methods: We employ long-term
phase-resolved multicolor photometry, mostly from automatic telescopes,
covering 42 yr for IL Hya, 28 yr for XX Tri, and 34 yr for DM UMa. For
one target, IL Hya, we present a new Doppler image from NSO data taken
in late 1996. Effective temperatures for our targets are determined from
all well-sampled observing epochs and are based on a V - IC
color-index calibration. Results: The effective temperature
change between the extrema of the rotational modulation for IL Hya and
XX Tri is in the range 50-200 K. The bolometric flux during maximum
of the rotational modulation, i.e., the least spotted states, varied
by up to 39% in IL Hya and up to 54% in XX Tri over the course of our
observations. We emphasize that for IL Hya it is just about half of the
total luminosity variation that can be explained by the photospheric
temperature (spots/faculae) changes, while for XX Tri it is even
about one third. The long-term, 0.m6 V-band variation
of DM UMa is more difficult to explain because little or no B -
V color index change is observed on the same timescale. Placing the
three stars with their light and color variations into H-R diagrams,
we find that their overall luminosities are generally too low compared
to predictions from current evolutionary tracks. Conclusions:
A change in the stellar radius due to strong and variable magnetic
fields during activity cycles likely plays a role in explaining the
anomalous brightness and luminosity of our three targets. At least for
IL Hya, a radius change of about 9% is suggested from mbol
and Teff, and is supported by independent v sin i
measurements. Appendix A is available in electronic form at <A
href="http://www.aanda.org/10.1051/0004-6361/201424695/olm">http://www.aanda.org</A>

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Title: The PLATO 2.0 mission
Authors: Rauer, H.; Catala, C.; Aerts, C.; Appourchaux, T.; Benz,
W.; Brandeker, A.; Christensen-Dalsgaard, J.; Deleuil, M.; Gizon,
L.; Goupil, M. -J.; Güdel, M.; Janot-Pacheco, E.; Mas-Hesse,
M.; Pagano, I.; Piotto, G.; Pollacco, D.; Santos, Ċ.; Smith, A.;
Suárez, J. -C.; Szabó, R.; Udry, S.; Adibekyan, V.; Alibert, Y.;
Almenara, J. -M.; Amaro-Seoane, P.; Eiff, M. Ammler-von; Asplund, M.;
Antonello, E.; Barnes, S.; Baudin, F.; Belkacem, K.; Bergemann, M.;
Bihain, G.; Birch, A. C.; Bonfils, X.; Boisse, I.; Bonomo, A. S.;
Borsa, F.; Brandão, I. M.; Brocato, E.; Brun, S.; Burleigh, M.;
Burston, R.; Cabrera, J.; Cassisi, S.; Chaplin, W.; Charpinet, S.;
Chiappini, C.; Church, R. P.; Csizmadia, Sz.; Cunha, M.; Damasso, M.;
Davies, M. B.; Deeg, H. J.; Díaz, R. F.; Dreizler, S.; Dreyer, C.;
Eggenberger, P.; Ehrenreich, D.; Eigmüller, P.; Erikson, A.; Farmer,
R.; Feltzing, S.; de Oliveira Fialho, F.; Figueira, P.; Forveille,
T.; Fridlund, M.; García, R. A.; Giommi, P.; Giuffrida, G.; Godolt,
M.; Gomes da Silva, J.; Granzer, T.; Grenfell, J. L.; Grotsch-Noels,
A.; Günther, E.; Haswell, C. A.; Hatzes, A. P.; Hébrard, G.; Hekker,
S.; Helled, R.; Heng, K.; Jenkins, J. M.; Johansen, A.; Khodachenko,
M. L.; Kislyakova, K. G.; Kley, W.; Kolb, U.; Krivova, N.; Kupka, F.;
Lammer, H.; Lanza, A. F.; Lebreton, Y.; Magrin, D.; Marcos-Arenal,
P.; Marrese, P. M.; Marques, J. P.; Martins, J.; Mathis, S.; Mathur,
S.; Messina, S.; Miglio, A.; Montalban, J.; Montalto, M.; Monteiro,
M. J. P. F. G.; Moradi, H.; Moravveji, E.; Mordasini, C.; Morel, T.;
Mortier, A.; Nascimbeni, V.; Nelson, R. P.; Nielsen, M. B.; Noack,
L.; Norton, A. J.; Ofir, A.; Oshagh, M.; Ouazzani, R. -M.; Pápics,
P.; Parro, V. C.; Petit, P.; Plez, B.; Poretti, E.; Quirrenbach, A.;
Ragazzoni, R.; Raimondo, G.; Rainer, M.; Reese, D. R.; Redmer, R.;
Reffert, S.; Rojas-Ayala, B.; Roxburgh, I. W.; Salmon, S.; Santerne,
A.; Schneider, J.; Schou, J.; Schuh, S.; Schunker, H.; Silva-Valio,
A.; Silvotti, R.; Skillen, I.; Snellen, I.; Sohl, F.; Sousa, S. G.;
Sozzetti, A.; Stello, D.; Strassmeier, K. G.; Švanda, M.; Szabó,
Gy. M.; Tkachenko, A.; Valencia, D.; Van Grootel, V.; Vauclair,
S. D.; Ventura, P.; Wagner, F. W.; Walton, N. A.; Weingrill, J.;
Werner, S. C.; Wheatley, P. J.; Zwintz, K.
2014ExA....38..249R Altcode: 2014ExA...tmp...41R; 2013arXiv1310.0696R
PLATO 2.0 has recently been selected for ESA's M3 launch opportunity
(2022/24). Providing accurate key planet parameters (radius, mass,
density and age) in statistical numbers, it addresses fundamental
questions such as: How do planetary systems form and evolve? Are there
other systems with planets like ours, including potentially habitable
planets? The PLATO 2.0 instrument consists of 34 small aperture
telescopes (32 with 25 s readout cadence and 2 with 2.5 s candence)
providing a wide field-of-view (2232 deg 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.

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Title: Time-series high-resolution spectroscopy and photometry of
ɛ Aurigae from 2006-2013: Another brick in the wall
Authors: Strassmeier, K. G.; Weber, M.; Granzer, T.; Schanne, L.;
Bartus, J.; Ilyin, I.
2014AN....335..904S Altcode:
We present continuous and time-resolved R = 55 000 optical
échelle spectroscopy of <ASTROBJ>ɛ Aurigae</ASTROBJ> from
2006-2013. Data were taken with the STELLA Echelle Spectrograph
of the robotic STELLA facility at the Observatorio del Teide in
Tenerife. Contemporaneous photometry with the Automatic Photoelectric
Telescopes at Fairborn Observatory in Arizona is presented for the
years 1996-2013. Spectroscopic observations started three years
prior to the photometric eclipse and are still ongoing. A total of
474 high-resolution échelle spectra are analyzed and made available
in this paper. We identify 368 absorption lines of which 161 lines
show the characteristic sharp disk lines during eclipse. Another
207 spectral lines appeared nearly unaffected by the eclipse. From
spectrum synthesis, we obtained the supergiant atmospheric parameters
T_eff = 7395±70 K, log g≈ 1, and [Fe/H] = +0.02±0.2 with ξ_t = 9
km s-1 , ζ_RT = 13 km s-1 , and v sin i = 28±3
km s-1 . The residual average line broadening expressed in
km s-1 varies with a period of 62.6±0.7 d, in particular at
egress and after the eclipse. Two-dimensional line-profile periodograms
show several periods, the strongest with ≈110 d evident in optically
thin lines as well as in the Balmer lines. Center-of-intensity weighted
radial velocities of individual spectral lines also show the 110-d
period but, again, additional shorter and longer periods are evident
and are different in the Balmer lines. The two main spectroscopic
Hα periods, ≈ 116 d from the line core and ≈ 150 d from the
center-of-intensity radial velocities, appear at 102 d and 139 d in the
photometry. The Hβ and Johnson VI photometry on the other hand shows
two well-defined and phase-coherent periods of 77 d and 132 d. We
conclude that Hα is contaminated by changes in the circumstellar
environment while the Hβ and VI photometry stems predominantly
from the non radial pulsations of the F0 supergiant. We isolate the
disk-rotation profile from 61 absorption lines and found that low
disk eccentricity generally relates to low disk rotational velocity
(but not always) while high disk eccentricity always relates to high
velocity. There is also the general trend that the disk-absorption
in spectral lines with higher excitation potential comes from disk
regions with higher eccentricity and thus also with higher rotational
velocity. The dependency on transition probability is more complex
and shows a bi-modal trend. The outskirts of the disk is distributed
asymmetrically around the disk and appears to have been built up mostly
in a tail along the orbit behind the secondary. Our data show that
this tail continues to eclipse the F0 Iab primary star even two years
after the end of the photometric eclipse. High-resolution spectra were
also taken of the other, bona-fide, visual-binary components of ɛ Aur
(ADS 3605BCDE). Only the C-component, a K3-4-giant, appears at the same
distance than ɛ Aur but its radial velocity is in disagreement with a
bound orbit. The other components are a nearby (≈ 7 pc) cool DA white
dwarf, a G8 dwarf, and a B9 supergiant, and not related to ɛ Aur. The
cool white dwarf shows strong DIB lines that suggest the existence
of a debris disk around this star. Based on data obtained with
the STELLA robotic telescopes in Tenerife, an AIP facility jointly
operated with IAC, and the Automatic Photoelectric Telescopes in
Arizona, jointly operated with Fairborn Observatory.

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Title: HIRES: the high resolution spectrograph for the E-ELT
Authors: Zerbi, F. M.; Bouchy, F.; Fynbo, J.; Maiolino, R.; Piskunov,
N.; Rebolo Lopez, R.; Santos, N.; Strassmeier, K.; Udry, S.; Vanzi,
L.; Riva, M.; Basden, A.; Boisse, I.; Bonfils, X.; Buscher, D.; Cabral,
A.; Dimarcantonio, P.; Di Varano, I.; Henry, D.; Monteiro, M.; Morris,
T.; Murray, G.; Oliva, Ernesto; Parry, I.; Pepe, F.; Quirrenbach, A.;
Rasilla, J. L.; Rees, P.; Stempels, E.; Valenziano, L.; Wells, M.;
Wildi, F.; Origlia, L.; Allende Prieto, C.; Chiavassa, A.; Cristiani,
S.; Figueira, P.; Gustafsson, B.; Hatzes, A.; Haehnelt, M.; Heng,
K.; Israelian, G.; Kochukhov, O.; Lovis, C.; Marconi, A.; Martins,
C. J. A. P.; Noterdaeme, P.; Petitjean, P.; Puzia, T.; Queloz, D.;
Reiners, A.; Zoccali, M.
2014SPIE.9147E..23Z Altcode:
The current instrumentation plan for the E-ELT foresees a High
Resolution Spectrograph conventionally indicated as HIRES. Shaped
on the study of extra-solar planet atmospheres, Pop-III stars and
fundamental physical constants, HIRES is intended to embed observing
modes at high-resolution (up to R=150000) and large spectral range
(from the blue limit to the K band) useful for a large suite of science
cases that can exclusively be tackled by the E-ELT. We present in
this paper the solution for HIRES envisaged by the "HIRES initiative",
the international collaboration established in 2013 to pursue a HIRES
on E-ELT.

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Title: Surface differential rotation of IL Hya from time-series
Doppler images
Authors: Kővári, Zsolt; Kriskovics, Levente; Oláh, Katalin; Vida,
Krisztián; Bartus, János; Strassmeier, Klaus G.; Weber, Michael
2014IAUS..302..379K Altcode: 2013arXiv1309.1378K
We present a time-series Doppler imaging study of the
K-subgiant component in the RS CVn-type binary system IL Hya (P
orb=12.905 d). From re-processing the unique long-term
spectroscopic dataset of 70 days taken in 1996/97, we perform a thorough
cross-correlation analysis to derive surface differential rotation. As
a result we get solar-type differential rotation with a shear value
α of 0.05, in agreement with preliminary suggestions from previous
attempts. A possible surface pattern of meridional circulation is
also detected.

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Title: Biosignatures from circular spectropolarimetry: key science
for ELTs?
Authors: Strassmeier, K. G.; Carroll, T. A.; Mallonn, M.
2014ebi..conf..4.7S Altcode:
Vegetation has a fivefold higher reflectivity in the NIR than in the
optical domain. The steep gradient at around 700 nm, the Vegetation Red
Edge (VRE), can in principle be used to discriminate exo-planets with
and without vegetation. Transiting exo-planets pose the possibility
to isolate their (absorption-line) spectrum from that of its host star
without the need for spatially resolving the planet. While the expected
difference of the Stokes-I amplitude between a Super- Earth with and
without an atmosphere in front of a G2V star would be just ≈3×10-5,
its differential Stokes-V signal could be larger by up to an order of
magnitude. Thus, a possible way out is to observe in polarized light
and use the known albedo-polarization relation for planetary surfaces
and/or atmospheres. Polarization degrees of up to 20% are expected
from planets in short-period orbits. Already the isolation of the
VRE from a transmission spectrum is beyond current instrumentation,
the aim to detect a differential circular polarization (CP) signal
from wavelengths blueward-minus-redward of the VRE in transmission
spectra of exoplanets is clearly left to the Extremely Large Telescopes
(ELT). While it is tempting to interpret such a simple CP detection
as a sign of chirality in the atmosphere of the exoplanet, e.g. due
to chlorophyll, its signal will be deeply buried in the photon noise
and systematics, even for ELTs. We present our current status of
signal-reconstruction algorithms used for magnetic- field mapping of
stellar surfaces and how these could be employed for the isolation
of biosignatures. We also present the current spectro-polarimetric
instrumentation for the LBT and the ESO E-ELT.

---------------------------------------------------------
Title: Detecting and quantifying stellar magnetic fields. Sparse
Stokes profile approximation using orthogonal matching pursuit
Authors: Carroll, T. A.; Strassmeier, K. G.
2014A&A...563A..56C Altcode: 2014arXiv1401.5749C
Context. In recent years, we have seen a rapidly growing number of
stellar magnetic field detections for various types of stars. Many
of these magnetic fields are estimated from spectropolarimetric
observations (Stokes V) by using the so-called center-of-gravity
(COG) method. Unfortunately, the accuracy of this method rapidly
deteriorates with increasing noise and thus calls for a more robust
procedure that combines signal detection and field estimation. Aims: We introduce an estimation method that provides not only
the effective or mean longitudinal magnetic field from an observed
Stokes V profile but also uses the net absolute polarization of
the profile to obtain an estimate of the apparent (i.e., velocity
resolved) absolute longitudinal magnetic field. Methods: By
combining the COG method with an orthogonal-matching-pursuit (OMP)
approach, we were able to decompose observed Stokes profiles with
an overcomplete dictionary of wavelet-basis functions to reliably
reconstruct the observed Stokes profiles in the presence of noise. The
elementary wave functions of the sparse reconstruction process were
utilized to estimate the effective longitudinal magnetic field and
the apparent absolute longitudinal magnetic field. A multiresolution
analysis complements the OMP algorithm to provide a robust detection and
estimation method. Results: An extensive Monte-Carlo simulation
confirms the reliability and accuracy of the magnetic OMP approach where
a mean error of under 2% is found. Its full potential is obtained for
heavily noise-corrupted Stokes profiles with signal-to-noise variance
ratios down to unity. In this case a conventional COG method yields
a mean error for the effective longitudinal magnetic field of up
to 50%, whereas the OMP method gives a maximum error of 18%. It is,
moreover, shown that even in the case of very small residual noise on
a level between 10-3 and 10-5, a regime reached
by current multiline reconstruction techniques, the conventional COG
method incorrectly interprets a large portion of the residual noise as
a magnetic field, with values of up to 100 G. The magnetic OMP method,
on the other hand, remains largely unaffected by the noise, regardless
of the noise level the maximum error is no greater than 0.7 G.

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Title: Chromospherically Active Stars in the RAVE Survey
Authors: Žerjal, M.; Zwitter, T.; Matijevič, G.; Strassmeier, K. G.
2014IAUS..298..298Z Altcode:
We present a qualitative characterization of activity levels of a large
database of ~44,000 candidate RAVE stars (unbiased, magnitude limited
medium resolution survey) that show chromospheric emission in the Ca II
infrared triplet and this vastly enlarges previously known samples. Our
main motivation to study these stars is the anti-correlation of
chromospheric activity and stellar ages that could be calibrated using
stellar clusters with known ages. Locally linear embedding used for
a morphological classification of spectra revealed 53,347 cases with
a suggested emission component in the calcium lines. We analyzed a
subsample of ~44,000 stars with S/N&gt;20 using a spectral subtraction
technique where observed reference spectra of inactive stars were used
as templates instead of synthetic ones. Both the equivalent width of
the excess emission for each calcium line and their sum is derived
for all candidate active stars with no respect to the origin of their
emission flux. ~17,800 spectra show a detectable chromospheric flux
with at least 2 σ confidence level. The overall distribution of
activity levels shows a bimodal shape, with the first peak coinciding
with inactive stars and the second with the pre-main-sequence cases.

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Title: Pulsation analysis and its impact on primary transit modeling
in WASP-33
Authors: von Essen, C.; Czesla, S.; Wolter, U.; Breger, M.; Herrero,
E.; Mallonn, M.; Ribas, I.; Strassmeier, K. G.; Morales, J. C.
2014A&A...561A..48V Altcode: 2013arXiv1311.3614V
 Aims: To date, WASP-33 is the only δ Scuti star known to be
orbited by a hot Jupiter. The pronounced stellar pulsations, showing
periods comparable to the primary transit duration, interfere with the
transit modeling. Therefore our main goal is to study the pulsation
spectrum of the host star to redetermine the orbital parameters of the
system by means of pulsation-cleaned primary transit light curves. Methods: Between August 2010 and October 2012 we obtained 457 h of
photometry of WASP-33 using small and middle-class telescopes located
mostly in Spain and in Germany. Our observations comprise the wavelength
range between the blue and the red, and provide full phase coverage of
the planetary orbit. After a careful detrend, we focus our pulsation
studies in the high frequency regime, where the pulsations that mostly
deform the primary transit exist. Results: The data allow us to
identify, for the first time in the system, eight significant pulsation
frequencies. The pulsations are likely associated with low-order
p-modes. Furthermore, we find that pulsation phases evolve in time. We
use our knowledge of the pulsations to clean the primary transit light
curves and carry out an improved transit modeling. Surprisingly,
taking into account the pulsations in the modeling has little
influence on the derived orbital parameters. However, the
uncertainties in the best-fit parameters decrease. Additionally,
we find indications for a possible dependence between wavelength and
transit depth, but only with marginal significance. A clear pulsation
solution, in combination with an accurate orbital period, allows
us to extend our studies and search for star-planet interactions
(SPI). Although we find no conclusive evidence of SPI, we believe
that the pulsation nature of the host star and the proximity between
members make WASP-33 a promising system for further SPI studies. Tables 1 and 10 and Fig. 8 are available in electronic form at <A
href="http://www.aanda.org">http://www.aanda.org</A>Photometry
is only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/561/A48">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/561/A48</A>

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Title: Multiperiodicity, modulations and flip-flops in variable star
light curves. II. Analysis of II Pegasus photometry during 1979-2010
Authors: Lindborg, M.; Mantere, M. J.; Olspert, N.; Pelt, J.; Hackman,
T.; Henry, G. W.; Jetsu, L.; Strassmeier, K. G.
2013A&A...559A..97L Altcode: 2013arXiv1304.4144L
 Aims: According to previously published Doppler images of the
magnetically active primary giant component of the RS CVn binary II Peg,
the surface of the star was dominated by one single active longitude
that was clearly drifting in the rotational frame of the binary system
during 1994-2002; later imaging for 2004-2010, however, showed decreased
and chaotic spot activity, with no signs of the drift pattern. Here
we set out to investigate from a more extensive photometric dataset
whether this drift is a persistent phenomenon, in which case it could
be caused either by an azimuthal dynamo wave or be an indication that
the binary system's orbital synchronization is still incomplete. On a
differentially rotating stellar surface, spot structures preferentially
on a certain latitude band could also cause such a drift, the disruption
of which could arise from the change of the preferred spot latitude. Methods: We analyzed the datasets using the carrier fit (CF) method,
which is especially suitable for analyzing time series in which a fast
clocking frequency (such as the rotation of the star) is modulated
with a slower process (such as the stellar activity cycle). 
Results: We combined all collected photometric data into one single
data set and analyzed it with the CF method. We confirm the previously
published results that the spot activity has been dominated by one
primary spotted region almost through the entire data set and also
confirm a persistent, nearly linear drift. Disruptions of the linear
trend and complicated phase behavior are also seen, but the period
analysis reveals a rather stable periodicity with Pspot =
6.71054d ± 0.00005d. After removing the linear trend from the data,
we identified several abrupt phase jumps, three of which are analyzed
in more detail with the CF method. These phase jumps closely resemble
what is called a flip-flop event, but the new spot configurations
do not persist for longer than a few months in most cases. 
Conclusions: There is some evidence that the regular drift without phase
jumps is related to the high state, while the complex phase behavior
and disrupted drift pattern are related to the low state of magnetic
activity. The most natural explanation of the drift is weak anti-solar
(pole rotating faster than the equator) differential rotation with a
coefficient k ≈ 0.002 combined with the preferred latitude of the
spot structure. The full predicted light curve over the whole data
span (Table 3) is only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/559/A97">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/559/A97</A>

---------------------------------------------------------
Title: Robotic observations of the most eccentric spectroscopic
binary in the sky
Authors: Strassmeier, K. G.; Weber, M.; Granzer, T.
2013A&A...559A..17S Altcode: 2013arXiv1310.2107S
Context. The visual A component of the Gliese 586AB system is a
double-lined spectroscopic binary consisting of two cool stars with
the exceptional orbital eccentricity of 0.976. Such an extremely
eccentric system may be important for our understanding of low-mass
binary formation. Aims: Precise stellar masses, ages, orbital
elements, and rotational periods are a prerequisite for comparing
stellar observations to angular-momentum evolution models. 
Methods: We present a total of 598 high-resolution échelle spectra
from our robotic facility STELLA from 2006-2012, which we used to
compute orbital elements of unprecedented accuracy. New Johnson VI
photometry for the two visual components is also presented. 
Results: Our double-lined orbital solution for the A system has
average velocity residuals for a measure of unit weight of 41 m
s-1 for the G9V primary and 258 m s-1 for the
M0V secondary, better by a factor ≈10 than the discovery orbit. The
orbit constrains the eccentricity to 0.97608 ± 0.00004 and the orbital
period to 889.8195 ± 0.0003 d. The masses of the two components
are 0.87 ± 0.05 M⊙ and 0.58 ± 0.03 M⊙
if the inclination is 55 ± 1.5° as determined from adaptive-optics
images, that is good to only 6% due to the error of the inclination,
although the minimum masses reached a precision of 0.3%. The flux
ratio Aa:Ab in the optical is between 30:1 in Johnson-B and 11:1 in
I. Radial velocities of the visual B-component (K0-1V) appear constant
to within 130 m s-1 over six years. Sinusoidal modulations
of Teff of Aa with an amplitude of ≈55 K are seen with
the orbital period. Component Aa appears warmest at periastron and
coolest at apastron, indicating atmospheric changes induced by the high
orbital eccentricity. No light variations larger than approximately
4 mmag are detected for A, while a photometric period of 8.5 ± 0.2
d with an amplitude of 7 mmag is discovered for the active star B,
which we interpret to be its rotation period. We estimate an orbital
period of ≈50 000 yr for the AB system. The most likely age of the AB
system is ≥2 Gyr, while the activity of the B component, if it were
a single star, would imply 0.5 Gyr. Both Aa and B are matched with
single-star evolutionary tracks of their respective mass. Based
on data obtained with the STELLA robotic telescope in Tenerife, an AIP
facility jointly operated by AIP and IAC, as well as on data products
from observations made with ESO Telescopes at the La Silla Paranal
Observatory under programme IDs 75.C-0733(A) and 60.A-9800(J).Full
Table 1 is only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/559/A17">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/559/A17</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: II Pegasus photometry during
1979-2010 (Lindborg+, 2013)
Authors: Lindborg, M.; Mantere, M. J.; Olspert, N.; Pelt, J.; Hackman,
T.; Henry, G. W.; Jetsu, L.; Strassmeier, K. G.
2013yCat..35590097L Altcode: 2013yCat..35599097L
We combine all collected photometric data into one single data set,
and analyze it with the Carrier Fit (CF) method. The first
data set (hereafter DATA1), published and analyzed by Rodono et
al. (2000A&amp;A...358..624R), covers the years 1973-1998. The
second data set (hereafter DATA2) was published by Messina
(2008A&amp;A...480..495M) covering the years 1992-2004, therefore
partly overlapping with DATA1. The third data set (hereafter DATA3)
consists of unpublished observations with the Wolfgang-Amadeus, the
university of Potsdam/Vienna twin automatic photoelectric telescope
(APT), covering the years 1996-2009, again partially overlapping with
the previous datasets. The fourth dataset (hereafter DATA4) was obtained
with the Tennessee State University T3 0.4-m Automated Photometric
Telescope at Fairborn Observatory in Arizona, covering the time span
of 1987-2010 (see also Roettenbacher et al. 2011AJ....141..138R,
for another analysis of the same dataset). (1 data file).

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

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Title: Chromospherically Active Stars in the RAdial Velocity
Experiment (RAVE) Survey. I. The Catalog
Authors: Žerjal, M.; Zwitter, T.; Matijevič, G.; Strassmeier, K. G.;
Bienaymé, O.; Bland-Hawthorn, J.; Boeche, C.; Freeman, K. C.; Grebel,
E. K.; Kordopatis, G.; Munari, U.; Navarro, J. F.; Parker, Q. A.;
Reid, W.; Seabroke, G.; Siviero, A.; Steinmetz, M.; Wyse, R. F. G.
2013ApJ...776..127Z Altcode: 2013arXiv1309.4274Z
RAVE, the unbiased magnitude limited survey of southern sky stars,
contained 456,676 medium-resolution spectra at the time of our
analysis. Spectra cover the Ca II infrared triplet (IRT) range, which
is a known indicator of chromospheric activity. Our previous work
classified all spectra using locally linear embedding. It identified
53,347 cases with a suggested emission component in calcium lines. Here,
we use a spectral subtraction technique to measure the properties
of this emission. Synthetic templates are replaced by the observed
spectra of non-active stars to bypass the difficult computations of
non-local thermal equilibrium profiles of the line cores and stellar
parameter dependence. We derive both the equivalent width of the
excess emission for each calcium line on a 5 Å wide interval and
their sum EWIRT for ~44,000 candidate active dwarf stars
with signal-to-noise ratio &gt;20, with no cuts on the basis of the
source of their emission flux. From these, ~14,000 show a detectable
chromospheric flux with at least a 2σ confidence level. Our set of
active stars vastly enlarges previously known samples. Atmospheric
parameters and, in some cases, radial velocities of active stars derived
from automatic pipelines suffer from systematic shifts due to their
shallower calcium lines. We re-estimate the effective temperature,
metallicity, and radial velocities for candidate active stars. The
overall distribution of activity levels shows a bimodal shape, with the
first peak coinciding with non-active stars and the second with the
pre-main-sequence cases. The catalog will be made publicly available
with the next RAVE public data releases.

---------------------------------------------------------
Title: Detection and initial characterisation of an exoplanet
atmosphere with small aperture telescopes
Authors: Bernt, I.; Müller, M.; Strassmeier, K. G.; Granzer, T.
2013EPSC....8...14B Altcode:
In the recent years atmospheres of exoplanets have been studied with
space-based telescopes like the HST or large aperture ground-based
telescopes like the Gran Telescopio Canarias. But as the number of
suitable exoplanets is rising, comparative studies of atmospheres
with a statistically meaningful amount of targets will follow, for
which the observational time with large telescopes is limited and
expensive. Our aim is to investigate whether it is possible to detect
and initially characterise the atmosphere of an exoplanet with small
aperture telescopes using chromatic variations in transit depths. We
collected multi-color transits in the years 2011 to 2013 using
the robotic 1.2m-telescope STELLA on Tenerife as well as the Nordic
Optical Telescope and the 70cm-telescope at the Leibniz Institute for
Astrophysics Potsdam. The highly inflated Hot Jupiter HAT-P-32 b was
chosen as target for our pilot study for its favorable large atmospheric
scale height and therefore enhanced atmospheric detectability. Models
of the atmospheric spectra of HAT-P-32 b indicate that the STELLA-data
can be used to distinguish between a dusty and a cloud-free atmosphere
using the gradient in transit depth of the observations in the blue
band and in the visible band. Here we want to present our project
together with the first results of the transit depth analysis.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Barycentric radial velocities of
Gl 586A (Strassmeier+, 2013)
Authors: Strassmeier, K. G.; Weber, M.; Granzer, T.
2013yCat..35590017S Altcode: 2013yCat..35599017S
Barycentric radial velocities of Gl 586A. Data from the STELLA
echelle spectrograph (SES), from the ELODIE archive (ELODIE),
from the SOPHIE archive (SOPHIE) and from Duquennoy et al. 1992
(CORAVEL). All velocities are in the STELLA radial velocity system
(see paper). Secondary velocities are set to -999.99 where they are
not available or not used in the paper (SOPHIE and CORAVEL). (1
data file).

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Title: Radial velocity membership for the open cluster IC4756
Authors: Weingrill, Joerg; Geller, Aaron; Strassmeier, Klaus; Barnes,
Sydney; Meibom, Soeren; Granzer, Thomas; Spada, Federico
2013noao.prop...44W Altcode:
IC 4756 is an ~800 Myr-old nearby (500 pc) open cluster that
conveniently splits the difference in age between the well-studied
Hyades (625 Myr) and NGC 6811 (1 Gyr) clusters. As a result, measuring
IC 4756 rotation periods offers us the chance to test the universality
of the intermediate-age rotational evolution of stars independent of any
theoretical models. Therefore we have performed precision time-series
photometry of the IC 4756 field with the CoRoT satellite, and derived
111 main sequence rotation periods in the cluster region. We have also
acquired new multicolor Stromgren photometry of the cluster. However,
heavy differential reddening and imprecise membership information do
not yet allow a satisfactory determination of the cluster parameters
and membership, far less interpretation of the rotation periods. We
propose here to use WIYN+Hydra to securely identify the cluster
members, determine the cluster parameters, and to fully interpret
the corresponding color-period diagram. This work will provide a new
benchmark open cluster for the community, and help to develop the
associated study of stellar rotation and gyrochronology.

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Title: Long-term photometry of three active red giants in close
binary systems: V2253 Oph, IT Com and IS Vir
Authors: Oláh, K.; Moór, A.; Strassmeier, K. G.; Borkovits, T.;
Granzer, T.
2013AN....334..625O Altcode: 2013arXiv1301.3435O
We present and analyze long-term optical photometric measurements
of the three active stars V2253 Oph, IT Com and IS Vir. All three
systems are single-lined spectroscopic binaries with an early K giant
as primary component but in different stages of orbital-rotational
synchronization. Our photometry is supplemented by 2MASS and WISE
near-IR and mid-IR magnitudes and then used to obtain more accurate
effective temperatures and extinctions. For V2253 Oph and IT Com,
we found their spectral energy distributions consistent with pure
photospheric emission. For IS Vir, we detect a marginal mid-IR excess
which hints towards a dust disk. The orbital and rotational planes
of IT Com appear to be coplanar, contrary to previous findings in
the literature. We apply a multiple frequency analysis technique
to determine photometric periods, and possibly changes of periods,
ranging from days to decades. New rotational periods of 21.55±0.03 d,
65.1±0.3 d, and 23.50±0.04 d were determined for V2253 Oph, IT Com,
and IS Vir, respectively. Splitting of these periods led to tentative
detections of differential surface rotations of δ P/P≈0.02 for
V2253 Oph and 0.07 for IT Com. Using a time-frequency technique based
on short-term Fourier transforms we present evidence of cyclic light
variations of length ≈ 10 yr for V2253 Oph and 5-6 yr for IS Vir. A
single flip-flop event has been observed for IT Com of duration 2-3
yr. Its exchange of the dominant active longitude had happened close to
a time of periastron passage, suggesting some response of the magnetic
activity from the orbital dynamics. The 21.55-d rotational modulation
of V2253 Oph showed phase coherence also with the orbital period, which
is 15 times longer than the rotational period, thus also indicating
a tidal feedback with the stellar magnetic activity.

---------------------------------------------------------
Title: Observational methods for stellar magnetism: from detection
to cartography
Authors: Strassmeier, Klaus G.; Carroll, Thorsten A.; Ilyin, Ilya;
Järvinen, Silva
2013IAUS..294..447S Altcode:
We review some of the currently used techniques to detect stellar
magnetic fields on cool stars. Emphasis is put on spectropolarimetry
with high-resolution spectrographs and its related data de-noising
techniques and multi-line inverse modeling. Detections and results
from Zeeman splittings and broadenings are briefly mentioned. We
discuss some of our most recent Zeeman Doppler Imaging (ZDI) results
and present a comparison of ZDI maps of the K-type WTTS V410 Tauri
and the planet-hosting F8 star HD 179949 with results from other groups.

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Title: The STELLA Robotic Observatory on Tenerife
Authors: Weber, M.; Strassmeier, K. G.; Granzer, T.
2013POBeo..92...21W Altcode:
The STELLA project is made up of two 1.2 m robotic telescopes to
simultaneously monitor stellar activity using a high-resolution
spectrograph on one telescope, and an imaging instrument on the
other telescope. The STELLA Échelle spectrograph (SES) along with
the building has been in operation successfully since 2006, and is
producing spectra covering the visual wavelength range between 390
and 870 nm at a spectral resolution of 55~000. The stability of the
spectrograph over the entire two year span, measured by monitoring 15
radial velocity standard stars, is 30 to 150 m/s rms. The Wide-field
stellar imager and photometer (WIFSIP) was put into operation in 2010,
when the SES-lightfeed was physically moved to the second telescope. We
will give an overview of the main scientific topics of the bulk of
the observing programs.

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Title: Flip-flops of <ASTROBJ>FK Comae Berenices</ASTROBJ>
Authors: Hackman, T.; Pelt, J.; Mantere, M. J.; Jetsu, L.; Korhonen,
H.; Granzer, T.; Kajatkari, P.; Lehtinen, J.; Strassmeier, K. G.
2013A&A...553A..40H Altcode: 2012arXiv1211.0914H
Context.<ASTROBJ>FK Comae</ASTROBJ> Berenices is a rapidly rotating
magnetically active star, the light curve of which is modulated by cool
spots on its surface. It was the first star where the "flip-flop"
phenomenon was discovered. Since then, flip-flops in the spot
activity have been reported in many other stars. Follow-up studies
with increasing length have shown, however, that the phenomenon is
more complex than was thought right after its discovery. Aims:
Therefore, it is of interest to perform a more thorough study of the
evolution of the spot activity in FK Com. In this study, we analyse
15 years of photometric observations with two different time series
analysis methods, with a special emphasis on detecting flip-flop type
events from the data. Methods: We apply the continuous period
search and carrier fit methods on long-term standard Johnson-Cousins
V-observations from the years 1995-2010. The observations were carried
out with two automated photometric telescopes, Phoenix-10 and Amadeus
T7 located in Arizona. Results: We identify complex phase
behaviour in 6 of the 15 analysed data segments. We identify five
flip-flop events and two cases of phase jumps, where the phase shift
is Δφ &lt; 0.4. In addition we see two mergers of spot regions and
two cases where the apparent phase shifts are caused by spot regions
drifting with respect to each other. Furthermore we detect variations
in the rotation period corresponding to a differential rotation
coefficient of |k| &gt; 0.031. Conclusions: The flip-flop cannot
be interpreted as a single phenomenon, where the main activity jumps
from one active longitude to another. In some of our cases the phase
shifts can be explained by differential rotation: two spot regions move
with different angular velocity and even pass each other. Comparison
between the methods show that the carrier fit utility is better in
retrieving slow evolution especially from a low amplitude light curve,
while the continuous period search is more sensitive in case of rapid
changes. Based on data obtained with the Amadeus T7 Automatic
Photoelectric Telescope (APT) at Fairborn Observatory, jointly operated
by the University of Vienna and AIP, the Phoenix-10 APT at Mt. Hopkins,
Arizona, and the Nordic Optical Telescope, Observatorio Roque de los
Muchachos, La Palma, Canary Islands.The photometric observations are
only available in electronic form at the CDS via anonymous ftp to
<A href="http://cdsarc.u-strasbg.fr">cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/553/A40">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/553/A40</A>

---------------------------------------------------------
Title: VizieR Online Data Catalog: UBVI light curves of FK Com
(Hackman+, 2013)
Authors: Hackman, T.; Pelt, J.; Mantere, M. J.; Jetsu, L.; Korhonen,
H.; Granzer, T.; Kajatkari, P.; Lehtinen, J.; Strassmeier, K. G.
2013yCat..35530040H Altcode: 2013yCat..35539040H
Differential Johnson V- and B-photometry of the star FK Comae (HD
117555) from automated photometric telescopes are presented. HD 117567
was used as the comparison star. Missing observations are denoted as
"99.0000". (2 data files).

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Title: The spectroscopic orbit of the K-giant binary γ Canis Minoris
Authors: Fekel, F. C.; Williamson, M. H.; Weber, M.; Strassmeier,
K. G.; Pourbaix, D.
2013AN....334..223F Altcode:
We have determined an improved orbit for the bright, evolved, double
lined binary γ Canis Minoris. The system has an orbital period
of 389.31 days and an eccentricity of 0.2586. We have revised the
secondary to primary mass ratio to 0.987. The spectral types of the
primary and secondary are K4 III and K1: III, respectively, and the
components have a V magnitude difference of 2.2. Orbital fits to the
Hipparcos astrometry are not definitive, but they suggest an orbital
inclination of ∼ 66o, which produces masses of 1.88 and
1.85 M⊙ for the components. A comparison with evolutionary
tracks results in an age of 1.3 Gyr. STELLA very low amplitude radial
velocity residuals of the secondary indicate a period of 278 days. We
interpret this as the rotation period of the secondary, detectable
because of star spots rotating in and out of view. This period is nearly
identical to the pseudosynchronous rotation period of the star. The
primary is rotating more slowly than its pseudosynchronous rate. Based partly on data obtained with the STELLA robotic telescope in
Tenerife, an AIP facility jointly operated with IAC.

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. XXIV. The
lithium-rich single K-giants DP Canum Venaticorum and DI Piscium
Authors: Kővári, Zs.; Korhonen, H.; Strassmeier, K. G.; Weber, M.;
Kriskovics, L.; Savanov, I.
2013A&A...551A...2K Altcode: 2013arXiv1301.0445K
 Aims: We present the first Doppler imaging study of the two
rapidly rotating, single K-giants DP CVn and DI Psc in order to
study the surface spot configuration and to pinpoint their stellar
evolutionary status. Methods: Optical spectroscopy and photometry
were used to determine the fundamental astrophysical properties. Doppler
imaging was applied to recover the surface temperature distribution
for both stars, while photometric light-curve inversions were carried
out for studying the long-term changes of the surface activity of
DP CVn. Surface differential rotation of DP CVn was estimated from
cross-correlating the available subsequent Doppler reconstructions
separated by roughly one rotation period. Results: Both stars
appear to have higher than normal lithium abundance, LTE log n of 2.28
(DP CVn) and 2.20 (DI Psc), and are supposed to be located at the
end of the first Li dredge-up on the RGB. Photometric observations
reveal rotational modulation with a period of 14.010 d (DP CVn) and
18.066 d (DI Psc). Doppler reconstructions from the available mapping
lines well agree in the revealed spot patterns, recovering rather
low latitude spots for both stars with temperature contrasts of ΔT
≈ 600-800 K below the unspotted photospheric background. Spots at
higher latitudes are also found but either with less contrast (DP
CVn) or with smaller extent (DI Psc). A preliminary antisolar-type
differential rotation with α = -0.035 is found for DP CVn from
cross-correlating the subsequent Doppler images. Long-term photometric
analysis supports the existence of active longitudes, as well as the
differential rotation. Based on observations obtained at the
Kitt Peak National Observatory, USA, and at the Canada-France-Hawaii
Telescope, USA.Tables 1 and 2 are only available in electronic form at
<A href="http://www.aanda.org">http://www.aanda.org</A>Photometric
data summarized in Table 2 are available in
electronic form at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">cdsarc.u-strasbg.fr</A>
(<A href="http://130.79.128.5">130.79.128.5</A>) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/551/A2">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/551/A2</A>

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Title: Editors' note: Cool Stars, Stellar Systems, and the Sun 17
Authors: López-Morales, Mercedes; Strassmeier, Klaus G.
2013AN....334....3L Altcode: 2013csss...17....3L
No abstract at ADS

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Title: Stellar differential rotation in theory and observation
Authors: Czesla, S.; Arlt, R.; Bonanno, A.; Strassmeier, K. G.; Huber,
K. F.
2013AN....334...89C Altcode: 2013csss...17...89C
Stellar differential rotation is intimately related to the stellar
magnetic dynamo and, thus, to stellar activity. In recent years,
significant progress in the measurement of differential rotation
on the basis of Doppler imaging techniques and the availability
of space-based long-term photometry has been achieved. Similarly,
simulations incorporate ever more details of the complexity of
convective zones. While some aspects of solar and stellar differential
rotation can be explained now, several important questions remain open
or controversial. In this splinter session, we discussed the latest
observational and theoretical progress in the field of differential
rotation.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Light curves of DP CVn and DI Psc
(Kovari+, 2013)
Authors: Kovari, Zs.; Korhonen, H.; Strassmeier, K. G.; Weber, M.;
Kriskovics, L.; Savanov, I.
2013yCat..35510002K Altcode: 2013yCat..35519002K
Differential photometric magnitudes of DP CVn and DI Psc obtained with
'Wolfgang' (in Stroemgren b, y) and 'Amadeus' (in Johnson-Cousins
V, Ic), the two automated photoelectric telescopes owned by the
Leibniz-Institute for Astrophysics Potsdam (formerly of University of
Vienna), located at Fairborn Observatory in Arizona, USA. Comparison
stars were HD1095129 (for DP CVn) and HD217019 (for DI Psc). (8
data files).

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Title: Strange Active Giants in Close Binary Systems
Authors: Oláh, K.; Moór, A.; Granzer, T.; Strassmeier, K. G.
2013CEAB...37..235O Altcode:
We selected six, well-observed close binary systems, all with evolved,
K-giant active primaries. The stars have similar spectral types but
different ages, orbits and secondary components. Some of the systems
show evidence for connection between the magnetic activity and binary
motion. Examples of huge long-term light variation which is hard to
explain, mid-infrared excess caused by circumstellar dust in the system,
multiple activity cycles and asynchron (both super- and subsynchron)
rotations are found among these strange binaries.

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Title: The GREGOR Solar Telescope on Tenerife
Authors: Schmidt, W.; von der Lühe, O.; Volkmer, R.; Denker, C.;
Solanki, S. K.; Balthasar, H.; Bello González, N.; Berkefeld, T.;
Collados Vera, M.; Hofmann, A.; Kneer, F.; Lagg, A.; Puschmann, K. G.;
Schmidt, D.; Sobotka, M.; Soltau, D.; Strassmeier, K. G.
2012ASPC..463..365S Altcode: 2012arXiv1202.4289S
2011 was a successful year for the GREGOR project. The telescope was
finally completed in May with the installation of the 1.5-meter primary
mirror. The installation of the first-light focal plane instruments was
completed by the end of the year. At the same time, the preparations
for the installation of the high-order adaptive optics were finished,
its integration to the telescope is scheduled for early 2012. This
paper describes the telescope and its instrumentation in their present
first-light configuration, and provides a brief overview of the science
goals of GREGOR.

---------------------------------------------------------
Title: The GREGOR Solar Telescope
Authors: Denker, C.; Lagg, A.; Puschmann, K. G.; Schmidt, D.; Schmidt,
W.; Sobotka, M.; Soltau, D.; Strassmeier, K. G.; Volkmer, R.; von
der Luehe, O.; Solanki, S. K.; Balthasar, H.; Bello Gonzalez, N.;
Berkefeld, T.; Collados Vera, M.; Hofmann, A.; Kneer, F.
2012IAUSS...6E.203D Altcode:
The 1.5-meter GREGOR solar telescope is a new facility for
high-resolution observations of the Sun. The telescope is located at the
Spanish Observatorio del Teide on Tenerife. The telescope incorporates
advanced designs for a foldable-tent dome, an open steel-truss telescope
structure, and active and passive means to minimize telescope and mirror
seeing. Solar fine structure can be observed with a dedicated suite
of instruments: a broad-band imaging system, the "GREGOR Fabry-Perot
Interferometer", and the "Grating Infrared Spectrograph". All post-focus
instruments benefit from a high-order (multi-conjugate) adaptive optics
system, which enables observations close to the diffraction limit of
the telescope. The inclusion of a spectrograph for stellar activity
studies and the search for solar twins expands the scientific usage
of the GREGOR to the nighttime domain. We report on the successful
commissioning of the telescope until the end of 2011 and the first
steps towards science verification in 2012.

---------------------------------------------------------
Title: The magnetic field topology of the weak-lined T Tauri star
V410 Tauri. New strategies for Zeeman-Doppler imaging
Authors: Carroll, T. A.; Strassmeier, K. G.; Rice, J. B.; Künstler, A.
2012A&A...548A..95C Altcode: 2012arXiv1211.2720C
 Aims: In a follow-up investigation we present Zeeman-Doppler maps
of the weak-lined T Tauri star (WTTS) V410 Tau. As a rapid rotating
star and a typical WTTS the stellar surface of V410 Tau is accessible
to surface imaging techniques and allows us to detect and reconstruct
the major magnetic surface features on this pre-main sequence star. Methods: The polarized signals we are measuring are on the order
of 10-4 to 10-3 and are hidden well below the
noise level of a single observation. A new line profile reconstruction
technique based on a singular value decomposition (SVD) allows us to
extract the weak polarized line profiles (Stokes V) as well as the
intensity profiles (Stokes I). One of the key features of the line
profile reconstruction is that the SVD line profiles are amenable to
radiative transfer modeling within our Zeeman-Doppler Imaging code
iMap. The code also utilizes a new iterative regularization scheme
which is independent of any additional surface constraints. To provide
more stability a vital part of our inversion strategy is to invert
both Stokes I and Stokes V profiles to simultaneously reconstruct the
temperature and magnetic field surface distribution of V410 Tau. A
new image-shear analysis is also implemented to allow the search
for image and line profile distortions induced by a differential
rotation of the star. Results: The magnetic field structure we
obtain for V410 Tau shows a good spatial correlation with the surface
temperature and is dominated by a strong field within the cool polar
spot. The Zeeman-Doppler maps exhibit a large-scale organization of
both polarities around the polar cap in the form of a twisted bipolar
structure. The magnetic field reaches a value of almost 2 kG within
the polar region but smaller fields are also present down to lower
latitudes. The pronounced non-axisymmetric field structure and the
non-detection of a differential rotation for V410 Tau supports the
idea of an underlying α2-type dynamo, which is predicted
for WTTS. Appendices are available in electronic form at <A
href="http://www.aanda.org">http://www.aanda.org</A>

---------------------------------------------------------
Title: Gregor@night: The future high-resolution stellar spectrograph
for the GREGOR solar telescope
Authors: Strassmeier, K. G.; Ilyin, I. V.; Woche, M.; Granzer,
T.; Weber, M.; Weingrill, J.; Bauer, S. -M.; Popow, E.; Denker, C.;
Schmidt, W.; von der Lühe, O.; Berdyugina, S.; Collados, M.; Koubsky,
P.; Hackman, T.; Mantere, M. J.
2012AN....333..901S Altcode:
We describe the future night-time spectrograph for the GREGOR solar
telescope and present its science core projects. The spectrograph
provides a 3-pixel resolution of up to R=87 000 in 45 échelle orders
covering the wavelength range 390-900 nm with three grating settings. An
iodine cell can be used for high-precision radial velocity work in the
500-630 nm range. The operation of the spectrograph and the telescope
will be fully automated without the presence of humans during night-time
and will be based on the successful STELLA control system. Future
upgrades include a second optical camera for even higher spectral
resolution, a Stokes-V polarimeter and a link to the laser-frequency
comb at the Vacuum Tower Telescope. The night-time core projects are a
study of the angular-momentum evolution of “The Sun in Time” and a
continuation of our long-term Doppler imaging of active stars.

---------------------------------------------------------
Title: A retrospective of the GREGOR solar telescope in scientific
literature
Authors: Denker, C.; von der Lühe, O.; Feller, A.; Arlt, K.;
Balthasar, H.; Bauer, S. -M.; Bello González, N.; Berkefeld, Th.;
Caligari, P.; Collados, M.; Fischer, A.; Granzer, T.; Hahn, T.;
Halbgewachs, C.; Heidecke, F.; Hofmann, A.; Kentischer, T.; Klva{ňa,
M.; Kneer, F.; Lagg, A.; Nicklas, H.; Popow, E.; Puschmann, K. G.;
Rendtel, J.; Schmidt, D.; Schmidt, W.; Sobotka, M.; Solanki, S. K.;
Soltau, D.; Staude, J.; Strassmeier, K. G.; Volkmer, R.; Waldmann,
T.; Wiehr, E.; Wittmann, A. D.; Woche, M.
2012AN....333..810D Altcode: 2012arXiv1210.3167D
In this review, we look back upon the literature, which had the
GREGOR solar telescope project as its subject including science cases,
telescope subsystems, and post-focus instruments. The articles date
back to the year 2000, when the initial concepts for a new solar
telescope on Tenerife were first presented at scientific meetings. This
comprehensive bibliography contains literature until the year 2012,
i.e., the final stages of commissioning and science verification. Taking
stock of the various publications in peer-reviewed journals and
conference proceedings also provides the “historical” context
for the reference articles in this special issue of Astronomische
Nachrichten/Astronomical Notes.

---------------------------------------------------------
Title: The 1.5 meter solar telescope GREGOR
Authors: Schmidt, W.; von der Lühe, O.; Volkmer, R.; Denker, C.;
Solanki, S. K.; Balthasar, H.; Bello Gonzalez, N.; Berkefeld, Th.;
Collados, M.; Fischer, A.; Halbgewachs, C.; Heidecke, F.; Hofmann,
A.; Kneer, F.; Lagg, A.; Nicklas, H.; Popow, E.; Puschmann, K. G.;
Schmidt, D.; Sigwarth, M.; Sobotka, M.; Soltau, D.; Staude, J.;
Strassmeier, K. G.; Waldmann , T. A.
2012AN....333..796S Altcode:
The 1.5 m telescope GREGOR opens a new window to the understanding
of solar small-scale magnetism. The first light instrumentation
includes the Gregor Fabry Pérot Interferometer (GFPI), a filter
spectro-polarimeter for the visible wavelength range, the GRating
Infrared Spectro-polarimeter (GRIS) and the Broad-Band Imager (BBI). The
excellent performance of the first two instruments has already been
demonstrated at the Vacuum Tower Telescope. GREGOR is Europe's largest
solar telescope and number 3 in the world. Its all-reflective Gregory
design provides a large wavelength coverage from the near UV up to at
least 5 microns. The field of view has a diameter of 150 arcsec. GREGOR
is equipped with a high-order adaptive optics system, with a subaperture
size of 10 cm, and a deformable mirror with 256 actuators. The science
goals are focused on, but not limited to, solar magnetism. GREGOR
allows us to measure the emergence and disappearance of magnetic flux
at the solar surface at spatial scales well below 100 km. Thanks to its
spectro-polarimetric capabilities, GREGOR will measure the interaction
between the plasma flows, different kinds of waves, and the magnetic
field. This will foster our understanding of the processes that heat the
chromosphere and the outer layers of the solar atmosphere. Observations
of the surface magnetic field at very small spatial scales will shed
light on the variability of the solar brightness.

---------------------------------------------------------
Title: GRIS: The GREGOR Infrared Spectrograph
Authors: Collados, M.; López, R.; Páez, E.; Hernández, E.; Reyes,
M.; Calcines, A.; Ballesteros, E.; Díaz, J. J.; Denker, C.; Lagg,
A.; Schlichenmaier, R.; Schmidt, W.; Solanki, S. K.; Strassmeier,
K. G.; von der Lühe, O.; Volkmer, R.
2012AN....333..872C Altcode:
This paper describes the main characteristics of GRIS (GREGOR Infrared
Spectrograph), the grating spectrograph installed in the recently
inaugurated (May 2012) 1.5-meter GREGOR telescope located at the
Observatorio del Teide in Tenerife. The spectrograph has a standard
Czerny-Turner configuration with parabolic collimator and camera mirrors
that belong to the same conic surface. Although nothing prevents its
use at visible wavelengths, the spectrograph will be initially used
in combination with the infrared detector of the Tenerife Infrared
Polarimeter (TIP-II) in standard spectroscopic mode as well as for
spectropolarimetric measurements.

---------------------------------------------------------
Title: Rotation, activity, and lithium abundance in cool binary stars
Authors: Strassmeier, K. G.; Weber, M.; Granzer, T.; Järvinen, S.
2012AN....333..663S Altcode: 2012arXiv1208.3741S
We have used two robotic telescopes to obtain time-series
high-resolution optical echelle spectroscopy and V I and/or by
photometry for a sample of 60 active stars, mostly binaries. Orbital
solutions are presented for 26 double-lined systems and for 19
single-lined systems, seven of them for the first time but all of them
with unprecedented phase coverage and accuracy. Eighteen systems turned
out to be single stars. The total of 6609 {R=55 000} échelle spectra
are also used to systematically determine effective temperatures,
gravities, metallicities, rotational velocities, lithium abundances
and absolute Hα-core fluxes as a function of time. The photometry
is used to infer unspotted brightness, {V-I} and/or b-y colors,
spot-induced brightness amplitudes and precise rotation periods. An
extra 22 radial-velocity standard stars were monitored throughout the
science observations and yield a new barycentric zero point for our
STELLA/SES robotic system. Our data are complemented by literature data
and are used to determine rotation-temperature-activity relations for
active binary components. We also relate lithium abundance to rotation
and surface temperature. We find that 74 % of all known rapidly-rotating
active binary stars are synchronized and in circular orbits but 26 % (61
systems) are rotating asynchronously of which half have {P_rot&gt;P_orb}
and {e&gt;0}. Because rotational synchronization is predicted to occur
before orbital circularization active binaries should undergo an extra
spin-down besides tidal dissipation. We suspect this to be due to a
magnetically channeled wind with its subsequent braking torque. We
find a steep increase of rotation period with decreasing effective
temperature for active stars, P_rot ∝ T_eff-7, for both
single and binaries, main sequence and evolved. For inactive, single
giants with {P_rot&gt;100} d, the relation is much weaker, {P_rot
∝ T_eff-1.12}. Our data also indicate a period-activity
relation for Hα of the form {R_Hα ∝ P_rot-0.24}
for binaries and {R_Hα ∝ P_rot-0.14} for singles. Its
power-law difference is possibly significant. Lithium abundances in
our (field-star) sample generally increase with effective temperature
and are paralleled with an increase of the dispersion. The dispersion
for binaries can be 1-2 orders of magnitude larger than for singles,
peaking at an absolute spread of 3 orders of magnitude near T_eff≈
5000 K. On average, binaries of comparable effective temperature appear
to exhibit 0.25 dex less surface lithium than singles, as expected
if the depletion mechanism is rotation dependent. We also find a
trend of increased Li abundance with rotational period of form log n
(Li) ∝ -0.6 log P_rot but again with a dispersion of as large as
3-4 orders of magnitude. Based on data obtained with the STELLA
robotic telescopes in Tenerife, an AIP facility jointly operated with
IAC, and the Automatic Photoelectric Telescopes in Arizona, jointly
operated with Fairborn Observatory.

---------------------------------------------------------
Title: All-sky mid-infrared imagery to characterize sky conditions
and improve STELLA's observational performance
Authors: Weber, Michael; Klebe, Dimitri; Strassmeier, Klaus; Granzer,
Thomas; Blatherwick, Ronald D.; Müller, Matthias
2012SPIE.8448E..1HW Altcode:
The All Sky Infrared Visible Analyzer (ASIVA) is an instrument
principally designed to characterize sky con- ditions for purposes
of improving ground-based astronomical observational performance. The
ASIVA's primary functionality is to provide radiometrically calibrated
imagery across the entire sky over the mid-infrared (IR) spectrum
(8-13 μm). Calibration procedures have been developed for purposes of
quantifying the photometric quality of the sky. These data products are
used to provide the STELLA scheduler with real-time measured conditions
of the sky/clouds, including thin cirrus to better optimize observing
strategy. We describe how this can be used in the denition of the
observing programs to make best use of the telescope time. Additional
research is underway to correlate infrared spectral radiance with
visible-spectrum extinction.

---------------------------------------------------------
Title: A spectropolarimetric focal station for the ESO E-ELT
Authors: Strassmeier, Klaus G.; DiVarano, Igor; Ilyin, Ilya; Woche,
Manfred; Laux, Uwe
2012SPIE.8444E..35S Altcode:
We present a conceptual design for a spectropolarimetric focal
station for ESO's European Extremely Large Telescope (E-ELT). It
uses the intermediate f/4.4 focus, the only symmetric focus of the
telescope. A dual channel, full Stokesvector polarimeter provides
on-axis light for the wavelength range 380-1600nm to up to two
spectrographs simultaneously via two pairs of fibers. With such
spectropolarimetric capability and a proper spectrograph for the
optical and the near infrared wavelengths, the E-ELT would be able
to provide the full parameter space of an incoming wavefront. Because
of the on-axis entrance location of the polarimeter collimator and an
entrance aperture of just 1.3 arcsec, the expected poor image quality
of the intermediate telescope focus is not directly relevant.

---------------------------------------------------------
Title: The STELLA robotic observatory on Tenerife
Authors: Weber, Michael; Granzer, Thomas; Strassmeier, Klaus G.
2012SPIE.8451E..0KW Altcode:
The STELLA project is made up of two 1.2m robotic telescopes to
simultaneously monitor stellar activity using a high-resolution
spectrograph on one telescope, and an imaging instrument on the
other telescope. The STELLA Echelle spectrograph (SES) along with
the building has been in operation successfully since 2006, and is
producing spectra covering the visual wavelength range between 390 and
900 nm at a resolution of 55 000. The stability of the spectrograph
over the entire two year span, measured by monitoring 15 radial
velocity standard stars, is 30 to 150 m/s rms. The Wide-field stellar
imager and photometer (WIFSIP) was put into operation in 2010, when the
SES-lightfeed was physically moved to the second telescope. We describe
the final instrument conguration in use now, and on the efficiency of
the robotic scheduling in use at the observatory.

---------------------------------------------------------
Title: Critical Fields and Growth Rates of the Tayler Instability
as Probed by a Columnar Gallium Experiment
Authors: Rüdiger, Günther; Gellert, Marcus; Schultz, Manfred;
Strassmeier, Klaus G.; Stefani, Frank; Gundrum, Thomas; Seilmayer,
Martin; Gerbeth, Gunter
2012ApJ...755..181R Altcode: 2012arXiv1201.2318R
Many astrophysical phenomena (such as the slow rotation of neutron
stars or the rigid rotation of the solar core) can be explained by
the action of the Tayler instability of toroidal magnetic fields in
the radiative zones of stars. In order to place the theory of this
instability on a safe fundament, it has been realized in a laboratory
experiment measuring the critical field strength, the growth rates,
as well as the shape of the supercritical modes. A strong electrical
current flows through a liquid metal confined in a resting columnar
container with an insulating outer cylinder. As the very small magnetic
Prandtl number of the gallium-indium-tin alloy does not influence
the critical Hartmann number of the field amplitudes, the electric
currents for marginal instability can also be computed with direct
numerical simulations. The results of this theoretical concept are
confirmed by the experiment. Also the predicted growth rates on the
order of minutes for the nonaxisymmetric perturbations are certified by
the measurements. That they do not directly depend on the size of the
experiment is shown as a consequence of the weakness of the applied
fields and the absence of rotation.

---------------------------------------------------------
Title: Modulated stellar and solar cycles: parallels and differences
Authors: Oláh, K.; van Driel-Gesztelyi, L.; Strassmeier, K. G.
2012IAUS..286..279O Altcode:
We present examples of activity cycle timescales on different types
of stars from lowmass dwarfs to more massive giants, with wide-ranging
rotation rates, and compare the observed cyclicities to the irradiance
based solar cycle and its modulations. Using annual spectral solar
irradiance in wavelength bands typical for stellar observations
reconstructed by Shapiro et al. (2011), a direct comparison can be
made between cycle timescales and amplitudes derived for the Sun and
the stars. We show that cycles on multiple timescales, known to be
present in solar activity, also show up on stars when the dataset is
long enough to allow recognition. The cycle lengths are not fixed,
but evolve - gradually during some periods but there are also changes
on short timescales. In case the activity is dominated by spots,
i.e., by cooler surface features, the star is redder when fainter,
whereas other type of activity make the stars bluer when the activity
is higher. We found the Sun to be a member of the former group, based
on reconstructed spectral irradiance data by Shapiro et al. (2011).

---------------------------------------------------------
Title: Magnetic Activity of Two Similar Subgiants in Binaries with
Very Different Mass Ratios: EI Eri and V711 Tau
Authors: Oláh, Katalin; Kővári, Zsolt; Vida, Krisztián;
Strassmeier, Klaus G.
2012IAUS..282..478O Altcode:
We use more than three decades-long photometry to study the activity
patterns on the two fast-rotating subgiant components in EI Eri (G5IV)
and V711 Tau (K1IV). From yearly mean rotational periods from the light
curves, we find that EI Eri, with well-measured solar-type differential
rotation, always has spots from the equator to high latitudes. The
measured differential rotation of V711 Tau is controversial, and in
any case is very small. The spots on the K1IV star in V711 Tau seem
to be tidally locked. The physical parameters of the two systems are
similar, with one remarkable difference: EI Eri has a low mass M4-5
dwarf companion, whereas V711 Tau has a G5V star in the system, thus
their mass centers are in very different positions. This may modify
the whole internal structure of the active stars, causing marked
differences in their surface features.

---------------------------------------------------------
Title: Differential Rotation in Two RS CVn Systems: σ Gem and ζ And
Authors: Kővári, Zsolt; Bartus, János; Kriskovics, Levente; Oláh,
Katalin; Vida, Krisztián; Ribárik, Orsolya; Strassmeier, Klaus G.
2012IAUS..282..197K Altcode:
The differentially rotating convective envelope is an indispensable
element of the magnetic dynamo working in RS CVn-systems. Tidal
coupling is responsible for maintaining fast rotation, and also the
observed high level of magnetic activity. In this work, we compare the
physical properties of two well known RS CVn-type binaries, that is
the long-period system σ Gem and the ellipsoidal variable ζ And. For
the comparison, we use the results obtained from processing time-series
Doppler images. We also aim at understanding how differential rotation
could be affected by tidal forces in such close binaries.

---------------------------------------------------------
Title: Determining the Cepheid Period-Luminosity Relation Using
Distances to Individual Cepheids from the Near-infrared Surface
Brightness Method
Authors: Storm, J.; Gieren, W.; Fouqué, P.; Barnes, T. G.; Granzer,
T.; Nardetto, N.; Pietrzyński, G.; Queloz, D.; Soszyński, I.;
Strassmeier, K. G.; Weber, M.
2012Msngr.147...14S Altcode:
The near-infrared surface brightness method has been applied to 111
Cepheids in the Milky Way, the Large Magellanic Cloud and the Small
Magellanic Cloud, and distances and luminosities to the individual
stars have thus been determined. As the Cepheid populations in these
galaxies have significantly different metallicities, the effect of
metallicity on the Cepheid Period-Luminosity (PL) relation can be
directly determined. We show that the K-band PL relation is very
insensitive to abundance and argue that it is the best Cepheid PL
relation for distance determination.

---------------------------------------------------------
Title: The STELLA échelle spectrograph, five years of robotic
high-resolution spectroscopy
Authors: Weber, M.; Strassmeier, K. G.; Granzer, T.
2012ASInC...7..165W Altcode:
The STELLA robotic observatory is made up of two 1.2m telescopes. One is
feeding an échelle spectrograph with a spectral resolution of 55,000
since 2006, the other is equipped with an imaging instrument with a
field of view of 22'. Data are collected during every clear night,
calibration data are also taken during bad weather periods to assure
the functionality of the system. All CCD frames are stored locally
and immediately queued for transfer to the AIP. All environmental
data together with meta-data about the scientific observations are
stored in a SQL database, which is replicated to our data center
in Potsdam. Data reduction is started after each observing night,
results of the post-reduction analysis, like radial velocity and
stellar parameters, along with the reduced spectra are inserted into
the database. This database, with information spanning from how often
a target is picked, when it has been successfully acquired, how big
were the guiding errors, all the way to radial velocities measurements
is an essential tool for both data analysis and quality control.

---------------------------------------------------------
Title: The STELLA control system
Authors: Granzer, T.; Weber, M.; Strassmeier, K. G.
2012ASInC...7..247G Altcode:
The STELLA autonomous observatory comprises two different telescopes
with different instrumentation, explicitly an imaging-photometer and
a high-resolution spectrograph. This different instrumentation also
demanded for different control software, which led to the decision
to design a generic solution to robotic observing strategies, which
not only can handle the existing hardware, but could also incorporate
new hardware or observing strategies at relative ease. This article
is about our solution.

---------------------------------------------------------
Title: Letter from the Editor
Authors: Strassmeier, Klaus G.
2012AN....333....3S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The STELLA Open Cluster Survey - Rotational Evolution of
Low-mass Stars: a Status Report
Authors: Fügner, D.; Granzer, T.; Strassmeier, K. G.
2011ASPC..448..863F Altcode: 2011csss...16..863F
Our study targets on measuring the rotational periods and absolute
parameters of a well-selected sample of cool cluster stars. If an
empirical law between rotational period, stellar age, and mass could
be established it would provide valuable boundary conditions for
evolutionary models. Current models predict a measurable difference of
the rotational period between a solidly rotating and a differentially
rotating star, and this could be tested. Our time-series observations
are made in the Sloan r bandpass. Using image-stacking, we intend to
boost the S/N to more than 500:1 even for the (early) M dwarfs in the
fields. For calculations of stellar properties, like age, metallicity,
gravity and surface temperature, we use the Strömgren system with
few very deep exposures. In this paper, we present the survey outline,
the instruments and the first steps already undertaken.

---------------------------------------------------------
Title: Oscillations and Magnetic Fields in the G8 Star EK Eridani
Authors: Dall, T. H.; Cunha, M.; Strassmeier, K. G.; Stello, D.;
Bruntt, H.
2011ASPC..448.1091D Altcode: 2011csss...16.1091D; 2010arXiv1012.1152D
Asteroseismology can provide information that is otherwise not easily
accessible, like the stellar mass and the evolutionary stage. Strong
magnetic fields are usually accompanied by rapid rotation, which makes
asteroseismology difficult due to spectral line broadening. We have
found what may turn out to be the Rosetta Stone of the stars: A slowly
rotating solar-like star with a strong magnetic field. We have recently
detected solar-like oscillations in this active sub-giant, but with
amplitudes much lower than expected. We suggest that the large-scale
magnetic field alters the pulsations, which become magnetoacoustic in
nature. Here we present our results and discuss possible implications
and how this may open up a new frontier in the studies of magnetic
fields and stellar evolution.

---------------------------------------------------------
Title: Binary-induced magnetic activity?. Time-series echelle
spectroscopy and photometry of HD 123351 = CZ CVn
Authors: Strassmeier, K. G.; Carroll, T. A.; Weber, M.; Granzer, T.;
Bartus, J.; Oláh, K.; Rice, J. B.
2011A&A...535A..98S Altcode: 2011arXiv1108.4673S
Context. Multi-wavelength time-series observations with high cadence and
long duration are needed to resolve and understand the many variations
of magnetically active late-type stars, which is an approach often used
to observe the Sun. Aims: We present a first and detailed study
of the bright and active K0IV-III star HD 123351. Methods: We
acquired a total of 955 high-resolution STELLA echelle spectra during
the years 2006-2010 and a total of 2260 photometric VIC
data points during 1998-2010. These data are complemented by some
spectra from CFHT and KPNO. Results: The star is found to be a
single-lined spectroscopic binary with a period of 147.8919 ± 0.0003
days and a large eccentricity of e = 0.8086 ± 0.0001. The rms of the
orbital solution is just 47 m s-1, making it the most precise
orbit ever obtained for an active binary system. The rotation period
is constrained from long-term photometry to be 58.32 ± 0.01 days. It
shows that HD 123351 is a very asynchronous rotator, rotating five times
slower than the expected pseudo-synchronous value. Two spotted regions
persisted throughout the 12 years of our observations. We interpret
them as active longitudes on a differentially rotating surface with a
ΔP/P of 0.076. Four years of Hα, Ca ii H&amp;K and He i D3 monitoring
identifies the same main periodicity as the photometry but dynamic
spectra also indicate that there is an intermittent dependence on the
orbital period, in particular for Ca ii H&amp;K in 2008. Line-profile
inversions of a pair of Zeeman sensitive/insensitive iron lines
yield an average surface magnetic-flux density of 542 ± 72 G. The
time series for 2008 is modulated by the stellar rotation as well as
the orbital motion, such that the magnetic flux is generally weaker
during times of periastron and that the chromospheric emissions vary
in anti-phase with the magnetic flux. We also identify a broad and
asymmetric lithium line profile and measure an abundance of log n(Li) =
1.70 ± 0.05. The star's position in the H-R diagram indicates a mass of
1.2 ± 0.1 M⊙ and an age of 6-7 Gyr. Conclusions:
We interpret the anti-phase relation of the magnetic flux with the
chromospheric emissions as evidence that there are two magnetic
fields present at the same time, a localized surface magnetic field
associated with spots and a global field that is oriented towards the
(low-mass) secondary component. We suggest that the inter-binary field
is responsible for the magnetic-flux dilution at periastron. It is
also likely to be responsible for the unexpected slow and asynchronous
rotation of the primary star. Based on data obtained with the
STELLA robotic telescope in Tenerife, an AIP facility jointly operated
by AIP and IAC, and the Potsdam Automatic Photoelectric Telescopes
(APT) in Arizona, jointly operated by AIP and Fairborn Observatory.

---------------------------------------------------------
Title: Calibrating the Cepheid period-luminosity relation from the
infrared surface brightness technique. I. The p-factor, the Milky
Way relations, and a universal K-band relation
Authors: Storm, J.; Gieren, W.; Fouqué, P.; Barnes, T. G.;
Pietrzyński, G.; Nardetto, N.; Weber, M.; Granzer, T.; Strassmeier,
K. G.
2011A&A...534A..94S Altcode: 2011arXiv1109.2017S
 Aims: We determine period-luminosity relations for Milky Way
Cepheids in the optical and near-IR bands. These relations can be
used directly as reference for extra-galactic distance determination
to Cepheid populations with solar metallicity, and they form the
basis for a direct comparison with relations obtained in exactly
the same manner for stars in the Magellanic Clouds, presented in
an accompanying paper. In that paper we show that the metallicity
effect is very small and consistent with a null effect, particularly
in the near-IR bands, and we combine here all 111 Cepheids from the
Milky Way, the LMC and SMC to form a best relation. Methods:
We employ the near-IR surface brightness (IRSB) method to determine
direct distances to the individual Cepheids after we have recalibrated
the projection factor using the recent parallax measurements to ten
Galactic Cepheids and the constraint that Cepheid distances to the
LMC should be independent of pulsation period. Results: We
confirm our earlier finding that the projection factor for converting
radial velocity to pulsational velocity depends quite steeply on
pulsation period, p = 1.550 - 0.186log (P) in disagrement with recent
theoretical predictions. We find PL relations based on 70 Milky Way
fundamental mode Cepheids of MK = -3.33( ± 0.09)(log (P)
- 1.0) - 5.66( ± 0.03), WVI = -3.26( ± 0.11)(log (P) -
1.0) - 5.96(±0.04). Combining the 70 Cepheids presented here with
the results for 41 Magellanic Cloud Cepheids which are presented in
an accompanying paper, we find MK = -3.30( ± 0.06)(log
(P) - 1.0) - 5.65( ± 0.02), WVI = -3.32( ± 0.08)(log
(P) - 1.0) - 5.92( ± 0.03). Conclusions: We delineate the
Cepheid PL relation using 111 Cepheids with direct distances from
the IRSB analysis. The relations are by construction in agreement
with the recent HST parallax distances to Cepheids and slopes are
in excellent agreement with the slopes of apparent magnitudes versus
period observed in the LMC. Full Table 3 is only available at the
CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/534/A94">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/534/A94</A>

---------------------------------------------------------
Title: On the design of the PEPSI spectropolarimeter for the LBT
Authors: Ilyin, I.; Strassmeier, K. G.; Woche, M.; Dionies, F.;
Di Varano, I.
2011AN....332..753I Altcode:
We present the design concept of the spectropolarimeter for the
high-resolution echelle spectrograph PEPSI to be installed at the
2×8.4 m Large Binocular Telescope (LBT) in Arizona. We discuss the
optical key elements, the principles of operations of the instrument
and its instrumental polarization effects.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Milky Way Cepheids radial
velocities (Storm+, 2011)
Authors: Storm, J.; Gieren, W.; Fouque, P.; Barnes, T. G.; Pietrzynski,
G.; Nardetto, N.; Weber, M.; Granzer, T.; Strassmeier, K. G.
2011yCat..35340094S Altcode: 2011yCat..35349094S
Repeated high precision radial velocity measurements for 14 galactic
Cepheids obtained with the STELLA telescope and echelle spectrograph
are presented together with the associated time stamps. From these data
radial velocity curves with good phase coverage can be established. The
Cepheids observed are: V496 Aql, TT Aql, VZ Cyg, {zeta} Gem, X Pup,
AQ Pup, BN Pup, LS Pup, VZ Pup, X Sgr, Y Sgr, BB Sgr, XX Sgr, YZ
Sgr. (2 data files).

---------------------------------------------------------
Title: Integration of a thermo-structural analysis with an optical
model for PEPSI polarimeter
Authors: Di Varano, Igor; Strassmeier, Klaus G.; Ilyin, Ilya; Woche,
Manfred; Kaercher, Hans J.
2011SPIE.8336E..0WD Altcode: 2011SPIE.8336E..31D
The two spectropolarimeters for PEPSI (Potsdam Echelle Polarimetric
and Spectroscopic Instrument) have been de¬signed in order to
reconstruct the full Stokes vector measuring linear and circular
polarization simultaneously with a re¬solving power of 120,000. The
polarimeters will be attached to the Gregorian focus of the so far
largest LBT 2x8.4m telescope and will feed together with permanent
focus stations the spectrograph via 44m long fibers connection. The
spectrograph will be located in a pressure-temperature controlled
chamber within the telescope pier. We present hereafter the last
results from combined structural and CFD analyses in order to fulfill
the optical requirements.

---------------------------------------------------------
Title: Physics of Sun and Star Spots (IAU S273)
Authors: Prasad Choudhary, Debi; Strassmeier, Klaus G.
2011IAUS..273.....P Altcode:
Preface; 1. Formation and decay of sunspots; 2. Solar magnetism;
3. Origin of solar activity; 4. Formation and evolution of
starspots; 5. Stellar magnetism; 6. Starspots and stellar activity;
7. Observational techniques; 8. Unified approach in understanding sun
and starspots; Author index; Subject index.

---------------------------------------------------------
Title: The zoo of starspots
Authors: Strassmeier, Klaus G.
2011IAUS..273..174S Altcode:
Starspots are being observed with many different techniques but not
always with coherent results. In particular not if model-dependent
data analysis must be employed, e.g. through two-dimensional spot
modelling of one-dimensional photometric light curves. I review the
zoo of currently available physical spot parameters, i.e. their size,
temperature and variability time scales, and also compare results from
different techniques. Most of the current values come from Doppler
imaging and multi-color photometry. I also list a few cases where
starspot detections turned out to be very different to the solar analog.

---------------------------------------------------------
Title: The spectroscopic orbit of Capella revisited
Authors: Weber, M.; Strassmeier, K. G.
2011A&A...531A..89W Altcode: 2011arXiv1104.0342W
Context. Capella is among the few binary stars with two evolved
giant components. The hotter component is a chromospherically active
star within the Hertzsprung gap, while the cooler star is possibly
helium-core burning. Aims: The known inclination of the
orbital plane from astrometry in combination with precise radial
velocities will allow very accurate masses to be determined for the
individual Capella stars. This will constrain their evolutionary
stage and possibly the role of the active star's magnetic field on
the dynamical evolution of the binary system. Methods: We
obtained a total of 438 high-resolution échelle spectra during the
years 2007-2010 and used the measured velocities to recompute the
orbital elements. Our double-lined orbital solution yields average
residuals of 64 m s-1 for the cool component and 297 m
s-1 for the more rapidly rotating hotter component. 
Results: The semi-amplitude of the cool component is smaller by 0.045
km s-1 than the orbit determination of Torres et al. from
data taken during 1996-1999 but more precise by a factor of 5.5, while
for the hotter component it is larger by 0.580 km s-1 and
more precise by a factor of 3.6. This corresponds to masses of 2.573 ±
0.009 M⊙ and 2.488 ± 0.008 M⊙ for the cool
and hot component, respectively. Their relative errors of 0.34% and
0.30% are about half of the values given in Torres et al. for a combined
literature-data solution but with absolute values different by 4% and 2%
for the two components, respectively. The mass ratio of the system is
therefore q = MA/MB = 0.9673 ± 0.0020. 
Conclusions: Our orbit is the most precise and also likely to be the
most accurate ever obtained for Capella. Based on data obtained
with the STELLA robotic telescope in Tenerife, an AIP facility jointly
operated by AIP and IAC.Full Table 1 is only available at the CDS
via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/531/A89">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/531/A89</A>

---------------------------------------------------------
Title: Towards observational MHD. Advances in spectropolarimetry
and the prospects for the E-ELT
Authors: Strassmeier, Klaus G.
2011IAUS..274..274S Altcode:
Polarization and wavelength are the bits of information attached to
every photon that reveal the most about its formation and subsequent
history. The E-ELT will, for the foreseeable future, be the most
powerful optical light-collecting machine ever built. The strength of
its combination, spectropolarimetry with the E-ELT, is the anchorage
in physics of astronomical observations. I present a strawman design
of a spectropolarimeter for its intermediate focus.

---------------------------------------------------------
Title: The Surface of V410 Tauri
Authors: Rice, J. B.; Strassmeier, K. G.; Kopf, M.
2011ApJ...728...69R Altcode:
We present Doppler images of the weak-lined T Tauri star V410 Tau
obtained with two different Doppler-imaging codes. The images are
consistent and show a cool extended spot, symmetric about the pole,
at a temperature approximately 750 K below the average photospheric
value. Smaller cool spots are found fairly uniformly distributed at
latitudes below the polar cap with temperatures about 450 K below the
average photospheric temperature. Resolution on the stellar surface
is limited to about 7° of arc, so structure within these spots
is not visible. Also at lower latitudes are hotter features with
temperatures up to 1000 K above the photosphere. A trial Doppler
image using a TiO molecular feature reproduced the cool polar cap
at a temperature about 100 K below the value from the atomic line
images. The equatorial features, however, were not properly reproduced
since Doppler imaging relies on information in the wings of lines for
reconstructing equatorial features, and for V410 Tau these molecular
band lines overlap. In 1993, V410 Tau had a large photometric amplitude
resulting from the concentration of cool spots on the hemisphere of the
star visible at phase 0°, a phenomenon known as preferred longitude. In
contrast, the small photometric amplitude observed currently is due to a
strong symmetric polar spot and the uniform distribution in longitude
of equatorial cool and warm spots. This redistribution of surface
features may be the beginning of a slow "flip-flop" for V410 Tau where
spot locations alternate between preferred longitudes. Flare events
linked to two of the hotter spots in the Doppler image were observed.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Spectroscopic orbit of Capella
(Weber+, 2011)
Authors: Weber, M.; Strassmeier, K. G.
2011yCat..35310089W Altcode: 2011yCat..35319089W
Barycentric STELLA radial velocities of Capella. (1 data file).

---------------------------------------------------------
Title: The First HELAS Local Helioseismology Workshop: Roadmap for
European local helioseismology
Authors: Strassmeier, Klaus G.
2011AN....332....3S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Modeling the Subsurface Structure of Sunspots
Authors: Moradi, H.; Baldner, C.; Birch, A. C.; Braun, D. C.; Cameron,
R. H.; Duvall, T. L.; Gizon, L.; Haber, D.; Hanasoge, S. M.; Hindman,
B. W.; Jackiewicz, J.; Khomenko, E.; Komm, R.; Rajaguru, P.; Rempel,
M.; Roth, M.; Schlichenmaier, R.; Schunker, H.; Spruit, H. C.;
Strassmeier, K. G.; Thompson, M. J.; Zharkov, S.
2010SoPh..267....1M Altcode: 2009arXiv0912.4982M; 2010SoPh..tmp..171M
While sunspots are easily observed at the solar surface, determining
their subsurface structure is not trivial. There are two main
hypotheses for the subsurface structure of sunspots: the monolithic
model and the cluster model. Local helioseismology is the only means
by which we can investigate subphotospheric structure. However, as
current linear inversion techniques do not yet allow helioseismology to
probe the internal structure with sufficient confidence to distinguish
between the monolith and cluster models, the development of physically
realistic sunspot models are a priority for helioseismologists. This
is because they are not only important indicators of the variety of
physical effects that may influence helioseismic inferences in active
regions, but they also enable detailed assessments of the validity of
helioseismic interpretations through numerical forward modeling. In
this article, we provide a critical review of the existing sunspot
models and an overview of numerical methods employed to model wave
propagation through model sunspots. We then carry out a helioseismic
analysis of the sunspot in Active Region 9787 and address the serious
inconsistencies uncovered by Gizon et al. (2009a, 2009b). We find that
this sunspot is most probably associated with a shallow, positive
wave-speed perturbation (unlike the traditional two-layer model)
and that travel-time measurements are consistent with a horizontal
outflow in the surrounding moat.

---------------------------------------------------------
Title: Stellar Imager (SI): developing and testing a predictive
dynamo model for the Sun by imaging other stars
Authors: Carpenter, Kenneth G.; Schrijver, Carolus J.; Karovska,
Margarita; Kraemer, Steve; Lyon, Richard; Mozurkewich, David;
Airapetian, Vladimir; Adams, John C.; Allen, Ronald J.; Brown, Alex;
Bruhweiler, Fred; Conti, Alberto; Christensen-Dalsgaard, Joergen;
Cranmer, Steve; Cuntz, Manfred; Danchi, William; Dupree, Andrea; Elvis,
Martin; Evans, Nancy; Giampapa, Mark; Harper, Graham; Hartman, Kathy;
Labeyrie, Antoine; Leitner, Jesse; Lillie, Chuck; Linsky, Jeffrey L.;
Lo, Amy; Mighell, Ken; Miller, David; Noecker, Charlie; Parrish, Joe;
Phillips, Jim; Rimmele, Thomas; Saar, Steve; Sasselov, Dimitar; Stahl,
H. Philip; Stoneking, Eric; Strassmeier, Klaus; Walter, Frederick;
Windhorst, Rogier; Woodgate, Bruce; Woodruff, Robert
2010arXiv1011.5214C Altcode:
The Stellar Imager mission concept is a space-based UV/Optical
interferometer designed to resolve surface magnetic activity and
subsurface structure and flows of a population of Sun-like stars,
in order to accelerate the development and validation of a predictive
dynamo model for the Sun and enable accurate long-term forecasting of
solar/stellar magnetic activity.

---------------------------------------------------------
Title: The magnetic field and the evolution of element spots on the
surface of the HgMn eclipsing binary ARAur
Authors: Hubrig, S.; Savanov, I.; Ilyin, I.; González, J. F.;
Korhonen, H.; Lehmann, H.; Schöller, M.; Granzer, T.; Weber, M.;
Strassmeier, K. G.; Hartmann, M.; Tkachenko, A.
2010MNRAS.408L..61H Altcode: 2010MNRAS.tmpL.125H
The system ARAur is a young late B-type double-lined eclipsing binary
with a primary star of HgMn peculiarity. We applied the Doppler imaging
method to reconstruct the distribution of Fe and Y over the surface
of the primary using spectroscopic time series obtained in 2005 and
from 2008 October to 2009 February. The results show a remarkable
evolution of the element distribution and overabundances. Measurements
of the magnetic field with the moment technique using several elements
reveal the presence of a longitudinal magnetic field of the order of
a few hundred gauss in both stellar components and a quadratic field
of the order of 8kG on the surface of the primary star. Based
on observations obtained at the 2.56-m Nordic Optical Telescope on
La Palma, the Karl-Schwarzschild-Observatorium in Tautenburg and the
STELLA robotic telescope on Tenerife. E-mail: shubrig@aip.de

---------------------------------------------------------
Title: Rotation and magnetic activity of the Hertzsprung-gap giant
31 Comae
Authors: Strassmeier, K. G.; Granzer, T.; Kopf, M.; Weber, M.; Küker,
M.; Reegen, P.; Rice, J. B.; Matthews, J. M.; Kuschnig, R.; Rowe,
J. F.; Guenther, D. B.; Moffat, A. F. J.; Rucinski, S. M.; Sasselov,
D.; Weiss, W. W.
2010A&A...520A..52S Altcode:
Context. The single rapidly-rotating G0 giant 31 Comae has been a puzzle
because of the absence of photometric variability despite its strong
chromospheric and coronal emissions. As a Hertzsprung-gap giant, it
is expected to be at the stage of rearranging its moment of inertia,
hence likely also its dynamo action, which could possibly be linked
with its missing photospheric activity. Aims: Our aim is to
detect photospheric activity, obtain the rotation period, and use it
for a first Doppler image of the star's surface. Its morphology could
be related to the evolutionary status. Methods: We carried
out high-precision, white-light photometry with the MOST satellite,
ground-based Strömgren photometry with automated telescopes, and
high-resolution optical echelle spectroscopy with the new STELLA
robotic facility. Results: The MOST data reveal, for the
first time, light variations with a full amplitude of 5 mmag and
an average photometric period of 6.80 ± 0.06 days. Radial-velocity
variations with a full amplitude of 270 m s-1 and a period
of 6.76 ± 0.02 days were detected from our STELLA spectra, which we
also interpret as due to stellar rotation. The two-year constancy
of the average radial velocity of +0.10 ± 0.33 km s-1
confirms the star's single status, as well as the membership in
the cluster Melotte 111. A spectrum synthesis gives Teff
= 5660 ± 42 K, log g = 3.51 ± 0.09, and [Fe/H] = -0.15 ± 0.03,
which together with the revised Hipparcos distance, suggests a mass
of 2.6 ± 0.1 M_⊙ and an age of ≈540 Myr. The surface lithium
abundance is measured to be nearly primordial. A detection of a strong
He i absorption line indicates nonradiative heating processes in the
atmosphere. Our Doppler images show a large, asymmetric polar spot,
cooler than Teff by ≈1600 K, and several small low-to-mid
latitude features that are warmer by ≈300-400 K and are possibly of
chromospheric origin. We computed the convective turnover time for 31
Com as a function of depth and found on average τC ≈ 5
days. Conclusions: 31 Com appears to be just at the onset of
rapid magnetic braking and Li dilution because its age almost exactly
coincides with the predicted onset of envelope convection. That we
recover a big polar starspot despite the Rossby number being larger
than unity, and thus no efficient (envelope) dynamo is expected,
leads us to conclude that 31 Com still harbors a fossil predominantly
poloidal magnetic field. However, the increasing convective envelope
may have just started an interface dynamo that now is the source of the
warm surface features and the corresponding UV and X-ray emission. Based on data obtained with the MOST satellite, a Canadian Space
Agency mission, operated jointly by Dynacon, Inc., and the Universities
of Toronto and British Columbia, with assistance from the University
of Vienna; the STELLA robotic telescope in Tenerife, an AIP facility
jointly operated by AIP and IAC, and the Vienna Automatic Photoelectric
Telescopes in Arizona, jointly operated by the University of Vienna and
AIP.Full Tables 2 and 3 are only available in electronic form at the
CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/520/A52">http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/520/A52</A>

---------------------------------------------------------
Title: Discovery of cyclic spot activity on the G8 giant HD 208472
Authors: Özdarcan, O.; Evren, S.; Strassmeier, K. G.; Granzer, T.;
Henry, G. W.
2010AN....331..794O Altcode:
% We present and analyze 17 consecutive years of U BV RI time-series
photometry of the spotted giant component of the RS CVn binary HD
208472. Our aim is to determine the morphology and the evolution of its
starspots by using period-search techniques and two-spot light-curve
modelling. Spots on HD208472 always occur on hemispheres facing the
observer during orbital quadrature and flip their location to the
opposite hemisphere every approximately six years. The times when
the spots change their preferential hemisphere correspond to times
when the light curve amplitudes are the smallest and when abrupt
changes of the photometric periods are observed. During these times
the star is also close to a relative maximum brightness, suggesting
a vanishing overall spottedness at each end of the previous cycle and
the start of a new one. We find evidence for a 6.28±0.06-yr brightness
cycle, which we interpret to be a stellar analog of the solar 11-year
sunspot cycle. We also present clear evidence for a brightening trend,
approximated with a 21.5±0.5-yr period, possibly due to a stellar
analog of the solar Gleissberg cycle. From the two-spot modelling we
also determine an upper limit for the differential-rotation coefficient
of α=Δ P/P of 0.004±0.010, which would be fifty times weaker than
on the Sun. Based on data obtained with the Amadeus T7 Automatic
Photoelectric Telescope at Fairborn Observatory, jointly operated by
the University of Vienna and AIP, the Tennessee State University T3 0.4
m APT at Fairborn Observatory, operated by Tennessee State University,
and the telescopes of the Ege University Observatory in Izmir.

---------------------------------------------------------
Title: VizieR Online Data Catalog: 31 Com radial velocities
(Strassmeier+, 2010)
Authors: Strassmeier, K. G.; Granzer, T.; Kopf, M.; Weber, M.; Kueker,
M.; Reegen, P.; Rice, J. B.; Matthews, J. M.; Kuschnig, R.; Rowe,
J. F.; Guenther, D. B.; Moffat, A. F. J.; Rucinski, S. M.; Sasselov,
D.; Weiss, W. W.
2010yCat..35200052S Altcode: 2010yCat..35209052S
We carried out high-precision, white-light photometry with the MOST
satellite, ground-based Stroemgren photometry with automated telescopes,
and high-resolution optical echelle spectroscopy with the new STELLA
robotic facility. (2 data files).

---------------------------------------------------------
Title: GREGOR telescope: start of commissioning
Authors: Volkmer, R.; von der Lühe, O.; Denker, C.; Solanki, S.;
Balthasar, H.; Berkefeld, T.; Caligari, P.; Collados, M.; Halbgewachs,
C.; Heidecke, F.; Hofmann, A.; Klvana, M.; Kneer, F.; Lagg, A.; Popow,
E.; Schmidt, D.; Schmidt, W.; Sobotka, M.; Soltau, D.; Strassmeier, K.
2010SPIE.7733E..0KV Altcode: 2010SPIE.7733E..18V
With the integration of a 1-meter Cesic primary mirror the GREGOR
telescope pre-commissioning started. This is the first time, that
the entire light path has seen sunlight. The pre-commissioning period
includes testing of the main optics, adaptive optics, cooling system,
and pointing system. This time was also used to install a near-infrared
grating spectro-polarimeter and a 2D-spectropolarimeter for the visible
range as first-light science instruments. As soon as the final 1.5
meter primary mirror is installed, commissioning will be completed,
and an extended phase of science verification will follow. In the near
future, GREGOR will be equipped with a multi-conjugate adaptive optics
system that is presently under development at KIS.

---------------------------------------------------------
Title: The Opto-mechanical design of the Antarctic Telescope ICE-T
Authors: Strassmeier, Klaus G.; Divarano, Igor; Woche, Manfred;
Kaercher, Hans J.; Eisenträger, Peter
2010SPIE.7733E..4US Altcode: 2010SPIE.7733E.152S
The International Concordia Explorer Telescope (ICE-T) is two 60cm
wide-field robotic Schmidt telescopes optimized for high-precision
CCD photometry in two separate bandpasses. The project is under
final design by an international consortium led by the Astrophysical
Institute Potsdam, Germany, and was foreseen to be placed at the
French-Italian Concordia Station on Dome C in Antarctica. Its core
scientific objective would be to detect and investigate the combined
effects of extra-solar planets, stellar magnetic activity and non-radial
pulsations on the structure and evolution of stars. We present the
optical, the mechanical, and the electronic design of the telescope
and lay out the operational constraints for its search for extrasolar
planets and magnetic stellar activity.

---------------------------------------------------------
Title: Thermal design and de-icing system for the Antarctic Telescope
ICE-T
Authors: Strassmeier, Klaus G.; Kärcher, Hans J.; Kühn, Jürgen;
Divarano, Igor
2010SPIE.7733E..1WS Altcode: 2010SPIE.7733E..58S
ICE-T, the International Concordia Explorer Telescope, is under
final design by an international consortium led by the Astrophysical
Institute Potsdam AIP, Germany, and is intended to be placed at the
French-Italian Concordia Station on Dome C in Antarctica. Experience
with smaller telescopes at Concordia has shown that under the weather
conditions at this site - with mean outside temperatures of -60° to
-80° C and temperature changes of 20° in short time intervals -
the ice-accumulation on the optical components during observation
is a major problem. Also, energy consumption at this site should
be minimized because fuel transport to the site is very costly. The
paper describes the thermal concept for the telescope where the waste
energy of the instrument electronics is used for heating the front
surfaces of the Schmidt optics. All other parts of the telescope are
protected by an insulated smooth cladding against the harsh outside
environment. The effectiveness of the thermal concept is verified by
CFD (Computer Fluid Dynamics) calculations.

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Title: Ellipsoidal primary of the RS CVn binary ζ Andromedae
. Investigation using high-resolution spectroscopy and optical
interferometry
Authors: Korhonen, H.; Wittkowski, M.; Kovári, Zs.; Granzer, Th.;
Hackman, T.; Strassmeier, K. G.
2010A&A...515A..14K Altcode: 2010arXiv1002.4201K
 Aims: We have obtained high-resolution spectroscopy, optical
interferometry, and long-term broad band photometry of the ellipsoidal
primary of the RS CVn-type binary system ζ And. These observations
are used to obtain fundamental stellar parameters and to study surface
structures and their temporal evolution. Methods: Temperature
maps of the stellar surface were obtained from high-resolution spectra
with Doppler imaging techniques. These spectra were also used to
investigate the chromospheric activity using the Hα line and to
correlate it with the photospheric activity. The possible cyclicity
in the spot activity was investigated from the long-term broad band
photometry. Optical interferometry was obtained during the same time
period as the high-resolution spectra. These observations were used to
derive the size and fundamental parameters of ζ And. Results:
Based on the optical interferometry the apparent limb darkened diameter
of ζ And is 2.55 ± 0.09 mas using a uniform disk fit. The expected ~4%
maximum difference between the long and short axes of the ellipsoidal
stellar surface cannot be confirmed from the current data which have
4% errors. The Hipparcos distance and the limb-darkened diameter
obtained with a uniform disk fit give stellar radius of 15.9 ± 0.8
R⊙, and combined with bolometric luminosity, it implies an
effective temperature of 4665 ± 140 K. The temperature maps obtained
from Doppler imaging show a strong belt of equatorial spots and hints
of a cool polar cap. The equatorial spots show a concentration around
the phase 0.75, i.e., 0.25 in phase from the secondary, and another
concentration spans the phases 0.0-0.4. This spot configuration is
reminiscent of the one seen in the earlier published temperature maps
of ζ And. Investigation of the Hα line reveals both prominences and
cool clouds in the chromosphere. These features do not seem to have a
clearly preferred location in the binary reference frame, nor are they
strongly associated with the cool photospheric spots. The investigation
of the long-term photometry spanning 12 years shows hints of a spot
activity cycle, which is also implied by the Doppler images, but the
cycle length cannot be reliably determined from the current data. Based on observations collected at the European Southern Observatory,
Chile (Prg. 081.D-0216(AB)); and with the Vienna automatic photometric
telescopes Wolfgang and Amadeus, Arizona, USA.

---------------------------------------------------------
Title: GREGOR solar telescope: Design and status
Authors: Volkmer, R.; von der Lühe, O.; Denker, C.; Solanki, S. K.;
Balthasar, H.; Berkefeld, T.; Caligari, P.; Collados, M.; Fischer, A.;
Halbgewachs, C.; Heidecke, F.; Hofmann, A.; Klvaňa, M.; Kneer, F.;
Lagg, A.; Popow, E.; Schmidt, D.; Schmidt, W.; Sobotka, M.; Soltau,
D.; Strassmeier, K. G.
2010AN....331..624V Altcode:
The integration and verification phase of the GREGOR telescope
reached an important milestone with the installation of the
interim 1 m SolarLite primary mirror. This was the first time
that the entire light path had seen sunlight. Since then extensive
testing of the telescope and its subsystems has been carried out. The
integration and verification phase will culminate with the delivery and
installation of the final 1.5 m Zerodur primary mirror in the summer of
2010. Observatory level tests and science verification will commence in
the second half of 2010 and in 2011. This phase includes testing of the
main optics, adaptive optics, cooling and pointing systems. In addition,
assuming the viewpoint of a typical user, various observational modes
of the GREGOR Fabry-Pérot Interferometer (GFPI), the Grating Infrared
Spectrograph (GRIS), and high-speed camera systems will be tested to
evaluate if they match the expectations and science requirements. This
ensures that GREGOR will provide high-quality observations with its
combination of (multi-conjugate) adaptive optics and advanced post-focus
instruments. Routine observations are expected for 2012.

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Title: Solar-like oscillations and magnetic activity of the slow
rotator EK Eridani
Authors: Dall, T. H.; Bruntt, H.; Stello, D.; Strassmeier, K. G.
2010A&A...514A..25D Altcode: 2010arXiv1003.0433D
 Aims: We aim to understand the interplay between non-radial
oscillations and stellar magnetic activity and test the feasibility
of doing asteroseismology of magnetically active stars. We investigate
the active slow rotator EK Eri which is the likely descendant of an Ap
star. Methods: We analyze 30 years of photometric time-series
data, 3 years of HARPS radial velocity monitoring, and 3 nights
of high-cadence HARPS asteroseismic data. We construct a high-S/N
HARPS spectrum that we use to determine atmospheric parameters
and chemical composition. Spectra observed at different rotation
phases are analyzed to search for signs of temperature or abundance
variations. An upper limit on the projected rotational velocity is
derived from very high-resolution CES spectra. Results: We
detect oscillations in EK Eri with a frequency of the maximum power
of ν_max = 320 ± 32 μHz, and we derive a peak amplitude per radial
mode of ≈0.15 m s-1, which is a factor of ≈3 lower
than expected. We suggest that the magnetic field may act to suppress
low-degree modes. Individual frequencies can not be extracted from the
available data. We derive accurate atmospheric parameters, refining our
previous analysis, finding T_eff = 5135 ± 80 K, log g = 3.39 ± 0.12,
and metallicity [M/H] = + 0.02 ± 0.04. Mass and radius estimates from
the seismic analysis are not accurate enough to constrain the position
in the HR diagram and the evolutionary state. We confirm that the main
light variation is due to cool spots, but that other contributions may
need to be taken into account. We tentatively suggest that the rotation
period is twice the photometric period, i.e., P_rot = 2P_phot = 617.6 d,
and that the star is a dipole-dominated oblique rotator viewed close
to equator-on. We conclude from our derived parameters that v sin i
&lt; 0.40 km s-1 and we show that the value is too low to
be reliably measured. We also link the time series of direct magnetic
field measurements available in the literature to our newly derived
photometric ephemeris. Based on data from the HARPS spectrograph
at the La Silla Observatory, European Southern Observatory, obtained
under programs IDs 77.C-0080 and 78.C-0233, and on data from the CES
spectrograph obtained from the ESO Science Archive Facility.

---------------------------------------------------------
Title: HD 1: The number-one star in the sky
Authors: Strassmeier, K. G.; Weber, M.; Granzer, T.; Dall, T. H.
2010AN....331..368S Altcode:
We present the first ever study of the bright star HD 1. The star
was chosen arbitrarily just because of its outstanding Henry Draper
number. Surprisingly, almost nothing is known about this bright 7.4 m
star. Our observations were performed as part of the commissioning of
the robotic telescope facility STELLA and its fiber-fed high-resolution
optical echelle spectrograph SES in the years 2007-2010. We found
long-term radial velocity variations with a full amplitude of 9 km
s-1 with an average velocity of -29.8 km s-1 and
suggest the star to be a hitherto unknown single-lined spectroscopic
binary. A preliminary orbit with a period of 6.2 years (2279±69
days) and an eccentricity of 0.50±0.01 is given. Its rms uncertainty
is just 73 m s-1 . HD 1 appears to be a G9-K0 giant of
luminosity class IIIa with T_eff = 4850±100 K, log g = 2.0±0.2,
L≈ 155 L_⊙, a mass of 3.0±0.3 M⊙, a radius of 17.7
R⊙, and an age of ≈350 Myr. A relative abundance analysis
led to a metallicity of [Fe/H] =-0.12±0.09. The α-element silicon may
indicate an overabundance of +0.13 though. The low strengths of some
s-process lines and a lower limit for the 12C/13C
isotope ratio of ≥16 indicate that HD 1 is on the first ascend of the
RGB. The absorption spectral lines appear rotationally broadened with a
v sin i of 5.5±1.2 km s-1 but no chromospheric activity is
evident. We also present photometric monitoring BV(RI)_C data taken in
parallel with STELLA. The star is likely a small-amplitude (&lt;10 mmag)
photometric variable although no periodicity was found. Based
on data obtained with the STELLA robotic telescope in Tenerife, an
AIP facility jointly operated by AIP and IAC, and the Vienna Automatic
Photoelectric Telescopes in Arizona, jointly operated by the University
of Vienna and AIP.

---------------------------------------------------------
Title: RS CVn binary IM Peg - investigation of stellar activity and
surface flows
Authors: Korhonen, Heidi; Weber, Michael; Wittkowski, Markus; Granzer,
Thomas; Strassmeier, Klaus G.
2010IAUS..264..267K Altcode:
We have obtained high resolution, high S/N spectra of the RS CVn
binary IM Peg using UVES spectrograph at Kueyen 8.2m telescope of
ESO VLT. We use Doppler imaging techniques to obtain stellar surface
temperature maps from the UVES data. The TempMap code allows us to
use surface differential rotation as an input parameter and thus to
try to construct the rotation pattern on the stellar surface as part
of the inversion process. The UVES observations are combined with
spectroscopic observations from another time period obtained at the
STELLA observatory. We obtain stellar surface temperature maps also
from these spectra. These Doppler images are used to study the magnetic
activity and surface differential rotation on IM Peg.

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Title: Development of the opto-mechanical design for ICE-T
Authors: di Varano, I.; Strassmeier, K. G.; Granzer, T.; Woche, M.
2010EAS....40..375D Altcode: 2009arXiv0909.4407D
ICE-T (International Concordia Explorer Telescope) is a double 60 cm
f/1.1 photometric robotic telescope, on a parallactic mount, which will
operate at Dome C, in the long Antarctic night, aiming to investigate
exoplanets and activity of the hosting stars. Antarctic Plateau site is
well known to be one of the best in the world for observations because
of sky transparency in all wavelengths and low scintillation noise. Due
to the extremely harsh environmental conditions (the lowest average
temperature is -80°C) the criteria adopted for an optimal design are
really challenging. Here we present the strategies we have adopted so
far to fulfill the mechanical and optical requirements.

---------------------------------------------------------
Title: Three Years of Experience with the STELLA Robotic Observatory
Authors: Granzer, Thomas; Weber, Michael; Strassmeier, Klaus G.
2010AdAst2010E..79G Altcode: 2010arXiv1010.3523G
Since May 2006, the two STELLA robotic telescopes at the Izana
observatory in Tenerife, Spain, delivered an almost uninterrupted
stream of scientific data. To achieve such a high level of autonomous
operation, the replacement of all troubleshooting skills of a regular
observer in software was required. Care must be taken on error handling
issues and on robustness of the algorithms used. In the current paper,
we summarize the approaches we followed in the STELLA observatory.

---------------------------------------------------------
Title: The STELLA Robotic Observatory on Tenerife
Authors: Strassmeier, Klaus G.; Granzer, Thomas; Weber, Michael;
Woche, Manfred; Popow, Emil; Järvinen, Arto; Bartus, Janos; Bauer,
Svend-Marian; Dionies, Frank; Fechner, Thomas; Bittner, Wilbert;
Paschke, Jens
2010AdAst2010E..19S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: VizieR Online Data Catalog: Starspots.
Authors: Strassmeier, K. G.
2010yCatp039001701S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Letter from the Editor
Authors: Strassmeier, K. G.
2010AN....331....3S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The Application of FORS1 Spectropolarimetry to the
Investigation of Cool Solar-like Stars
Authors: Korhonen, H.; Hubrig, S.; Kővári, Zs.; Weber, M.;
Strassmeier, K.; Hackman, T.; Wittkowski, M.
2009Msngr.138...15K Altcode:
The low resolution spectropolarimetric observations obtained with FORS1
at the VLT have often been used for investigating magnetic fields in
hot stars. Here we describe the first investigation of the magnetic
field over the stellar rotation in a cool late-type star, FK Com, based
on FORS1 spectropolarimetry. We measure the mean longitudinal magnetic
field from nine circularly polarised spectra, and study its behaviour
over the stellar rotation. The magnetic field measurements are compared
to a simultaneous stellar surface temperature map obtained with Doppler
imaging techniques. These observations reveal two cool spots on the
surface, and indicate that the main cool region coincides with the
maximum value of the mean longitudinal magnetic field. Additionally,
only 0.25 in phase apart from the main spot, the secondary spot is
located at a similar phase to the field minimum. The observations can
be interpreted as two spots having different magnetic field polarities,
implying that the starspot configuration on FK Com is similar to that
observed in the Sun.

---------------------------------------------------------
Title: On the differential rotation of CoRoT-2a
Authors: Fröhlich, H. -E.; Küker, M.; Hatzes, A. P.; Strassmeier,
K. G.
2009A&A...506..263F Altcode:
We apply a robust spot model to fit the light curve of CoRoT-2a. The
spots are assumed to be long-living and each has its own rotation
period. A model with three circular spots reproduces the basic features
of the longitude-time spot coverage map. One of the spots exhibits
a noticeably lower rotational frequency than the other two. From
the rotational frequencies of the three dark features we infer a
differential rotation of above 0.11 rad/d, in rough agreement with
theoretical models. Mean field models of angular momentum transport
by convection and meridional flow lead to an equatorial rotational
frequency that exceeds that of the poles by 0.09 rad/d. The spot
decay corresponds to a turbulent magnetic diffusivity of (1.2±
0.1)× 1013 cm^2/s. Based on observations obtained
with CoRoT. The CoRoT space mission, launched on December 27th 2006,
has been developed by CNES, with the contribution of Austria, Belgium,
Brazil, ESA, Germany and Spain.

---------------------------------------------------------
Title: Starspots
Authors: Strassmeier, Klaus G.
2009A&ARv..17..251S Altcode: 2009A&ARv.tmp....6S; 2009A&ARv.tmp....8S
Starspots are created by local magnetic fields on the surfaces of
stars, just as sunspots. Their fields are strong enough to suppress
the overturning convective motion and thus block or redirect the
flow of energy from the stellar interior outwards to the surface and
consequently appear as locally cool and therefore dark regions against
an otherwise bright photosphere (Biermann in Astronomische Nachrichten
264:361, 1938; Z Astrophysik 25:135, 1948). As such, starspots are
observable tracers of the yet unknown internal dynamo activity and
allow a glimpse into the complex internal stellar magnetic field
structure. Starspots also enable the precise measurement of stellar
rotation which is among the key ingredients for the expected internal
magnetic topology. But whether starspots are just blown-up sunspot
analogs, we do not know yet. This article is an attempt to review our
current knowledge of starspots. A comparison of a white-light image of
the Sun (G2V, 5 Gyr) with a Doppler image of a young solar-like star
(EK Draconis; G1.5V, age 100 Myr, rotation 10 × Ω Sun)
and with a mean-field dynamo simulation suggests that starspots can
be of significantly different appearance and cannot be explained
with a scaling of the solar model, even for a star of same mass and
effective temperature. Starspots, their surface location and migration
pattern, and their link with the stellar dynamo and its internal energy
transport, may have far reaching impact also for our understanding of
low-mass stellar evolution and formation. Emphasis is given in this
review to their importance as activity tracers in particular in the
light of more and more precise exoplanet detections around solar-like,
and therefore likely spotted, host stars.

---------------------------------------------------------
Title: Spot evolution and active longitudes on FK Com: more than a
decade of detailed surface mapping
Authors: Korhonen, H.; Berdyugina, S. V.; Ilyin, I. V.; Strassmeier,
K. G.; Hackman, T.
2009RMxAC..36..323K Altcode:
Stellar surface maps can be obtained from high resolution, high
signal-to-noise spectra using Doppler imaging techniques. In this
work we present new surface temperature maps of the giant FK Com for
2004-2007, and combine them with our earlier maps. The detailed images
of the stellar surface span now almost 15 years. Together with the
photometric observations this unique time series is used to study
the spot evolution, spot life times, and possible permanent active
longitudes on FK Com.

---------------------------------------------------------
Title: Multiple and changing cycles of active stars. II. Results
Authors: Oláh, K.; Kolláth, Z.; Granzer, T.; Strassmeier, K. G.;
Lanza, A. F.; Järvinen, S.; Korhonen, H.; Baliunas, S. L.; Soon,
W.; Messina, S.; Cutispoto, G.
2009A&A...501..703O Altcode: 2009arXiv0904.1747O
Aims: We study the time variations in the cycles of 20 active stars
based on decade-long photometric or spectroscopic observations. Methods: A method of time-frequency analysis, as discussed in a
companion paper, is applied to the data. Results: Fifteen stars
definitely show multiple cycles, but the records of the rest are too
short to verify a timescale for a second cycle. The cycles typically
show systematic changes. For three stars, we found two cycles in each
of them that are not harmonics and vary in parallel, indicating a
common physical mechanism arising from a dynamo construct. The positive
relation between the rotational and cycle periods is confirmed for the
inhomogeneous set of active stars. Conclusions: Stellar activity
cycles are generally multiple and variable.

---------------------------------------------------------
Title: From Gauß to Biermann: Highlights from the first 117 years
of publications in Astronomische Nachrichten/Astronomical Notes
Authors: von Berlepsch, R.; Strassmeier, K. G.
2009AN....330..589V Altcode:
We present facsimiles of some of the scientifically and historically
most relevant papers published in Astronomische Nachrichten/Astronomical
Notes (AN) between 1821 and 1938. Almost all of these papers were
written and printed in German and it is sometimes not completely
straightforward to find these original works and then to cite the
historically correct version, e.g. in case of a series of articles
or editorial letters. It was common during the early years that many
contributions were made in form of letters to the editor. We present a
summary for these original works with an English translation of their
titles. Among the highlights are the originals of the discovery of
stellar parallaxes by Friedrich Wilhelm Bessel, the discovery of the
solar cycle by Heinrich Schwabe, the discovery of the planet Neptune
by Johann Gottfried Galle, the first ever measured stellar radial
velocity by Hermann Vogel, the discovery of radio emission from the
Sun by Wilsing and Scheiner, the first ever conducted photoelectric
photometry of stars by Paul Guthnick and up to the pioneering work
by Karl Schwarzschild, Ejnar Hertzsprung, Erwin Finlay Freundlich
and others. As a particular gimmick we present the still world record
holding shortest paper ever published; by Johannes Hartmann in AN 226,
63 (1926) on Nova Pictoris. Our focus is on contributions in the early
years and published until 1938 near the verge of the second world war.

---------------------------------------------------------
Title: Cosmic Magnetic Fields (IAU S259)
Authors: Strassmeier, Klaus G.; Kosovichev, Alexander G.; Beckman,
John E.
2009IAUS..259.....S Altcode:
Preface K. G. Strassmeier, A. G. Kosovichev and J. E. Beckman;
Organising committee; Conference photograph; Conference participants;
Session 1. Interstellar magnetic fields, star-forming regions and
the Death Valley Takahiro Kudoh and Elisabeta de Gouveia Dal Pino;
Session 2. Multi-scale magnetic fields of the Sun; their generation
in the interior, and magnetic energy release Nigel O. Weiss;
Session 3. Planetary magnetic fields and the formation and evolution
of planetary systems and planets; exoplanets Karl-Heinz Glassmeier;
Session 4. Stellar magnetic fields: cool and hot stars Swetlana Hubrig;
Session 5. From stars to galaxies and the intergalactic space Dimitry
Sokoloff and Bryan Gaensler; Session 6. Advances in methods and
instrumentation for measuring magnetic fields across all wavelengths
and targets Tom Landecker and Klaus G. Strassmeier; Author index;
Object index; Subject index.

---------------------------------------------------------
Title: A Fast Stokes Profile Synthesis
Authors: Kopf, M.; Carroll, T. A.; Strassmeier, K. G.
2009ASPC..405..535K Altcode:
The disk integration process in Doppler imaging and Zeeman-Doppler
imaging requires excessive calculations of local Stokes profiles and
thus has high computational demands. We present a novel approximation
method for the polarized radiative transfer calculation, base on a
Principal Component Analysis and Artificial Neural Networks. A set of
local line profiles is decomposed into their respective eigenspectra and
Artificial Neural Networks are trained, to approximate the non-linear
mapping between atmospheric parameters and principal components. In
test calculations we demonstrate the reliability and precision of this
fast radiative transfer approximation method.

---------------------------------------------------------
Title: A New Zeeman-Doppler Imaging Code for Active Late
Type-stars. An Application to II Peg
Authors: Kopf, M.; Carroll, T. A.; Ilyin, I.; Strassmeier, K. G.;
Tuominen, I.
2009ASPC..405..517K Altcode:
The fact, that late-type stars exhibit complex and small scale surface
magnetic fields, imposes special requirements on their observation as
well as on their modeling and reconstruction. Our new Zeeman-Doppler
imaging code iMap, which we present here, was particularly designed for
the application to late type stars. It does full radiative transfer
calculations and utilizes a regularization scheme which is based on
local maximum entropy. Furthermore a new multi-line cross-correlation
technique by means of a Principal Component Analysis is used to enhance
the quality of individual observed polarized line profiles. In a
first application we present Zeeman-Doppler images of II Pegasi, which
reveal a surprisingly large scale surface structure with one predominant
magnetic longitude, containing a mainly radially oriented field.

---------------------------------------------------------
Title: Cosmic Magnetic Fields (IAU S259)
Authors: Strassmeier, Klaus G.; Kosovichev, Alexander G.; Beckman,
John E.
2009cmf..book.....S Altcode:
Preface K. G. Strassmeier, A. G. Kosovichev and J. E. Beckman;
Organising committee; Conference photograph; Conference participants;
Session 1. Interstellar magnetic fields, star-forming regions and
the Death Valley Takahiro Kudoh and Elisabeta de Gouveia Dal Pino;
Session 2. Multi-scale magnetic fields of the Sun; their generation
in the interior, and magnetic energy release Nigel O. Weiss;
Session 3. Planetary magnetic fields and the formation and evolution
of planetary systems and planets; exoplanets Karl-Heinz Glassmeier;
Session 4. Stellar magnetic fields: cool and hot stars Swetlana Hubrig;
Session 5. From stars to galaxies and the intergalactic space Dimitry
Sokoloff and Bryan Gaensler; Session 6. Advances in methods and
instrumentation for measuring magnetic fields across all wavelengths
and targets Tom Landecker and Klaus G. Strassmeier; Author index;
Object index; Subject index.

---------------------------------------------------------
Title: First measurement of the magnetic field on FK Com and its
relation to the contemporaneous star-spot locations
Authors: Korhonen, H.; Hubrig, S.; Berdyugina, S. V.; Granzer, Th.;
Hackman, T.; Schöller, M.; Strassmeier, K. G.; Weber, M.
2009MNRAS.395..282K Altcode: 2008arXiv0812.0603K; 2009MNRAS.tmp..407K
In this study, we present simultaneous low-resolution longitudinal
magnetic field measurements and high-resolution spectroscopic
observations of the cool single giant FK Com. The variation of the
magnetic field over the rotational period of 2.4d is compared with the
star-spot location obtained using Doppler imaging techniques, V-band
photometry and V - I colours. The chromospheric activity is studied
simultaneously with the photospheric activity using high-resolution
observations of the Hα, Hβ and Hγ line profiles. Both the maximum
(272 +/- 24G) and minimum (60 +/- 17G) in the mean longitudinal
magnetic field, &lt;Bz&gt;, are detected close to the
phases where cool spots appear on the stellar surface. A possible
explanation for such a behaviour is that the active regions at the
two longitudes separated by 0.2 in phase have opposite polarities. *
Based on the observations collected at the European Southern
Observatory, Chile (Prg. 280.D-5075); at the automatic STELLar Activity
(STELLA) observatory at Tenerife, Spain; and with the Vienna automatic
photometric telescopes Wolfgang and Amadeus, Arizona, USA. E-mail:
hkorhonen@eso.org

---------------------------------------------------------
Title: The isolated neutron star RBS1774 revisited. Revised XMM-Newton
X-ray parameters and an optical counterpart from deep LBT-observations
Authors: Schwope, A. D.; Erben, T.; Kohnert, J.; Lamer, G.; Steinmetz,
M.; Strassmeier, K.; Zinnecker, H.; Bechtold, J.; Diolaiti, E.;
Fontana, A.; Gallozzi, S.; Giallongo, E.; Ragazzoni, R.; de Santis,
C.; Testa, V.
2009A&A...499..267S Altcode: 2009arXiv0902.4110S
We report optical B-band observations with the Large Binocular
Telescope (LBT) of the isolated neutron star RBS1774. The stacked
image with a total exposure of 2fh5 reveals a candidate optical
counterpart at mB = 26.96 ± 0.20 at position α (2000) =
21^h43^m03fs40, δ(2000) = +06degr54^prime17farcs5, within the joint
Chandra and XMM-Newton error circles. We analyse archival XMM-Newton
observations and derive revised spectral and positional parameters. The
predicted optical flux from the extrapolated X-ray spectrum is likely
twice as high as reported before. The measured optical flux exceeds
the extrapolated X-ray spectral flux by a factor ∼40 (15-60 at
1σ confidence). We interpret our detection and the spectral energy
distribution as further evidence of a temperature structure over the
neutron star's surface and present a pure thermal model reflecting
both the SED and the pulsed fraction of the light curve. Based
on observations obtained with XMM-Newton, an ESA science mission with
instruments and contributions directly funded by ESA Member States and
NASA. Based on data acquired using the Large Binocular Telescope
(LBT). The LBT is an international collaboration among institutions
in the US, Italy, and Germany. LBT Corporation partners are the
University of Arizona, on behalf of the Arizona university system;
Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft,
Germany, representing the Max Planck Society, the Astrophysical
Institute Potsdam, and Heidelberg University; Ohio State University;
and the Research Corporation, on behalf of the University of Notre Dame,
the University of Minnesota, and the University of Virginia.

---------------------------------------------------------
Title: Zeeman-Doppler imaging: old problems and new methods
Authors: Carroll, Thorsten A.; Kopf, Markus; Strassmeier, Klaus G.;
Ilyin, Ilya
2009IAUS..259..633C Altcode: 2009arXiv0903.1008C
Zeeman-Doppler Imaging (ZDI) is a powerful inversion method to
reconstruct stellar magnetic surface fields. The reconstruction
process is usually solved by translating the inverse problem
into a regularized least-square or optimization problem. In this
contribution we will emphasize that ZDI is an inherent non-linear
problem and the corresponding regularized optimization is, like many
non-linear problems, potentially prone to local minima. We show how this
problem will be exacerbated by using an inadequate forward model. To
facilitate a more consistent full radiative transfer driven approach
to ZDI we describe a two-stage strategy that consist of a principal
component analysis (PCA) based line profile reconstruction and a fast
approximate polarized radiative transfer method to synthesize local
Stokes profiles. Moreover, we introduce a novel statistical inversion
method based on artificial neural networks (ANN) which provide a fast
calculation of a first guess model and allows to incorporate better
physical constraints into the inversion process.

---------------------------------------------------------
Title: Spectropolarimetry with PEPSI at the LBT: accuracy
vs. precision in magnetic field measurements
Authors: Ilyin, Ilya; Strassmeier, Klaus G.; Woche, Manfred; Hofmann,
Axel
2009IAUS..259..663I Altcode:
We present the design of the new PEPSI spectropolarimeter to be
installed at the Large Binocular Telescope (LBT) in Arizona to measure
the full set of Stokes parameters in spectral lines and outline its
precision and the accuracy limiting factors.

---------------------------------------------------------
Title: The chromospherically active binary star EI Eridani:
II. Long-term Doppler imaging
Authors: Washuettl, A.; Strassmeier, K. G.; Weber, M.
2009AN....330..366W Altcode: 2008arXiv0811.3221W
Data from 11 years of continuous spectroscopic observations of the
active RS CVn-type binary star EI Eridani - gained at NSO/McMath-Pierce,
KPNO/Coudé Feed and during the MUSICOS 98 campaign - were used to
obtain 34 Doppler maps in three spectroscopic lines for 32 epochs, 28
of which are independent of each other. Various parameters are extracted
from our Doppler maps: average temperature, fractional spottedness, and
longitudinal and latitudinal spot-occurrence functions. We find that
none of these parameters show a distinct variation nor a correlation
with the proposed activity cycle as seen from photometric long-term
observations. This suggests that the photometric brightness cycle
may not necessarily be due to just a cool spot cycle. The general
morphology of the spot pattern remains persistent over the whole period
of 11 years. A large cap-like polar spot was recovered from all our
images. A high degree of variable activity was noticed near latitudes of
≈60-70° where the appendages of the polar spot emerged and dissolved.

---------------------------------------------------------
Title: Zeeman-Doppler imaging of II Peg
Authors: Carroll, Thorsten A.; Kopf, Markus; Strassmeier, Klaus G.;
Ilyin, Ilya; Tuominen, Ilkka
2009IAUS..259..437C Altcode:
We present Zeeman-Doppler images of the active K2 star II Peg for
the years 2004 and 2007. The surface magnetic field was reconstructed
with our new ZDI code iMap which provides a full polarized radiative
transfer driven inversion to simultaneously reconstruct the surface
temperature and magnetic vector field distribution. II Peg shows a
remarkable large scale magnetic field structure for both years. The
magnetic field is predominantly located at high latitudes and is
arranged in active longitudes. A dramatic evolution in the magnetic
field structure is visible for the two years, where a dominant and
largely unipolar field in 2004 has changed into two distinct and large
scale bipolar structures in 2007.

---------------------------------------------------------
Title: Field optimization and CCD data simulation for the antarctic
International Concordia Explorer Telescope (ICE-T)
Authors: Fügner, D.; Fuhrmann, C.; Strassmeier, K. G.
2009AN....330..330F Altcode:
We performed extensive data simulations for the planned
ultra-wide-field, high-precision photometric telescope ICE-T
(International Concordia Explorer Telescope). ICE-T consists of two 60
cm-aperture Schmidt telescopes with a joint field of view simultaneously
in two photometric bandpasses. Two CCD cameras, each with a single
10.3k×10.3k thinned back-illuminated device, would image a sky field
of 65 square degrees. Given a location of the telescope at Dome C on
the East Antarctic Plateau, we searched for the star fields that best
exploit the technical capabilities of the instrument and the site. We
considered the effects of diurnal air mass and refraction variations,
solar and lunar interference, interstellar absorption, overexposing of
bright stars and ghosts, crowding by background stars, and the ratio
of dwarf to giant stars in the field. Using NOMAD, SSA, Tycho-2 and
2MASS-based stellar positions and BVIJH magnitudes for these fields,
we simulated the effects of the telescope's point-spread-function, the
integration, and the co-addition times. Simulations of transit light
curves are presented for the selected star fields and convolved with
the expected instrumental characteristics. For the brightest stars,
we showed that ICE-T should be capable of detecting a 2 R_Earth Super
Earth around a G2 solar-type star, as well as an Earth around an M0-star
- if these targets were as abundant as hot Jupiters. Simultaneously,
the telescope would monitor the host star's surface activity in an
astrophysically interpretable manner.

---------------------------------------------------------
Title: Starspots: signatures of stellar magnetic activity
Authors: Strassmeier, Klaus G.
2009IAUS..259..363S Altcode:
Starspots, just as Sunspots, are among the most obvious tracers and
signatures of stellar surface magnetic activity. Emphasized already
several decades ago as the origin for the rotationally modulated
brightness of cool late-type stars, it is just now that we start to
trace individual surface features in great enough detail to understand
their magnetic behavior and interaction. Starspots also became the
most important “noise” for detecting extra-solar planets and could
possibly be decisive when it comes to detect another Earth. Since this
is not a review, and because indirect imaging techniques are covered
in other papers in this volume, I focus in this paper on some specific
detections of starspots and introduce four new facilities particularly
suited for starspot research in the near future.

---------------------------------------------------------
Title: Time series Doppler imaging using STELLA
Authors: Weber, Michael; Strassmeier, Klaus G.; Granzer, Thomas
2009IAUS..259..427W Altcode:
One of the core programs of the STELLA robotic observatory is to
monitor the stellar activity on a sample of stars using Doppler
imaging. We present first preliminary results of the rapidly rotating,
single giant star HD 31993 from the first two years of operation. We
confirm the presence and orientation of differential rotation on the
stellar surface.

---------------------------------------------------------
Title: Zeeman-Doppler Imaging of II Peg - Magnetic field restructuring
from 2004 to 2007
Authors: Carroll, T. A.; Kopf, M.; Strassmeier, K. G.; Ilyin, I.;
Tuominen, I.
2009arXiv0903.1016C Altcode:
We present Zeeman-Doppler images of the active K2 star II Peg for
the years 2004 and 2007. The surface magnetic field was reconstructed
with our new ZDI code "iMap" which provides a full polarized radiative
transfer driven inversion to simultaneously reconstruct the surface
temperature and magnetic vector field distribution. II Peg shows a
remarkable large scale magnetic field structure for both years. The
magnetic field is predominantly located at high latitudes and is
arranged in active longitudes. A dramatic evolution in the magnetic
field structure is visible for the two years, where a dominant and
largely unipolar field in 2004 has developed into two distinct and
large scale bipolar structures in 2007.

---------------------------------------------------------
Title: The chromospherically active binary star EI Eridani:
I. Absolute dimensions
Authors: Washuettl, A.; Strassmeier, K. G.; Granzer, T.; Weber, M.;
Oláh, K.
2009AN....330...27W Altcode:
We present a detailed determination of the astrophysical parameters of
the chromospherically active binary star EI Eridani. Our new radial
velocities allow to improve the set of orbital elements and reveal
long-term variations of the barycentric velocity. A possible third-body
orbit with a period of {≈ 19} years is presented. Absolute parameters
are determined in combination with the {Hipparcos} parallax. EI Eri's
inclination angle of the rotational axis is confined to 56.0 ° ±
4.5 °, its luminosity class {IV} is confirmed by its radius of {2.37
± 0.12} R_{⊙}. A comparison to theoretical stellar evolutionary
tracks suggests a mass of 1.09 ± 0.05 M_{⊙} and an age of ≈ 6.15
Gyr. The present investigation is the basis of our long-term Doppler
imaging study of its stellar surface.

---------------------------------------------------------
Title: The Small IRAIT telescope. Photometric time-series during
the polar night
Authors: Briguglio, R.; Tosti, G.; Strassmeier, K. G.; Bruntt, H.;
Nesci, R.; Sabbatini, L.
2009MmSAI..80..147B Altcode:
The Small IRAIT is a 25 cm telescope which was deployed and installed at
Dome C, on the high antarctic plateau, in 2007. During the polar night
an intensive photometric program was carried out: despite the harshness
of the polar winter, the telescope worked in a semi-robotic way giving
us a large amount of photometric data and precious informations about
technology and procedures for polar missions.

---------------------------------------------------------
Title: The E-ELT: A Chance to Measure Cosmic Magnetic Fields
Authors: Strassmeier, K. G.; Ilyin, I. V.
2009ASSP....9..255S Altcode: 2009svlt.conf..255S
Magnetic fields affect the evolution of structure in the Universe and
drive solar and stellar activity which is a key to life's origin and
survival. However, our understanding of how cosmic magnetic fields
form and evolve is currently very limited. Our close-up look at the
Sun has enabled the creation of approximate dynamo models (which took
us 100 years), but none yet predict the level of magnetic activity
of the Sun or any other star. Therefore, major progress requires the
understanding of solar, stellar and galactic magnetism in general and
that in turn requires a population study. These population studies are
now being thought about or some attempts are underway. The current
4-12 m class telescopes eventually provide the targets for future
ELT magnetic-field observations of more complex and distant objects,
even of the early Universe, and of more exotic objects like habitable
extraterrestrial planets.

---------------------------------------------------------
Title: Letter from the Editor
Authors: Strassmeier, Klaus G.
2009AN....330....3S Altcode:
As of 2007, Astronomische Nachrichten -- Astronomical Notes has
reached its all-time high regarding the ISI journal impact factor,
with an impressive increase of 60% compared to 2005. We now rank at
1,461, as shown in the statistics below. This is solely due to the
increased quality of the published articles: In 2006, Astronomische
Nachrichten -- Astronomical Notes published 208 research papers and
received 1,033 citations -- five citations per paper on average. In
2007, we have published 177 research papers with roughly the same
number of citations. In co-operation with Wiley InterScience we have
achieved an average online publication time of just 4.5 months. We
hope that the year 2008 will be comparably prosperous. As in the past,
publication in Astronomische Nachrichten -- Astronomical Notes continues
to be free of charge. Also, all articles of the first issue of each
volume can be downloaded free of charge, as can all articles labelled
“Editor's Choice”, which are additionally featured with a color
image on the front cover.

---------------------------------------------------------
Title: Dynamos and magnetic fields of the Sun and other cool stars,
and their role in the formation and evolution of stars and in the
habitability of planets
Authors: Schrijver, Karel; Carpenter, Ken; Karovska, Margarita; Ayres,
Tom; Basri, Gibor; Brown, Benjamin; Christensen-Dalsgaard, Joergen;
Dupree, Andrea; Guinan, Ed; Jardine, Moira; Miesch, Mark; Pevtsov,
Alexei; Rempel, Matthias; Scherrer, Phil; Solanki, Sami; Strassmeier,
Klaus; Walter, Fred
2009astro2010S.262S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Monitoring mass motions of Betelgeuse's photosphere using
robotic telescopes .
Authors: Weber, M.; Carroll, T.; Granzer, T.; Steffen, M.; Strassmeier,
K. G.
2009MmSAI..80..743W Altcode:
We started monitoring Betelgeuse using STELLA/SES, the STELLA
échelle spectrograph fed by a robotic 1.2 m telescope on Tenerife,
and the automatic photometric telescope (APT) T7 in Arizona in fall
2008. In this first observing season, we have collected 67 high
resolution spectra from 390 to 900 nm at a resolution of 50,000 and
a S/N between 100 and 300, and a comparable number of photometric
observations in the Halpha filter. In this presentation, we report on
the initial findings based on this first data set: Radial velocities,
effective temperature (along with surface gravity and metallicity) are
automatically computed by the STELLA/SES data reduction &amp; analysis
pipeline. We compare these global measurements and the photometric
brightness with velocities and temperature indicators derived from
individual spectral lines, to bring these values in line with recently
published observations. Furthermore we compute synthetic line profiles
from state-of-the-art 3D stellar convection models, and compare the
line-profiles, their shapes and positions to our observations. The
final aim of the observing program is to find out if the spectral line
variations can be explained using these non-magnetic convection models.

---------------------------------------------------------
Title: First time-series optical photometry from Antarctica. sIRAIT
monitoring of the RS CVn binary V841 Centauri and the δ-Scuti star
V1034 Centauri
Authors: Strassmeier, K. G.; Briguglio, R.; Granzer, T.; Tosti, G.;
Divarano, I.; Savanov, I.; Bagaglia, M.; Castellini, S.; Mancini,
A.; Nucciarelli, G.; Straniero, O.; Distefano, E.; Messina, S.;
Cutispoto, G.
2008A&A...490..287S Altcode:
Context: Eradicating the problems associated with the Earth's day-night
cycle is mandatory for long and continuous time-series photometry
and had been achieved with either large ground-based networks of
observatories at different geographic longitudes or when conducted
from space. A third possibility is offered by a polar location
with astronomically-qualified site characteristics. Aims: We
present the first scientific stellar time-series optical photometry
from Dome C in Antarctica and analyze approximately 13 000 CCD frames
acquired in July 2007. Methods: The optical pilot telescope of
the “International Robotic Antarctic Infrared Telescope”, named
“small IRAIT” (sIRAIT), and its UBVRI CCD photometer were used
in BVR for a continuous 243 h (10.15 days) with a duty cycle of 98%
and a cadence of 155 s. The prime targets were the chromospherically
active, spotted binary star V841 Cen and the non-radially pulsating
δ-Scuti star V1034 Cen. Results: We confirmed the known
0.2-day fundamental period of V1034 Cen and detected a total of 23
further periods between 2.2 h and 3.5 days. In July 2007, V841 Cen's
V amplitude due to spots appeared to be at a record high of 0.4 m in
V. We completed a spot-model analysis with a light-curve inversion
technique and discovered the star with a spot filling factor of 44%
of the visible hemisphere, among the highest ever measured values for
active stars, and a temperature-difference photosphere minus spot of
750 ± 100 K. Its odd-numbered (for a single site) rotation period
was determined with a higher precision than before (5.8854 ± 0.0026
days), despite our comparably short data set. The rms scatter from a
2.4-h data subset was 3 mmag in V and 4.2 mmag in R. The differential
data quality is 3-4 times higher than with the 25 cm Fairborn Automatic
Photoelectric Telescope in southern Arizona and is probably due to the
exceptionally low scintillation noise at Dome C. Conclusions:
We conclude that high-precision CCD photometry with exceptional time
coverage and cadence can be acquired at Dome C in Antarctica and be
successfully used to complete time-series astrophysics.

---------------------------------------------------------
Title: Magnetic activity on V889 Herculis. Combining photometry
and spectroscopy
Authors: Järvinen, S. P.; Korhonen, H.; Berdyugina, S. V.; Ilyin,
I.; Strassmeier, K. G.; Weber, M.; Savanov, I.; Tuominen, I.
2008A&A...488.1047J Altcode:
Aims: In this paper we analyse photometric and spectroscopic
observations of the young active dwarf V889 Her. We present new surface
temperature maps, and compare them to earlier published Doppler maps,
as well as to the results obtained from long-term photometry. Methods: The light curve inversions and surface temperature maps
were obtained using the Occamian approach inversion technique. Results: The 12 years of photometric records on V889 Her suggest
a possible photometric cycle of approximately 9 years. Variability
on this time scale is detected in the maximum, minimum, and mean
photometric magnitudes. The spots prefer to concentrate on two
active longitudes that are approximately 180° apart. Furthermore,
one flip-flop event, i.e., a sudden change of the dominant active
longitude by 180°, is detected at the time of the global maximum
activity. The wings of the Ca II 8662 Å indicate that the quiet
photosphere of the V889 Her is similar to the one of the present
Sun supporting earlier determined atmospheric parameters, while the
chromosphere of V889 Her shows signs of much stronger activity. The
temperature maps reveal that the polar regions are covered by spots,
which are about 1500 K cooler than the quiet photosphere. The mean
spot latitude varies slightly with time. It appears that the spot
latitudes from our Doppler images and the spot migration rates
revealed by photometry indicate a weaker differential rotation than
reported earlier, but in the same (solar-like) direction. Based
on observations made with 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. Table [see full textsee
full textsee full text] and Figs. [see full textsee full textsee full
text]-[see full textsee full textsee full text] are only available in
electronic form at http://www.aanda.org

---------------------------------------------------------
Title: The chromospherically active binary star EI Eridani I. Absolute
dimensions
Authors: Washuettl, A.; Strassmeier, K. G.; Granzer, T.; Weber, M.;
Oláh, K.
2008arXiv0809.0782W Altcode:
We present a detailed determination of the astrophysical parameters of
the chromospherically active binary star EI Eridani. Our new radial
velocities allow to improve the set of orbital elements and reveal
long-term variations of the barycentric velocity. A possible third-body
orbit with a period of approximately 19 years is presented. Absolute
parameters are determined in combination with the Hipparcos parallax. EI
Eri's inclination angle of the rotational axis is confined to 56.0
plus/minus 4.5 degrees, its luminosity class IV is confirmed by its
radius of 2.37 plus/minus 0.12 R_Sun. A comparison to theoretical
stellar evolutionary tracks suggests a mass of 1.09 plus/minus 0.05
M_Sun and an age of approximately 6.15 Gyr. The present investigation is
the basis of our long-term Doppler imaging study of its stellar surface.

---------------------------------------------------------
Title: A fast method for Stokes profile synthesis. Radiative transfer
modeling for ZDI and Stokes profile inversion
Authors: Carroll, T. A.; Kopf, M.; Strassmeier, K. G.
2008A&A...488..781C Altcode: 2008arXiv0807.3850C
Context: The major challenges for a fully polarized radiative
transfer driven approach to Zeeman-Doppler imaging are still the
enormous computational requirements. In every cycle of the iterative
interplay between the forward process (spectral synthesis) and the
inverse process (derivative based optimization) the Stokes profile
synthesis requires several thousand evaluations of the polarized
radiative transfer equation for a given stellar surface model. Aims: To cope with these computational demands and to allow for
the incorporation of a full Stokes profile synthesis into Doppler-
and Zeeman-Doppler imaging applications as well as into large scale
solar Stokes profile inversions, we present a novel fast and accurate
synthesis method for calculating local Stokes profiles. Methods:
Our approach is based on artificial neural network models, which
we use to approximate the complex non-linear mapping between the
most important atmospheric parameters and the corresponding Stokes
profiles. A number of specialized artificial neural networks, are
used to model the functional relation between the model atmosphere,
magnetic field strength, field inclination, and field azimuth, on one
hand and the individual components (I,Q,U,V) of the Stokes profiles,
on the other hand. Results: We performed an extensive statistical
evaluation and show that our new approach yields accurate local as well
as disk-integrated Stokes profiles over a wide range of atmospheric
conditions. The mean rms errors for the Stokes I and V profiles are
well below 0.2% compared to the exact numerical solution. Errors for
Stokes Q and U are in the range of 1%. Our approach does not only offer
an accurate approximation to the LTE polarized radiative transfer it,
moreover, accelerates the synthesis by a factor of more than 1000.

---------------------------------------------------------
Title: The STELLA robotic observatory: first two years of
high-resolution spectroscopy
Authors: Weber, Michael; Granzer, Thomas; Strassmeier, Klaus G.;
Woche, Manfred
2008SPIE.7019E..0LW Altcode: 2008SPIE.7019E..19W
The STELLA project consists of two robotic 1.2m telescopes to
simultaneously monitor stellar activity with a high resolution
echelle spectrograph on one telescope, and a photometric imaging
instrument on the other telescope. The STELLA observatory is located
at the Observatorio del Teide on the Canary island of Tenerife. The
STELLA Echelle spectrograph (SES) has been operated in robotic mode
for two years now, and produced approximately 10,000 spectra of the
entire optical range between 390 and 900 nm at a spectral resolution
of 55,000 with a peak shutter-open time of 93%. Although we do not
use an iodine cell nor an actively stabilized chamber, its average
radial velocity precision over the past two years was 60 to 150m/s rms,
depending on target. The Wide-Field STELLA Imaging Photometer (WIFSIP)
is currently being tested and will enter operation early 2009. In this
paper, we present an update report on the first two years of operation.

---------------------------------------------------------
Title: Waveguide image-slicers for ultrahigh resolution spectroscopy
Authors: Beckert, Erik; Strassmeier, Klaus G.; Woche, Manfred;
Eberhardt, Ramona; Tünnermann, Andreas; Andersen, Michael
2008SPIE.7018E..2JB Altcode: 2008SPIE.7018E..82B
Waveguide image-slicer prototypes with resolutions up to 310.000 for the
fiber fed PEPSI echelle spectrograph at the LBT and single waveguide
thicknesses of down to 30 μm have been manufactured. The waveguides
were macroscopically prepared, stacked up to an order of 7 and thinned
back to square stack cross sections. A high filling ratio was achieved
by realizing homogenous adhesive gaps of 4.6 μm, using index matching
adhesives for TIR within the waveguides. The image-slicer stacks can
be used in immersion mode and are miniaturized to be implemented in a
set of four, measurements indicate an overall efficiency of above 80%
for them.

---------------------------------------------------------
Title: Small IRAIT: telescope operations during the polar night
Authors: Briguglio, R.; Tosti, G.; Busso, M.; Bagaglia, M.;
Nucciarelli, G.; Mancini, A.; Castellini, S.; Strassmeier, K. G.;
Straniero, O.; Sabbatini, L.
2008SPIE.7016E..0HB Altcode:
Small IRAIT is a 25 cm Cassegrain telescope, installed at Dome C,
on the high Antarctic plateau, during 2007 winter campaign. It
performed a first test of multiband (UBVRI) photometry from Dome C,
taking advantage of its remote control system that allowed a 10 days,
98% duty cycle run on a chromospherically active, spotted star in Cen
(V841); it also tested multiband acquisition on open clusters, AGB
stars, blazars (PKS2155), eclipsing binaries. In situ optimization made
the telescope able to operate in the cold, harsh Antarctic environment.

---------------------------------------------------------
Title: The chromospherically active, triple, ellipsoidal, and
eclipsing binary HD 6286 = BE Piscium: a laboratory for binary
evolution
Authors: Strassmeier, K. G.; Bartus, J.; Fekel, F. C.; Henry, G. W.
2008A&A...485..233S Altcode:
Aims: We present a detailed analysis of the star HD 6286 = BE
Psc from 16 years of spectroscopic observations and 18 seasons of
photometric ones. The star is an evolved, chromospherically active,
eclipsing binary, consisting of a K1 giant plus an F6 dwarf/subgiant
in a circular orbit with a period of 35.671 days. A faint, close
visual companion of spectral type ≈G0 makes the system triple. The
orbital inclination of the eclipsing pair is 81.8deg. Methods:
We have obtained simultaneous solutions with our extensive set of
radial velocities and BVI light curves that include the star spot
variability of the K giant, the ellipticity of the K giant, and the
eclipses of the spectroscopic binary system. Results: Our spot
solutions suggest persistent polar spots, one in each hemisphere,
that are cooler than the surrounding photosphere by 810±150 K over
the timespan of our observations. The K giant and the F6 dwarf/subgiant
have masses of 1.56 M⊙ and 1.31 M⊙ and mean
radii of 12.0 and 1.9 R⊙, respectively. The masses have
uncertainties of just ≈1.5%. No irradiation effect was detected. We
compared our results to theoretical evolutionary tracks that suggest
an age for the system of ≈2.7 Gyr. The modest logarithmic lithium
abundance of the primary of 1.30 (upper limit) indicates that the star
may have already experienced its first dredge up. The rotation period
of the primary is 35.49 ± 0.01 days and appears to be synchronized
with the orbital period of the eclipsing pair to within 0.5%. Our data
are inconclusive as to whether the secondary is synchronized. Conclusions: Circularization of the orbit has taken place, and we
conclude that the rapid increase in the size of the K giant, as it
evolved across the Hertzsprung gap and up the base of the giant branch,
likely caused the orbit to become circular.

---------------------------------------------------------
Title: PEPSI: the Potsdam Echelle Polarimetric and Spectroscopic
Instrument for the LBT
Authors: Strassmeier, K. G.; Woche, M.; Ilyin, I.; Popow, E.; Bauer,
S. -M.; Dionies, F.; Fechner, T.; Weber, M.; Hofmann, A.; Storm,
J.; Materne, R.; Bittner, W.; Bartus, J.; Granzer, T.; Denker, C.;
Carroll, T.; Kopf, M.; DiVarano, I.; Beckert, E.; Lesser, M.
2008SPIE.7014E..0NS Altcode: 2008SPIE.7014E..21S
We present the status of PEPSI, the bench-mounted fibre-fed and
stabilized "Potsdam Echelle Polarimetric and Spectroscopic Instrument"
for the 2×8.4m Large Binocular Telescope in southern Arizona. PEPSI
is under construction at AIP and is scheduled for first light in
2009/10. Its ultra-high-resolution mode will deliver an unprecedented
spectral resolution of approximately R=310,000 at high efficiency
throughout the entire optical/red wavelength range 390-1050nm without
the need for adaptive optics. Besides its polarimetric Stokes IQUV mode,
the capability to cover the entire optical range in three exposures at
resolutions of 40,000, 130,000 and 310,000 will surpass all existing
facilities in terms of light-gathering-power times spectral-coverage
product. A solar feed will make use of the spectrograph also during day
time. As such, we hope that PEPSI will be the most powerful spectrometer
of its kind for the years to come.

---------------------------------------------------------
Title: Light-curve inversions with truncated least-squares principal
components: Tests and application to HD 291095 = V1355 Orionis
Authors: Savanov, I. S.; Strassmeier, K. G.
2008AN....329..364S Altcode:
We present a new inversion code that reconstructs the stellar surface
spot configuration from the light curve of a rotating star. Our code
employs a method that uses the truncated least-squares estimation of
the inverse problem's objects principal components. We use spot filling
factors as the unknown objects. Various test cases that represent a
rapidly-rotating K subgiant are used for the forward problem. Tests are
then performed to recover the artificial input map and include data
errors and input-parameter errors. We demonstrate the robustness of
the solution to false input parameters like photospheric temperature,
spot temperature, gravity, inclination, unspotted brightness and
different spot distributions and we also demonstrate the insensitivity
of the solution to spot latitude. Tests with spots peppered over the
entire stellar surface or with phase gaps do not produce fake active
longitudes. The code is then applied to ten years of V and I-band
light curve data of the spotted sub-giant HD 291095. A total of 22
light curves is presented. We find that for most of the time its
spots were grouped around two active longitudes separated on average
by 180°. Switches of the dominant active region between these two
longitudes likely occurred about every 3.15±0.23 years while the
amplitude modulation of the brightness occurred with a possible period
of 3.0±0.15 years. For the first time, we found evidence that the
times of the activity flips coincide with times of minimum light as
well as minimum photometric amplitude, i.e. maximum spottedness. From
a comparison with simultaneous Doppler images we conclude that the
activity flips likely take place near the rotational pole of the star.

---------------------------------------------------------
Title: Chromospheric features of LQ Hydrae from Hα line profiles
Authors: Frasca, A.; Kovári, Zs.; Strassmeier, K. G.; Biazzo, K.
2008A&A...481..229F Altcode: 2008arXiv0801.3898F
We analyze the Hα spectral variability of the rapidly-rotating K1-dwarf
LQ Hya using high-resolution Hα spectra recorded during April-May
2000. Chromospheric parameters were computed from the Hα profile as
a function of rotational phase. We find that all these parameters vary
in phase, with a higher chromospheric electron density coinciding with
the maximum Hα emission. We find a clear rotational modulation of the
Hα emission that is better emphasized by subtracting a reference
photospheric template built up with a spectrum of a non-active
star of the same spectral type. A geometrical plage model applied
to the Hα variation curve allows us to derive the location of the
active regions that come out to be close in longitude to the most
pronounced photospheric spots found with Doppler imaging applied to
the photospheric lines in the same spectra. Our analysis suggests that
the Hα features observed in LQ Hya in 2000 are a scaled-up version
of the solar plages as regards dimensions and/or flux contrast. No
clear indication of chromospheric mass motions emerges.

---------------------------------------------------------
Title: Letter from the Editor
Authors: Strassmeier, Klaus G.
2008AN....329....3S Altcode:
As of 2006, Astronomische Nachrichten -- Astronomical Notes has
reached its all-time high regarding the ISI journal impact factor,
with an impressive increase of 60% compared to 2005. We now rank at
position 1,399, as shown in the statistics below. This is solely due
to the increased number and quality of published articles: In 2006,
Astronomische Nachrichten -- Astronomical Notes published 208 research
papers and received 1,033 citations -- five citations per paper on
average. In 2007, we have published 177 research papers, and one may
be curious to see how their factor will develop. In co-operation with
Wiley InterScience we have achieved an average o nline publication
time of just 4.5 months. As in the past, publication in Astronomische
Nachrichten -- Astronomical Notes} continues to be free of charge. Also,
all articles of the first issue of each volume can be downloaded
free of charge, as can all articles labelled “Editor's Choice”,
which are additionally featured with a color image on the front cover.

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Title: Solar Physics and the Solar-Stellar Connection at Dome C
Authors: Denker, C.; Strassmeier, K. G.
2008EAS....33...97D Altcode: 2007arXiv0712.1471D
Solar magnetic fields evolve on many time-scales, e.g., the generation,
migration, and dissipation of magnetic flux during the 22-year magnetic
cycle of the Sun. Active regions develop and decay over periods of
weeks. The build-up of magnetic shear in active regions can occur
within less than a day. At the shortest time-scales, the magnetic
field topology can change rapidly within a few minutes as the result of
eruptive events such as flares, filament eruptions, and coronal mass
ejections. The unique daytime seeing characteristics at Dome C, i.e.,
continuous periods of very good to excellent seeing during almost the
entire Antarctic summer, allow us to address many of the top science
cases related to the evolution of solar magnetic fields. We introduce
the Advanced Solar Photometric Imager and Radiation Experiment and
present the science cases for synoptic solar observations at Dome
C. Furthermore, common science cases concerning the solar-stellar
connection are discussed in the context of the proposed International
Concordia Explorer Telescope.

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Title: Stellar Activity with BRITE: the “Aurigae” field
Authors: Strassmeier, K. G.
2008CoAst.152..124S Altcode:
Photometric time series of active stars can pin down some of the
ingredients that govern the stellar magnetic field, itself being the
driver of all non-thermal stellar emissions. Among the most important
-- and least understood -- astrophysical ingredients is stellar
rotation and its subtle latitudinal dependence called differential
rotation. Rotation switches on and maintains the internal dynamo,
itself a phenomenon from the interaction of turbulent plasma motions and
large-scale shearing forces in the deep stellar interior. I propose to
observe the active binary Capella, made up of two giants in exposed
locations in the HR-diagram. Along with Capella (α Aur), another
eight stars brighter than 4th magnitude would be in the field-of-view
of BRITE, among them such benchmark variables as ζ Aur or θ Aur.

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Title: First time-series optical photometry from Dome C
Authors: Strassmeier, K. G.; Granzer, T.; Briguglio, R.; Tosti,
G.; Bagaglia, M.; Castellini, S.; Mancini, A.; Nucciarelli, G.;
Straniero, O.
2008EAS....33..267S Altcode: 2008arXiv0807.2970S
First time-series observations with the 25-cm sIRAIT Antarctic pilot
telescope from May 2007 are presented and show that the site is well
suited for time-series high-precision photometry. Our target stars were
one spotted 5.998-day rotating variable and one short-period δ-Scuti
star. A total of 13 000 BVR CCD frames covered a time series of 243
consecutive hours.

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Title: Main tasks for IRAIT installation at Dome C
Authors: di Varano, I.; Nucciarelli, G.; Tosti, G.; Busso, M.;
Strassmeier, K. G.
2008EAS....33..279D Altcode:
IRAIT (International Robotic Antarctic Infrared Telescope) is a
telescope with an 80 cm aperture, ready for installation at Dome
C. Equipped with AMICA (Antarctic Multiband Infrared CAmera), the
main focal plane instrument, it will observe in near (1 5 μ) and
mid infrared regions (5 28 μ), benefiting from the exceptional site
characteristics. The installation will start in December 2007. An
overview of interfacing devices and the integration of various IRAIT
subsystems are here presented.

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Title: Science with ICE-T: Exoplanets and stellar/solar activity
Authors: Strassmeier, K. G.; Granzer, T.; Denker, C.; Fuhrmann, C.;
Fügner, D.; Woche, M.; Divarano, I.; Cutispoto, G.; Herber, A.;
Horne, K.; Rafanelli, P.; Bortoletto, F.; Ribas, I.; Tosti, G.
2008EAS....33..199S Altcode:
We present the science case for ICE-T, the International Concordia
Explorer Telescope, a double telescope optimized for ultra-high and
ultra wide field optical time-series photometry from Dome C. ICE-T
consists of two 60 cm 8^circ×8°-FOV Schmidt telescopes for Sloan
g and i photometry and one independent 25 cm, solar, full-disk, Ca
ii-K imaging telescope on a single mount. ICE-T is therefore operable
during night and day. A 28 cm narrow-field Maksutov spectrophotometric
telescope for night-time aerosol measurements (TAVERN-SP) will be
provided by AWI early on and operated in parallel with IRAIT and
later with ICE-T. The low scintillation noise and the long continuous
darkness are among the unique properties for high precision optical
time-series photometry.

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Title: Zeeman-Doppler imaging of late-type stars: The surface magnetic
field of II Peg
Authors: Carroll, T. A.; Kopf, M.; Ilyin, I.; Strassmeier, K. G.
2007AN....328.1043C Altcode: 2007arXiv0712.3769C
Late-type stars in general possess complicated magnetic surface
fields which makes their detection and in particular their modeling and
reconstruction challenging. In this work we present a new Zeeman-Doppler
imaging code which is especially designed for the application to
late-type stars. This code uses a new multi-line cross-correlation
technique by means of a principal component analysis to extract
and enhance the quality of individual polarized line profiles. It
implements the full polarized radiative transfer equation and uses an
inversion strategy that can incorporate prior knowledge based on solar
analogies. Moreover, our code utilizes a new regularization scheme
which is based on local maximum entropy to allow a more appropriate
reproduction of complex surface fields as those expected for late-type
stars. In a first application we present Zeeman-Doppler images of II
Pegasi which reveal a surprisingly large scale surface structure with
one predominant (unipolar) magnetic longitude which is mainly radially
oriented .

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Title: Changing stellar activity cycles
Authors: Oláh, K.; Strassmeier, K. G.; Granzer, T.; Soon, W.;
Baliunas, S. L.
2007AN....328.1072O Altcode:
We investigated continuous long-term photometric datasets of thirteen
active stars, Ca II variability of one single main-sequence star, and
10.7cm radio data of the Sun, with simple Fourier- and time-frequency
analysis. The data reflect the strength of the activity manifested
in magnetic spots. All studied stars show multiple (2 to 4) cycles of
different lengths. The time-frequency analysis reveals, that in several
cases of the sample one or two of the cycles exhibit continuous changes
(increase or decrease). For four stars (V711 Tau, IL Hya, HK Lac,
HD 100180) and for the Sun we find that the cycle length changes are
strong, amounting to 10-50% during the observed time intervals. The
cycle lengths are generally longer for stars with longer rotational
periods.

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Title: Surface velocity network with anti-solar differential rotation
on the active K-giant σ Geminorum
Authors: Kovári, Zs.; Bartus, J.; Švanda, M.; Vida, K.; Strassmeier,
K. G.; Oláh, K.; Forgács-Dajka, E.
2007AN....328.1081K Altcode: 2007arXiv0711.0771K
We demonstrate the power of the local correlation tracking technique
on stellar data for the first time. We recover the spot migration
pattern of the long-period RS CVn-type binary σ Gem from a set of six
Doppler images from 3.6 consecutive rotation cycles. The resulting
surface flow map suggests a weak anti-solar differential rotation
with {α≈-0.0022±0.0016}, and a coherent poleward spot migration
with an average velocity of 220±10 m s-1. This result
agrees with our recent findings from another study and could also be
confirmed theoretically.

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Title: Anti-solar differential rotation and surface flow pattern on
UZ Libræ
Authors: Vida, K.; Kovári, Zs.; Švanda, M.; Oláh, K.; Strassmeier,
K. G.; Bartus, J.
2007AN....328.1078V Altcode: 2007arXiv0711.1187V
We re-investigate UZ Libræ spectra obtained at KPNO in 1998 and
2000. From the 1998 data we compose 11 consecutive Doppler images using
the Ca I-6439, Fe I-6393 and Fe I-6411 lines. Applying the method
of average cross-correlation of contiguous Doppler images we find
anti-solar differential rotation with a surface shear of α≈-0.03. The
pilot application of the local correlation tracking technique for the
same data qualitatively confirms this result and indicates complex flow
pattern on the stellar surface. From the cross-correlation of the two
available Doppler images in 2000 we also get anti-solar differential
rotation but with a much weaker shear of α≈-0.004.

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Title: Study of FK Comae Berenices. V. Spot evolution and detection
of surface differential rotation
Authors: Korhonen, H.; Berdyugina, S. V.; Hackman, T.; Ilyin, I. V.;
Strassmeier, K. G.; Tuominen, I.
2007A&A...476..881K Altcode:
Aims:We investigate the spot evolution and the surface differential
rotation of the single late-type giant FK Com. Methods: A total
of 18 new surface temperature maps of FK Com are calculated with
the Doppler imaging technique for the years 1993-2003. Photometric
observations from 2002-2004 are also given. The new and previously
published spectroscopic and photometric observations are used to
study the spot locations and lifetimes, and to estimate the value of
the surface differential rotation. Results: The phases of the
active regions determined from the Doppler images follow closely the
active longitudes determined earlier from the long-term photometric
observations. One active longitude can remain active for several
years, but the exact spot configuration within the active longitude
changes on much shorter time scales, indicating that the spot
lifetime is months instead of years. There are periods during which
the spot configuration changes even within days. Measurements using
spot latitudes from the Doppler images and spot rotation periods
from the photometric observations yield a surface differential
rotation law of Ω=(151.30°/day ± 0.09°/day)-(1.78°/day ±
0.12°/{day})sin2ψ and the relative differential rotation
coefficient α=0.012± 0.002 for FK Comae. Based on observations
obtained at the Nordic Optical Telescope, Observatorio Roque de los
Muchachos, La Palma, Canary Islands, Spain; the Kitt Peak National
Observatory, USA; the National Astronomical Observatory, Rozhen,
Bulgaria; Automatic Photometric Telescopes Phoenix 10, Wolfgang and
Amadeus, Arizona, USA. Tables 2a-c are only available in electronic
form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)
or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/476/881 Figures
2 and 3 are only available in electronic form at http://www.aanda.org

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Title: VizieR Online Data Catalog: Differential photometry of FK Com
(Korhonen+, 2007)
Authors: Korhonen, H.; Berdyugina, S. V.; Hackman, T.; Ilyin, I. V.;
Strassmeier, K. G.; Tuominen, I.
2007yCat..34760881K Altcode:
In the present work we publish new photometric observations of
the very active single giant, FK Com for the time period between
the 1st of January 2002 and the 8th of July 2004. The observations
have been carried out with three different automatic photometric
telescopes: Phoenix 10, Wolfgang and Amadeus, all located in Arizona,
USA. Observations contain measurements at the following bands: Johnson
U, B and V, Cousins I and Stroemgren b and y. The observations are
differential photometry in respect to the primary comparison star HD
117567. (3 data files).

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Title: Anti-solar differential rotation on the active K-giant σ
Geminorum
Authors: Kovári, Zs.; Bartus, J.; Strassmeier, K. G.; Vida, K.;
Švanda, M.; Oláh, K.
2007A&A...474..165K Altcode:
The active K1 giant σ Gem and its differential surface rotation is
revisited. We refine our previous inconclusive result by recovering
the spot migration pattern of this long-period RS CVn-type binary
through application of the technique of “average cross-correlation
of contiguous Doppler images” to a set of six Doppler images from
3.6 consecutive rotation cycles. We find an anti-solar differential
rotation law with a shear of α≈ -0.022±0.006. We also find evidence
of a poleward migration trend of spots with an average velocity of
≈300 m s-1.

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Title: PEPSI: The Potsdam Echelle Polarimetric and Spectroscopic
Instrument for the Large Binocular Telescope
Authors: Strassmeier, K. G.; Woche, M.; Andersen, M.; Ilyin, I.
2007AN....328..627S Altcode:
No abstract at ADS

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Title: The PEPSI "deep spectrum" project
Authors: Steffen, Matthias; Strassmeier, Klaus G.
2007AN....328..632S Altcode:
No abstract at ADS

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Title: Doppler Imaging of Stars with Roche-Geometry
Authors: Kővári, Zs.; Bartus, J.; Oláh, K.; Strassmeier, K. G.;
Rice, J. B.; Weber, M.; Forgács-Dajka, E.
2007IAUS..240..587K Altcode: 2007IAUS..240Q.212K
Tests are carried out on retrieving Doppler maps from distorted stars
in close binaries to estimate how Doppler imaging may be aliased by
ellipticity. Maps obtained for the distorted shape are compared with
the results of the simple spherical approximation, using real data of
the RS CVn-type close binary star ζ Andromedae.

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Title: Doppler Imaging of Close Binaries
Authors: Strassmeier, Klaus G.
2007IAUS..240..170S Altcode: 2006IAUS..240E..15S
Many of the interesting spotted stars are in close binaries, where
one can find almost any rotational period due to the rotational
synchronization with the orbital motion. Binaries are thus good
laboratories to study the impact of particular astrophysical parameters
that nature usually does not make easily observable. On rapidly-rotating
stars, we may indirectly resolve the surface by a tomographic imaging
technique and map the surface temperature distribution as a proxy
of the (predominantly radial) magnetic field. Binaries are not as
straightforward to map as single stars and I will show some examples
where it was successful and some where it failed. Eclipses help to
further constrain the solution from line-profile variations and may
give some clues on the amount of unresolved features in the images. I
present one case of a bright giant of 100 solar luminosities in a close
binary with even a deformed surface geometry but otherwise solar-type
behavior. One of the basic goals is to learn about the impact of
inter-binary magnetic fields on the evolution of binaries and stars in
general and to provide conclusive constraints for numerical MHD models.

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Title: Future facilities for solar and stellar activity research
Authors: Strassmeier, Klaus G.
2007HiA....14..297S Altcode:
I try to list the currently ongoing instrumental activities for solar
and stellar activity research. Only projects that lead to operational
ground-based facilities no later than 2013 and to operational
space-based observatories no later than 2016 are considered. Any
facility already in operation or any instrument under construction
but with a very wide range of usage is excluded from this listing
(like e.g. ALMA, Herschel or SOFIA). No details on science programs are
given. The text is organized according to space, radio, and optical/IR
projects.

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Title: Joint Discussion 8 Solar and stellar activity cycles
Authors: Kosovichev, Alexander G.; Strassmeier, Klaus G.
2007HiA....14..271K Altcode:
The solar magnetic field and its associated atmospheric activity
exhibits periodic variations on a number of time scales. The 11-year
sunspot cycle and its underlying 22-year magnetic cycle are, besides
the 5-minute oscillation, the most widely known. Amplitudes and
periods range from a few parts per million (ppm) and 2 3 minutes for
p-modes in sunspots, a few 10 ppm and 10 minutes for the granulation
turn around, a few 100 ppm and weeks for the lifetime of plages and
faculae, 1000 ppm and 27 days for the rotational signal from spots, to
the long-term cycles of 90 yr (Gleissberg cycle), 200 - 300 yr (Wolf,
Spörer, Maunder minima), 2,400 yr from 14C tree-ring data,
and possibly in excess of 100,000 yr.

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Title: The International Concordia Explorer Telescope (ICE-T):
an Ultimate Transit-Search Experiment for Dome C
Authors: Strassmeier, K. G.; Andersen, M. I.; Granzer, T.; Korhonen,
H.; Herber, A.; Cutispoto, G.; Rafanelli, P.; Horne, K.
2007ASPC..366..332S Altcode:
ICE-T is a fully robotic telescope for astrophysics and atmospheric
research for the Antarctic station Concordia at Dome C. ICE-T
consists of two 60cm optical ultra-wide-field Schmidt telescopes
and one 18cm narrow-field Maksutov spectrophotometric telescope
on a single mount. The dual 60cm will be mainly used for a transit
search due to extrasolar planets while the 18-cm will be used for
measuring aerosol optical depths. ICE-T is a team effort of the German
Alfred-Wegener-Institute for Polar Research, the Italian Universities of
Padova and Perugia, the INAF Observatory Catania, and the Catalonian
IEEC in Barcelona, Spain, and the AIP with collaboration from the
University of New South Wales, Australia and the University of St
Andrews, U.K..

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Title: WIFSIP: Wide-field Imager for the Robotic Observatory STELLA
Authors: Korhonen, H.; Strassmeier, K. G.; Granzer, T.; Weber, M.;
Staude, A.; Schwope, A. D.; Andersen, M. I.; Järvinen, A. S.
2007ASPC..366...93K Altcode:
STELLA is an observatory on the Spanish island of Tenerife, hosting two
robotic 1.2 meter telescopes (STELLA-I and STELLA-II) that operate
in fully unattended mode (see Fig. ref{stella}). From mid 2007
onwards STELLA-I will host the Wide Field Stella Imaging Photometer
(WIFSIP). One of the core science projects for WIFSIP is the time series
study of open clusters of different ages. This study is mainly intended
for investigating the stellar properties and magnetic activity in open
clusters of different ages up to 2 Gyr, but the long photometric time
series obtained are also suited for finding planet transits.

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Title: Telescope and instrument robotization at Dome C
Authors: Strassmeier, K. G.; Agabi, K.; Agnoletto, L.; Allan, A.;
Andersen, M. I.; Ansorge, W.; Bortoletto, F.; Briguglio, R.; Buey,
J. -T.; Castellini, S.; Coudé du Foresto, V.; Damé, L.; Deeg,
H. J.; Eiroa, C.; Durand, G.; Fappani, D.; Frezzotti, M.; Granzer, T.;
Gröschke, A.; Kärcher, H. J.; Lenzen, R.; Mancini, A.; Montanari,
C.; Mora, A.; Pierre, A.; Pirnay, O.; Roncella, F.; Schmider, F. -X.;
Steele, I.; Storey, J. W. V.; Tothill, N. F. H.; Travouillon, T.;
Vittuari, L.
2007AN....328..451S Altcode: 2004astro.ph..8233Z
This article reviews the situation for robotization of telescopes
and instruments at the Antarctic station Concordia on Dome C. A
brain-storming meeting was held in Tenerife in March 2007 from which
this review emerged. We describe and summarize the challenges for
night-time operations of various astronomical experiments at conditions
“between Earth and Space” and conclude that robotization is likely
a prerequisite for continuous astronomical data taking during the
2000-hour night at Dome C.

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Title: Small IRAIT Telescope: photometry and asteroseismology at
Dome C
Authors: Tosti, G.; Nucciarelli, G.; Bagaglia, M.; Mancini, A.;
Castellini, S.; Straniero, O.; Briguglio, R.; Strassmeier, K. G.;
Stello, D.; IRAIT Collaboration
2007CoAst.150..315T Altcode:
Small IRAIT is a 25 cm telescope planned to be installed at Dome C
during February 2007. It will be equipped with a CCD, a filter wheel,
two photomultipliers and a liquid crystal tunable filter. Small IRAIT
is intended to: test astronomical measurements from Dome C; provide
site qualification and suitability for asteroseismology by taking
advantage of the low scintillation level and the possibility for
long uninterrupted observations. Small IRAIT will be the forerunner
of the IRAIT telescope that will be installed during the Antarctic
Summer 2007-2008.

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Title: GREGOR: the New German Solar Telescope
Authors: Balthasar, H.; von der Lühe, O.; Kneer, F.; Staude, J.;
Volkmer, R.; Berkefeld, T.; Caligari, P.; Collados, M.; Halbgewachs,
C.; Heidecke, F.; Hofmann, A.; Klvaňa, M.; Nicklas, H.; Popow, E.;
Puschmann, K.; Schmidt, W.; Sobotka, M.; Soltau, D.; Strassmeier,
K.; Wittmann, A.
2007ASPC..368..605B Altcode: 2007arXiv0704.2693B
GREGOR is a new open solar telescope with an aperture of 1.5 m. It
replaces the former 45-cm Gregory Coudé telescope on the Canary island
Tenerife. The optical concept is that of a double Gregory system. The
main and the elliptical mirrors are made from a silicon-carbide material
with high thermal conductivity. This is important to keep the mirrors
on the ambient temperature avoiding local turbulence. GREGOR will be
equipped with an adaptive optics system. The new telescope will be ready
for operation in 2008. Post-focus instruments in the first stage will be
a spectrograph for polarimetry in the near infrared and a 2-dimensional
spectrometer based on Fabry-Pérot interferometers for the visible.

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Title: Doppler imaging of stellar surface structure. XXIII. The
ellipsoidal K giant binary ζ Andromedae
Authors: Kővári, Zs.; Bartus, J.; Strassmeier, K. G.; Oláh, K.;
Weber, M.; Rice, J. B.; Washuettl, A.
2007A&A...463.1071K Altcode:
Aims:We present the first Doppler images of the bright RS CVn-type
binary ζ And. The star is a magnetically active K1 giant with its
rotation synchronized to the 17.8-day orbital period. Our revised
lithium abundance of log n=1.2 places ζ And in the vicinity of Li-rich
RGB stars but it is nevertheless a Li-normal chromospherically active
binary star. The star seems to undergo its first standard dredge-up
dilution. Methods: Four consecutive Doppler images were obtained
from a continuous 67-night observing run at NSO-McMath in 1996/97. An
additional single image was obtained from a continuous 19-night run at
KPNO in 1997/98. These unique data allow to compute a small time series
of the evolution of the star's surface structure. All line-profile
inversions are done with a modified TempMap version that takes into
account the non-spherical shape of the star. Representative test
reconstructions are performed and demonstrate the code's reliability
and robustness. Results: High and low-latitude spot activity was
recovered together with an asymmetric polar cap-like feature. The latter
dominated the first half of the two-month time series in 1996/97. The
second half showed mostly medium-to-high latitude activity and only a
fainter polar spot. The coolest areas were restored with a temperature
contrast of about 1000±200 K. Some weaker features at equatorial
latitudes were also recovered but these could be partially spurious and
appear blurred due to imperfect phase coverage. We use our line profiles
to reconstruct an average non-sphericity of R_pole/R_point=0.96
which would, if not taken into account, mimic a temperature
difference pole-to-equator of ≈220 K, especially at the phases of
quadrature. Finally, we apply two different methods for restoring
surface differential rotation and found a weak solar-type rotation
law with a shear ΔΩ≈0.95°/day (α=ΔΩ/Ω_eq=+0.049±0.003),
i.e. roughly a factor of four weaker at a rotation rate roughly 1.5
times faster than the Sun's. Figures A.1-A.3 and Table A.1 are
only available in electronic form at http://www.aanda.org

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Title: ARCO: a program for Automatic Reduction of CCD Observations
Authors: Distefano, E.; Messina, S.; Cutispoto, G.; Parihar, P. S.;
Comparato, M.; Busá, I.; Lanza, A. F.; Lanzafame, A. C.; Pagano,
I.; Strassmeier, K. G.
2007EAS....25..165D Altcode:
The huge amount of CCD photometric data collected by robotic telescopes
(as for instance the ICE-T telescope to be installed at Dome-C) requires
a fully automated approach to the reduction and analysis procedures. To
this end, we are developing a pipeline, making use of IRAF, DAOPHOTII
and tasks build up by us, which will enable to automatically extract
differential magnitude time series. Both aperture and PSF photometry
methods are used to build a proper sample of comparison stars, with
the best method between the two being automatically selected. Finally,
the search of rotational periods is performed. To test our package,
we present results obtained using a 4-year dataset of a field in the
Orion Nebula Cluster (ONC) containing about 350 stars (150 of which
turned out to be periodic variables).

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Title: Gregor@Night
Authors: Strassmeier, K. G.; Woche, M.; Granzer, T.; Andersen, M. I.;
Schmidt, W.; Koubsky, P.
2007msfa.conf...51S Altcode:
Gregor@Night is the concept for a fiber-fed double echelle spectrograph
for the night-time use of GREGOR. Its design specifications are driven
by a science case based on the solar-stellar connection, ranging from
the search and characterization of solar analogs, the characterization
of late-type stars with exoplanets, asteroseismology with high time
resolution and cadence, stellar cycle analogs and many other related
topics. The spectrographs are based on a white-pupil design with a
110 mm beam and are optimized for the wavelength ranges 360-490 nm and
510-870 nm, respectively and achieve a two-pixel resolution of 100,000
for an entrance aperture of 3" at 20% throughput. The instrument would
be fully automated and no on-site night observer required.

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Title: Ultra-High Precision, Ultra-Wide-Field Optical Photometry
Authors: Strassmeier, K. G.
2007EAS....25..233S Altcode:
The low scintillation noise and the long continuous darkness are
among the unique properties of the Dome-C site on the east Antarctic
plateau. Ultra-high precision optical photometry is therefore among the
techniques best suited for this particular site. We propose a telescope
(ICE-T) optimized for ultra-high and ultra wide field photometry for
Dome C. It consists of two 60cm optical ultra-wide-field Wynne-Schmidt
telescopes and one 18cm narrow-field Maksutov spectrophotometric
telescope on a single mount. ICE-T is currently a team effort of
the German Alfred-Wegener-Institute for Polar Research, the Italian
Universities of Padova and Perugia, the INAF Observatory Catania, and
the Catalonian IEEC in Barcelona, Spain, and the AIP, with collaboration
from the University of New South Wales, Australia and the University
of St. Andrews, UK. In this paper, I discuss some of the many problems
associated with sub-milli-mag photometry.

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Title: Solar-Like Activity and Planetary Transits
Authors: Lanza, A. F.; Bonomo, A. S.; Cutispoto, G.; Busã, I.;
Lanzafame, A. C.; Messina, S.; Pagano, I.; Strassmeier, K. G.
2007EAS....25..161L Altcode:
Late-type MS stars display optical variability on different time scales
due to the presence of photospheric brightness inhomogeneities produced
by surface magnetic fields, analogous to cool spots and bright faculae
observed in the Sun. We are developing methods to model the optical
variability of main-sequence late-type stars to understand the impact
of solar-like activity on the detection of planetary transits and
to significantly improve the detection efficiency. Our techniques
will also allow to map the longitude distribution of active regions
on stars that harbor planets and to look for a possible connection
between stellar activity and the presence of planets around a star.

---------------------------------------------------------
Title: Resolving stellar surface spots
Authors: Strassmeier, K. G.; Carroll, T.; Rice, J. B.; Savanov, I. S.
2007MmSAI..78..278S Altcode:
Doppler imaging of stellar surfaces is a novel technique with
similarities to medical brain tomography (instead of a fixed brain and a
rotating scanner, astronomers have a fixed spectrograph and a rotating
brain, star of course). The number of free (internal) parameters is
of the order of the number of surface grid points and only constrained
by the number of input data points. This obviously ill-posed situation
requires modern inversion algorithms with penalty functions of the form
of maximum entropy or Tikhonov etc.. We present a brief status review
of our Doppler imaging codes at AIP that span from temperature and
spot-filling-factor mapping to full Stokes-based magnetic field mapping.

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Title: New high resolution solar telescope GREGOR
Authors: Volkmer, R.; von der Lühe, O.; Kneer, F.; Staude, J.;
Balthasar, H.; Berkefeld, T.; Caligari, P.; Collados, M.; Halbgewachs,
C.; Heidecke, F.; Hofmann, A.; Klvaña, M.; Sobotka, M.; Nicklas, H.;
Popow, E.; Puschmann, K. G.; Schmidt, W.; Soltau, D.; Strassmeier,
K.; Wittmann, A. D.
2007msfa.conf...39V Altcode:
The 1.5m solar telescope GREGOR is being constructed at Tenerife,
Spain. Its purpose is to observe with high spatial and spectral
resolution small-scale dynamic magnetic features on the Sun. The
telescope is completely open with retractable dome and actively cooled
primary mirror made of silicon carbide to minimize thermal effects
on the image quality. After completion it will be one of the most
powerful solar telescopes. This paper presents a general overview of
the telescope characteristics and the current status.

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Title: First Doppler images of the very young K2-dwarf PW Andromedae =
HD 1405
Authors: Strassmeier, K. G.; Rice, J. B.
2006A&A...460..751S Altcode:
Aims.We present the first Doppler images of the single pre-main-sequence
star PW And. Its position in the HR-diagram suggests it to be in the
rapid-braking phase just prior to arrival on the ZAMS. Methods:
.Images are obtained from seven individual spectral lines as well
as from 5-nm wide chunks of spectrum that invert a total of 58 line
profiles simultaneously. Results: .Cool spots with temperature
differences with respect to the stellar photosphere of up to 1200 K
are detected. Spot occurrence is mostly within an equatorial band up
to ±40° of the stellar equator and thus contradicts magnetic-flux
tube emergence models based on young K-star properties that predict
an emerging latitude in two distinct bands of +45-55°. This confirms
previous suggestions that current magnetic-flux tube models predict
emergence latitudes too low for G-dwarfs and too high for K-dwarfs,
which may be caused by the fact that the G-dwarf models heavily rely on
comparisons with the Sun. We also redetermine the absolute parameters
of PW And in the light of a missing Hipparcos parallax and revise
its age to be more near 20 Myr, in agreement with its logarithmic
lithium abundance of 2.87±0.05. A precise rotational period of
1.76159d±0.00006 was found from our photometric data in 2004.

---------------------------------------------------------
Title: STELLA Robotic Observatory for Stellar Activity Research
Authors: Bartus, J.; Kõvári, Zs.; Oláh, K.; Granzer, T.;
Strassmeier, K. G.; Weber, M.
2006PADEU..17..101B Altcode:
The STELLA Robotic Observatory (abbreviation for STELLar Activity)
is a long-term project for observing and monitoring activity tracers
on cool stars with two robotic telescopes: STELLA-I equipped with a
high resolution echelle spectrograph, a large-format CCD imager and
photometer, and STELLA-II also equipped with an optical CCD imager and
photometer. After listing the most important technical details we focus
on some of the scientific programs planned for routine observations
of active stars by STELLA.

---------------------------------------------------------
Title: Spot Modelling of ζ Andromedae
Authors: Kővári, Zsolt; Oláh, Katalin; Bartus, János; Strassmeier,
Klaus G.; Granzer, Thomas
2006Ap&SS.304...55K Altcode: 2006Ap&SS.tmp...90K
The photometric light modulation of ζ Andromedae originates from
the distorted geometry of the primary, and additionally, from spots
of which parameters (temperature, size, location) are variable in
time. We present spot modelling results for six two-colour light
curves which show that spots preferably appear on the stellar surface
towards the companion star and opposite to it, where the distortion
also causes dimming. Therefore, simple fitting of the measured data
for the ellipticity effect does not yield correct result. Instead,
ellipticity calculated from exact stellar parameters should be removed
from the data to get reliable spotted light curves.

---------------------------------------------------------
Title: STELLA: Two New Robotic Telescopes for Binary-Star Research
Authors: Strassmeier, Klaus G.
2006Ap&SS.304..397S Altcode: 2006Ap&SS.tmp...34S
Several new robotic telescopes had or will see first light in 2005/2006
and are designed for either wide-field imaging, high-precision
photometry or even for high-resolution echelle spectroscopy. These
telescopes are in the 1 2 m class and therefore will focus on very
specific tasks. Here, I present an update of the robotic STELLA
facility currently under construction in Tenerife and emphasize its
science capabilities for binary-star research. Among the many science
applications of STELLA is the monitoring of magnetic activity in
single and binary stars and their relation to age, rotation rate,
metallicity and binarity per se.

---------------------------------------------------------
Title: The International Concordia Explorer Telescope: a joint
telescope for atmospheric and astrophysical applications at Dome C
Authors: Strassmeier, K. G.; Herber, A.; Vitale, V.; Cutispoto, G.;
Ribasi, I.; Korhonen, H.; Andersen, M.; Granzer, T.
2006IAUSS...7E..18S Altcode:
ICE-T is a fully robotic telescope for astrophysics and atmospheric
research in Antarctica and is based on the “Star Photometer”
project within TAVERN, the quantification of tropospheric aerosol
and thin clouds variability over the east Antarctic plateau including
the radiation budget. This poster introduces the joint science case,
the conceptual design, and the anticipated data handling plan. ICE-T
consists of two 60cm optical ultra-wide-field Schmidt telescopes and
one 18cm narrow-field Maksutov spectrophotometric telescope on a single
mount for the Antarctic station Concordia at Dome C.

---------------------------------------------------------
Title: A Fast Stokes Profile Synthesis for Zeeman-Doppler-Imaging
Authors: Kopf, M.; Carroll, T. A.; Strassmeier, K. G.
2006IAUJD...8E..23K Altcode:
We present a novel method for a fast LTE spectrum synthesis in
magnetic stellar atmospheres suitable for Doppler-Imaging and
Zeeman-Doppler-Imaging of active stars. The enormous computational
demands for Doppler-Imaging and in particular Zeeman-Doppler-Imaging
techniques require extensive calculations of local Stokes profiles over
the entire stellar disk. Tabling techniques as used for conventional
Doppler-Imaging to reduce the computational burden are not a feasible
alternative for Zeeman-Doppler-Imaging of active stars with complex
temperature and magnetic surface distributions. Also methods like
the weak-field approximation which allows a fast estimate of Stokes V
profiles do not provide the required accuracy in general. Artificial
neural networks (ANN's) provide a new tool to approximate the full
polarized radiative transfer under varying atmospheric conditions. Our
method is based on a decomposition of Stokes line profiles, into their
respective eigenspectra via a principal component analysis (PCA). A
set of ANN's is then trained to calculate the reduced eigenspectrum
of local Stokes line profiles as a function of the line of sight,
effective temperature and the magnetic field configuration. The
accuracy of the PCA-ANN synthesis is evaluated by comparison with a
conventional numerical solution of the RTE which is based on a quadratic
DELO method. Moreover, we present a number of test inversions with
our Doppler-Imaging and Zeeman-Doppler-Imaging code to demonstrate
the potential of this new method. The precision and the impressive
speed of the PCA-ANN spectrum synthesis offers a viable and promising
alternative for an on-the-fly calculation of local and disk integrated
Stokes spectra.

---------------------------------------------------------
Title: Late-Type Active Stars: Rotation &amp; Companions
Authors: Dall, T. H.; Strassmeier, K. G.; Bruntt, H.
2006Ap&SS.304..195D Altcode: 2006Ap&SS.tmp...17D
Rapid rotation has been established empirically as the controlling
factor for the magnetic field strength and the magnetic activity
level of single late-type (F-M) stars. The dynamo theories explain
this fact as due to interaction between differential rotation and
helical motion in the transition layer between the convective envelope
and the radiative interior. The presence of a close companion even
down to the size of a “hot Jupiter” could alter the physical
processes responsible for the activity, by introducing longitude- and
latitude-dependencies and inhomogenious chemical abundances effects
that cannot be ignored in the attempt to understand magnetic activity
on late type stars. Here we present first results for the well-known,
single, active star, HD 27536. Binarity is established by very precise
radial velocity (RV) measurements using HARPS spectra. The spectral
line bisectors are examined for correlations between RV and bisector
shape to distinguish between the effects of stellar activity and
unseen companions.

---------------------------------------------------------
Title: Doppler Images of ζ Andromedae
Authors: Kővári, Zsolt; Oláh, Katalin; Bartus, János; Strassmeier,
Klaus G.; Weber, Michael; Washuettl, Albert; Rice, John B.; Csizmadia,
Szilárd
2006Ap&SS.304..375K Altcode: 2006Ap&SS.tmp..110K
Doppler images are presented for the RS CVn-type binary ζ And. Our
upgraded Doppler imaging code TempMapɛ takes into account
the distorted geometry of the primary giant component. On the maps
several low latitude spots are restored with a temperature contrast of
about 1000 K. Some weak polar features are also found. Cross-correlation
of the consecutive Doppler-maps suggests solar-like differential
surface rotation.

---------------------------------------------------------
Title: Challenges in optics for Extremely Large Telescope
instrumentation
Authors: Spanò, P.; Zerbi, F. M.; Norrie, C. J.; Cunningham, C. R.;
Strassmeier, K. G.; Bianco, A.; Blanche, P. A.; Bougoin, M.; Ghigo,
M.; Hartmann, P.; Zago, L.; Atad-Ettedgui, E.; Delabre, B.; Dekker,
H.; Melozzi, M.; Snÿders, B.; Takke, R.
2006AN....327..649S Altcode: 2006astro.ph..3763S
We describe and summarize the optical challenges for future
instrumentation for Extremely Large Telescopes (ELTs). Knowing the
complex instrumental requirements is crucial for the successful design
of 30-60 m aperture telescopes. After all, the success of ELTs will
heavily rely on its instrumentation and this, in turn, will depend on
the ability to produce large and ultra-precise optical components like
light-weight mirrors, aspheric lenses, segmented filters, and large
gratings. New materials and manufacturing processes are currently
under study, both at research institutes and in industry. In the
present paper, we report on its progress with particular emphasize on
volume-phase-holographic gratings, photochromic materials, sintered
silicon-carbide mirrors, ion-beam figuring, ultra-precision surfaces,
and free-form optics. All are promising technologies opening new degrees
of freedom to optical designers. New optronic-mechanical systems will
enable efficient use of the very large focal planes. We also provide
exploratory descriptions of “old” and “new” optical technologies
together with suggestions to instrument designers to overcome some of
the challenges placed by ELT instrumentation.

---------------------------------------------------------
Title: Polar night operation at Dome C with "Star Photometer"
and ICE-T
Authors: Herber, A.; Gröschke, A.; Vitale, V.; Strassmeier, K.
2006IAUSS...7E..34H Altcode:
Atmospheric aerosol optical depth (AOD) data from the Antarctic
plateau are very sparse. Some AOD measurements were performed during
austral summer but none during winter, although some night aerosol
information has been gathered from Lidar measurements in the coastal
areas. Satellite measurements are very difficult as a consequence of
the low AOD values, the high surface reflectivity, and the long and
cold polar night. The application of an astronomical "Star Photometer",
by using stellar light as a pencil probe through the atmosphere, can
close this gap. Year-round measurements based on Lidar, Sun and Star
Photometers, and in-situ measurements will allow a detailed study of
the inter-annual and seasonal variations of AOD over the high interior
plateau, especially the effects and variability during polar night. The
combined atmospheric and astronomical German activities at Dome C are
part of the international project TAVERN (quantification of tropospheric
aerosol and thin clouds variability including the radiation budget over
the east Antarctic plateau) under responsibility of CNR-ISAC Bologna;
and also recognized by the EU network ARENA (Antarctic Research: A
European Network in Astronomy). With the "Star Photometer" we intend to
observe bright stars for the atmospheric AOD program in 2009 but later
on, roughly in 2012, to extend the nightly observations with the help
of a more ambitious astronomical experiment called ICE-T (International
Concordia Explorer Telescope). Both systems will be installed in a
specially designed 4m Radom and should enable a combined analysis to
study horizontal features of nightly aerosols. This activity is planned
in extension of ICE-T's own astronomical program, i.e. planet transit
search, stellar surface activity, and various miscellaneous topics.

---------------------------------------------------------
Title: Doppler Imaging of Rapidly-Rotating M Stars
Authors: Strassmeier, Klaus G.
2006Ap&SS.304..333S Altcode: 2006Ap&SS.tmp...35S
With the advent of 8 12m-class telescopes and powerful new
spectrographs, we can now extend the Doppler-imaging technique to
the cool (and faint) end of the main sequence. At a spectral type
of approximately M2, stars are thought to become fully convective
and cannot possess an overshoot layer between a radiative core and
a convective envelope which, as in the case of the Sun and similar
stars, likely harbors the dynamo. Therefore, one could expect a
fundamentally different magnetic-field topology than on the Sun and
thus a qualitatively different surface temperature distribution with
new, hitherto unknown, magnetic activity phenomena. Unfortunately,
most single M stars do not rotate sufficiently fast for Doppler
imaging and one has to “use” binaries or pre-main-sequence stars
in which M stars appear spun up or, in binaries, synchronized to the
orbital motion.

---------------------------------------------------------
Title: Current and future observations of solar and stellar activity
from the ground and space
Authors: Strassmeier, K. G.
2006IAUJD...8E..37S Altcode:
My main goal is to summarize the current and future instrumentation
that is or will be used for solar and stellar activity work, with
special emphasize on long-term status in relation to cycle studies. Many
space and ground-based systems are or were not intentionally invented
and designed for use on stellar activity issues, e.g. the exoplanet
finding missions, but nevertheless bear a great potential for stellar
cycle research. I also emphasize the potential of almost space-quality
sites on Earth (Dome C, Dome A) or the commercialized approach with
micro and even nano satellites.

---------------------------------------------------------
Title: The RS CVn binary HK Lacertae: long-term photometry from
Sonneberg sky-patrol plates
Authors: Fröhlich, H. -E.; Kroll, P.; Strassmeier, K. G.
2006A&A...454..295F Altcode:
Long-term photographic photometry of the active long-period RS
CVn binary HK Lac (HD 209813) was obtained from more than 2000
Sonneberg Sky-Patrol plates taken between 1956 and 1996. We achieve an
internal accuracy of 0.07 m. The correspondence with contemporaneous
high-precision photoelectric photometry from automatic telescopes
is striking and successfully demonstrates the feasibility of our
approach. Based on a Bayesian time series analysis, we improve the
previously published cycle period to 13.37± 0.08 years, and present
evidence of an additional period of 9.48± 0.13 years. This establishes
the multi-periodicity of dynamo action in these overactive stars
as compared to the Sun. The already known 6.7-years cycle turns out
to be an overtone of the dominating 13.4-years cycle. Our long-term
photographic photometry even allowed the detection of the star's mean
rotational period of 24.35 days.

---------------------------------------------------------
Title: The new 1.5m solar telescope GREGOR: first light and start
of commissioning
Authors: Volkmer, Reiner; von der Lühe, Oskar; Kneer, Franz; Staude,
Jürgen; Berkefeld, Thomas; Caligari, Peter; Halbgewachs, Clemens;
Heidecke, Frank; Schmidt, Wolfgang; Soltau, Dirk; Nicklas, Harald;
Wittmann, Axel; Balthasar, Horst; Hofmann, Axel; Strassmeier, Klaus;
Sobotka, Michal; Klvana, Miroslav; Collados, Manuel
2006SPIE.6267E..0WV Altcode: 2006SPIE.6267E..29V
The integration of the three main silicon carbide mirrors into the new
1.5 m solar telescope GREGOR at Izana on Tenerife, Spain is planned
during 2006. We expect first light at the end of 2006. A progress
report about integration of the optics and mechanics and planning of
the commissioning phase of the telescope and post focus instruments
will be presented at the meeting. The GREGOR telescope is build by a
consortium of the Kiepenheuer Institut fur Sonnenphysik in Freiburg,
the Astrophysikalische Institut Potsdam, the Institut fur Astronomie
Gottingen and additional national and international Partners.

---------------------------------------------------------
Title: Study of FK Comae Berenices. VI. Spot motions, phase jumps
and a flip-flop from time-series modelling
Authors: Oláh, K.; Korhonen, H.; Kővári, Zs.; Forgács-Dajka, E.;
Strassmeier, K. G.
2006A&A...452..303O Altcode:
Aims.Time-series spot modelling was used to follow the longitude
changes of active regions responsible for the light variability of
FK Com between 1987-2004. Methods: .The photometric data are
analysed in the time-series mode of a spot modelling code. A scenario
of one polar and two low-latitude active regions (hereafter spots,
for simplicity) depicts the light variations very well. The role of
the polar spot remains unclear because photometry in general does
not provide direct latitudinal surface resolution, however, Doppler
imaging results of FK Com also show very high latitude or even polar
spots besides the low-latitude ones. We also used a light-curve
inversion method to confirm some of the results. Results:
.The two low-latitude spots slowly migrate around 90° and 270°
longitudes with quasiperiods of 5.8 and 5.2 years. The spots prefer
to stay alternately on one or the other, but on the same hemisphere
of the star, with a separation of typically 90-140°. We monitored a
flip-flop in the light curve of FK Comae in 1999. The two low-latitude
spots, being ≈140-180° from each other during the season, gradually
decreased until they both practically vanished. Shortly thereafter,
two new spots appeared and started to grow. One of the new spots
was near the location of the old one, whereas the other turned up
90° shifted in longitude; consequently, the activity as a whole was
shifted to the other hemisphere of the star. We followed a phase jump
in 1997, when the two low-latitude spots got closer in longitude and
finally merged, or else one of them vanished. A new spot appeared soon,
shifted by 100° in longitude, but the activity remained on the same
hemisphere. Conclusions: .The difference between flip-flops and
phase jumps is demonstrated. The derived longitude changes of activity
centres may allow us to better constrain the theoretical modelling on
the time-behaviour of stellar magnetic activity.

---------------------------------------------------------
Title: The International Robotic Antarctic Infrared Telescope (IRAIT)
Authors: Tosti, Gino; Busso, Maurizio; Nucciarelli, Giuliano; Bagaglia,
Marco; Roncella, Fabio; Mancini, Alberto; Castellini, Sonia; Mariotti,
Mirco; Babucci, Ezio; Chiocci, Gianfranco; Straniero, Oscar; Dolci,
Mauro; Valentini, Gaetano; di Varano, Igor; Pelusi, Danilo; Di Rico,
Gianluca; Ragni, Maurizio; Abia, Carlos; Domínguez, Inma.; Corcione,
Leonardo; Porcu, Francesco; Conconi, Paolo; De Caprio, Vincenzo;
Riva, Alverto; Molinari, Emilio; Zerbi, Filippo M.; Bortoletto, Favio;
Bonoli, Carlotta; D'Alessandro, Maurizio; Colomé, Josep; Isern, Jordi;
Briguglio, Runa; Cacciani, Alessandro; Farnesini, Lucio; Checcucci,
Bruno; Strassmeier, Klaus G.
2006SPIE.6267E..1HT Altcode: 2006SPIE.6267E..47T
Thanks to exceptional coldness, low sky brightness and low content of
water vapour of the above atmosphere Dome C, one of the three highest
peaks of the large Antarctic plateau, is likely to be the best site
on Earth for thermal infrared observations (2.3-300 μm) as well as
for the far infrared range (30 μm-1mm). IRAIT (International Robotic
Antarctic Infrared Telescope) will be the first European Infrared
telescope operating at Dome C. It will be delivered to Antarctica at
the end of 2006, will reach Dome C at the end of 2007 and the first
winter-over operation will start in spring 2008. IRAIT will offer a
unique opportunity for astronomers to test and verify the astronomical
quality of the site and it will be a useful test-instrument for a new
generation of Antarctic telescopes and focal plane instrumentations. We
give here a general overview of the project and of the logistics and
transportation options adopted to facilitate the installation of IRAIT
at Dome C. We summarize the results of the electrical, electronics
and networking tests and of the sky polarization measurements carried
out at Dome C during the 2005-2006 summer-campaign. We also present
the 25 cm optical telescope (small-IRAIT project) that will installed
at Dome C during the Antarctic summer 2006-2007 and that will start
observations during the 2007 Antarctic winter when a member of the IRAIT
collaboration will join the Italian-French Dome C winter-over team.

---------------------------------------------------------
Title: Binarity, activity and metallicity among late-type
stars. I. Methodology and application to HD 27536 and HD 216803
Authors: dall, T. H.; Bruntt, H.; Strassmeier, K. G.
2005A&A...444..573D Altcode: 2005astro.ph..8577D
We present the first in a series of papers that attempt to investigate
the relation between binarity, magnetic activity, and chemical surface
abundances of cool stars. In the current paper, we lay out and test two
abundance analysis methods and apply them to two well-known, active,
single stars, <ASTROBJ>HD 27536</ASTROBJ> (G8IV-III) and <ASTROBJ>HD
216803</ASTROBJ> (K5V), presenting photospheric fundamental parameters
and abundances of Li, Al, Ca, Si, Sc, Ti, V, Cr, Fe, Co and Ni. The
abundances from the two methods agree within the errors for all elements
except calcium in HD 216803, which means that either method yields the
same fundamental model parameters and the same abundances. Activity
is described by the radiative loss in the Ca ii H and K lines with
respect to the bolometric luminosity, through the activity index
R_HK. Binarity is established by very precise radial velocity (RV)
measurements using HARPS spectra. The spectral line bisectors are
examined for correlations between RV and bisector shape to distinguish
between the effects of stellar activity and unseen companions. We show
that HD 27536 exhibit RV variations mimicking the effect of a low-mass
(m ∼ 4 M_J) companion in a relatively close (a ∼ 1 AU) orbit. The
variation is strongly correlated with the activity, and consistent with
the known photometric period P = 306.9 d, demonstrating a remarkable
coherence between R_HK and the bisector shape, i.e. between the
photosphere and the chromosphere. We discuss the complications involved
in distinguishing between companion and activity induced RV variations.

---------------------------------------------------------
Title: Surface imaging with atomic and molecular features. I. A new
inversion technique and first numerical tests
Authors: Savanov, I. S.; Strassmeier, K. G.
2005A&A...444..931S Altcode:
We present a new Doppler-imaging inversion code that uses quasi-optimal
filtering of the object's principal components of a Fisher information
matrix. The new code allows one to perform the reconstruction of
stellar surface temperature maps using molecular features like TiO,
CO, OH, CN etc. which are numerous in spectra of late-type dwarfs. It
is possible to use atomic and molecular features simultaneously in the
restoration. Our tests verify the robustness of OPC but also emphasize
its dependency on the various atomic and molecular line lists. Without
inclusion of molecules, Doppler imaging of stars with photospheric
temperatures below ≈4250 K (K7-M0) remains unreliable.

---------------------------------------------------------
Title: The life of stars and their planets
Authors: Catala, C.; Aerts, C.; Aigrain, S.; Antonello, E.;
Appourchaux, T.; Auvergne, M.; Baglin, A.; Barge, P.; Barstow, M. A.;
Baudin, F.; Boumier, P.; Collier Cameron, A.; Christensen-Dalsgaard,
J.; Cutispoto, G.; Deeg, H.; Deleuil, M.; Desidera, S.; Donati, J. -F.;
Favata, F.; Foing, B. H.; Gameiro, J. F.; Garcia, R.; Garrido, F.;
Horne, K.; Lanza, A. F.; Lanzafame, A. C.; Lecavelier Des Etangs,
A.; Léger, A.; Mas-Hesse, M.; Messina, S.; Micela, G.; Michel, E.;
Monteiro, M. J. P. F. G.; Mosser, B.; Noels, A.; Pagano, I.; Piotto,
G.; Poretti, E.; Rauer, H.; Roca-Cortes, T.; Rodono, M.; Rouan, D.;
Roxburgh, I.; Schneider, J.; Strassmeier, K.; Turck-Chièze, S.;
Vauclair, S.; Vidal-Madjar, A.; Weiss, W. W.; Wheatley, P.
2005ESASP.588...99C Altcode: 2005tssc.conf...99C
We lack a reliable scenario for the formation and evolution of stars
and their planetary systems, involving key factors such as magnetic
fields and turbulence. We present the case for a mission concept that
will clarify these problems and give us a global view of the evolution
of combined star and planetary systems. This will be achieved by
simultaneously addressing the search for planetary transits in front
of a large number of stars, including many nearby stars, the study of
their internal structure and evolution via asteroseismology, and that
of their magnetic activity, via UV monitoring.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Long-term photographic photometry
of HK Lac (Froehlich+, 2006)
Authors: Froehlich, H. -E.; Kroll, P.; Strassmeier, K. G.
2005yCat..34540295F Altcode:
A photographic light-curve, from 1956 to 1996, of the RS CVn binary
HK Lacertae is presented. For each of the 2037 data points the Julian
Date (geocentric) and the BT magnitude (Tycho-2 photometric system)
is given. Brightnesses are with respect to the BT brightness of HD
210731 (BT=8.090mag). (1 data file).

---------------------------------------------------------
Title: Spatially resolving the accretion shocks on the
rapidly-rotating M0 T-Tauri star MN Lupi
Authors: Strassmeier, K. G.; Rice, J. B.; Ritter, A.; Küker, M.;
Hussain, G. A. J.; Hubrig, S.; Shobbrook, R.
2005A&A...440.1105S Altcode:
We obtained high-resolution, high-quality VLT/UVES spectra
to reconstruct the two-dimensional surface structure of the
rapidly-rotating classical T-Tauri star MN Lupi on two separate
nights. Both surface maps show a structured warm (5000 K) band centered
around the pole at a latitude of ≈65°. Located within the band are
two hot spots with temperatures of approximately or possibly even
in excess of 5800 K, i.e. 2000 K above the effective photospheric
temperature. Both maps appear with an adjacent equatorial band of
temperature 3400 K, some 400-500 K below the effective photospheric
temperature. While we interpret the two hot spots and the warm
high-latitude band to be the heating points from two accretion impacts
at the time of our observations and their redistributed energy trailed
due to the fast stellar rotation, respectively, the cool equatorial
band may not be cool after all but due to obscuration of the stellar
surface by the innermost region of the disk. The fact that the hot spots
appear at high stellar latitude is in agreement with the magnetospheric
accretion model that proposes material funnelling onto the star along
a predominantly dipolar magnetic field at roughly 50° latitude. The
evidence of ongoing disk accretion, together with the very fast rotation
of MN Lupi of just 3-4 times below its break-up velocity, suggests that
the accretion mechanism is the cause of its rapid surface rotation. We
present a model of magnetic star-disk coupling for MN Lupi that predicts
a polar surface magnetic field of ≈3 kG.

---------------------------------------------------------
Title: Spots on EK Draconis. Active longitudes and cycles from
long-term photometry
Authors: Järvinen, S. P.; Berdyugina, S. V.; Strassmeier, K. G.
2005A&A...440..735J Altcode:
We analyse photometric observations of the young active star EK Dra,
altogether about 21 years. Similar to the ZAMS stars LQ Hya and AB
Dor, EK Dra shows long-lived, non-axisymmetric spot distribution with
active longitudes on opposite hemispheres. At least two activity
cycle can be found from the data. The first cycle originates from
repeated switches of the activity between two active longitudes in
about (2-2.25)-year intervals, resulting in a cycle of about (4-4.5)
years. The second cycle is of the order of 10.5 years and comes from
migration of the active longitudes. Our data cover two consecutive
cycles. The periodicity is also present in the maximum, the mean and
the minimum stellar brightness. Additionally, there is a long-term
trend. If we combine our data with the Sonneberg plate measurements, we
can conclude that the overall brightness of EK Dra has been continuously
decreasing at least for the last 45 years. A comparison with current
sunspot activity reveals many similarities between the Sun and EK Dra.

---------------------------------------------------------
Title: Erratum: “A High-Resolution Spectrum of the TrES-1 Parent
Star”
Authors: Strassmeier, Klaus G.; Rice, John B.
2005IBVS.5648....1S Altcode:
We present a high-resolution (R=120,000) spectrum of the lithium region
of the parent star of the newly-discovered transiting planet TrES-1
(GSC02652-01324, K0V, V=11.8mag). No lithium seems to be present at
the surface of TrES-1.

---------------------------------------------------------
Title: The new 1.5 solar telescope GREGOR: progress report and
results of performance tests
Authors: Volkmer, Reiner; von der Lühe, Oskar; Kneer, Franz; Staude,
Jürgen; Berkefeld, Thomas; Caligari, Peter; Halbgewachs, Clemens;
Schmidt, Wolfgang; Soltau, Dirk; Nicklas, Harald; Wittmann, Axel;
Balthasar, Horst; Hofmann, Axel; Strassmeier, Klaus; Sobotka, Michal;
Klvana, Miroslav; Collados, Manuel
2005SPIE.5901...75V Altcode:
The telescope structure including control system and the complete
retractable dome of the new 1.5 m solar telescope GREGOR were
assembled during 2004 at Izana on Tenerife, Spain. The GREGOR
telescope is build by a consortium of the Kiepenheuer Institut fuer
Sonnenphysik, the Astrophysikalische Institut Potsdam, the Institut
fuer Astrophysik Goettingen and additional national and international
Partners. Pointing, tracking and thermal tests were made to verify
the proposed performance. The results of these tests and a progress
report of the project will be presented.

---------------------------------------------------------
Title: VizieR Online Data Catalog: V light curves of EK Dra
(Jaervinen+, 2005)
Authors: Jaervinen, S. P.; Berdyugina, S. V.; Strassmeier, K. G.
2005yCat..34400735J Altcode:
We analyse photometric observations of the young active dwarf EK Dra,
spanning altogether 21 years, and including previously unpublished
data. The data in Table 2 was observed at the Fairbourn Observatory
in southern Arizona using Amadeus, a 0.75m automatic photoelectric
telescope (APT) of the University of Vienna. Amadeus is optimised
for red wavelengths with an EMI-9828 tube and Johnson-Cousins
V(RI)C filters. Differential V magnitudes are variable
(EK Dra) - comparison (HD 129390) and check (HD 129798) - comparison
(HD 129390). HD 129390 Vmag=7.567 (1 data file).

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Title: Indications for anti-solar differential rotation of giant stars
Authors: Weber, M.; Strassmeier, K. G.; Washuettl, A.
2005AN....326..287W Altcode:
Observational evidence of anti-solar differential rotation of K-type
giant stars is presented. Time-series Doppler imaging based on 70
nights of spectroscopic data was used to derive the spot evolution of
the stellar surfaces. The relative differential rotation parameters
(α) of the binary stars IM Peg, HD 208472, and HK Lac were obtained
using two techniques, cross-correlation analysis and the sheared-image
method. Additionally, two previously published single giant stars are
revisited and qualitatively compared to recent theoretical models.

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Title: Stellar activity cycles: observing the dynamo?
Authors: Strassmeier, K. G.
2005AN....326..269S Altcode:
The enormous complexity of the atmospheric structure observed on the
Sun makes it very difficult to compare the Sun with “solar-type
stars”. Clearly, we need to identify parameters that can be
observed on the Sun as well as on other stars which can be interpreted
unambiguously. The most widely accepted dynamo signature is the presence
of an activity cycle, well documented for the Sun and for main-sequence
stars due to the Mount Wilson Ca II H&amp;K project. Only recently have
we detected spatial information, differential rotation and possibly
meridional flows on other stars and thereby adding another constraint
for its interpretation within a dynamo theory. Again, the picture is not
complete yet, despite that there is just a single main ingredient that
acts as the driving mechanism for activity in all atmospheric layers
and the convective envelope of a solar-type star: the dynamo-related
magnetic field. I stress the importance of mapping stellar surfaces as
fingerprints of the underlying dynamo action over long periods of time.

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Title: Differential rotation of LQ Hya and IL Hya from a time-series
of Doppler images
Authors: Kővári, Zs.; Weber, M.; Strassmeier, K. G.
2005ESASP.560..731K Altcode: 2005csss...13..731K
No abstract at ADS

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Title: Evolution of stellar active regions: differential rotation
of five K giants
Authors: Weber, M.; Strassmeier, K. G.
2005ESASP.560.1029W Altcode: 2005csss...13.1029W
No abstract at ADS

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Title: Science with the STELLA robotic observatory
Authors: Weber, M.; Strassmeier, K. G.; Bartus, J.; Korhonen, H.;
Kővári, Zs.; Oláh, K.; Schwope, A.; Staude, A.; Steffen, M.
2005ESASP.560.1025W Altcode: 2005csss...13.1025W
No abstract at ADS

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Title: First Doppler images of ζ Andromedae
Authors: Kővári, Zs.; Bartus, J.; Strassmeier, K. G.; Oláh, K.;
Rice, J. B.; Washuettl, A.; Csizmadia, Sz.
2005ESASP.560..727K Altcode: 2005csss...13..727K
No abstract at ADS

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Title: PEPSI, the High-Resolution Optical-IR Spectrograph for the LBT
Authors: Andersen, Michael; Strassmeier, Klaus; Hoffman, Axel; Woche,
Manfred; Spano, Paolo
2005hris.conf...57A Altcode:
PEPSI is a high resolution fibre feed optical-IR polarimetric echelle
spectrograph for the Large Binocular Telescope (LBT). PEPSI utilizes the
two 8.4m LBT apertures to simultaneously record four polarization states
at a resolution of 120.000. The extension of the coverage towards the IR
is mainly motivated by the larger Zeeman splitting of IR lines, which
would allow to study weaker/fainter magnetic structures on stars. The
two optical arms, which also have an integral light mode with R up to
300.000, are under construction, while the IR arm is being designed.

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Title: Doppler imaging of active binary stars
Authors: Strassmeier, K. G.
2004ASPC..318...69S Altcode: 2004ssrc.conf...69S
Binaries can be used as astrophysical laboratories to study a much
larger range of parameters than nature would normally foresee for a
single star. A good example is the evolution of the stellar magnetic
field and its tracers. Solar analogy tells us that the surface starspot
distribution, and its variation in time, is a fingerprint of the
underlying dynamo process and its subsequent magnetic-field eruption as
bipolar spots or spot groups. But is this also true for more massive
and less massive stars, even for fully convective stars? I show how
astronomers nowadays resolve a stellar surface by means of a tomographic
imaging technique and recover the surface temperature distribution
as a tracer of the magnetic field and, of course, also emphasize
its limitations. The technique requires relatively high-resolution
high-S/N spectra well sampled over a rotation period of the star and is,
so far, mainly technology driven. Therefore, I will present also an
update of future instrumentation for stellar-activity work. Finally,
I focus the scientific discussion on three recent studies of active
double-lined spectroscopic binaries as three representative proxies
of stellar activity throughout the HR-diagram.

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Title: Robotic Astronomy. Proceedings of the 3rd Potsdam Thinkshop
on Robotic Astronomy
Authors: Strassmeier, K. G.; Hessman, F. V.
2004AN....325..455S Altcode:
From July 12-15, 2004, the third Potsdam Thinkshop was held in the
Hotel Dorint “Sanssouci” in Potsdam, Germany on the topic of ROBOTIC
ASTRONOMY. Its aim was to bring together astronomers and technicians
from any field in astronomy to review the current status of robotic
telescope projects and to discuss the future science cases for such
installations. Part of the “Thinkshop” concept of this meeting was
to jointly think about new scientific projects tailored to the unique
capabilities of modern robotic telescopes, small and large.

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Title: The STELLA robotic observatory
Authors: Strassmeier, K. G.; Granzer, T.; Weber, M.; Woche, M.;
Andersen, M. I.; Bartus, J.; Bauer, S. -M.; Dionies, F.; Popow, E.;
Fechner, T.; Hildebrandt, G.; Washuettl, A.; Ritter, A.; Schwope, A.;
Staude, A.; Paschke, J.; Stolz, P. A.; Serre-Ricart, M.; de la Rosa,
T.; Arnay, R.
2004AN....325..527S Altcode:
STELLA is a robotic observatory with two fully automatic telescopes
(STELLA-I and STELLA-II) located at the Teide Observatory in Tenerife,
Spain. Not only the telescopes are automatic but also the entire
observatory, no human presence is needed for observing - not even
in remote control. STELLA-I supports a high-resolution, fiber-fed
and bench-mounted echelle spectrograph and a wide-field CCD imaging
photometer while STELLA-II feeds a similar but wide-band imaging
photometer and a testbed for prototype adaptive optics for robotic
telescopes. The first telescope is scheduled for first light in November
2004, the second telescope for March 2005.

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Title: Progress report of the 1.5 m solar telescope GREGOR
Authors: Volkmer, Reiner; von der Lühe, Oskar F.; Kneer, Franz;
Staude, Jürgen; Berkefeld, Thomas; Caligari, Peter; Schmidt,
Wolfgang; Soltau, Dirk; Nicklas, Harald; Wiehr, Eberhardt; Wittmann,
Axel; Balthasar, Horst; Hofmann, Axel; Strassmeier, Klaus; Sobotka,
Michal; Klvana, Miroslav; Collados, Manuel
2004SPIE.5489..693V Altcode:
GREGOR is the new 1.5 m solar telescope assembled on Tenerife, Spain, by
the German consortium of the Kiepenheuer Institut fur Sonnenphysik, the
Astronomischen Institut Potsdam, the Universitats-Sternwarte Gottingen
and other national and international Partners. The refurbishment of
the building is almost finished. The manufacturing of the telescope
structure and the optics is still in progress. After the integration of
the new complete retractable dome in July 2004 the telescope structure,
optic and post focus instruments will be assembled during the rest of
the year. First light is planned during May 2005.

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Title: A robotic reflective Schmidt telescope for Dome C
Authors: Strassmeier, K. G.; Andersen, M. I.; Steinbach, M.
2004AN....325..626S Altcode:
This paper lays out a wide-field robotic Schmidt telescope (RST) for the
Antarctic site Dome C. The telescope is based on 80/120cm reflective
Schmidt optics, built originally for a space project, and a mosaic of
four 7.5k×7.5k 8-μm thinned CCDs from the PEPSI/LBT wafer run. The
telescope's total field of view (FOV) would be 5o circular
(minimum 3o× 3o square) with a plate scale of
0.7 arcsec per pixel. Limiting magnitude is expected to be V=21.5mag
in 60 sec for a field of 9 square degrees.

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Title: A High-Resolution Spectrum of the TrES-1 Parent Star
Authors: Strassmeier, Klaus G.; Rice, John B.
2004IBVS.5566....1S Altcode:
We present a high-resolution (R=120,000) spectrum of the lithium region
of the parent star of the newly-discovered transiting planet TrES-1
(GSC02652-01324, K0V, V=11.8mag). No lithium seems to be present at
the surface of TrES-1.

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Title: Can we use adaptive optics for UHR spectroscopy with PEPSI
at the LBT?
Authors: Sacco, Germano G.; Pallavicini, Roberto; Spano, Paolo;
Andersen, Michael; Woche, Manfred F.; Strassmeier, Klaus G.
2004SPIE.5490..398S Altcode:
We investigate the potential of using adaptive optics (AO) in the V,
R, and I bands to reach ultra-high resolution (UHR, R &gt;= 200,000)
in echelle spectrographs at 8-10m telescopes. In particular, we
investigate the possibility of implementing an UHR mode for the
fiber-fed spectrograph PEPSI (Potsdam Echelle Polarimetric and
Spectrographic Instrument) being developed for the Large Binocular
Telescope (LBT). By simulating the performances of the advanced AO
system that will be available at first light at the LBT, and by using
first-order estimates of the spectrograph performances, we calculate
the total efficiency and signal to noise ratio (SNR) of PEPSI in the
AO mode for stars of different magnitudes, different fiber core sizes,
and different fractions of incident light diverted to the wavefront
sensor. We conclude that AO can provide a significant advantage, of
up to a factor ~2 in the V, R and I bands, for stars brighter than
mR ~ 12 - 13. However, if these stars are observed at UHR
in non-AO mode, slit losses caused by the need to use a very narrow
slit can be compensated more effectively by the use of image slicers.

---------------------------------------------------------
Title: Optical design of the PEPSI high-resolution spectrograph at LBT
Authors: Andersen, Michael I.; Spano, Paolo; Woche, Manfred;
Strassmeier, Klaus G.; Beckert, Erik
2004SPIE.5492..381A Altcode:
PEPSI is a high-resolution, fiber fed echelle spectrograph with
polarimetric capabilities for the LBT. In order to reach a maximum
resolution R=120.000 in polarimetric mode and 300.000 in integral
light mode with high efficiency in the spectral range 390-1050~nm, we
designed a white-pupil configuration with Maksutov collimators. Light
is dispersed by an R4 31.6 lines/mm monolithic echelle grating mosaic
and split into two arms through dichroics. The two arms, optimized
for the spectral range 390-550~nm and 550-1050~nm, respectively,
consist of Maksutov transfer collimators, VPH-grism cross dispersers,
optimized dioptric cameras and 7.5K x 7.5K 8~μ CCDs. Fibers of
different core sizes coupled to different image-slicers allow a high
throughput, comparable to that of direct feed instruments. The optical
configuration with only spherical and cylindrical surfaces, except for
one aspherical surface in each camera, reduces costs and guarantees
high optical quality. PEPSI is under construction at AIP with first
light expected in 2006.

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Title: An atmospheric model for UZ Librae from mean Hα-line profiles
Authors: Zboril, M.; Strassmeier, K. G.; Avrett, E. H.
2004A&A...421..295Z Altcode:
We present the results from fitting a semi-empirical atmospheric
model including a chromosphere and a transition region to the mean
(seasonal) Balmer Hα line profiles of the RS CVn-type K0-giant UZ
Librae. As a first step, a static 1D spherical model was applied
to the mean component of the Hα-emission core and its profile. The
main result of the fitting is that the transition region begins at a
log mass depth of -1.8 g cm-2 at a temperature of 7400 K
(approximately 3000 K warmer than the photosphere) and then has a steep
increase to the peak temperature of ≈106 K. A stellar
model in plane-parallel mode with “partial-frequency redistribution”
option in the line transfer gave roughly the best fit. Subsequently,
two-Gaussian fitting of the phase-dependent Hα -line profiles yields a
complex velocity field. The radial velocities, from both the absorption
reversal and the main emission component, display rotational and/or
orbital modulation. The largest differences between consecutive line
profiles occur mostly in the red line wings, suggesting the existence
of both an inward-pointed velocity field and sporadic radiation events
possibly related to flares. The total Hα emission, as derived from the
equivalent width, possibly also displays rotational modulation. Indirect
evidence is presented for the existence of circumstellar matter in form
of an Hα absorption shell. Finally, a preliminary elemental abundance
analysis suggests sub-solar metallicity of [M/H]≈ -0.5 dex based on
ATLAS models, or -0.7 dex based on PHOENIX models.

---------------------------------------------------------
Title: The science case of the PEPSI high-resolution echelle
spectrograph and polarimeter for the LBT
Authors: Strassmeier, K. G.; Pallavicini, R.; Rice, J. B.; Andersen,
M. I.
2004AN....325..278S Altcode:
We lay out the scientific rationale for and present the instrumental
requirements of a high-resolution adaptive-optics Echelle spectrograph
with two full-Stokes polarimeters for the Large Binocular Telescope
(LBT) in Arizona. Magnetic processes just like those seen on the Sun
and in the space environment of the Earth are now well recognized in
many astrophysical areas. The application to other stars opened up a
new field of research that became widely known as the solar-stellar
connection. Late-type stars with convective envelopes are all affected
by magnetic processes which give rise to a rich variety of phenomena on
their surface and are largely responsible for the heating of their outer
atmospheres. Magnetic fields are likely to play a crucial role in the
accretion process of T-Tauri stars as well as in the acceleration and
collimation of jet-like flows in young stellar objects (YSOs). Another
area is the physics of active galactic nucleii (AGNs) , where the
magnetic activity of the accreting black hole is now believed to be
responsible for most of the behavior of these objects, including their
X-ray spectrum, their notoriously dramatic variability, and the powerful
relativistic jets they produce. Another is the physics of the central
engines of cosmic gamma-ray bursts, the most powerful explosions
in the universe, for which the extreme apparent energy release are
explained through the collimation of the released energy by magnetic
fields. Virtually all the physics of magnetic fields exploited in
astrophysics is somehow linked to our understanding of the Sun's and
the star's magnetic fields.

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Title: Doppler imaging of stellar surface structure. XXII. Time-series
mapping of the young rapid rotator LQ Hydrae
Authors: Kovári, Zs.; Strassmeier, K. G.; Granzer, T.; Weber, M.;
Oláh, K.; Rice, J. B.
2004A&A...417.1047K Altcode:
We reconstruct a time series of 28 surface temperature maps
(Doppler-images) of the spotted single K2-dwarf LQ Hya from 35
consecutive stellar rotations in Nov.-Dec. 1996. Two more maps are
obtained from data in late April and early May 2000. All maps show
spot activity preferably at low latitudes between -20 deg and +50 deg,
with a concentration in a band centered at around +30 deg, and with only
occasional evidence for a higher-latitude spot extension. No trace of a
polar spot is found at any of the above epochs. Most of this morphology
can be reproduced by our flux-tube emergence model, except for the
equatorial activity where the strong Coriolis force due to the rapid
rotation always deflects flux tubes to higher latitudes. We also present
the detection of weak differential surface rotation from a number
of cross-correlation maps of the time-series images in late 1996. A
solar-type differential rotation law, i.e. the equator rotating faster
than the poles, with ΔΩ=+0.022 rad/day (lap time of ≈280 days) is in
agreement with the data. Using the available photoelectric observations
from 21 years we refine the rotation period to 1.60066±0.00013 days
and find a remarkable phase coherence over the course of 21 years,
supporting the recent finding of active longitudes by Berdyugina et
al. Furthermore, our photometry shows a complex multi-cyclic long-term
brightness variability with three periods of 13.8±2.8 years, its
harmonic 6.9±0.8 and 3.7±0.3 years, respectively. The 3.7-year period
would be in good agreement with the fundamental-mode oscillation period
predicted by Kitchatinov et al. from a distributed-dynamo model, but
remains to be confirmed. Table 1 and Fig. 5 are only available
in electronic form at http://www.edpsciences.org

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Title: Multisite observations of SU Aurigae
Authors: Unruh, Y. C.; Donati, J. -F.; Oliveira, J. M.; Collier
Cameron, A.; Catala, C.; Henrichs, H. F.; Johns-Krull, C. M.; Foing,
B.; Hao, J.; Cao, H.; Landstreet, J. D.; Stempels, H. C.; de Jong,
J. A.; Telting, J.; Walton, N.; Ehrenfreund, P.; Hatzes, A. P.;
Neff, J. E.; Böhm, T.; Simon, T.; Kaper, L.; Strassmeier, K. G.;
Granzer, Th.
2004MNRAS.348.1301U Altcode: 2004astro.ph..1081U
We present results from the 1996 Multi-Site Continuous Spectroscopy
(MUSICOS) campaign on the T Tauri star SU Aurigae. We find a 2.7-d
periodicity in the HeI (587.6 nm) line, and somewhat longer, less
well-pronounced periodicities in the Balmer lines and in Na D. Our
observations support the suggestion that the wind and infall signatures
are out of phase on SU Aur. We present Doppler images of SU Aur that
have been obtained from least-squares deconvolved profiles. Images taken
about one rotation apart show only limited overlap, in particular at low
latitudes. This is due in part to limitations in signal-to-noise ratio,
and in part to line-profile deformations that arise from short-lived
and/or non-surface features. The agreement at high latitudes is better
and suggests that at least some longer-lived features are present. The
analysis of Stokes V profiles yields a marginal magnetic field detection
during one of the phases.

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Title: The Solar-Stellar Connection and Disconnection
Authors: Strassmeier, K. G.
2004IAUS..219...11S Altcode: 2003IAUS..219E..39S
The study of stellar activity is now an almost classical astronomical
topic because the first observations were made almost hundred years ago
and many thousands of papers were published in the meantime. However
the complexity of the atmospheric and interior structure as observed
on the Sun is hard if not impossible to extrapolate to solar-type
stars. Yet there is just a single main ingredient that acts as the
driving mechanism for activity in all atmospheric layers and the
convective envelope: the dynamo-driven magnetic field. In my talk I
will try to give examples where the solar analogy holds and where ist
is clearly not appropriate. I stress the importance of mapping stellar
surfaces as fingerprints of the underlying dynamo action.

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Title: Eddington and stellar-rotation studies: light curve analysis
tools and ground-based follow-up spectroscopy
Authors: Strassmeier, K. G.; Oláh, K.
2004ESASP.538..149S Altcode: 2004sshp.conf..149S
Eddington will produce a data stream of light curves for some tens of
thousands of stars. This means that a clever algorithm must predetermine
what type of variability is expected for a particular target, and
then suggest and apply the proper analysis tool. We investigate the
feasibility of such an algorithm by comparing the chances of detecting
the solar rotational period from the long-term Sun-as-a-star ACRIM
data by means of Fourier and wavelet period-search techniques. We
first create artificial data with a spot-modelling code that includes
differential surface rotation, and then try to recover the rotation
signal from the Fourier spectrum. Then, we present the example of the
rapidly-rotating spotted star UZ Librae, where ground-based time-series
photometry obtained with automatic telescopes indeed revealed signal
from a differentially rotating stellar surface. Finally, we discuss the
urgent need for ground-based preparatory and follow-up spectroscopy and
introduce our own support possibilities. We emphasise that all proposed
joint Eddington-support efforts, with our Spanish colleagues on the
Canary islands and our Italian and American colleagues in Arizona,
strongly suggest that the planet-finding field is in the northern
hemisphere.

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Title: Linking Thin Flux Tube MHD Models to Apparent Stellar Surface
Activity
Authors: Granzer, T.; Strassmeier, K. G.
2004IAUS..219..546G Altcode: 2003IAUS..219E.133G
Doppler Imaging provides us with a growing number of surface maps of
fast-rotating late-type stars. These maps often reveal solar-spot like
star spots. As the resemblance to sun-spots is striking it appears
feasible to apply an MHD model gained from studying our Sun's spots to
these highly-active stars. In this poster we want to directly compare
stellar spot patterns derived from theory with actual observations. The
rise of thin magnetic flux-tubes from the bottom of an outer stellar
convection zone up to the photosphere is followed numerically. The
emergence points of the flux-tubes in the photosphere of the model
stars are than compared to Doppler-imaging derived surface maps. With
this comparison the feasibility of applying a solar-analog model
is discussed.

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Title: Doppler imaging of stellar surface structure. XXI. The
rapidly-rotating solar-type star HD 171488 = V889 Hercules
Authors: Strassmeier, K. G.; Pichler, T.; Weber, M.; Granzer, T.
2003A&A...411..595S Altcode:
We present the first Doppler image of the single G0-dwarf HD 171488. As
a 30-Myr young field star with a lithium abundance of ~140-times
that of the Sun and a rotation 20 times faster, it is hardly a
“solar analog” but could be termed an “infant Sun”. Its position
in the H-R diagram suggests it to be in the rapid-braking phase just
prior to arrival on the ZAMS. Our Doppler images from four spectral
lines show a cool polar spot and various high-latitude spot features
with a temperature contrast of 500-1600 K relative to the effective
(photospheric) temperature. Low-to-medium latitude features may be
present but appear to be biased by the uneven phase coverage of our
spectra and are too weak to be conclusively judged significant. We
determine the rotational period to be 1.3371 +/- 0.0002 days and find
a long-term, possibly cyclic variation of the mean V brightness of
~7 yrs. A constant radial velocity of -23.6 +/- 1.5 km s-1
suggests that HD 171488 is indeed a single star. Rising flux-tube models
indicate preferred surfacing latitudes between 25 degr-60 degr for HD
171488 while our Doppler images reveal mostly high-latitude spots in
excess of 60 degr . We emphasize that this discrepancy exists for all
rapidly rotating single G dwarfs observed so far.

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Title: Differential rotation on UZ Librae
Authors: Oláh, K.; Jurcsik, J.; Strassmeier, K. G.
2003A&A...410..685O Altcode:
We analysed a time series of nine consecutive years of high-precision
photometry of the spotted RS CVn star UZ Lib by using a discrete
Fourier-transform technique and a non-linear least-squares
minimization. The main period of 4.77 days due to stellar rotation was
resolved into three individual periods separated by -0.2% and +0.4%
around the main period. The stability of the spot pattern over many
years, as derived from our contemporaneous Doppler images, allowed
us to relate the different periods to co-existing spots at different
latitudes, and thus to the direct determination of the strength and
the sign of the differential rotation. The main period originates
from the equatorial surface regions and is practically the same as
the orbital period from independent radial-velocity measurements,
suggesting that the stellar equator is tidally locked to the orbital
motion. The higher latitudes rotate slightly faster than the equator,
suggesting non-solar differential rotation with a parameter of alpha
=Delta Omega /Omega =-0.0026, 80 times weaker than on the solar
surface, and a lap time of Pequator/alpha ~ -1800 days,
i.e. 14 times longer than for the Sun.

---------------------------------------------------------
Title: Tracing the Spot Evolution on the Moderately-Rotating K1-Giant
σ Geminorum
Authors: Strassmeier, K. G.; Kovári, Z.; Washuettl, A.; Weber, M.;
Rice, J. B.; Bartus, J.
2003csss...12..927S Altcode:
We present a simultaneous photometric and spectroscopic imaging analysis
of the long-period RS CVn binary σ Gem, covering 3.6 consecutive
rotation cycles with high time resolution. From six overlapping but
consecutive Doppler maps we trace the evolution of individual spots
throughout the time range covered. All spots group either along a
band at approximately +45 ° latitude and a width of 30 °, or appear
centered at the equator. No polar spot is detected. We did not find
a conclusive migration pattern from the cross-correlation maps from
one rotation to the next and attribute this to a masking effect of
short-term spot changes.

---------------------------------------------------------
Title: Doppler Imaging of Stellar Surface Structure: The Differential
Rotation of the K-giant IL Hydrae
Authors: Weber, M.; Strassmeier, K. G.; Washuettl, A.
2003csss...12..922W Altcode:
We re-determined the differential rotation law at the surface of the K
giant IL Hydrae (Prot≈12.9 days). Using new NSO and KPNO
spectra covering five consecutive rotations in 1996 and two rotations
15 days apart in 2000, we cross-correlate three independent Doppler
images from 1996 and two from 2000. Assuming a solar-like differential
rotation law, we derive α=Ω1/Ω0≈ -0.047 and
1/ΔΩ≈277 days. This is more than double the solar value of 120
days and in the opposite direction, i. e. the polar regions rotate
faster than the equatorial regions. This result is in contrast to
earlier measurements showing a weak differential rotation in the same
direction as the Sun, but based on only two Doppler images taken one
year apart. This indicates, that average spot lifetimes on IL Hya are
on the order of a few stellar rotations.

---------------------------------------------------------
Title: STELLA: Status Report
Authors: Hempelmann, A.; Schmitt, J. H. M. M.; Hagen, H.; Strassmeier,
K.; Arlt, K.; Granzer, T.; Hildebrandt, G.; Weber, M.; Woche, M.
2003csss...12.1085H Altcode:
STELLA is a joint project between the Hamburger Sternwarte and
the Astrophysical Institute Potsdam for an automatically operating
spectroscopic telescope. The scientific goals are observation and
monitoring of stellar activity. By agreement with the Astrophysical
Institute of the Canary Islands, STELLA will be installed at the Teide
Observatory on the island of Tenerife. The actual progress in design
and construction of the telescope, the instruments and the control
software is presented in this report.

---------------------------------------------------------
Title: Spotted Stars in the Pleiades and Orion Nebular Cluster
Authors: Granzer, T.; Strassmeier, K. G.
2003csss...12..763G Altcode:
We present the results of extensive MHD simulations aiming to predict
star spot patterns on stars in two well-known stellar clusters, the
Pleiades (100 Myr) and the Orion Nebular Cluster (2 Myr). The emergence
of thin magnetic flux tubes is studied from their origin at the base
of the convective zone up to the photosphere. The mass/rotational grid
of the stellar models is wide enough to cover all stellar types where
theory predicts the possibility of starspot formation. In particular,
masses between 4.0 M⊙ and 0.4 M⊙ and
rotational rates from 0.25 Ω⊙ to 25 Ω⊙
are considered.

---------------------------------------------------------
Title: MUSICOS Observations of the Chromospherically Active Binary
Star EI Eridani
Authors: Washuettl, A.; Strassmeier, K. G.; Foing, B.; MUSICOS98 Team
2003csss...12.1008W Altcode:
We present first results on spectroscopic observations of the
rapidly-rotating active binary star EI Eridani obtained during the
MUSICOS multi-site campaign in 1998. Eight sites around the globe were
involved in order to achieve surface images within a few rotations as EI
Eridani's critical rotation period of 1.945 days makes it impossible
to obtain time-resolved images from a single site. The data were
split into groups in order to obtain consecutive, independent Doppler
images. The preliminary results confirm the existence of a stable
polar spot that changes in size and shape while low-latitute spots
are found to be short lived. For the first time, it is possible to
achieve consecutive, time-resolved Doppler images for EI Eridani. A
preliminary investigation of differential rotation contradicts the
results from Hatzes &amp; Vogt (1992).

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. XX. The
rapidly-rotating single K2-giant HD 31993 = V1192 Orionis
Authors: Strassmeier, K. G.; Kratzwald, L.; Weber, M.
2003A&A...408.1103S Altcode:
We present two Doppler images from two consecutive stellar rotations
of the single K2-giant HD 31993. Each Doppler image is reconstructed
from spectra obtained within a single stellar rotation. With its
25-day rotational period and a radius of ~18 solar radii, HD 31993 is
considered a very rapidly rotating star and thus allows the application
of the Doppler-imaging technique, despite the unusually long period. All
maps reveal 7 isolated, predominantly low-latitude spots with a
temperature difference, photosphere minus spot, of just ~200 K. No polar
spot or high-latitude activity above, say, +60° is seen. A large warm
feature is detected at high latitude and is believed to be real. These
spots act as tracers for a cross correlation analysis and yield a clear
signature of anti-solar differential surface rotation, i.e. the polar
regions rotating faster than the equator, with alpha =0.125 +/-0.05
corresponding to a lap time of ~200 days. A detailed parameter study
is carried out to verify the reality of the HD 31993 maps.

---------------------------------------------------------
Title: Halpha variations of the spotted G dwarf AP 149
Authors: Savanov, I.; Strassmeier, K.; Romanyuk, I.; Kudryavtsev, D.
2003IBVS.5440....1S Altcode:
High resolution spectroscopic observations of G dwarf AP 149 in the
alpha Persei cluster result in the estimations of variations of the
equivalent widths and fluxes radiated in H-alpha line.

---------------------------------------------------------
Title: The Potsdam Echelle Polarimetric and Spectroscopic Instrument
(PEPSI) for the LBT
Authors: Strassmeier, K. G.; Hofmann, A.; Woche, M.
2003ANS...324...28S Altcode: 2003ANS...324..D02S
No abstract at ADS

---------------------------------------------------------
Title: Das Large Binocular Telescope. Ein Projekt nimmt Gestalt an
Authors: Strassmeier, Klaus G.
2003S&W....42e..30S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The ICE spectrograph for PEPSI at the LBT: preliminary
optical design
Authors: Pallavicini, Roberto; Zerbi, Filippo M.; Spano, Paolo;
Conconi, Paolo; Mazzoleni, Ruben; Molinari, Emilio; Strassmeier,
Klaus G.
2003SPIE.4841.1345P Altcode:
We present a preliminary design study for a high-resolution echelle
spectrograph (ICE) to be used with the spectropolarimeter PEPSI under
development at the LBT. In order to meet the scientific requirements
and take full advantage of the peculiarities of the LBT (i.e. the
binocular nature and the adaptive optics capabilities), we have designed
a fiber-fed bench mounted instrument for both high resolution (R ≍
100,000; non-AO polarimetric and integral light modes) and ultra-high
resolution (R ≍ 300,000; AO integral light mode). In both cases,
4 spectra per order (two for each primary mirror) shall be accomodated
in a 2-dimensional cross dispersed echelle format. In order to obtain a
resolution-slit product of ≍ 100,000 as required by the science case,
we have considered two alternative designs, one with two R4 echelles
in series and the other with a sigle R4 echelle and fiber slicing. A
white-pupil design, VPH cross-dispersers and two cameras of different
focal length for the AO and non-AO modes are adopted in both cases. It
is concluded that the single-echelle fiber-slicer solution has to be
preferred in terms of performances, complexity and cost. It can be
implemented at the LBT in two phases, with the long-camera AO mode
added in a second phase depending on the availability of funds and
the time-scale for implementation of the AO system.

---------------------------------------------------------
Title: PEPSI spectro-polarimeter for the LBT
Authors: Strassmeier, Klaus G.; Hofmann, Axel; Woche, Manfred F.; Rice,
John B.; Keller, Christoph U.; Piskunov, N. E.; Pallavicini, Roberto
2003SPIE.4843..180S Altcode:
PEPSI (Postham Echelle Polarimetric and Spectroscopic Instrument) is
to use the unique feature of the LBT and its powerful double mirror
configuration to provide high and extremely high spectral resolution
full-Stokes four-vector spectra in the wavelength range 450-1100nm. For
the given aperture of 8.4m in single mirror mode and 11.8m in double
mirror mode, and at a spectral resolution of 40,000-300,000 as designed
for the fiber-fed Echelle spectrograph, a polarimetric accuracy between
10-4 and 10-2 can be reached for targets with
visual magnitudes of up to 17th magnitude. A polarimetric accuracy
better than 10-4 can only be reached for either targets
brighter than approximately 10th magnitude together wiht a substantial
trade-off wiht the spectral resolution or with spectrum deconvolution
techniques. At 10-2, however, we will be able to observe
the brightest AGNs down to 17th magnitude.

---------------------------------------------------------
Title: VizieR Online Data Catalog: sigma2 CrB radial
velocities (Strassmeier+,
Authors: Strassmeier, K. G.; Rice, J. B.
2003yCat..33990315S Altcode:
High-resolution spectroscopic observations were obtained with the Gecko
Coude spectrograph at the 3.6-m Canada-France-Hawaii telescope (CFHT)
in two observing runs each two nights long in May 17-18, 2000 and May
21-22, 2000. This splitting of nights was mandatory in order to obtain
full phase coverage because the orbital period (and the rotational
periods) is 1.14 days, and thus close to the day-night cycle. (2
data files).

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. XIX. The
solar-type components of the close binary sigma2 Coronae
Borealis
Authors: Strassmeier, K. G.; Rice, J. B.
2003A&A...399..315S Altcode:
We present the first Doppler image for both stellar components of the
F9+G0 ZAMS binary sigma 2 CrB and found evidence for the
coexistence of cool and warm spots on both stars. Cool spots appear
mainly at polar or high latitudes while a confined equatorial warm
belt appears on the trailing hemisphere of each of the two stars with
respect to the orbital motion. We also present an update of the TempMap
imaging code that allows us to solve the stellar surface temperature
distribution on both binary components simultaneously, including
photometric input. Several test reconstructions are performed to
demonstrate its reliability and robustness. Our new orbital solution
results in very precise masses for both components - good to 0.4% -
and confirms the spectral classifications of F9 and G0 for the primary
and secondary, respectively. The visual component, sigma 1
CrB, seems to be G4 rather than G0. All three components are on or
very close to the ZAMS which is also confirmed by the relatively high
lithium abundance of about twenty times the solar abundance. Photometric
light variations are detected with a period of 1.157+/- 0.002 days that
we interpret to be the rotation period of both binary components. A
0\fm04 dimming in y together with a reddening of 0\fm01 in b-y during
the year 2000 suggests a long-term spot variability compatible with
a period of at least 260 days.

---------------------------------------------------------
Title: Time-series photometric spot modelling VI. A new computer
code and its application to 23 years of photometry of the active
giant IM Pegasi
Authors: Ribárik, G.; Oláh, K.; Strassmeier, K. G.
2003AN....324..202R Altcode:
We present and apply a new computer program named SpotModeL to
analyze single and multiple bandpass photometric data of spotted
stars. It is based on the standard analytical formulae from Budding
and Dorren. The program determines the position, size, and temperature
of up to three spots by minimizing the fit residuals with the help of
the Marquardt-Levenberg non-linear least-squares algorithm. We also
expand this procedure to full time-series analysis of differential
data, just as real observations would deliver. If multi-bandpass
data are available, all bandpasses can be treated simultaneously
and thus the spot temperature is solved for implicitly. The program
may be downloaded and used by anyone. In this paper, we apply our
code to an ~23 year long photometric dataset of the spotted RS CVn
giant IM Peg. We extracted and modelled 33 individual light curves,
additionally, we fitted the entire V dataset in one run. The resulting
spot parameters reflect the long term light variability and reveal two
active longitudes on the substellar point and on the antipode. The
radius and longitude of the dominant spot show variations with 29.8
and 10.4 years period, respectively. Our multicolour data suggests
that the spot temperature is increasing with the brightening of the
star. The average spot temperature from V,I_C is 3550+/- 150 K or
approximately 900 K below the effective temperature of the star.

---------------------------------------------------------
Title: EK Draconis: Long-term photometry on Sonneberg Sky-Patrol
plates
Authors: Fröhlich, H. -E.; Tschäpe, R.; Rüdiger, G.; Strassmeier,
K. G.
2002A&A...391..659F Altcode:
We performed long-term photometry of the young solar analog EK
Draconis (HD 129333) using 1030 blue-sensitive Sky-Patrol plates
taken at Sonneberg Observatory from 1958 onwards. A secular dimming
of 0.0057+/- 0.0008 mag/y beginning around 1975 was found. Hence, the
recent trend first observed with Automatic Photoelectric Telescopes
(APTs) is confirmed and traced back to the mid-seventies.

---------------------------------------------------------
Title: Design study of the PEPSI polarimeter for the LBT
Authors: Hofmann, A.; Strassmeier, K. G.; Woche, M.
2002AN....323..510H Altcode:
We present the conceptual design of the two polarimetric channels of the
PEPSI spectropolarimeter for the Large Binocular Telescope (LBT). The
two direct Gregorian f/15 focii of the LBT will take up two identical
but independent full-Stokes IQUV polarimeters that themselves fiberfeed
a high-resolution Echelle spectrograph (see the accompanying paper by
Zerbi et al.). The polarizing units will be based on super-achromatic
Fresnel-rhomb retarders and Foster prisms. A total of four fibers are
foreseen to simultaneously direct two ordinary and two extraordinary
light beams to the Echelle spectrograph. Both polarimetric units are
layed out in a modular design, each one optimized to the polarization
state in which it is used. A number of observing modes can be chosen
that are optimized to the type of polarization that is expected from
the target, e.g. circularly and linearly polarized light simultaneously,
or linearly polarized light in both polarimeters, or integral light from
one and polarized light from the other telescope, a.s.o.. Calibration
would be provided for each polarimeter separately.

---------------------------------------------------------
Title: Time series photometric spot modelling V. Phase coherence
of spots on UZ Librae
Authors: Oláh, K.; Strassmeier, K. G.; Granzer, T.
2002AN....323..453O Altcode:
We present spot models for nine years of continuous VI_C photometry
of UZ Lib from 1993-2001. The relatively stable double-humped light
curve shape suggests extreme phase coherence. From the spot-modelling
analysis, we found that the major spots or spot groups are always
located on the hemisphere facing the secondary star and exactly
in the opposite hemisphere anti-facing the secondary. Several
single-humped light curves and our suggested binary scenario rule
out a pure ellipsoidal variability as the cause of the double-humped
light curve shape. We try to explain this preferred spot pattern
with a magnetic-field structure that connects the two components, as
suggested earlier for RS CVn stars in general. A possible 4.8 years
spot cycle is found from the long-term brightness variations but needs
confirmation. We rediscuss the basic astrophysical data of UZ Lib. The
Hipparcos parallax is likely wrong, a possible reason could be that
UZ Lib is e.g., a triple system.

---------------------------------------------------------
Title: Introduction to this volume. Proceedings of the 1st
Potsdam Thinkshop on Sunspots &amp; Starspots
Authors: Strassmeier, K. G.; Washuettl, A.; Schwope, A.
2002AN....323..155S Altcode:
This volume of AN contains the proceedings of the 1st Potsdam Thinkshop
on Sunspots &amp; Starspots held in Potsdam from May 6 to 10, 2002. The
aim of this meeting was to bring together the solar and stellar
community on a particular topic and discuss various inter-disciplinary
results related to magnetic field. All contributions are fully refereed.

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. XVIII. The very
active RS CVn binary UZ Librae revisited
Authors: Oláh, K.; Strassmeier, K. G.; Weber, M.
2002A&A...389..202O Altcode:
We present eight Doppler images of UZ Librae from the years 1994,
1996, 1997, 1998 and 2000. These maps indicate a preferred temperature
distribution from one year to the other and suggest preferred spot
locations for at least the seven years of our observations. Two
equatorial active regions appear facing towards and opposite the
(unseen) companion star. A large and cool polar spot, with two or maybe
three appendages extending down to a latitude of 40 degr -50 degr ,
is present and causes the long-term light variability of UZ Lib. The
appendages appear at longitudes very similar to the two equatorial
active regions and sometimes are possibly even attached to them. No
coherent sign of differential rotation is found for the equatorial
regions up to a latitude of approximately +50 degr , but the polar
appendages may indicate a general acceleration of the polar regions. If
interpreted as being due to differential rotation, if real at all,
then UZ Lib clearly exhibits a non-solar flow pattern.

---------------------------------------------------------
Title: A new concept and a preliminary design for a high resolution
(HR) and very-high resolution (VHR) spectrograph for the LBT
Authors: Zerbi, F. M.; Spanò, P.; Conconi, P.; Molinari, E.;
Mazzoleni, R.; Pallavicini, R.; Strassmeier, K. G.
2002AN....323..499Z Altcode: 2002astro.ph..3039Z
A way to fully exploit the large collecting area of modern 8-10m
class telescopes is high resolution spectroscopy. Many astrophysical
problems from planetary science to cosmology benefit from spectroscopic
observations at the highest resolution currently achievable and
would benefit from even higher resolutions. Indeed in the era of
8-10m class telescopes no longer the telescope collecting area but
the size of the beam - which is related to the maximum size in which
reflection gratings are manufactured - is what mainly limits the
resolution. A resolution-slit product Rvarphi =~ 40,000 is the maximum
currently provided by a beam of 20 cm illuminating the largest grating
mosaics. We present a conceptual design for a spectrograph with Rvarphi
=~ 80,000, i.e. twice as large as that of existing instruments. Examples
of the possible exploitation of such a high Rvarphi value, including
spectropolarimetry and very high resolution (R ~ 300,000), are discussed
in detail. The new concept is illustrated through the specific case of
a high resolution spectropolarimeter for the Large Binocular Telescope.

---------------------------------------------------------
Title: Starspot cycles from long-term photometry
Authors: Oláh, K.; Strassmeier, K. G.
2002AN....323..361O Altcode:
We continue investigating the photometric cycle lengths of some active
stars. Using datasets now up to 34 years long we confirm previously
derived activity cycles for the shorter period systems of our sample
(LQ Hya, V833 Tau, EI Eri, V711 Tau, HU Vir and IL Hya), but find
different cycle lengths for the two long-period giants HK Lac and IM
Peg. We add UZ Lib to our previous sample. The connection between the
rotational period and cycle length seems evident for the shortest
derived cycle lengths. A similar connection between the rotational
period and the longer cycle lengths is not as clear, taking into
account recent results on the time variability of the longer term solar
cycles. While the time base of the observations puts an upper limit
to the detectable lengths of the longer cycles, a general dependence
of the cycle period on the rotation rate is maintained. The length
of the shortest cycle that we found for LQ Hya agrees with the cycle
period derived from dynamo modelling of this star.

---------------------------------------------------------
Title: Doppler images of starspots
Authors: Strassmeier, K. G.
2002AN....323..309S Altcode:
I present a literature survey of the currently available Doppler images
of cool stars. The 65 individual stars with Doppler images consist
of 29 single stars and 36 components in close binaries. Out of the
total, 31 were observed only once but 12 stars are (or were) being
monitored for years. Each image for each star is identified with the
time when it was observed, whether photometry was used in the imaging,
the inclination of the stellar rotation axis, the vsin i, the stellar
rotation period, and whether a polar spot and/or a high-latitude or
low-latitude spot was seen. The type of variable star and its M-K
spectral classification is also listed to identify the evolutionary
status. The sample consists of 3 classical T Tauri stars, 8 weak-lined
T Tauri's, 27 main-sequence stars, 9 subgiants, and 18 giants. The
total number of Doppler images is 245 as of June 2002.

---------------------------------------------------------
Title: Stellar activity studies with Eddington
Authors: Strassmeier, K. G.
2002ESASP.485..189S Altcode: 2002sshp.conf..189S
I present a brief outline of the use of Eddington data for stellar
activity studies. The most important stellar parameters that could be
obtained from secondary targets within both main science fields are
stellar rotation, differential rotation, meridional flows, stellar cycle
morphology spot lifetimes, and flare activity. Due to the vast amount
of data, one may hope to find relations between stellar pulsation and
magnetic activity, and between stellar flares and the existence of
Vulcan-type planets.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Effective temperatures of K-M
giants (Strassmeier+, 2000)
Authors: Strassmeier, K. G.; Schordan, P.
2002yCatp001032103S Altcode:
A high-resolution spectroscopic survey in the 6380-6460{AA} region
of 224 slowly-rotating M-K class III giants is presented. Spectral
line-depth ratio are calibrated against effective temperature obtained
from B-V and V-I color indices in the range 3200-7500K (M6-A9). A table
of polynomial coefficients for 12 line-ratio-Teff relations can be
used to derive Teff of F-M stars to within 33K (rms), and of early-F
and mid-to-late M stars to within 77-106K (rms). (2 data files).

---------------------------------------------------------
Title: The Wolfgang and Amadeus Automatic Photoelectric Telescopes. A
“Kleine-Nacht-Musik” during the first five years of routine
operation
Authors: Granzer, T.; Reegen, P.; Strassmeier, K. G.
2001AN....322..325G Altcode:
We present a summary of five years of continuous operation of the
University of Vienna twin Automatic Photoelectric Telescopes (APTs)
-- Wolfgang and Amadeus. These two telescopes are part of the Fairborn
Observatory facility located in the Sonoran desert close to Washington
Camp in southern Arizona. The detection and distinction procedure
between weather-induced data-quality loss and systematic data-quality
loss turned out to be a crucial task. Therefore, special emphasis is
laid on the data quality monitoring tools developed throughout the
years. Furthermore, we summarize the scientific highlights from the
first five years of operation

---------------------------------------------------------
Title: Automation hardware and software for the STELLA-I robotic
telescope
Authors: Granzer, T.; Weber, M.; Strassmeier, K. G.
2001AN....322..295G Altcode:
STELLA-I will be among the first fully robotic telescopes for
high-resolution Echelle spectroscopy. First light is scheduled for
summer 2002. We present a first status report on the development of the
computer hardware and the operating software for the STELLA facility.

---------------------------------------------------------
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.
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: The STELLA project: two 1.2m robotic telescopes for
simultaneous high-resolution Echelle spectroscopy and imaging
photometry
Authors: Strassmeier, K. G.; Granzer, T.; Weber, M.; Woche, M.;
Hildebrandt, G.; Bauer, S. -M.; Paschke, J.; Roth, M. M.; Washuettl,
A.; Arlt, K.; Stolz, P. A.; Schmitt, J. H. M. M.; Hempelmann, A.;
Hagen, H. -J.; Ruder, H.; Palle, P. L.; Arnay, R.
2001AN....322..287S Altcode:
We present an overview and a brief report on the status of the STELLA
project (abbreviation for STELLar Activity). The STELLA-I telescope
will be the first robotic telescope that feeds a bench-mounted
high-resolution Echelle spectrograph with a set of 50 and 100 μm
fibres and provides spectral resolutions of up to 47,000 with a
1 arcsec slit. The spectrograph is a white-pupil design located
in a separated temperature-controlled room to guarantee long-term
stability. The building will have a roll-off roof and is capable to
host two telescopes. First light for STELLA-I is planned for summer
2002. STELLA-II is foreseen to be a photometric imaging telescope for
the optical and near-infrared wavelengths and will follow in 2003.

---------------------------------------------------------
Title: The first close-up of the “flip-flop” phenomenon in a
single star
Authors: Korhonen, H.; Berdyugina, S. V.; Strassmeier, K. G.;
Tuominen, I.
2001A&A...379L..30K Altcode: 2001astro.ph.10517K
We present temperature maps of the active late-type giant FK Com which
exhibit the first imagining record of the “flip-flop” phenomenon
in a single star. The phenomenon, in which the main part of the spot
activity shifts 180° in longitude, discovered a decade ago in FK Com,
was reported later also in a number of RS CVn binaries and a single
young dwarf. With the surface images obtained right before and after
the “flip-flop”, we clearly show that the “flip-flop” phenomenon in
FK Com is caused by changing the relative strengths of the spot groups
at the two active longitudes, with no actual spot movements across the
stellar surface, i.e. exactly as it happens in other active stars. Based
on the observations obtained at the Kitt Peak National Observatory,
USA; the Automatic Photometric Telescope, Phoenix 10, Arizona, USA;
the Nordic Optical Telescope, Observatorio Roque de los Muchachos,
La Palma, Canary Islands, Spain.

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. XVII. The
solar-type Pleiades star HII 314 = V1038 Tauri
Authors: Rice, J. B.; Strassmeier, K. G.
2001A&A...377..264R Altcode:
We present the first Doppler image of a solar-type G dwarf in the
Pleiades open cluster. As such, the star represents the Sun at an
age of approximately 100 Myr and could be an important target for
further progress in magnetic-braking and angular-momentum-transport
theories. Our image reconstructions were done from a full spectrum
inversion with a total of 38 spectral lines but we also present
single-line inversions using the prominent Li I 6707-Å line and the
nearby Ca I 6717-Å line. The maps reveal cool spots at or near the pole
and within the equatorial regions, in contradiction to our predictions
from flux-tube modelling that only medium-latitude spots should be
seen. The maps also show several warm spots near the equatorial regions
but their reality needs to be confirmed. A polar spot is recovered
but likely consists of several smaller spots at very high latitudes
touching the visible pole instead of a big cap-like spot as seen on
some RS CVn binaries.

---------------------------------------------------------
Title: Study of FK Comae Berenices. III. Photometry for the years
1993-2001
Authors: Korhonen, H.; Berdyugina, S. V.; Tuominen, I.; Andersen,
M. I.; Piironen, J.; Strassmeier, K. G.; Grankin, K. N.; Kaasalainen,
S.; Karttunen, H.; Mel'nikov, S. Yu.; Shevchenko, V. S.; Trisoglio,
M.; Virtanen, J.
2001A&A...374.1049K Altcode:
We present 8 years of previously unpublished photometric observations
of FK Com together with the determination of the stability of the
primary comparison star HD 117567. The observations have been carried
out between 1993 and 2001 at four different observatories and they
consist of 5157 data points in total: U(903), B(994), V(1643), R(166),
I_c(573), b(461) and y(417). We also analyse this new data together with
the previously published photometric observations. The V magnitude shows
variations with dominant periods of about 3, 6, 12, 14 and 31 years. The
short-term light curve variations appear to be caused by rearrangement
of approximately constant amount of cool spots. From the values
for different colours obtained during the brightest season observed,
corresponding to the supposedly unspotted surface, the spectral type of
FK Com is determined to be G7 III. Based on the observations obtained
at Phoenix 10, Arizona, USA; Wolfgang and Amadeus, Arizona, USA;
Mount Maidanak Observatory, Uzbekistan; La Palma KVA 0.6 m Cassegrain
telescope, La Palma, Spain. Tables 2a-e are only available in electronic
form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5)
or via http:/ /cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/374/1049

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. XVI. A
time-series analysis of the moderately-rotating K1-giant sigma
Geminorum
Authors: Kovári, Zs.; Strassmeier, K. G.; Bartus, J.; Washuettl,
A.; Weber, M.; Rice, J. B.
2001A&A...373..199K Altcode:
We present a simultaneous photometric and spectroscopic imaging analysis
of the long-period RS CVn binary sigma Gem, covering 3.6 consecutive
rotation cycles with high time resolution. From six overlapping but
consecutive Doppler maps we trace the evolution of individual spots
throughout the time range covered. All spots group either along a
band at approximately +45 degrees latitude and a width of 30 degrees,
or appear centered at the equator. No polar spot is detected. We did
not find a conclusive migration pattern from the cross-correlation
maps from one rotation to the next and attribute this to a masking
effect of short-term spot changes.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Photometry of FK Com for 1993-2001
(Korhonen+, 2001)
Authors: Korhonen, H.; Berdyugina, S. V.; Tuominen, I.; Andersen,
M. I.; Piironen, J.; Strassmeier, K. G.; Grankin, K. N.; Kaasalainen,
S.; Karttunen, H.; Mel'Nikov, S. Yu.; Shevchenko, V. S.; Trisoglio,
M.; Virtanen, J.
2001yCat..33741049K Altcode:
We report 8 years of previously unpublished photometric observations
of FK Com. The observations have been carried out between 1993 and
2001 with six different telescopes: 60 cm at Mt. Maidanak (Tashkent,
Uzbekistan), Phoenix 10, Wolfgang and Amadeus located in Arizona,
USA, and 20cm and 60 cm KVA on La Palma, Spain. Observations contain
measurements at the following bands: Johnson U, B, V and R, Bessel R,
Cousins I and Stromgren b and y. The observations are differential
photometry in respect to the primary comparison star HD 117567. NOTE:
Table 1 in the paper contains some small misprints in the Julian
dates. Also for Wolfgang and Amadeus the number of observations given
in Table1 at each band is slightly less than actually given in Table2c
and Table2d. This is caused by accidentally using a limiting error
of 0.01 in magnitudes when creating Table 1. In Table 2 the limiting
error for Wolfgang and Amadeus is 0.02 mag, as mentioned in the paper
itself. In Table2a-e 99.0000 means that no observations were available
at that time at that band or that the error in the magnitude was larger
than 0.02. (5 data files).

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. XV. A possible
detection of differential rotation and local meridional flows on
the rapidly-rotating giant HD 218153 = KU Pegasi
Authors: Weber, M.; Strassmeier, K. G.
2001A&A...373..974W Altcode:
Time-resolved Doppler images of the rapidly rotating, but long-period
(25 days), giant KU Pegasi show several cool low-to-medium latitude
spots as well as an asymmetric polar feature. The average spot
temperature is about 700 K below the photospheric temperature of 4700
K. KU Peg is one of the most massive, and currently the most evolved,
late-type star with a Doppler image. We obtained two independent
images from two consecutive stellar rotations covering 50 nights with
a total of 43 spectra. From a cross-correlation analysis of the two
maps, we detect systematic longitudinal and latitudinal shifts that we
tentatively interpret as latitude-dependent differential rotation and
local meridional flows, respectively. The differential-rotation pattern
is more complex than on the Sun, but on average in the sense that the
poles rotate slower than the stellar equator, i.e. in the same direction
and also of the same order than on the Sun. The latitudinal shifts
are of the order of 0.4° day-1 towards the stellar pole
and occur at longitudes of around 40° and 330°. The residual {Hα }
profiles show a stationary emission component at rest wavelength and a
blue-shifted absorption. The latter suggests an outward pointed velocity
field with a flow velocity of approximately 35 km s-1.

---------------------------------------------------------
Title: Time-series photometric spot modeling. IV. The multi-periodic
K5Ve binary V833 Tauri
Authors: Oláh, K.; Strassmeier, K. G.; Kovári, Zs.; Guinan, E. F.
2001A&A...372..119O Altcode:
We analysed all the existing photometric observations of V833 Tau and
found long-term variability on time scales of ~70 years, 6.5 years
and 2.4 years. Using V and IC-band data from 1990-2000,
we obtained starspot surface distributions from 20 suitable light
curves. We found that the spot-area changes generally follow the
long-term light variations. Spot temperatures are determined for each
of the datasets and an average value of 1230 K+/-270 K relative to
the photosphere is found. This value agrees with previous results
from TiO modeling (1330 K+/-110 K). Small scale spot temperature and
area changes are recovered during 1997-1999, that we explain with a
variable spot/faculae ratio. A powerful flare in UBV(RI)C
was observed in 1993 November. A 10 000 K fit yielded a total emitted
flare energy of more than 1034 ergs from an area of about
1.3% of the stellar surface, 60% of it in the V(RI)C
bands. The flare characteristics are compared to another, 100-times
smaller flare observed earlier in 1983.

---------------------------------------------------------
Title: High-Resolution Optical and Near-IR Spectropolarimetry and
Spectroscopy with the LBT
Authors: Strassmeier, K. G.
2001slbt.work..187S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: A study of the chromospherically active binaries UX Fornacis
and AG Doradus
Authors: Washuettl, A.; Strassmeier, K. G.
2001A&A...370..218W Altcode:
This paper presents a time-series spectrum analysis of the two
chromospherically active binary stars, UX Fornacis and AG Doradus. To
investigate the rotational behaviour, in combination with activity in
the Hα line, we obtained almost 40 high-resolution, high-S/N spectra
for each system. Both binaries, UX For and AG Dor, show Hα of the
primary star in absorption but filled in by chromospheric emission
while the Hα line of the secondaries appear in pure emission. Line
variations are seen and are approximately 5-sigma detections but are
not linked to the orbital nor the rotational periods and seem to be
erratic. We obtained new orbital elements for both systems and used
them in combination with Hipparcos parallaxes and our Hα -spectrum
synthesis to determine absolute parameters. We present the first
Doppler image of the AG Dor primary using line-profile variations of
the Fe i lambda 6546 line. The image reveals a cool polar feature and
three equatorial spots with an average surface temperature difference,
photosphere minus spots, of up to 1500 K for the polar spot and ~800 K
for the equatorial spots. Since AG Dor is one of the slowest rotators
(vsin i=18 km s-1 ) that has ever been Doppler imaged,
we present several tests to demonstrate the external consistency
of our map. Based on observations obtained at the European Southern
Observatory, La Silla, Chile.

---------------------------------------------------------
Title: On the rotation period of Capella
Authors: Strassmeier, K. G.; Reegen, P.; Granzer, T.
2001AN....322..115S Altcode:
We present differential Hα and Hβ photometry of the very bright RS
CVn-binary Alpha Aurigae (Capella) obtained with the Vienna automatic
photoelectric telescope in the years 1996 through 2000. Low-level
photometric variations of up to 0m.04 are detected in Hα. A
multifrequency analysis suggests two real periods of 106 +/- 3
days and 8.64 +/- 0.09 days, that we interpret to be the rotation
periods of the cool and the hot component of the Capella binary,
respectively. These periods confirm that the hotter component of
Capella rotates asynchronously, while the cooler component appears to
be synchronized with the binary motion. The combined Hα data possibly
contains an additional period of 80.4 days that we, however, believe is
either spurious and was introduced due to seasonal amplitude variations
or stems from a time-variable circumbinary mass flow. The rotational
periods result in stellar radii of 14.3 +/- 4.6 Rsun and 8.5 +/- 0.5
Rsun for the cool and hot component, respectively, and are in good
agreement with previously published radii based on radiometric and
interferometric techniques. The long-period eclipsing binary Aurigae
served as our check star, and we detected complex light variations
outside of eclipse of up to 0m.15 in Hα and 0m.20 in Hβ. Our frequency
analysis suggests the existence of at least three significant periods
of 132, 89, and 73 days. One of our comparison stars (HD 33167, F5V)
was discovered to be a very-low amplitude variable with a period of
2.6360 +/- 0.0055 days.

---------------------------------------------------------
Title: Differential Rotation Analysis of six Long-period K-giants
Authors: Weber, M.; Strassmeier, K. G.; Washuettl, A.
2001AGM....18..P89W Altcode: 2001AGAb...18R.179W
We computed Doppler maps for the stars IL Hya (K0III-IV,
Prot=12.9 days), HK Lac (K0III, 24.4 days), HD 218153(K0III,
24.96 days), HD 208472 (K0III, 22.6 days), IM Peg (K1III, 24.6 days),
and II Peg (K2IV, 6.7 days) based on observations taken at the National
Solar Observatory (NSO) with the McMath-Pierce main telescope using
the stellar spectrograph from October 1996 to January 1997 and, in
the case of IL Hya, also at Kitt Peak National Observatory (KPNO)
from March to May 2000. Depending on the rotational period of the
star, two (HD 218153) to five (II Peg) independent Doppler maps
were obtained. These consecutive Doppler maps were cross-correlated,
which resulted in ccf-maps that show the spot changes on the stellar
surface from one map to the other (typically with a time difference
of one to 1.5 stellar rotations). We then tried to fit a solar-like
differential rotation law (Ω(b) = Ω0 - Ω1
sin2 b) to the cross-correlation function (ccf) to get a
quantitative measure of the differential rotation. In this poster,
we present the full set of, so far unpublished, maps of our long-term
Doppler imaging program on K giants.

---------------------------------------------------------
Title: MUSICOS Observations of the Chromospherically Active Binary
Star EI Eridani
Authors: Washuettl, A.; Strassmeier, K.; Foing, B.
2001AGM....18..P50W Altcode: 2001AGAb...18Q.160W
We present results on spectroscopic observations of the rapidly-rotating
active binary star EI Eridani obtained during the MUSICOS multi-site
campaign in 1998. Seven sites around the globe were involved in order
to achieve a surface image within a few rotations as EI Eridani's
critical rotation period of 1.945 days makes it impossible to
obtain time-resolved images from a single site. The data were split
into groups in order to achieve consecutive, independent Doppler
Images. Furthermore, simultaneous photospheric and chromospheric
activity monitoring was carried out.

---------------------------------------------------------
Title: Doppler Imaging as a Test for Binary Star Formation Theories
Authors: Strassmeier, Klaus G.
2001IAUS..200..305S Altcode:
Photospheric Doppler images for both stellar components of the
double-lined spectroscopic binary V824 Ara reveal surface temperature
inhomogeneities of up to 1800 K on both stars. The absolute brightness
and the mass of the two stars suggest that they are very close to
the main sequence -- but not yet on the ZAMS -- if an inclination
of the orbital plane (and rotational axes) of 52 degrees is adopted
as suggested by the Doppler imaging. Since both stars are active,
we solve for the inclinations of the rotation axes of both stellar
components separately and emphasize that it can be used to test
coplanarity predictions from binary star-formation theories. We find
that the spin inclinations for the individual components of V824 Ara
agree to within their uncertainties.

---------------------------------------------------------
Title: The Multiple Periods and Spot Temperatures of V833 Tau
(CD-ROM Directory: contribs/olah1)
Authors: Oláh, K.; Strassmeier, K. G.
2001ASPC..223.1030O Altcode: 2001csss...11.1030O
No abstract at ADS

---------------------------------------------------------
Title: Latest Results in Doppler Imaging (CD-ROM Directory:
contribs/strass1)
Authors: Strassmeier, K. G.
2001ASPC..223..271S Altcode: 2001csss...11..271S
No abstract at ADS

---------------------------------------------------------
Title: Magnetic Activity in Binary Stars
Authors: Strassmeier, Klaus G.
2001LNP...563...48S Altcode: 2001bist.conf...48S
"Activity" is a term that came originally from solar astrophysics,
where astronomers refer to the quiet Sun and the active Sun depending
on whether our star is in a state of sunspot minimum or maximum,
respectively. More physically, we mean with activity all phenomena
inside and outside of a star that are related to its magnetic field,
e.g. the rise of flux tubes in a stellar convection zone and their
appearance as spots and plages on the stellar surface or magnetically
induced particle acceleration and its braking effect on the stellar
rotation, or simply the interplay between a magnetic field and its
surrounding plasma. Bear three things in mind, a magnetic field plays
a key role in many astrophysical processes, its mathematical treatment
can be somewhat complicated and, therefore, is always the first process
that is neglected. The stellar magnetic field is intimately related to
stellar rotation and the quest to understand stellar magnetic activity
is thus always a quest to understand stellar rotation. In this lecture,
we will focus on the many aspects of stellar rotation and compare the
situation of binary stars with their single star counterparts whenever
appropriate. I will concentrate on the available observations and their
interpretations even though that fundamental progress will also come
from the detailed inclusion of magnetic fields in, e.g., radiation
hydrodynamics. We emphasize how important considerations of magnetic
activity will become once the new generation of large telescopes is
turned to late-type binary stars. Parts of the topics in this lecture
are adapted and updated from my reference (111) which appeared in
German language. I have tried, however, to avoid topics that were
already covered in the excellent review by Guinan &amp; Giménez (36).

---------------------------------------------------------
Title: Automation Hardware &amp; Software for the STELLA Robotic
Telescope
Authors: Weber, M.; Granzer, Th.; Strassmeier, K. G.
2001AGM....18.P233W Altcode:
The STELLA telescope (a joint project of the AIP, Hamburger Sternwarte
and the IAC) is to operate in fully robotic mode, with no human
interaction necessary for regular operation. Thus, the hardware must
be kept as simple as possible to avoid unnecessary failures, and
the environmental conditions must be monitored accurately to protect
the telescope in case of bad weather. All computers are standard PCs
running Linux, and communication with specialized hardware is done via
a RS232/RS485 bus system. The high level (java based) control software
consists of independent modules to ease bug-tracking and to allow the
system to be extended without changing existing modules. Any command
cycle consists of three messages, the actual command sent from the
central node to the operating device, an immediate acknowledge, and
a final done message, both sent back from the receiving device to the
central node. This reply-splitting allows a direct distinction between
communication problems (no acknowledge message) and hardware problems
(no or a delayed done message). To avoid bug-prone packing of all the
sensor-analyzing software into a single package, each sensor-reading
and interaction with other sensors is done within a self-contained
thread. Weather-decision making is therefore totally decoupled from
the core control software to avoid dead-locks in the core module.

---------------------------------------------------------
Title: The STELLA Project: a 1.2m Robotic Telescope for
High-resolution Echelle Spectroscopy
Authors: Strassmeier, K. G.; Granzer, T.; Weber, M.; Woche, M.;
Hildebrandt, J.; Arlt, K.; Washuettl, A.; Bauer, S. -M.; Paschke,
J.; Roth, M.; Schmitt, J. H. M. M.; Hempelmann, A.; Hagen, A.
2001AGM....18.P232S Altcode:
In this poster, we present a brief overview and report on the status
of the STELLA project (abbreviation for STELLar Activity; see also
poster by Weber et al.). The STELLA telescope at the Teide Observatory
on the Island of Tenerife will be the first robotic telescope that
feeds a bench-mounted echelle spectrograph with a set of 50 and 100μm
fibres and provides resolutions of between 50,000 and 25,000. The
spectrograph is a FEROS-like design and will be located in a separated
temperature-controlled room within the STELLA building to guarantee
long-term stability. The building will be a roll-off roof building
capable of hosting two telescopes. First light for STELLA-1 is planned
for fall 2002.

---------------------------------------------------------
Title: Temperature Surface Imaging as a Tracer for Stellar Magnetic
Fields
Authors: Strassmeier, K. G.; Rice, J. B.; Granzer, T.; Weber, M.
2001ASPC..248..223S Altcode: 2001mfah.conf..223S
No abstract at ADS

---------------------------------------------------------
Title: Doppler Images of HD 218153 and HK Lac (CD-ROM Directory:
contribs/weber)
Authors: Weber, M.; Washuettl, A.; Strassmeier, K. G.
2001ASPC..223.1314W Altcode: 2001csss...11.1314W
No abstract at ADS

---------------------------------------------------------
Title: Doppler Imaging from Artificial Data. Testing the
Temperature-Inversion Code TempMap (CD-ROM Directory:
contribs/strass3)
Authors: Strassmeier, K. G.; Rice, J. B.
2001ASPC..223.1296S Altcode: 2001csss...11.1296S
No abstract at ADS

---------------------------------------------------------
Title: Doppler Imaging of the Pre-Main-Sequence Binary V824 Ara =
HD 155555 (CD-ROM Directory: contribs/strass4)
Authors: Strassmeier, K. G.; Rice, J. B.
2001ASPC..223.1302S Altcode: 2001csss...11.1302S
No abstract at ADS

---------------------------------------------------------
Title: Rapid Spot Changes on the RS CVn Binary V711 Tau = HR 1099
(CD-ROM Directory: contribs/bartus)
Authors: Bartus, J.; Strassmeier, K. G.
2001ASPC..223.1189B Altcode: 2001csss...11.1189B
No abstract at ADS

---------------------------------------------------------
Title: The Vienna-KPNO Search for Doppler-imaging
Candidates. Photometric Results (CD-ROM Directory: contribs/granzer1)
Authors: Granzer, Th.; Strassmeier, K. G.
2001ASPC..223.1226G Altcode: 2001csss...11.1226G
No abstract at ADS

---------------------------------------------------------
Title: On the Rotation Period of Capella (CD-ROM Directory:
contribs/strass5)
Authors: Strassmeier, K. G.; Reegen, P.; Granzer, Th.
2001ASPC..223.1069S Altcode: 2001csss...11.1069S
No abstract at ADS

---------------------------------------------------------
Title: STELLA: two new 1.2 m Robotic Telescopes for Monitoring
Stellar Activity
Authors: Strassmeier, Klaus G.
2001AGM....18JD102S Altcode:
STELLA (abbreviation for STELLar Activity) is a long-term project
for monitoring activity tracers on cool stars with fully robotic
telescopes. The first telescope, STELLA-1, feeds a bench-mounted echelle
spectrograph with a set of 50-100 μm fibres according to resolutions
of 50,000 to 25,000. The spectrograph is located in a separated
temperature controlled room to guarantee long-term stability. A
second telescope, STELLA-2, with identical dimensions, is foreseen
as a photometric/imaging telescope at the same site. STELLA-1 is a
joint venture of the Astrophysical Institute Potsdam (AIP) and the
Hamburger Sternwarte, STELLA-2 is a joint project of the AIP with the
University of Tübingen, both in close collaboration with the Instituto
de Astrofísica de Canarias. STELLA will be located at the Teide
Observatory on Tenerife. First light for STELLA-1 is planned for fall
2002. I will briefly outline the technical and operational highlights.

---------------------------------------------------------
Title: Latest Doppler images of the RS CVn Binary EI Eridani (CD-ROM
Directory: contribs/washuet)
Authors: Washuettl, A.; Strassmeier, K. G.; Collier-Cameron, A.
2001ASPC..223.1308W Altcode: 2001csss...11.1308W
No abstract at ADS

---------------------------------------------------------
Title: Star Spot Patterns on Young Stars: Theoretical Approach
(CD-ROM Directory: contribs/granzer2)
Authors: Granzer, Th.; Caligari, P.; Schüssler, M.; Strassmeier, K. G.
2001ASPC..223.1232G Altcode: 2001csss...11.1232G
No abstract at ADS

---------------------------------------------------------
Title: The Vienna-KPNO Search for Doppler-Imaging
Candidates. Spectroscopic Results (CD-ROM Directory: contribs/strass2)
Authors: Strassmeier, K. G.; Washuettl, A.; Granzer, Th.; Scheck,
M.; Weber, M.
2001ASPC..223.1291S Altcode: 2001csss...11.1291S
No abstract at ADS

---------------------------------------------------------
Title: Doppler imaging from artificial data. Testing the temperature
inversion from spectral-line profiles
Authors: Rice, J. B.; Strassmeier, K. G.
2000A&AS..147..151R Altcode:
We present extensive numerical tests of our temperature-based
image reconstruction code TempMap. Two test cases that represent
a rapidly-rotating low-inclination star and a moderately-rotating
high-inclination star are used for the forward problem. Tests are
then made to recover the original input map and include data errors
and input-parameter errors. The former include variations of photon
noise, continuum displacement, continuum slopes, scattered light in the
spectrograph, and phase gaps with and without continuum information. The
input-parameter tests include the confusion in the recovery of hot
versus cool spots, uncertainties of atmospheric parameters such as
radial-tangential macroturbulence and gravity, and the influence of
line strength and line damping. In general, we find that the geometric
information is less dependent on photon noise and on input errors than
the temperature information. Our test inversions also show that, at
the vsin i of these test cases, no significant gain in image quality
is achieved once S/N of 300:1 is surpassed.

---------------------------------------------------------
Title: The BF Aurigae system. A close binary at the onset of mass
transfer
Authors: Kallrath, J.; Strassmeier, K. G.
2000A&A...362..673K Altcode:
Because the question of the mass ratio of the early-type system BF
Aur has not yet fully been clarified, we present and analyse new UBV
photometry and nearly contemporaneous radial velocity observations. From
a simultaneous least squares analysis of the photometric light curves
and the new radial velocity curves we derive a mass ratio of q=1.048+/-
0.02. With even much more accurate photometric and spectroscopic
data the mass ratio remains weakly defined. The resulting stellar
parameters are consistent with line ratios derived from old and
our new spectra and available Strömgren indices. We confirm earlier
conclusions that BF Aur is detached and that the more massive component
is almost filling its Roche lobe. New data indicating a period change
support the interpretation that mass exchange has already started or
is about to start. Tables A1-A5 are available electronically only at
the CDS via anonymous ftp (130.79.128.5) ftp://cdsarc.u-strasbg.fr
or http://cdsweb.u-strasbg.fr/index.htm

---------------------------------------------------------
Title: Study of FK Comae Berenices --- II. Spot evolution from 1994
to 1997
Authors: Korhonen, H.; Berdyugina, S. V.; Hackman, T.; Strassmeier,
K. G.; Tuominen, I.
2000A&A...360.1067K Altcode: 2000astro.ph..7088K
We present new surface (Doppler) images of the late-type single giant
FK Com for June-July 1996, July-August 1996, April 1997 and June
1997. These images are compared with the previously published images
from 1994 and 1995. The consecutive maps are cross- correlated to see
the possible migration of the spots and the effects of differential
rotation. The cross-correlation confirms an average longitudinal
spot migration of 0.22 ± 0.03 in phase within a year. This movement
is probably an artifact caused by a difference between the accepted
rotation period and the real photometric period for these years. If
this is true, then the photometric rotation period for these years
is 2.d4037 ± 0.0005. Measurements from these four years and six maps
limit the surface differential rotation to α = 0.0001 ± 0.0002, where
α is the difference between polar and equatorial angular velocities
relative to the equatorial angular velocity. Based on the observations
obtained at the Nordic Optical Telescope, Observatorio Roque de los
Muchachos, La Palma, Canary Islands, Spain; the National Astronomical
Observatory, Rozhen, Bulgaria; the Kitt Peak National Observatory,
USA; the Automatic Photometric Telescope, Phoenix 10, Arizona, USA.

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure --- XIV. The
double-lined pre-main-sequence binary V 824 Arae = HD 155555
Authors: Strassmeier, K. G.; Rice, J. B.
2000A&A...360.1019S Altcode:
Photospheric Doppler images for both stellar components of the
double-lined pre-main-sequence binary V 824 Ara reveal surface
temperature inhomogeneities of up to 1800 K on both stars. The spot
geometry on the hotter primary is dominated by an elongated, tilted,
equatorial feature but our maps from two spectral regions consistently
also show a polar spot cooler by 1700 K. The secondary star has spots
mainly at low and very high latitudes but not a full-sized polar cap. A
flux-tube simulation with appropriate stellar models for V 824 Ara
suggests that any polar or high-latitude spot must have formed after
flux-tube emergence. Generally, the low-latitude spots on both stellar
components appear to be mostly concentrated on the hemispheres turned
away from each other while the asymmetry of the polar spot on the
primary points in the direction of the orbital motion. We present new
radial velocities and use them to re- evaluate the orbital elements and
to derive absolute parameters for both stellar components. The absolute
brightness and mass of the two stars suggest that they are very close to
the main sequence - but not yet on the ZAMS - if an inclination of the
orbital plane (and rotational axes) of 52̂ is adopted as suggested
by the Doppler imaging. Since both stars are active, we solve for
the inclinations of both stellar components separately and find that
the values agree to within their uncertainties. Based on observations
collected at the European Southern Observatory

---------------------------------------------------------
Title: Wolfgang-Amadeus: the University of Vienna twin robotic
photoelectric telescopes
Authors: Strassmeier, Klaus G.; Granzer, Thomas; Boyd, Louis J.;
Epand, Donald H.
2000SPIE.4011..157S Altcode:
We describe the operations model for our two robotic photoelectric
telescopes and give a brief status report after more than three years
of routine operation in southern Arizona. The telescopes operate fully
unattended, also the observatory itself is automatic. A site-control
computer monitors weather sensors and operates the roof while the
telescope control computers operate the photometers and accept input
files from and provides nightly observations to the astronomer in
Vienna. In the first three years of operation a total of 3.3 million
individual scientific measurements were made.

---------------------------------------------------------
Title: VizieR Online Data Catalog: BF Aur UBV photometry (Kallrath+,
2000)
Authors: Kallrath, J.; Strassmeier, K. G.
2000yCat..33620673K Altcode:
Because the question of the mass ratio of the early-type system
BF Aur has not yet fully been clarified, we present and analyse
new UBV photometry and nearly contemporaneous radial velocity
observations. From a simultaneous least squares analysis of the
photometric light curves and the new radial velocity curves we
derive a mass ratio of q=1.048+/-0.02. With even much more accurate
photometric and spectroscopic data the mass ratio remains weakly
defined. The resulting stellar parameters are consistent with the line
ratios derived from old and our new spectra and available Stroemgren
indices. We confirm earlier conclusions that BF Aur is detached and
that the more massive component is almost filling its Roche lobe. New
data indicating a period change support the interpretation that mass
exchange has already started or is about to start. (5 data files).

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. XIII. The
flaring RS CVn-binary HD 291095 = V1355 Orionis
Authors: Strassmeier, K. G.
2000A&A...357..608S Altcode:
We present the first Doppler images of the newly discovered RS CVn
binary HD 291095. The star is a synchronuously rotating subgiant in a
4-day spectroscopic binary with an unseen companion and is particularly
interesting because it is one of the few evolved stars that show large
flares. Three consecutive years of moderate-resolution KPNO spectra and
continuous VI and by photometry with our APTs reveal a large, cool, and
long-living asymmetric polar spot. Its temperature is approximately 1100
K below the average photospheric temperature. Several low latitude and
even equatorial spots were evident at the same time. We interpret this
latitudinal spot bimodality to be due to a combination of poleward
meridional circulation and more frequent magnetic reconnections
near the pole than near the equator. During the 1998 Doppler-imaging
observations, a strong flare in Hα was detected which coincided with
a meridian passage of the most asymmetric part of the polar spot. We
estimate a total flare energy of 5x1034 erg typical for
flares on very active RS CVn systems. No photospheric heating is
evident in our surface maps from optically thin spectral lines of
various temperature sensitivities.

---------------------------------------------------------
Title: Multiperiodic light variations of active stars
Authors: Oláh, K.; Kolláth, Z.; Strassmeier, K. G.
2000A&A...356..643O Altcode:
We studied the long-term light behaviour of ten rapidly-rotating active
stars (LQ Hya, V833 Tau, EI Eri, V711 Tau, BY Dra, HU Vir, IL Hya, VY
Ari, HK Lac, IM Peg) with Fourier analysis. Using photometric databases
of up to 30 years in length, we search for periodic or quasi-periodic
long-term variations of the overall light levels. Out of the ten
stars studied, nine show cyclic variability and six of those seem
to vary on two or multiple time-scales. Using additional data from
the literature, we found that cycle lengths were generally longer
for stars with longer rotation periods. The inverse Rossby numbers
of these stars show a correlation with omega cyc/Omega (=
Prot/Pcyc) calculated from the shortest cycle
length. The cycle lengths of several stars agree well with other types
of cycles determined earlier. Using artificial test data, we found that
the cyclic variation of the average light level is determined by the
change in the spot/plage coverage alone and that spot migration does
not play a significant role in the shape or length of the long-term
brightness changes.

---------------------------------------------------------
Title: The Vienna-KPNO search for Doppler-imaging candidate
stars. I. A catalog of stellar-activity indicators for 1058 late-type
Hipparcos stars
Authors: Strassmeier, K.; Washuettl, A.; Granzer, Th.; Scheck, M.;
Weber, M.
2000A&AS..142..275S Altcode:
We present the results from a spectroscopic Ca ii H&amp;K survey of
1058 late-type stars selected from a color-limited subsample of the
Hipparcos catalog. Out of these 1058 stars, 371 stars were found to
show significant H&amp;K emission, most of them previously unknown;
23% with strong emission, 36% with moderate emission, and 41% with
weak emission. These spectra are used to determine absolute H&amp;K
emission-line fluxes, radial velocities, and equivalent widths
of the luminosity-sensitive Sr ii line at 4077 Ä. Red-wavelength
spectroscopic and Strömgren y photometric follow-up observations
of the 371 stars with H&amp;K emission are used to additionally
determine the absolute Hα -core flux, the lithium abundance from the
Li i 6708 Å equivalent width, the rotational velocity vsin i, the
radial velocity, and the light variations and its periodicity. The
latter is interpreted as the stellar rotation period due to an
inhomogeneous surface brightness distribution. 156 stars were found
with photometric periods between 0.29 and 64 days, 11 additional
systems showed quasi-periodic variations possibly in excess of ~50
days. Further 54 stars had variations but no unique period was found,
and four stars were essentially constant. Altogether, 170 new variable
stars were discovered. Additionally, we found 17 new SB1 (plus 16
new candidates) and 19 new SB2 systems, as well as one definite and
two possible new SB3 systems. Finally, we present a list of 21 stars
that we think are most suitable candidates for a detailed study with
the Doppler-imaging technique. Tables A1--A3 are only available in
electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr
(130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html

---------------------------------------------------------
Title: Distribution of starspots on cool stars. II. Pre-main-sequence
and ZAMS stars between 0.4 Msun and 1.7 Msun
Authors: Granzer, Th.; Schüssler, M.; Caligari, P.; Strassmeier, K. G.
2000A&A...355.1087G Altcode:
We study the dynamics of magnetic flux tubes in young stars with masses
between 0.4 Msun and 1.7 Msun and for rotation
rates between 0.25 Omegasun and 63 Omegasun
. The resulting latitudinal emergence patterns at the stellar
surface are compared with observed distributions of starspots in
stellar latitude. The stellar models considered cover the range of
evolutionary stages from shortly after the Hayashi phase down to
the ZAMS, i.e. from the classical and weak-line T Tauri stars to
the alpha -Persei stars. We use numerical simulations to follow the
evolution of magnetic flux tubes from their origin at the bottom of the
convection zone up to near-surface layers. We find a strong increase of
emergence latitude with increasing rotation rate, a moderate decrease
with increasing stellar mass, and a stronger decrease with stellar
age. At very early evolutionary stages, when the central radiative
zone is still quite small, we find magnetic flux emergence both in
low latitudes as well as in the polar areas. High-latitude emergence
is predicted in slightly more evolved pre-main-sequence and young
main-sequence stars, but truly polar spots on these stars require an
additional transport mechanism acting after magnetic flux emergence at
the surface, probably meridional circulation or poleward slip of the
`anchored' part of the erupted flux tubes. We discuss our findings in
the light of the results obtained from Doppler-imaging studies.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Stellar activity of late-type stars
(Strassmeier+ 2000)
Authors: Strassmeier, K. G.; Washuettl, A.; Granzer, T.; Scheck, M.;
Weber, M.
2000yCat..41420275S Altcode:
We present the results from a spectroscopic CaII H&amp;K survey of 1058
late-type stars selected from a color-limited subsample of the Hipparcos
(Cat. &lt;I/239&gt;) catalog. Out of these 1058 stars, 371 stars were
found to show significant H&amp;K emission, most of them previously
unknown; 23% with strong emission, 36% with moderate emission, and 41%
with weak emission. These spectra are used to determine absolute H&amp;K
emission-line fluxes, radial velocities, and equivalent widths of the
luminosity-sensitive Sr II line at 4077Å. Red-wavelength spectroscopic
and Stroemgren y photometric follow-up observations of the 371 stars
with H&amp;K emission are used to additionally determine the absolute
Hα-core flux, the lithium abundance from the Li I 6708Å equivalent
width, the rotational velocity vsini, the radial velocity, and the
light variations and its periodicity. (3 data files).

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. XII. Rapid spot
changes on the RS CVn binary V711 Tauri = HR 1099
Authors: Strassmeier, K. G.; Bartus, J.
2000A&A...354..537S Altcode:
We present a time series of Doppler images of the RS CVn binary V711
Tauri from spectra taken during 57 consecutive nights in November and
December 1996. VRI-band APT photometry throughout the entire observing
season is used to support the Doppler imaging. A set of altogether
37 overlapping images from the Ca i-6439 line allows us to trace the
latitudinal and longitudinal migration of individual starspots and their
morphological evolution. We confirm the poleward migration scenario
discovered by Vogt &amp; Hatzes (\cite{vog:hat}) and obtain an average
latitudinal migration rate of +0.41+/-0.23 (rms) °/day. Of the five
spots detected, one was migrating clockwise and one counter clockwise
with respect to the orbital period. One feature possibly changed its
direction of migration. The two dominating polar features remained
at their respective longitudes. Therefore, we are unable to fully
attribute the poleward migration to differential rotation and suggest
that a combination of differential rotation, meridional circulation,
and local crosstalk between starspots causes the observed migration
pattern. For one low-latitude spot, the latitudinal migration was
briefly interrupted and seen to reverse before it resumed its poleward
migration. We possibly witnessed the merging of two spots after they
got too close to each other. One spot became significantly cooler
shortly before it merged with the bigger and already cooler polar spot,
suggesting that some flux exchange took place likely due to a partial
reconnection of their magnetic field lines. The polar spot appeared
in our images as a non-axisymmetric feature barely covering the actual
stellar rotation pole and was not a cap-like feature as seen in several
previous maps. Relative spot temperatures varied between 400 K for
the weakest features and 1100 K for the main polar spot.

---------------------------------------------------------
Title: Doppler imaging of magnetically-active stars
Authors: Strassmeier, Klaus G.; Weber, Michael; Washuettl, Albert;
Granzer, Thomas; Pichler, Thomas
2000noao.prop...44S Altcode:
Recent images from our KPNO Coude-feed program of long-period spotted
giant stars showed the largest surface spots yet discovered. Spots
sixty times larger than the entire Sun were recorded. In this proposal,
we will attempt to continue the mapping of further candidate stars. The
new targets are selected from the just finished Vienna-KPNO Ca II H&amp;
K survey (also done at the Coude feed) which discovered 371 new active
stars and produced twenty new Doppler-imaging candidates. Some of these
stars are the targets of this proposal. If the proposed targets of M-K
class IV and III indeed also show such large spots at intermediate
and/or high latitudes as suggested from our previous images, the
solar-based flux-tube model of Schussler et al. for the origin of
starspots must be reconsidered.

---------------------------------------------------------
Title: Doppler imaging of HD 218153 and HK Lac
Authors: Weber, M.; Strassmeier, K. G.; Washuettl, A.
2000ASPC..198..495W Altcode: 2000scac.conf..495W
No abstract at ADS

---------------------------------------------------------
Title: Doppler Imaging of Cool Dwarf Stars
Authors: Strassmeier, K. G.
2000vlms.conf..215S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The Vienna-KPNO search for Doppler-imaging candidate
stars. I. First spectroscopic results
Authors: Strassmeier, K. G.; Washuettl, A.; Granzer, Th.; Scheck,
M.; Weber, M.
2000ASPC..198..487S Altcode: 2000scac.conf..487S
No abstract at ADS

---------------------------------------------------------
Title: The Vienna-KPNO search for Doppler-imaging candidate
stars. II. First photometric results
Authors: Granzer, Th.; Strassmeier, K. G.
2000ASPC..198..491G Altcode: 2000scac.conf..491G
No abstract at ADS

---------------------------------------------------------
Title: A temperature calibration for MK-class III giants from
high-resolution spectral line-depth ratios
Authors: Strassmeier, K. G.; Schordan, P.
2000AN....321..277S Altcode:
A high-resolution spectroscopic survey in the 6380-6460 Å \ region
of 224 slowly-rotating M-K class III giants is presented. Spectral
line-depth ratios are calibrated against effective temperature obtained
from B-V and V-I color indices in the range 3200-7500 K (M6-A9). A
table of polynomial coefficients for 12 line-ratio-T_eff relations
can be used to derive T_eff of F-M stars to within 33 K (rms), and of
early-F and mid-to-late M stars to within 77-106 K (rms).

---------------------------------------------------------
Title: VizieR Online Data Catalog: Photometric monitoring of 47
late-type stars (Strassmeier+, 1999)
Authors: Strassmeier, K. G.; Serkowitsch, E.; Granzer, T.
1999yCat..41400029S Altcode:
We present continuous multicolor photometry for 47 stars from October
1996 through June 1997. Altogether, 7073 V(RI)c, UBV,
and by data points, each the average of three individual readings,
were acquired with three automatic photoelectric telescopes (APTs)
at Fairborn Observatory in southern Arizona. Most of our targets are
chromospherically active single and binary stars of spectral type
G to K but there are also four pre-main-sequence objects and three
pulsating stars in our sample. The light variability is generally due
to rotational modulation of an asymmetrically spotted stellar surface
and therefore precise rotational periods and their seasonal variations
are determined from Fourier analysis. We also report on photometric
variations of γ CrB (A0V) with a period of 0.44534 days. All data
are available in numerical form. (6 data files).

---------------------------------------------------------
Title: Starspot photometry with robotic telescopes. UBV(RI)_C and
by light curves of 47 active stars in 1996/97
Authors: Strassmeier, K. G.; Serkowitsch, E.; Granzer, Th.
1999A&AS..140...29S Altcode:
We present continuous multicolor photometry for 47 stars from
October 1996 through June 1997. Altogether, 7073 V(RI)_c, UBV,
and by data points, each the average of three individual readings,
were acquired with three automatic photoelectric telescopes (APTs)
at Fairborn Observatory in southern Arizona. Most of our targets are
chromospherically active single and binary stars of spectral type
G to K but there are also four pre-main-sequence objects and three
pulsating stars in our sample. The light variability is generally due
to rotational modulation of an asymmetrically spotted stellar surface
and therefore precise rotational periods and their seasonal variations
are determined from Fourier analysis. We also report on photometric
variations of gamma CrB (A0V) with a period of 0.44534 days. All
data are available in numerical form. All data are available from
CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via
http://cdsweb.u-strasbg.fr/Abstract.html

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. XI. The super
starspots on the K0 giant HD 12545: larger than the entire Sun
Authors: Strassmeier, K. G.
1999A&A...347..225S Altcode:
The active K0 giant HD 12545 is the star with the largest starspots
ever observed. We report a record light-curve amplitude of 0\fm63 in
V and 0\fm17 in V-I in January 1998. At the same time, HD 12545 was at
its brightest magnitude since the discovery of its light variability in
1985. We present the first Doppler image of HD 12545 from observations
during this state of high-amplitude light variability and find that
the star exhibits one cool high-latitude spot of gigantic dimensions
(~12x20 solar radii, i.e. 60 times the extension of the largest sunspot
group or 10,000 times larger areal coverage). Furthermore, our map
shows one smaller cool spot and one equatorial warm (bright) spot. The
warm spot is situated approximately 180 degr from the large cool spot
in the opposite hemisphere and is the cause of the exceptionally large
light-curve amplitude and the stellar brightening. Within our model,
no light-curve nor a reasonable line-profile solution with only cool
spots was possible. Surprisingly, the fact that HD 12545 is brighter at
a time of high spot activity is in agreement with solar analogy. Our
data also allow to refine the orbital elements of HD 12545 and we use
the Hipparcos parallax to determine absolute astrophysical quantities
for this rapidly rotating K giant.

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. X. The FK
Comae-type star HD 199178 = V 1794 Cygni
Authors: Strassmeier, K. G.; Lupinek, S.; Dempsey, R. C.; Rice, J. B.
1999A&A...347..212S Altcode:
Doppler imaging is used to derive the surface temperature distribution
of the FK Comae star HD 199178 for five observing epochs between 1988
and 1997. Our maps are mainly based on Ca i 6439-Ä line profiles
and simultaneous and contemporary BV and VI photometry. All images
of HD 199178 are characterized by a large polar spot and several
low-latitude spots with an average surface temperature difference,
photosphere minus spots, of 710+/-260(rms) K for the equatorial spots,
~1700 K for the polar spot, and 1300+/-300(rms) K for the polar-spot
appendages. The lifetime of some of the low-latitude spots was found
to be as short as one month or even less. The lifetime of the polar
spot and most of its very cool appendages must exceed the time of our
observations, i.e. 9 years or approximately 1000 stellar rotations, and
could be as long as 12 years since its discovery by Vogt in 1985. Two
consecutive Doppler maps in 1989 show no evidence for differential
surface rotation, nor is there substantial evidence for the existence
of active longitudes in any of our five images. Instead, we suspect
that most of the time variability of the surface features on HD 199178
is short term and possibly chaotic in origin. We conclude that spot
lifetimes estimated from the timing of light-curve minima could lead
to grossly overestimated lifetimes of individual spots. With the aid
of our optical spectra and the Hipparcos parallax, we redetermine the
absolute stellar parameters of HD 199178 and confirm it to be a single
G5III-IV star and find 1.65 M_sun and 11 L_sun with T_eff~ 5450 K,
log g=2.5, and solar abundances.

---------------------------------------------------------
Title: Wechselvolles Antlitz: Flecken auf der Sonne und auf Sternen.
Authors: Strassmeier, K. G.
1999S&WSp...4...42S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Orbital elements and physical parameters of ten
chromospherically active binary stars
Authors: Fekel, F. C.; Strassmeier, K. G.; Weber, M.; Washuettl, A.
1999A&AS..137..369F Altcode:
Orbital elements have been determined for 10 chromospherically active
binaries from a combination of new velocities and velocities in the
literature. First orbits for three binaries, HD 33363, HD 152178,
and HD 208472, are presented, as well as updated orbits for seven
other binaries. Two of the latter systems, LN Peg and HD 106225 were
discovered to be triple, and both short- and long-period orbits have
been computed for each. Fundamental properties have been determined
for the chromopherically active primary in each system. Appendix
A and Tables A1 to A15 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/Abstract.html

---------------------------------------------------------
Title: VizieR Online Data Catalog: 10 active binary radial velocities
(Fekel+, 1999)
Authors: Fekel, C.; Strassmeier, K. G.; Weber, M.; Washuettl, A.
1999yCat..41370369F Altcode:
Orbital elements have been determined for 10 chromospherically active
binaries from a combination of new velocities and velocities in the
literature. First orbits for three binaries, HD 33363, HD 152178,
and HD 208472, are presented, as well as updated orbits for seven
other binaries. Two of the latter systems, LN Peg and HD 106225 were
discovered to be triple, and both short- and long-period orbits have
been computed for each. Fundamental properties have been determined
for the chromospherically active primary in each system. (2 data files).

---------------------------------------------------------
Title: Evolved, single, slowly rotating ... but magnetically
active. The G8-giant HR 1362 = EK Eridani revisited
Authors: Strassmeier, K. G.; Stȩpień , K.; Henry, G. W.; Hall, D. S.
1999A&A...343..175S Altcode:
We rediscuss the unusual case of the slowly rotating late-type giant HR
1362, which exhibits a very unusual high level of magnetic activity. New
BVRI photometry from two robotic telescopes from 1991 through 1998
together with previously published photometric data gives a very precise
photometric period of 306.9+/-0.4 days. With the aid of high-resolution
(R=120,000) optical spectra and the Hipparcos parallax we redetermine
the absolute parameters of HR 1362 and find it to be a single G8IV-III
star of 14 L_sun and a mass of 1.85 M_sun with T_eff=5125 K, log g=3.25,
and solar abundances. Lithium is not significantly different from
solar and we obtain log n(Li)=1.14 from a detailed spectrum synthesis
including both isotopes at 6708 Angstroms. Vsin i and macroturbulence
are determined from fits of disk-integrated models to the observed line
profiles as well as their Fourier transforms and are 1.5+/-0.5 km s(-1)
\ and ~5 km s(-1) , respectively. The minimum radius from vsin i and
P_rot is only then in agreement with the spectral classification and the
bolometric luminosity from the Hipparcos parallax if the inclination of
the stellar rotation axis is nearly 90°. We concur with the arguments
of Stȩpień (\cite{step}) that HR 1362 is an evolved Ap star, and
therefore the magnetic field is possibly of galactic origin rather
than dynamo generated.

---------------------------------------------------------
Title: a Survey for Rapidly-Rotating ca II H&amp; K Emission-Line
Stars
Authors: Strassmeier, Klaus G.; Washuettl, Albert; Granzer, Thomas
1999noao.prop...22S Altcode:
The existence of ultra-rapidly rotating G-K stars in open clusters has
been explained by a loss of braking due to dynamo saturation. However,
there is an alternative explanation, namely that these stars all
have their magnetic fields concentrated in polar spots and thus
have no torque arms for efficient braking. In the present program,
we propose to search for new G-K rapid rotators in the field (because
they are much brighter) - especially in the Hertzsprung gap - by means
of a spectroscopic survey of Ca II H&amp; K emission in a brightness
and color-limited sample of Hipparcos stars. Strong Ca II H&amp; K
emission is indirectly a sign of rapid rotation and an extended sample,
especially of evolved G-K stars, is urgently needed to test the polar-
spot hypothesis. In the first part of this survey, carried out with
the coudee feed in September 1998, covering right ascensions between
18^h and 5^h, we identified 118 new H&amp; K emission line stars out
of 469 targets observed. The present proposal aims to complete the
sky coverage for right ascensions between 6^h and 17^h.

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. IX. A
high-resolution image of the weak-lined T Tauri star HDE 283572 =
V987 Tauri
Authors: Strassmeier, K. G.; Rice, J. B.
1998A&A...339..497S Altcode:
We present a Doppler image of the T Tauri star HDE 283572 from a set of
high-quality spectroscopic line profiles and simultaneous multicolor
photometry from October 1997. Additional photometry throughout the
entire observing season was obtained with a robotic telescope and is
used to determine the precise photometric period of 1.5495+/-0.0002
days that we interpret to be the stellar rotation period. Further
relevant astrophysical parameters like mass, luminosity, radius,
effective temperature, gravity, and elemental abundances are obtained
and discussed. HDE 283572 shows one of the largest and coolest polar
spots ever observed and confirms an earlier map by Joncour et al. from
Pic-du-Midi data. We also compare our map with predicted magnetic
flux-tube distributions from MHD simulations and suggest that the
polar spot on HDE 283572 was possibly created by a strong poleward
meridional flow.

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. VII. The very
young, single K2-dwarf LQ Hydrae
Authors: Rice, J. B.; Strassmeier, K. G.
1998A&A...336..972R Altcode:
A Doppler image of the young K2V star LQ Hya is presented for March 1995
and is compared with earlier images taken in 1991 and 1993. Comparison
is also made with a recently completed image of EK Dra, another young
star that is more nearly one solar mass than LQ Hya. The image for
1995 seems to show a consistent pattern of spot concentration to
the equatorial region in either a continuous wide band of features
averaging only about 600 K cooler than photospheric or perhaps a
double band symmetrically located either side of the equator like the
solar pattern. A weak polar feature is evident but it is apparently a
somewhat less pronounced depression in temperature than seen in 1991
and of reduced area. The polar feature is less pronounced than that of
EK Dra and the spot pattern at the equator of LQ Hya does not extend to
latitudes as far toward the poles as does the pattern of spots at the
equatorial and mid-latitudes of EK Dra. When these results are compared
with theoretical predictions for the location of spots on such young
stars of solar mass, it appears surprising that the observations for
LQ Hya and EK Dra are not reversed given that LQ Hya is apparently
significantly less massive than EK Dra.

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. VIII. The
effectively single and rapidly-rotating G8-giant HD 51066 = CM
Camelopardalis
Authors: Strassmeier, K. G.; Bartus, J.; Kovari, Zs.; Weber, M.;
Washuettl, A.
1998A&A...336..587S Altcode:
We present first Doppler images of HD 51066 from observations in 1994,
1995, 1996 and 1997, and find evidence for a vanishing polar spot in
accordance with the system's long-term brightness increase. Several
small spots with Delta T~500 K appear also at low latitudes. Our
cross-correlation maps indicate a latitude-dependent phase-shift pattern
between annual maps. New and continuous BVRI photometry from 1996 to
1998 is presented and suggest a photometric period of 16.053+/-0.004
days, that we interpret to be the stellar rotation period. Additional
optical spectroscopy and the Hipparcos data are used to obtain absolute
stellar parameters for HD 51066. A comparison with evolutionary tracks
and the assumption of angular-momentum and magnetic-flux conservation
suggest that the main-sequence progenitor was a very rapidly-rotating Bp
star with a several kiloGauß\ magnetic field. We also examine the Hα
line profiles in this star and find some evidence that its equivalent
width is modulated with the stellar rotation period in phase with the
photospheric starspots. Our radial velocities indicate that HD 51066 is
likely a long-period (~10 yrs) spectroscopic binary and a preliminary
orbit is presented. We emphasize that HD 51066 is an interesting
target for studies of evolutionary angular-momentum loss because it
is effectively single, significantly evolved but still rapidly rotating.

---------------------------------------------------------
Title: Pulsation in lambda Bootis stars
Authors: Paunzen, E.; Weiss, W. W.; Kuschnig, R.; Handler, G.;
Strassmeier, K. G.; North, P.; Solano, E.; Gelbmann, M.; Kuenzli,
M.; Garrido, R.
1998A&A...335..533P Altcode:
In this paper we present a further step in applying asteroseismic
techniques to the group of lambda Bootis stars which can be
characterized as nonmagnetic A to F-type Population I dwarfs with
significant (surface) underabundances of Fe-peak elements. Since
no conclusive theory explaining the origin of the observed abundance
anomalies exists, an extensive photometric survey for pulsation in this
group has been initiated. Knowledge about the pulsational properties
(most members are located within the classical instability strip)
could help to establish constrains about the overall abundance of
these stars as well as on the evolutionary status. New photometric
observations were carried out for eleven stars. Variability was detected
in four stars (e.g. lambda Bootis itself) whereas the remaining seven
objects are probably constant. In total, 52 members of this group have
been photometrically investigated so far. With 22 pulsating and 30
“constant” stars, we derive a ratio of at least 50 % for variable
to nonvariable members inside the classical instability strip. This
result is based on high quality Hipparcos and new photometric data. The
observed log /lineρ//lineρ_⊙ and log P values for the pulsating
members are compatible with standard (solar abundant) delta Scuti
models supporting the hypothesis that the found abundance anomalies are
restricted to the surface only. Otherwise the pulsational properties
of this group are not outstanding compared to “normal” delta Scuti
stars, indicating that the mechanism driving the pulsations is very
similar. Based on observations obtained at ESO-La\,Silla, CTIO, SAAO,
McDonald Observatory, Instituto Astrofisica Andalucia Observatory and
with the Hipparcos satellite

---------------------------------------------------------
Title: Aktive Sterne. Laboratorien der solaren Astrophysik.
Authors: Strassmeier, K. G.
1998S&W....37..622S Altcode:
Magnetically active stars show similar activity cycles as one can
observe on the Sun. In this paper an overview of the solar activity
cycle and its relation to the magnetic field is given and compared with
observations of solar-like stars. Furthermore observations concerning
extrasolar planets around solar-like stars are briefly discussed.

---------------------------------------------------------
Title: HD 84800: A new delta Scuti variable
Authors: Paunzen, E.; Strassmeier, K. G.; Weiss, W. W.
1998IBVS.4566....1P Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Spectroscopic and photometric variations of HR 5
Authors: Weber, M.; Strassmeier, K. G.
1998IBVS.4573....1W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: A CAII H&amp;K survey of gamma Doradus candidates
Authors: Kaye, Anthony B.; Strassmeier, Klaus G.
1998MNRAS.294L..35K Altcode:
In an investigation of the starspot hypothesis as it applies to
the `slowly variable' F-type dwarfs, we spectroscopically observed
eight promising gamma Doradus candidates to search for Caii H&amp;K
emission. We found that there are no significant emission reversals
in the cores of these resonance lines. Based on the ceiling flux
calculations of the Caii K line and on calculations of the Rossby
number, we conclude that there is no support for the presence of strong
magnetic activity and the starspot hypothesis in these objects.

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. VI. HD 129333 =
EK Draconis: a stellar analog of the active young Sun
Authors: Strassmeier, K. G.; Rice, J. B.
1998A&A...330..685S Altcode:
We present the first Doppler images of the single G1.5V-star EK
Draconis from high-resolution CFHT spectra obtained in 1995. EK Dra
is an important target for investigating the evolution of stellar
magnetism because it resembles the rapidly-rotating young Sun. From
the inversion of a total of 12 spectral lines we reconstruct several
cool spots at low and medium latitudes but the dominating feature
is located consistently at a latitude of ~70-80° , thus, at far
higher latitudes than where our Sun shows spots. In fact, our data
indicate that this feature could be an appendage of a larger polar
cap-like spot as seen on other rapidly-rotating stars, however, due
to the small vsin i of just 17.3+/-0.4 kms(-1) \ the cap's existence
remains inconclusive. Spot temperatures between Delta T~1200 K and
400 K are recovered. We have used the non-parametrized convective-flux
description of Canuto &amp; Mazzitelli for our input model atmospheres
and found good agreement with local line profiles computed from
standard mixing-length atmospheres. New phase-resolved UBVRI data
spanning the 1996/97 observing season indicate a surprisingly short
photometric period of 2.599+/-0.001 days, which is different by 7%
from the longest seasonal period found so far but in good agreement
with the long-term photometric period of 2.605 days. We interpret these
differences as being due to differential surface rotation and adopt the
long-term photometric period to be the rotation period of EK Dra. Our
data also confirms the continuing decline of the mean brightness seen
since 1994 and we suspect the high-latitude feature to be the cause.

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. V. The
long-period RSCVn binary HD81410 = ILHydrae
Authors: Weber, M.; Strassmeier, K. G.
1998A&A...330.1029W Altcode:
Multiwavelength Doppler images of the long-period RS CVn binary IL
Hydrae from March 1994 and Feb.-March 1995 reveal a cool polar spot
and several features at low latitudes. Their average temperature is
approximately 500K below the photospheric temperature of 4700K. Due
to the relatively small rotational velocity of 26.5+/-1 kms(-1)
\ and the relatively cool, low-gravity atmosphere with many weak
absorption blends, Doppler imaging of IL Hydrae is challenging but
resulted in encouragingly similar maps from altogether seven spectral
regions near 6400 Angstroms. Latitude-dependent differential rotation
is detected from our Doppler maps and indicate faster rotation at
the stellar equator as compared to the polar regions. Lines from the
secondary component are sometimes seen in our red-wavelength spectra
and a double-lined spectroscopic orbit is presented. We also give
a more precise rotational period from three consecutive years of
V-band photometry. A spectral classification of K0III-IV and a mass
of 2.2+/-0.2 M_sun for the primary, and mid to late F main sequence
or maybe ~G0V-IV and a mass of 1.3+/-0.2 M_sun for the secondary, are
suggested. Hα \ equivalent widths measured over a single rotation cycle
exhibit a sinusoidal variation in phase with the photospheric V-band
light curve. The maximum of the residual Hα \ emission coincides with
the lightcurve minimum and is thus likely linked to the starspot-covered
stellar surface. A steady, redshifted absorption component possibly
indicates an isotropic inward flow at the Hα \ line-forming region
at approximately 60 kms(-1) .

---------------------------------------------------------
Title: Doppler Imaging of the Young, Single, Solar-Type Stars LQ
Hya and EK DRA
Authors: Strassmeier, K. G.; Rice, J. B.
1998ASPC..154.2048S Altcode: 1998csss...10.2048S
This poster paper presents the first Doppler image of a truly solar-like
star (EK Dra) and a further image of the ZAMS K-dwarf LQ Hya from
1995. EK Dra shows a very high latitude spot feature close to the
rotation pole while the more rapidly-rotating star LQ Hya has more
like a low-latitude band of spots.

---------------------------------------------------------
Title: MUSICOS Observations of SU AUR
Authors: Unruh, Yvonne C.; Donati, J. -F.; Balona, L.; Bohm, T.;
Cao, H.; Catala, C.; Collier Cameron, A.; Ehrenfreund, P.; Foing,
B.; Granzer, T.; Hao, J.; Hatzes, A.; Henrichs, H.; Johns-Krull,
C.; de Jong, J.; Kennelly, T.; Landstreet, J.; Morrison, N.; Mullis,
C.; Neff, J.; Oliveira, J.; Schrijvers, C.; Simon, T.; Stempels, E.;
Strassmeier, K. G.; Telting, J.; Walton, N.
1998ASPC..154.2064U Altcode: 1998csss...10.2064U
We present first results of the high-resolution observations of SU Aur
obtained through the MUSICOS network in 1996 Nov. The data set is unique
in that it gives us complete phase coverage for almost two rotation
periods of SU Aur. This is particularly valuable for T Tauri stars as
they can vary dramatically on the time scale of one rotation period.

---------------------------------------------------------
Title: From Top to Bottom --- the Multiwavelength Campaign of V824
ARA (HD 155555)
Authors: Dempsey, Robert; Neff, James; Strassmeier, Klaus; Linsky,
Jeffrey; Lim, Jeremy; Donati, J. -F.; Walter, Fred; Budding, Edwin;
Marang, Fred; Jordan, Ian; Walker, Stan; Downing, David G.; Inwood,
Doug; Petterson, Orlon
1998ASPC..154.1402D Altcode: 1998csss...10.1402D
In the spring of 1996, we conducted a multiwavelength campaign on V824
Ara (HD 155555, P=1.68d, G5 IV + K0 IV-V) covering one continuous,
complete rotation cycle. At the core of this campaign were observations
using the GHRS on HST. In all, ~46,000 spectra, many in rapid
readout mode, were obtained with the GHRS covering the C IV, Mg II,
and Fe XXI wavelength regions at 11-15 separate phases. Simultaneous
observations were made with the EUVE. Radio observations (3.5 &amp;
6 cm) were conducted at the Australian Telescope while ground based
optical spectroscopic and photometric observations were made at ESO,
CTIO, AAT and SAAO. Additional amateur photometry were obtained
from New Zealand before, during, and after the campaign. Our primary
intent is to obtain a 3-D model of the atmosphere, extending from the
photosphere to the corona. Variability was clearly detected including
several flares observed in the HST, EUVE and radio data. We present
preliminary results from modeling the UV Transition region (TR)
lines using an anisotropic macroturbulence model proposed by Gray
(1976, The Observation and Analysis of Stellar Photospheres, Cambridge
Astrophysics Series). Previous studies of TR lines in late-type active
stars have used multiple gaussians to fit the observed line profiles,
adding additional, broad components to account for the extended wings
observed in several active systems including V711 Tau (HR 1099). This
broad component has been interpreted as arising from the continuous
presence of microflaring (Wood et al., 1995, ApJ, 458, 761). We discuss
how anisotropic macroturbulence can also fit the Mg II profiles and,
in some cases, with smaller residuals than is possible using only
gaussians.

---------------------------------------------------------
Title: From Top to Bottom: The Multiwavelength Campaign of V824 ARA
(HD 155555)
Authors: Dempsey, Robert; Neff, James; Strassmeier, Klaus; Linsky,
Jeffrey; Lim, Jeremy; Donati, J. -F.; Walter, Fred; Budding, Edwin;
Marang, Fred; Jordan, Ian; Walker, Stan; Downing, David G.; Inwood,
Doug; Petterson, Orlon
1998fmml.conf.....D Altcode:
A great deal of progress has been made in recent years in decomposing
the 2-D structure in the atmospheres of late-type stars. Doppler
images of many photospheres - single stars, T Tauri stars, Algols,
RS CVn binaries to name a few are regularly published. Ultraviolet
spectral images of chromospheres appear in the literature but are
less common owing to the difficult nature of obtaining complete
phase coverage. Zeeman doppler images of magnetic fields are now
feasible. Performing Doppler imaging of the same targets over
many seasons has also been accomplished. Even when a true image
reconstruction is not possible due to poor spectral resolution, we can
still infer a great deal about spatial structure if enough phases are
observed. However, it is increasingly apparent that to make sense of
recent results, many different spectral features spanning a range of
formation temperature and density must be observed simultaneously for
a coherent picture to emerge. Here we report on one such campaign. In
1996, we observed the southern hemisphere RS CVn binary V824 Ara
(P=1d.68, G51V+K0V-IV) over one complete stellar rotation with the
Hubble Space Telescope and EUVE. In conjunction, radio and optical
photometry and spectroscopy were obtained from the ground. Unique to
this campaign is the complete phase coverage of a number of activity
proxy indicators that cover source temperatures ranging from the
photosphere to the corona.

---------------------------------------------------------
Title: Doppler Imaging of the RS CVn Binary IL Hydrae
Authors: Weber, M.; Strassmeier, K. G.
1998ASPC..154.1366W Altcode: 1998csss...10.1366W
We present preliminary results of a study linking rotational period to
photospheric surface activity derived from Doppler images. New Doppler
images of 15 stars of spectral classification G to K, luminosity
class III to V and rotational periods of 1.5 to 25 days have been
computed. These Doppler images - along with previously published
material - were averaged into latitudinal strips and their temperature
distribution correlated with evolutionary status and rotational period.

---------------------------------------------------------
Title: Photometric Monitoring of Spotted T Tauri Stars
Authors: Granzer, Th.; Strassmeier, K. G.
1998cvsw.conf..229G Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Stellar Variability as a Tool in Astrophysics. A Joint Research
Initiative in Austria
Authors: Strassmeier, Klaus G.
1998RvMA...11..197S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Hα Line-Profile Variability in Chromospherically Active Stars
Authors: Weber, M.; Washuettl, A.; Strassmeier, K. G.
1998cvsw.conf..231W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Evolved Stars: What Happens to Activity Off the Main Sequence
Authors: Strassmeier, K. G.; Fekel, F. C.; Gray, D. F.; Hatzes, A. P.;
Schmitt, J. H. M. M.; Solanki, S. K.
1998ASPC..154..257S Altcode: 1998csss...10..257S
Magnetic activity on the main sequence has been well studied, in
contrast to researches on sub-giants, giants, and supergiant stars. In
this discussion we will address three main topics associated with
activity in evolved stars: (1) rotation regimes for evolved stars;
(2) rotation-activity relations in the H-R diagram; (3) polar spots.

---------------------------------------------------------
Title: Doppler Imaging of EI Eridani
Authors: Washuettl, Albert; Strassmeier, Klaus G.; Collier-Cameron,
Andrew
1998ASPC..154.2073W Altcode: 1998csss...10.2073W
We present Doppler images of the rapidly rotating active close
binary star EI Eridani. Several Doppler images have been produced
since 1984 making use of different versions of the Doppler imaging
technique. They all show high-latitude spots surrounding or covering the
rotational pole as well as some smaller spots on lower latitudes. The
high-latitude/polar spot seems to be long-lived (at least a decade) but
changes its shape on comparatively short timescales (of the order of one
month). From time to time spots along the stellar equator also occur,
but their lifetimes tend to be relatively short (weeks). Furthermore,
long-term photometric observations revealed the existence of a magnetic
cycle which has been estimated to be around 11 years. We also present
time-resolved Doppler images from EI Eri obtained at McMath/NSO in
fall 1996 during 70 consecutive nights. The final aim of this program
is to investigate the spot evolution over the whole activity cycle.

---------------------------------------------------------
Title: Predicted Starspot Distributions on Pre-MS Stars
Authors: Granzer, Th.; Strassmeier, K. G.; Schussler, M.; Caligari, P.
1998ASPC..154.1977G Altcode: 1998csss...10.1977G
We present an application of the magnetic flux-tube model of Caligari
(1995, 1991) to pre-main-sequence stars. This model was originally
designed as an explanation for sunspots. The primary goal is to
derive the emerging latitude of flux tubes for a large parameter
volume including stellar mass, age, and rotational period. Since the
original model worked well in explaining certain sunspot features,
the next step would be to compare our model predictions with observed
starspot distributions obtained by Doppler imaging techniques.

---------------------------------------------------------
Title: Photospheric and chromospheric activity of the bright and
single G5 dwarf HR 4864 = HD 111395
Authors: Strassmeier, K. G.; Granzer, Th.; Weber, M.
1997IBVS.4538....1S Altcode:
We present new photometric and spectroscopic data for HR 4864 and
conclude that the star is a spotted and chromospherically active
solar-type star.

---------------------------------------------------------
Title: A large X-ray flare on HU Virginis
Authors: Endl, M.; Strassmeier, K. G.; Kurster, M.
1997A&A...328..565E Altcode:
We present two ROSAT-HRI observations of the RS CVn-type binary
HU Virginis (=HD 106225). The first observation covers almost three
consecutive rotation cycles of HU Virginis or a total of 26.7 days and
an exposure time of 35 ksec. On JD 2,449,544 a long duration flare
was detected and observed for 1.5 days. This event was releasing
a total energy of ~ 7.7(+3.3}_{-1.9) x 10(36) erg in the 0.1-2.4
keV bandpass. The good coverage of the onset and maximum phase of
the flare light curve allowed a detailed comparison with two solar
flare models. We derived an estimate for the size of the active region
responsible for the flare. The resulting loop size is of the order of
one stellar radius. One year later, in 1995, HU Virginis was again
observed by ROSAT continuously for 8 days and a total exposure time
of 69 ksec. The X-ray flux shows variability on time scales shorter
than the rotational period.

---------------------------------------------------------
Title: Starspot photometry with robotic telescopes: Continuous UBV
and V(RI)_C photometry of 23 stars in 1991-1996
Authors: Strassmeier, K. G.; Bartus, J.; Cutispoto, G.; Rodono, M.
1997A&AS..125...11S Altcode:
We report on the progress of our ongoing photometric monitoring program
of spotted late-type stars with automatic photoelectric telescopes
(APTs) on Mt. Hopkins in Arizona and on Mt. Etna in Sicily. We present
9,250 differential UBV and/or V(RI)_C observations for altogether 23
chromospherically active stars, singles and binaries, pre main sequence
and post main sequence, taken between 1991 and 1996. The variability
mechanism of our target stars is mostly rotational modulation by an
asymmetrically spotted stellar surface. Therefore, precise rotational
periods and their seasonal variations are determined using baselines
between 3 years for HD 129333 to 34 years for V410 Tauri. We report the
largest V light-curve amplitude of any spotted star observed to date:
0.65" for V410 Tau in 1994-95. Long-term variations of the overall light
levels of our target stars are sometimes of similar amplitude as the
rotational modulation itself and are most likely caused by an analog
of the solar 11-year spot cycle but mostly without a well-defined
periodicity. For some of our target stars (HD 12545, HD 17433, EI
Eri, V410 Tau, LQ Hya, and HD 106225) we estimate a probable cycle
period. A complete light curve of the semi-regular S-type giant HR
Pegasii is presented. All data are available via the WorldWideWeb. Data
are available at the CDS via anonymous ftp.

---------------------------------------------------------
Title: Wolfgang-Amadeus: The University of Vienna Twin Automatic
Photoelectric Telescope
Authors: Strassmeier, K. G.; Boyd, L. J.; Epand, D. H.; Granzer, Th.
1997PASP..109..697S Altcode:
We describe the University of Vienna twin automatic photoelectric
telescope (APT) located at the new Fairborn Observatory at Washington
Camp in southern Arizona. Not only are the telescopes fully automatic,
also the observatory itself is automatic. A site-control computer
monitors weather sensors and operates the roof while the telescope
control computer operates the photometer and accepts input files
from and provides nightly observations to the astronomer; no direct
operating personnel is needed. Both telescopes have 0.75-m primary
mirrors, a CCD finder camera, and an environmentally controlled
single-channel photoelectric photometer with filter combinations
optimized for use in the blue (Wolfgang) and in the red (Amadeus)
wavelength for asteroseismology of non-radially pulsating variables,
and for monitoring asymtotic-giant-branch stars. Some first results
are presented. (SECTION: Astronomical Instrumentation)

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. IV. The
rapidly-rotating G5III-IV star HD 112313 = IN Comae.
Authors: Strassmeier, K. G.; Hubl, B.; Rice, J. B.
1997A&A...322..511S Altcode:
We present the first Doppler image of the rapidly-rotating G5 giant
in the unusual IN Comae triple system. Our average image from three
spectral regions and two continuum color indices shows mostly low to
high latitude features but not a prominent polar cap-like spot. A
parameter study of the stellar and atomic input quantities aims to
better quantify the reliability of our Doppler image. A time series of
330 high-precision Stroemgren by and Johnson V measurements in 1996 show
only one real photometric period (5.913+/-0.005days) that we interpret
to be the rotation period of the G5 giant. We found no evidence for
the 0.25-day period claimed earlier by Kuczawska &amp; Mikolajewski
(1993AcA....43..445K). Optical spectra of several activity indicators
are presented and discussed. IN Comae exhibits an unusual broad Hα
emission line and a central absorption feature. This profile shape is
also seen for the CaII infrared-triplet lines as well as for the sodium
doublet and the HeI D_3_ line. No LiI 6707.8 line is present. New
radial velocity measurements from our red-wavelength spectra do not
indicate a short-period binary but would be consistent with the G5
star being the outer, third component of this triple system.

---------------------------------------------------------
Title: Time-series photometric SPOT modeling. III. Thirty years in
the life of HK Lacertae.
Authors: Olah, K.; Kővári, Zs.; Bartus, J.; Strassmeier, K. G.;
Hall, D. S.; Henry, G. W.
1997A&A...321..811O Altcode:
We present a spot modeling analysis of the active late-type giant HK Lac
using 30 years of photometry, including 600 new data points from the
last six years. We have analyzed folded light curves and, when we had
long continuous data sets, applied a new computer code for time-series
modeling. The validity of the modeling results was tested as a function
of the photometric noise. We have determined the unspotted brightness
of HK Lac in the BV(RI)_C_ bandpasses and obtained a spot temperature of
{DELTA}T=1200+/-100K. Polar active regions were recovered throughout the
modeling because no other scenario was able to describe both the mean
light variability of over 0.25mag accompanied by rotational modulation
of similar amplitude. This result has gotten strong theoretical support
recently (see Schuessler). The active regions preferably cluster around
two orbital phases separated by =~110°. New spot appearances within
active regions and, possibly, their interactions with the old ones
could be the cause of rapid changes in the light curves.

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. III. The X-ray
source HD 116544 = IN Virginis.
Authors: Strassmeier, K. G.
1997A&A...319..535S Altcode:
We present the first Doppler image of the EXOSAT X-ray source EXO
1321.8-0203, recently identified to be a chromospherically active
star exhibiting periodic light variations and consequently named
INVirginis. Our high-resolution spectra show INVirginis to be a
single-lined spectroscopic binary with an orbital period of 8.2
days, very strong CaII emission, and an inverse P-Cygni type Hα
line profile. A detailed spectrum synthesis yields a photospheric
temperature of 4600+/-70 K and logg=3.5-4.0 and slight overabundance of
the heavy elements but otherwise solar abundances. We redetermine the
photometric period from a new set of photometry obtained with a robotic
photoelectric telescope in the years 1994 and 1995 and conclude that
IN Virginis is more likely a K2-3 subgiant instead of a K5 dwarf or K4
subgiant as previously published. The Doppler images from March 1994
show a cool polar spot that is dominated by a large appendage reaching
a latitude of +40°. Its average temperature difference, photosphere
minus polar spot, is 1000K. Additionally, three equatorial spots are
clearly recovered but have ΔT=~400K. Possibly, we also detected a warm
equatorial feature with ΔT=~-150K. We emphasize that Doppler imaging
of IN Virginis is very challenging because of both the small vsin i
of the star (24.0km/s) and its relatively cool photosphere causing
many weak absorption-line blends. Still, maps from the different lines
appear encouragingly similar.

---------------------------------------------------------
Title: Aktive Sterne. Laboratorien der solaren Astrophysik.
Authors: Strassmeier, K. G.
1997asld.book.....S Altcode:
Contents: 1. Das Weltbild, in dem wir leben. 2. Stellare
Aktivitäten. 3. "Alles Walzer" - die Rotation der Sterne. 4. Rotation
in Doppelsternen. 5. Rotationsmodulierte Datenanalyse. 6. Stellare
Magnetfelder. 7. Unsere Sonne als Stern. 8. Sternflecken:
Aktivitätsphänomene der Photosphäre. 9. Aktive
Chromosphären. 10. Röntgenstrahlung aktiver Sterne. 11. Alles fließt:
Geschwindigkeitsfelder. 12. Extrasolare Planeten: Endlich!

---------------------------------------------------------
Title: VizieR Online Data Catalog: UBV &amp; V(RI)c photometry of
23 active stars (Strassmeier+ 1997)
Authors: Strassmeier, K. G.; Bartus, J.; Cutispoto, G.; Rodono, M.
1997yCat..41250011S Altcode:
We report on the progress of our ongoing photometric monitoring program
of spotted late-type stars with automatic photoelectric telescopes
(APTs) on Mt. Hopkins in Arizona and on Mt. Etna in Sicily. We present
9250 differential UBV and/or V(RI)c observations for altogether 23
chromospherically active stars, singles and binaries, pre-main-sequence
and post-main-sequence, taken between 1991 and 1996. For a description
of the UBV and (RI)c photometric system, see e.g. &lt;GCPD/01&gt;
and &lt;GCPD/54&gt; (6 data files).

---------------------------------------------------------
Title: Aktive Sterne
Authors: Strassmeier, Klaus G.
1997akst.book.....S Altcode:
Die Sonne ist ein ziemlich durchschnittlicher Stern, der sich vor
allem durch seine geringe Entfernung zur Erde auszeichnet. Bei
näherer Betrachtung entpuppt sich die Sonnenoberfläche jedoch als
wahrer "Hexenkessel" mit Magnetfeldern aller Art, Sonnenflecken,
Plasmaeruptionen und plötzlichen Explosionen, die alle einen
fundamentalen Einfluß auf unseren Planeten haben, einen Einfluß,
den wir erst mit modernster Astronomie messen und verstehen
gelernt haben. Dieses Buch erklärt die spannenden Innenwelten, die
physikalischen Grundlagen und Funktionsweisen der Sonne und der anderen
aktiven Sterne. Die aktuellsten Forschungsergebnisse und neuestes
Datenmaterial werden fundiert, aber auch für Laien verständlich,
aufbereitet und mit über 200 Bildern, teilweise Aufnahmen mit dem
Hubble Weltraumteleskop, illustriert.

---------------------------------------------------------
Title: From Top to Bottom - the Multiwavelength Campaign of V824 ARA
(HD 155555)
Authors: Dempsey, Robert; Neff, James; Strassmeier, Klaus; Linsky,
Jeffrey; Lim, Jeremy; Donati, J. -F.; Walter, Fred; Marang, Fred;
Budding, Edwin; Jordan, Ian; Walker, Stan; Downing, David G.; Inwood,
Doug; Petterson, Orlon; Petterson, Orlon
1997stsc.rept.....D Altcode:
A great deal of progress has been made in recent years in decomposing
the 2-D structure in the atmospheres of late-type stars. Doppler
images of many photospheres single stars, T Tauri stars, Algols,
RS CVn binaries to name a few - are regularly published
(Strassmeier 1996; Richards and Albright 1996; Rice and Strassmeier
1996; Kuerster et al. 1994). Ultraviolet spectral images of
chromospheres appear in the literature (e.g., Walter et al. 1987;
Neff et al. 1989) but are less common owing to the difficult nature of
obtaining complete phase coverage. Zeeman doppler images of magnetic
fields are now feasible (e.g., Donati et al. 1992). Performing Doppler
imaging of the same targets over many seasons has also been accomplished
(e.g, Vogt et al. 1997). Even when a true image reconstruction is not
possible due to poor spectral resolution, we can still infer a great
deal about spatial structure if enough phases are observed. However,
it is increasingly apparent that to make sense of recent results,
many different spectral features spanning a range of formation
temperature and density must be observed simultaneously for a coherent
picture to emerge. Here we report on one such campaign. In 1996,
we observed the southern hemisphere RS CVn binary V824
Ara (P=1d.68, G5IV+K0V-IV-IV) over one complete stellar
rotation with the Hubble Space Telescope and EUVE. In conjunction,
radio and optical photometry and spectroscopy were obtained from the
ground. Unique to this campaign is the complete phase coverage of a
number of activity proxy indicators that cover source temperatures
ranging from the photosphere to the corona.

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. II. The
weak-lined T Tauri star V410 Tauri.
Authors: Rice, J. B.; Strassmeier, K. G.
1996A&A...316..164R Altcode:
We present a new Doppler image of the rapidly-rotating weak-lined T
Tauri star V410 Tauri and compare this new map with one previously
published from observations taken over a year earlier. We find cool
spots at both equatorial latitudes and at high latitudes with the
high latitude spots being cooler and showing greater area and having
greater longevity than the equatorial spots. A comparison of the two
maps shows little relative change in the positions of the equatorial
spots compared to the spots at high latitude suggesting very little
differential rotation and what there is appears to be in the same sense
as the Sun. Global spot lifetime would appear to be on the order of
the time interval between the two maps, that is about a year. There
are several hot features evident supporting the claim for the existence
of such features based on our map of Nov. 1992.

---------------------------------------------------------
Title: Doppler imaging of stellar surface structure. I. The
rapidly-rotating RS CVn binary UZ Librae.
Authors: Strassmeier, K. G.
1996A&A...314..558S Altcode:
We present the first Doppler image of the rapidly-rotating K0III star
of the single-lined RS CVn binary UZ Librae. Our analysis incorporates
line profile variations from three spectral regions (around CaI 6439A,
FeI 6411A and FeI 6393A) and continuum variations from simultaneous
VRI photometry. All images recover a polar feature consisting of
mainly three "appendages" between latitudes of +60deg and +80deg. This
polar feature is not like a polar cap as previously seen on other RS
CVn stars but consists primarly of the three appendages. Up to six
equatorial features were also detected and have temperature differences
between 200 and 400K cooler than the photospheric temperature of
4800K. Images from individual spectral lines show an encouraging
amount of consistent detail, especially for the location but also
for the shape of certain features. The recovery of the temperature
scale is on average also similar but can be somewhat different for
particular surface features. This is most noticeable for the larger of
the three polar appendages; we found it 30% cooler from the CaI line
and the FeI 6411-A line than from the FeI 6393-A line. We suspect such
differences are partially due to external errors of the line profile
data and slightly inaccurate input physics. New photometry and radial
velocity measurements are used to recompute the photometric period
and the orbital elements of UZ Librae.

---------------------------------------------------------
Title: VizieR Online Data Catalog: Chromospherically Active Binaries
(Strassmeier+ 1993)
Authors: Strassmeier, K. G.; Hall, D. S.; Fekel, F. C.
1996yCat.5076....0S Altcode:
Stars always appear in order of increasing right-ascension for the
epoch 2000.0. For the current version of the catalog, the literature
was searched through December 31, 1991 although a few later references
are included. Additionally, some entries are cited with "private
communication", which make this catalog also a first-hand source. A
number in parentheses behind an entry always corresponds to a reference
given in the bibliography. See the 1988 publication for specific
requirements and restrictions in compiling these catalogs. See the
source reference for more details about this catalog. The following
binary systems, which were listed in the first edition of the catalog,
were not included in the present edition due to insufficient evidence
for chromospheric activity: eta And 26 Aql 4 UMi nu2 Sgr tau Sgr the following stars are chromospherically active but are components
in a "wide" binary and were not included. HD 25893 HD 79211 Forty
three new binary systems have been included in the present edition. (12 data files).

---------------------------------------------------------
Title: Photometry of the Active Star UZ Librae
Authors: Paunzen, E.; Strassmeier, K. G.
1996IBVS.4294....1P Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Observational evidence for polar spots
Authors: Strassmeier, K. G.
1996IAUS..176..289S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Stellar surface structure: proceedings of the 176th Symposium
of the International Astronomical Union, held in Vienna, Austria,
October 9-13, 1995.
Authors: Strassmeier, Klaus G.; Linsky, Jeffrey L.
1996IAUS..176.....S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Austrian astronomy today: a joint research initiative in
stellar astrophysics
Authors: Breger, M.; Dorfi, E. A.; Hron, J.; Strassmeier, K. G.; Weiss,
W. W.; Oberhummer, H.; Hanslmeier, A.; Lustig, G.; Schober, H. J.
1995IAUS..176P...4B Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Hα line-profile variations of the two active binary systems
AG Dor and UX For
Authors: Washüttl, A.; Strassmeier, K. G.
1995IAUS..176P.172W Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Stellar temperatures from line-depth ratios: the influence
of macroscopic velocity fields
Authors: Stift, M. J.; Strassmeier, K. G.
1995IAUS..176P..29S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Doppler imaging of IN Comae: two possible rotation periods
Authors: Hubl, B.; Strassmeier, K. G.
1995IAUS..176P..96H Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Detection of a large X-ray flare on the RS CVn binary HU
Virginis
Authors: Endl, M.; Strassmeier, K. G.; Kürster, M.
1995IAUS..176P.203E Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Stellar Surface Structure: Doppler Imaging with the VLT-UVES
Authors: Strassmeier, K. G.
1995svlt.conf...87S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Stellar surface structure
Authors: Strassmeier, Klaus G.
1995IAUS..176P....S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Photometry of the Active Stars HD127535 and HD202077
Authors: Strassmeier, K. G.; Paunzen, E.; North, P.
1994IBVS.4066....1S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Stellar Irradiance Variations due to Surface Temperature
Inhomogeneities
Authors: Strassmeier, K. G.
1994SoPh..152..314S Altcode: 1994IAUCo.143..314S; 1994svs..coll..314S
Observations of rotational modulation of continuum brightness and
photospheric and chromospheric spectral-line profiles of late-type
stars indicate the presence of very inhomogeneous surface temperature
distributions. We present three stellar examples (VY Ari, HR 7275,
HU Vir) where time-series photometry is used to trace the evolution of
spotted regions. Simultaneous spectroscopy and Doppler imaging for one
of the three stars (HU Virgo, Fig. 1) makes it possible to compute the
temperature distribution of the photosphere and the relative intensity
distribution of parts of the chromosphere (from CaII K and Hα line
profiles). The combination of time-series spot modeling and Doppler
imaging enabled us to determine thesign and amount of differential
surface rotation on HU Vir. We found a big, cool polar spot (see figure
below) and a differential (surface) rotation law where higher-latitude
regions rotate faster than lower-latitude regions (opposite to
what we see on the Sun). Currently, this ensemble of techniques --
is only applicable to stars overactive by approximately a factor of
100 as compared to the active Sun, e.g. the evolved components in RS
CVn-type binaries and some rapidly-rotating, single, pre-main sequence
stars or giant stars. Stellar rotation is a fundamental parameter for
(magnetic) activity. Starspots, or any other surface inhomogeneities,
allow one to derive very precise stellar rotation rates and, if
coupled with seismological observations of solar-type stars, could
provide information on the internal angular momentum distribution in
overactive late-type stars.

---------------------------------------------------------
Title: A Doppler image of the weak T Tauri star V410 Tau
Authors: Strassmeier, K. G.; Welty, A. D.; Rice, J. B.
1994A&A...285L..17S Altcode:
We have monitored the weak-lined T Tauri star V410 Tau spectroscopically
for six nights in 1992. We detected periodic line-profile variations
that are used to obtain a Doppler image of this star, the first
of a pre-main sequence T Tauri star. Inverse solutions from
three moderately-strong absorption lines show consistent surface
inhomogeneities of the effective temperature distribution of up to
1200K cooler and at least 500K hotter than the nominal photospheric
temperature of 4400K. Our maps thus verify the proposed existence of
hot spots on weak-lined T Tauri stars. All features are evident at low
and very high latitudes even covering the rotational pole but not a cool
polar cap-like spot as seen previously for several other active stars.

---------------------------------------------------------
Title: Chromospheric activity in G and K giants: the spectroscopic
data base
Authors: Strassmeier, K. G.
1994A&AS..103..413S Altcode:
I present high-resolution CCD spectra of CaII H and K emission lines
of 59 evolved stars of spectral type G and K and luminosity Class III,
III-IV, and IV. This includes active stars like RS CVn binaries but
also active and inactive single stars. Most of the objects were observed
for the first time and several were discovered to be chromospherically
active. Spectra for ten stars of luminosity Class V are also given.

---------------------------------------------------------
Title: Starspot Activity on the G0III Star 31 Comae
Authors: Strassmeier, K. G.; Washuttl, A.; Rice, J. B.
1994IBVS.3994....1S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Time-series photometric SPOT modeling. II. Fifteen years of
photometry of the bright RS CVN binary HR 7275.
Authors: Strassmeier, K. G.; Hall, D. S.; Henry, G. W.
1994A&A...282..535S Altcode:
We present a time-dependent spot modeling analysis of 15 consecutive
years of V-band photometry of the long-period (Porb =
28.6 days) RS CVn binary HR 7275. This baseline in time is one of the
longest, uninterrupted intervals a spotted star has been observed. The
spot modeling analysis yields a total of 20 different spots throughout
the time span of our observations. The distribution of the observed spot
migration rates is consistent with solar-type differential rotation
and suggests a lower limit of the differential-rotation coefficient
of 0.022 +/-0.004. The observed, maximum lifetime of a single spot
(or spot group) is 4.5 years, the minimum lifetime is approximately
one year, but an average spot lives for 2.2 years. If we assume that
the mechanical shear by differential rotation sets the upper limit
to the spot lifetime, the observed maximum lifetime in turn sets an
upper limit to the differential-rotation coefficient, namely 0.04 +/-
0.01. This would be differential rotation just 5 to 8 times less than
the solar value and one of the strongest among active binaries. We found
no conclusive evidence for the existence of a periodic phenomenon that
could be attributed to a stellar magnetic cycle.

---------------------------------------------------------
Title: Three-Dimensional Doppler Imaging of the Active Atmosphere
of HU Virgo
Authors: Strassmeier, Klaus G.
1994ASPC...64..480S Altcode: 1994csss....8..480S
No abstract at ADS

---------------------------------------------------------
Title: Stellar Photometry with a Whole-Earth Robotic Telescope
Authors: Strassmeier, Klaus G.
1994ASPC...55..205S Altcode: 1994oaem.conf..205S
No abstract at ADS

---------------------------------------------------------
Title: Rotational-modulation mapping of the active atmosphere of
the RS Canum Venaticorum binary HD 106225.
Authors: Strassmeier, K. G.
1994A&A...281..395S Altcode:
Observations of rotational modulation of photospheric absorption lines,
chromospheric emission lines, and the continuum brightness of the RS CVn
binary HD 106225 Pord = 10.4 days) are reported. From Doppler
imaging of four photosperic lines we obtain the surface temperatures
distribution at two observing epochs in 1991. Spot temperatures
on HD 106225 were determined from three different proxy indicators
(photometric broad-band colors, line-depth ratios, and line-profile
shapes) and yield values between 1000-1500 K. Simultaneous Ca II H and
K and H-alpha line-profile variations provide some clues on the spatial
relation between the temperature distribution of the photosphere and
the location of active regions in the chromosphere and we present,
for the first time, a crude three-dimensional picture of a stellar
atmosphere. Simultaneous and contemporaneous UBV photometry is used to
trace the evolution of spotted regions in 1991. We applied a time-series
spot modeling code and found a fairly stable spot configuration with
two major spots. Only small and sporadic spot-area changes were present
in 1991, which likely are unrelated to a long-term cycle.

---------------------------------------------------------
Title: Chromospheric activity in G an K giants and their
rotation-activity relation.
Authors: Strassmeier, K. G.; Handler, G.; Paunzen, E.; Rauth, M.
1994A&A...281..855S Altcode:
We obtained high-resolution CCD spectra of Ca II H and K emission
lines of 59 evolved stars of spectral type G and K and luminosity
class III, III-IV, and IV. Our sample includes active stars like RS CVn
binaries but also active and inactive single stars. Whenever possible
we determine absolute emission line surface fluxes and use them,
supplemented by previously published fluxes from high-resolution
spectra, to quantify the rotation-activity relation for evolved
stars. We find that the Ca II surface fluxes from evolved stars scale
linearly with stellar rotational velocity and that the flux from the
cooler stars depends stronger upon rotation than the flux from the
hotter stars, in agreement with previous findings for main-sequence
stars. However, large scatter indicates that rotational velocity might
not be the only relevant parameter. We also present some evidence
for the existence of a 'basal' flux for evolved stars that scales
approximately with the eight power of the effective surface temperature.

---------------------------------------------------------
Title: Doppler Imaging of Stars
Authors: Rice, J.; Wehlau, W.; Strassmeier, K.; Matthews, J.; Hill, G.
1994BCFHT..30...20R Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Time-Series Photometric SPOT Modeling of the RS CVn Binary
HR 7275
Authors: Strassmeier, Klaus G.; Hall, Douglas S.
1994ASPC...64..483S Altcode: 1994csss....8..483S
No abstract at ADS

---------------------------------------------------------
Title: A catalog of chromospherically active binary stars (second
edition).
Authors: Strassmeier, K. G.; Hall, D. S.; Fekel, F. C.; Scheck, M.
1993A&AS..100..173S Altcode:
The catalog contains 206 spectroscopic binary systems with at least
one late-type component that shows Ca II H and K emission in its
spectrum. These systems include the classical RS CVn binaries and BY
Dra binaries. The catalog summarizes information on the photometric,
spectroscopic, orbital, and physical properties of the systems as
well as space motions and positions. Up to 42 'parameters' for each
stellar system are listed followed by the appropriate reference to
direct interested colleagues to the original papers. A comprehensive
selection of further information for each star is given in the
individual notes. In addition, the catalog contains a candidate list
of 138 stars that have similar characteristics but are not definitely
known binaries or have not had Ca II H and K emission observed.

---------------------------------------------------------
Title: Sternflecken - Die Beobachtung solarer Phänomene auf anderen
Sternen.
Authors: Strassmeier, K. G.
1993Sterb..36...42S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Surface features of the lower atmosphere of HD 82558 (=LQ
Hydrae).
Authors: Strassmeier, K. G.; Rice, J. B.; Wehlau, W. H.; Hill, G. M.;
Matthews, J. M.
1993A&A...268..671S Altcode:
We present simultaneous high-resolution CCD spectra and UBVRI photometry
of the very active young single K2 dwarf star LQ Hya. The star displays
extreme chromospheric activity as well as having a large and variable
spot distribution. We applied the Doppler-imaging technique to nine
different photospheric absorption lines of various strengths. By
averaging all individual maps together spurious surface features
from one spectral line are suppressed in the final map and only
consistent features show up. This greatly enhances the reliability of
our Doppler image of LQ Hya. Individual images obtained from the weak
line profiles together with the photometry yielded mainly low-latitude
surface features. The strongest lines together with photometry yielded
large features at the rotation pole. The surface temperature range is
only a few hundred degrees. Four starspot regions were detected from
Doppler imaging. Extended regions of lesser temperature depression are
also evident. Additionally we found rotational modulation of certain
temperature-sensitive line ratios in agreement with simultaneous NIR
continuum photometry, verifying the 'cool' nature of the starspots
on LQ Hya. Chromospheric parameters were computed from H-alpha as a
function of rotational phase. We present evidence that lower electron
densities occur at times when a cool starspot is in view, indicating
a less dense chromosphere above a spotted region.

---------------------------------------------------------
Title: Activity tracers.
Authors: Strassmeier, Klaus G.
1993ASPC...40..605S Altcode: 1993IAUCo.137..605S; 1993ist..proc..605S
The vast variety of solar-like phenomena on other late-type stars,
so-called activity tracers, provide an important tool for studying the
structure of active stellar atmospheres and their connection to the
stellar interior via strong magnetic fields. These "chromospherically
active" stars include single and binary stars as well as pre- and
post-main sequence objects and have rapid rotation and deep convective
layers in common. They serve as astrophysical laboratories to study
the vast phenomenology of activity tracers: starspots, plages,
flares, prominences, which might be seen as enhanced analogs of
solar activity and could be spatially resolved due to rotationally
modulated indicators. In this paper the author reviews the current
observational material and discusses its impact on the knowledge of
"active" atmospheres, especially in the context of stellar rotation.

---------------------------------------------------------
Title: No Chromospheric Activity Seen in the Very Eccentric
Double-Lined Binary Gliese 586A
Authors: Strassmeier, K. G.
1992IBVS.3781....1S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Line Profile Asymmetries in Chromospherically Active Stars
Authors: Dempsey, Robert C.; Bopp, Bernard W.; Strassmeier, Klaus G.;
Granados, Arno F.; Henry, Gregory W.; Hall, Douglas S.
1992ApJ...392..187D Altcode:
A powerful, new probe of chromospheric activity, cross-correlation,
has been developed and applied to a variety of stars. In this particular
application, an entire CCD spectrum of an active star is correlated with
the spectrum of a narrow-line, inactive star of similar spectral type
and luminosity class. Using a number of strong lines in this manner
enables the detection of absorption profile asymmetries at moderate
resolution (lambda/Delta lambda about 40,000) and S/N 150:1. This
technique has been applied to 14 systems mostly RS CVn's, with 10 not
greater than nu sin i not greater than 50 km/s and P not less than
7 d. Distortions were detected for the first time in five systems:
Sigma Gem, IM Peg, GX Lib, UV Crb, and Zeta And. Detailed modeling,
incorporating both spectral line profiles and broad-band photometry,
is applied to Sigma Gem. Profile asymmetries for this star are fitted by
two high-latitude spots covering 5 percent of the stellar surface. The
derived spot temperature of 3400 K is lower than found in previous
studies. In addition, two well-known systems have been studied: HD
199178 and V711 Tau. Polar spots are found on both.

---------------------------------------------------------
Title: Time-series photometric SPOT modeling. I. Parameter study
and applicationto HD 17433 = VY Arietis.
Authors: Strassmeier, K. G.; Bopp, B. W.
1992A&A...259..183S Altcode:
New UBVRI photometry of the active chromosphere binary HD 17433 (VY) Ari
from 1987 through 1991 is presented, and the long-term and short-term
spot behavior is studied. A 0.2 mag variation of the mean brightness
and a maximum wave amplitude of up to 0.4 mag in 1988 are found. The
newly measured photometric period of 16.42 d suggests asynchronous
rotation of the primary component by about 30 percent.

---------------------------------------------------------
Title: On the starspot temperature of HD 12545.
Authors: Strassmeier, K. G.; Olah, K.
1992A&A...259..595S Altcode:
We have applied two different versions of the photometric
spot-modeling technique to the spotted RS CVn-type binary HD
12545. New UBV(RI)c photometry from early 1991 showed the
star with an exceptionally large amplitude of 0.50 mag in V and 0.12
mag in V - I and a rotation period of 24.30 +/- 0.02 d which suggests
a spot coverage of approximately 20 percent of the entire stellar
surface. Such large light and color amplitudes allowed us to separate
effects of wavelength-dependent limb darkening from spot temperature
with high confidence. This in turn makes it possible to obtain the,
so far, most precise relative starspot temperature of 1100 +/- 35
K for a spotted, late-type star other than the sun. The U - B and
B - V values and the minimum radius for HD 12545 suggest a K0III
classification rather than the G5IV reported earlier. From a single,
high-resolution spectrum of HD 12545 we found a strong LiI 6707 A line
with an equivalent width of 100 +/- 15 mA (log n(Li) is approximately
equal to 1.75), suggestive of a relatively young giant. In contrast,
with our new spectral type classification, minimum stellar radius,
and the observed mass function, we determine a space-velocity vector
of 105 km/s, suggestive of an old disk star.

---------------------------------------------------------
Title: Stellar Atmosphere Inhomogeneities from High-Resolution
Spectroscopy
Authors: Strassmeier, K. G.
1992ESOC...40..167S Altcode: 1992hrsw.conf..167S
No abstract at ADS

---------------------------------------------------------
Title: On the Rotation Period of HD 39576
Authors: Strassmeier, K. G.; Maitzen, H. M.; Pranka, M.
1992IBVS.3735....1S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The Polar-spot Structure on HD26337
Authors: Strassmeier, K. G.
1992LNP...397...50S Altcode: 1992sils.conf...50S
No abstract at ADS

---------------------------------------------------------
Title: Starspot photometry: observational review and interplay
with spectroscopy.
Authors: Strassmeier, Klaus G.
1992ASPC...34...39S Altcode: 1992robt.proc...39S
Most of what we know about starspots comes from time variations
of broad-band lightcurves. A review is presented of the current
observational knowledge of starspots on RS CVn-like F, G, and K stars,
T Tauri, and W UMa-type stars. Recent Doppler maps are compared with
photometric results.

---------------------------------------------------------
Title: Doppler imaging of hig-latitude SPOT activity on HD 26337.
Authors: Strassmeier, K. G.; Rice, J. B.; Wehlau, W. H.; Vogt, S. S.;
Hatzes, A. P.; Tuominen, I.; Piskunov, N. E.; Hackman, T.; Poutanen, M.
1991A&A...247..130S Altcode:
Three different versions of the Doppler-imaging technique are applied
to the spotted RS CVn-type binary HD 26337 = Ei Eri. New high-resolution
high-S/N spectroscopy was obtained along with simultaneous BV photometry
during 1988. Images were generated independently by three separate
groups using different versions of the Doppler-imaging technique but the
same data. All maps from Ca I 6439 A showed a cool asymmetric spot at
the pole or at high latitudes generally surrounding the rotation pole
and also some smaller equatorial spots. The maps from Fe I exhibit
detailed differences to the maps from Ca I. The equatorial features
were found to change on short time-scales (weeks). It is inferred that
the polar spot is short-lived (years) but changes its appearance on the
same several-week time-scale. Simultaneous and contemporary broad-band
photometry was found to be crucial as additional data in the mapping
procedure and as a reliability test of the Doppler-imaging solution.

---------------------------------------------------------
Title: HD 181943: an Active Single Subgiant with Lithium
Authors: Strassmeier, K. G.
1991IBVS.3618....1S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Surface Imaging of Ei-Eridani
Authors: Hackman, T.; Piskunov, N. E.; Poutanen, M.; Strassmeier,
K. G.; Tuominen, I.
1991LNP...380..321H Altcode: 1991IAUCo.130..321H; 1991sacs.coll..321H
We present maps of the temperature distribution on the spotted
RS CVn-type binary EI Eri (HD 26337), obtained by means of the
surface imaging technique described in the Colloquium (Piskunov,
1991). Images were calculated for two separate lines for two epochs
of observation. For one epoch we also calculated an image using a
blend of several lines. The reliability of the maps is confirmed by
comparing the simultaneous photometric observations with the light
curves calculated from the temperature maps.

---------------------------------------------------------
Title: Line Profile Asymmetries in Chromospherically Active Stars
Authors: Dempsey, R. C.; Bopp, B. W.; Strassmeier, K. G.
1991BAAS...23Q.822D Altcode:
No abstract at ADS

---------------------------------------------------------
Title: No "Chromospheric Activity" Seen in eta And
Authors: Strassmeier, K. G.; Hron, J.
1990IBVS.3545....1S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The spectral classification of chromospherically active binary
stars with composite spectra.
Authors: Strassmeier, K. G.; Fekel, F. C.
1990A&A...230..389S Altcode:
This paper presents and analyzes blue and red-wavelength high-resolution
spectra of twelve chromospherically active binary or triple systems
with composite spectra. Spectral classifications for the individual
stellar components are derived by means of the 'spectrum-synthesis'
technique and are compared to stellar evolutionary models and observed
masses and/or mass ratios. Also presented is a carefully selected set
of MK reference stars of luminosity class III, IV, and V, and spectral
type A9-K5, and v sin i less than 10 km/s, to cover the spectral range
of the components of chromospherically active binary systems of the RS
CVn-type. New values of v sin i are determined for some of the reference
and program stars. Two spectroscopic binaries have been discovered.

---------------------------------------------------------
Title: HR 1362: A Test Case for Stellar Dynamo Theories
Authors: Strassmeier, Klaus G.; Hall, Douglas S.; Barksdale, William
S.; Jusick, Anthony T.; Henry, Gregory W.
1990ApJ...350..367S Altcode:
An analysis of 11 yr of photometry of HR 1362 = EK Eri has shown
a well-established photometric period of 335 days. This confirms
an earlier period determination of about 310 days from 3 yr of APT
data and is consistent with a new v sin i determination of 2 + or -
2 km/s. Recent Ca II H and K observations show moderately strong H
and K emission lines at a flux level of log F prime (K) of about 6.5
ergs sq m/s. If the photometric period is interpreted as the rotation
period, this surface flux is more than one order of magnitude larger
than what can be expected from empirical activity versus rotation
relationships. The spectrum and the U-B and B-V colors are consistent
with a single G8 III-IV spectral classification, while the V-R and
V-I values indicate a small color excess, typical of chromospherically
active stars.

---------------------------------------------------------
Title: Chromospheric CA II H and K and H alpha Emission in Single
and Binary Stars of Spectra Types F6--M2
Authors: Strassmeier, Klaus G.; Fekel, Francis C.; Bopp, Bernard W.;
Dempsey, Robert C.; Henry, Gregory W.
1990ApJS...72..191S Altcode:
New observations of the Ca II H and K and H-epsilon region and/or the
Balmer H-alpha line are presented for 100 mostly very active stars but
also for weak or inactive stars with suspected activity. Correlations
between chromospheric activity at Ca II H and K and H-alpha and
effective surface temperature and rotation are identified, and several
new stars with chromospheric Ca II H and K emission are discovered. No
single activity-rotation relation can be derived for all luminosity
classes, and there is clear evidence that evolved stars are generally
more active than main-sequence stars of the same rotation period. Binary
within the evolved stars appears to play no role, while main-sequence
binary stars show generally higher levels of activity than their single
counterparts. Chromospheric emission in the Ca II H and K lines depends
on surface temperature in that flux declines with cooler temperature.

---------------------------------------------------------
Title: On Chromospheric Emission and Photometric Variability of
Active Late Type Stars
Authors: Strassmeier, K. G.
1990ASIC..319..509S Altcode: 1990acb..proc..509S
No abstract at ADS

---------------------------------------------------------
Title: Synoptic Doppler Imaging and Photometry of Spotted
Chromospherically Active Stars
Authors: Strassmeier, K. G.
1990ASIC..319..485S Altcode: 1990acb..proc..485S
No abstract at ADS

---------------------------------------------------------
Title: Photometric and Spectroscopic Modeling of Starspots on the
RS Canum Venaticorum Binary HD 26337
Authors: Strassmeier, Klaus G.
1990ApJ...348..682S Altcode:
Results are presented on photometric and spectroscopic observations made
in 1987-1988 on the rapidly rotating G5 subgiant in the single-lined RS
CVn binary HD 26337. Results show the existence of a cool polar spot
on HD 26337, which is rather long lived, persisting at least the nine
years of the photometry observations. The polar spot contributes only
insignificantly to the light curve amplitude, but is crucial for the
overall brightness of the system. Evidence is also found for extremely
rapid light curve shape variations on a time scale of only one or two
rotation cycles. These changes could be modeled by rapidly decreasing
a spot area.

---------------------------------------------------------
Title: Photoelectric Photometry of the Rs-Canum Binary Ei-Eridani
= HD26337
Authors: Hooten, J. T.; Strassmeier, K. G.; Hall, D. S.; Barksdale,
W. S., Jr.; Bertoglio, A.; Cortesi, S.; Cutispoto, G.; Engelbrektson,
S.; Ganis, M.; Gómez, J. M.; Casas, R.; Gallart, C.; Jariod, E.;
Ito, Y.; Melillo, F. J.; Ohshima, O.; Poole, R. S.; McLaughlin, T. A.;
Powell, H. D.; Nix, R. M.; Soder, J.; Wasson, R.
1989Ap&SS.155...45H Altcode:
DifferentialUBV(RI) KC andUBVRI photometry of the RS
CVn binary EI Eridani obtained during December 1987 and January 1988
at fourteen different observatories is presented. A combined visual
bandpass light curve, corrected for systematic errors of different
observatories, utilizes the photometric period of 1.945 days to
produce useful results. Analysis shows the visual light curve to
have twin maxima, separated by about 0.4 phase, and a full amplitude
of approximately 0.06 mag for the period of observation, a smaller
amplitude than reported in the past. The decrease in amplitude may
be due to a decrease or homogenization of spot coverage. To fit the
asymmetrical light curve, a starspot model would have to employ at
least two spotted regions separated in longitude.

---------------------------------------------------------
Title: Sternflecken.
Authors: Strassmeier, Klaus G.; Hall, Douglas S.
1989S&W....28..230S Altcode:
The study of starspots is discussed. The history of starspot
observation is summarized, and observational methods are described. The
possibilities for amateur observations are briefly addressed. The
chromospheres of active stars are examined. Whether 'superstarspots'
are coronal holes or active regions is discussed.

---------------------------------------------------------
Title: Ultraviolet, Visible, and Radio Observations of EI Eri
Authors: Neff, J. E.; Walter, F. M.; Skinner, S. L.; Brown, A.;
Strassmeier, K. G.; Rodono, M.; Cutispoto, G.; Jankov, S.; Char, S.
1989BAAS...21..747N Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Variability of LR Hya = HD 91816 not Confirmed
Authors: Strassmeier, K. G.
1989IBVS.3290....1S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: The Photometric Variability of the Chromospherically Active
Binary Star HD 80715
Authors: Strassmeier, Klaus G.; Hooten, James T.; Hall, Douglas S.;
Fekel, Francis C.
1989PASP..101..107S Altcode:
Differential UBVRI photometry of the double-lined BY Dra system HD
80715 (K3 V + K3 V) obtained in December 1987 is presented. The star
is found to be a variable with a full amplitude of 0.06 mag in V and
a period similar or equal to the orbital period of 3.804 days. The
mechanism of the variability is interpreted as rotational modulation
due to dark starspots. In an attempt to detect chromospheric activity,
high-resolution CCD spectra were obtained at Ca II H and K and at Fe
I 6430 A and Ca I 6439 A, the photospheric lines normally used for
Doppler imaging. HD 80715 shows double H and K emission features at
a constant flux level for each component.

---------------------------------------------------------
Title: Chromospherically Active Stars. VI. HD 136901 = UV CrB:
A Massive Ellipsoidal K Giant Single-Lined Spectroscopic Binary
Authors: Fekel, Francis C.; Kirkpatrick, J. Davy; Yang, Xinxing;
Strassmeier, Klaus G.
1989AJ.....97..202F Altcode:
The variable star HD 136901 = UV CrB is a chromospherically active K2
III single-lined spectroscopic binary with an orbital period of 18.665
days. It has modest-strength Ca H and K emission and UV features,
while H-alpha is a strong absorption feature containing little or
no emission. The inclination of the system is 53 + or - 12 deg. The
v sin i of the primary is 42 + or - 2 km/s, resulting in a minimum
radius of 15.5 + or - 0.8 solar. When compared with the Roche lobe
radius, this results in a mass ratio of 2.90 or larger. Additional
constraints indicate that the secondary has a mass between 0.85 and
1.25 solar. Thus, the mass of the primary is at least 2.5 solar and
probably is in the range 2.5-4 solar.

---------------------------------------------------------
Title: Photometric Variability in Chromospherically Active
Stars. III. The Binary Stars
Authors: Strassmeier, Klaus G.; Hall, Douglas S.; Boyd, Louis J.;
Genet, Russell M.
1989ApJS...69..141S Altcode:
Differential UBV photometry of 49 late-type chromospherically active
binary stars has been obtained. A total of 12,353 differential UBV
magnitudes have been acquired and are used to determine seasonal
photometric periods, amplitudes, mean brightnesses, maximum spot
amplitudes, 'unspotted' differential magnitudes, and times of minimum
light. Standard Fourier techniques are used to investigate the cause
of the light variability. Eight stars are found which exhibit light
variations due not to spot activity but rather to ellipticity and/or
reflection effect. Others show combinations of all three effects. Some
of the systems also show substantial differences between their
rotational and orbital period.

---------------------------------------------------------
Title: Status Report on the International Campaign of Simultaneous
VRI Photometry and Spectroscopy of EI Eri = HD 26337
Authors: Strassmeier, K. G.; Hooten, J. T.
1988IAPPP..34...21S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Photometric Variability of Chromospherically Active
Stars. I. The Constant Stars
Authors: Strassmeier, Klaus G.; Hall, Douglas S.
1988ApJS...67..439S Altcode:
Over 3800 differential UBV observations for 15 known or suspected
chromospherically active stars are presented. All stars turned out
to exhibit no light variations over the period of observation from
1983 through 1987. Three additional nonactive stars already known
to be constant have been used to determine the external and internal
precision of the data.

---------------------------------------------------------
Title: Photometric Variability in Chromospherically Active
Stars. II. The Rapidly Rotating Single Stars
Authors: Strassmeier, Klaus G.; Hall, Douglas S.
1988ApJS...67..453S Altcode:
Differential UBV photometry of five variable chromospherically active
single stars carried out from 1983 through 1987 is reported. About 1000
individual measures are used to determine their photometric behavior,
a result presumably of spot activity. All observations were made with
a fully automatic telescope.

---------------------------------------------------------
Title: Starspot modeling of ten years of photometry of the long-period
RS CVn binary sigma Geminorum.
Authors: Strassmeier, K. G.; Hall, D. S.; Eaton, J. A.; Landis, H. J.;
Barksdale, W. S.; Reisenweber, R. C.; Powell, B. E.; Fernandes, M.;
Zeigler, K. W.; Renner, T. R.; Wasson, R.; Nielsen, P.; Louth, H.;
Chambliss, C. R.; Fortier, G.; Grim, B. S.; Turner, L. C.; Stelzer,
H. J.; Slauson, D. M.; Fried, R. E.; Brettman, O. H.; Engelbrektson,
S.; Krisciunas, K.; Miles, R.
1988A&A...192..135S Altcode:
The authors present new UBV photometry of the long period
(Porb = 19.6 days) RS CVn binary σ Gem made between 1981
and 1986 at 22 different observatories. Together with earlier data
presented by Fried et al. (1983), σ Gem has now been monitored since
the discovery of its light variability in 1977. With these ten years of
differential photometry in hand the authors investigate the long-term
spot behavior with a standard spot-modeling computer program. They found
a cyclic variation of the total spotted area with a period of ≈2.7 yr,
a maximum spot coverage of 12% in 1986, a maximum wave amplitude of 0.15
mag in 1984, and mean colors which are not entirely consistent with
the K1 III spectral classification. From the spot-migration rate the
authors derived a more recent photometric period of 19.410 days. They
also discuss some anomalies in the spot motions which occurred between
1984 and 1985.

---------------------------------------------------------
Title: A catalog of chromospherically active binary stars.
Authors: Strassmeier, K. G.; Hall, D. S.; Zeilik, M.; Nelson, E.;
Eker, Z.; Fekel, F. C.
1988A&AS...72..291S Altcode:
The authors have compiled a catalog of 168 chromospherically active
binary stars including the class of RS Canum Venaticorum binaries,
BY Draconis binaries and other binaries which show "strong" Ca II H
and K emission in their spectra. The catalog contains information on
the photometric, spectroscopic, orbital and physical properties of the
systems as well as the space motions and positions. Summarized in a
candidate list are an additional 37 stars having similar characteristics
but which are not definitely known binaries or have not had H and K
emission observed. A bibliography and notes for each star are included
to direct interested workers to primary references for each of the
systems. The catalog contains stars in both the northern and the
southern sky.

---------------------------------------------------------
Title: A multiple spot model for simultaneous solution of light
curves and distorted line profiles of spotted stars
Authors: Strassmeier, Klaus G.
1988Ap&SS.140..223S Altcode:
This paper is devoted to the effects of dark starspots on observed light
curves and line profiles. A new formulation of the starspot model with
multiple spots and arbitrary spot shapes is derived which allows for
a numerical solution of light and colour curves and distorted line
profiles simultaneously. The effects of differential rotation and
the existence of a penumbra have also been considered. A parameter
study demonstrates the influences of different spot parameters on the
theoretical light curves and rotation profiles. The computer code is
applicable for single stars as well as for eclipsing close binaries
allowing for ellipticity effect and reflection effect.

---------------------------------------------------------
Title: Request for VRI Photometry of the RS CVn Type Binary HD 26337
during 15. through 30. December 1987
Authors: Strassmeier, Klaus G.
1987IBVS.3049....1S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: Request for VRI Photometry of the RS CVn Type Binary HD 26337
Authors: Strassméier, K. G.
1987IAPPP..28...24S Altcode:
No abstract at ADS

---------------------------------------------------------
Title: H-alpha and LiI Observations of the RS CVn Type Binaries:
sigma Gem, alpha Aur, 93 Leo and HR 6469
Authors: Strassmeier, K. G.; Weichinger, S.; Hanslmeier, A.
1986IBVS.2937....1S Altcode:
No abstract at ADS