Bibcode
Arentoft, T.; Grundahl, F.; White, T. R.; Slumstrup, D.; Handberg, R.; Lund, M. N.; Brogaard, K.; Andersen, M. F.; Silva Aguirre, V.; Zhang, C.; Chen, X.; Yan, Z.; Pope, B. J. S.; Huber, D.; Kjeldsen, H.; Christensen-Dalsgaard, J.; Jessen-Hansen, J.; Antoci, V.; Frandsen, S.; Bedding, T. R.; Pallé, P. L.; Garcia, R. A.; Deng, L.; Hon, M.; Stello, D.; Jørgensen, U. G.
Bibliographical reference
Astronomy and Astrophysics, Volume 622, id.A190, 12 pp.
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2
2019
Journal
Citations
22
Refereed citations
20
Description
Context. Asteroseismic analysis of solar-like stars allows us to
determine physical parameters such as stellar mass, with a higher
precision compared to most other methods. Even in a well-studied cluster
such as the Hyades, the masses of the red giant stars are not well
known, and previous mass estimates are based on model calculations
(isochrones). The four known red giants in the Hyades are assumed to be
clump (core-helium-burning) stars based on their positions in
colour-magnitude diagrams, however asteroseismology offers an
opportunity to test this assumption. Aims: Using asteroseismic
techniques combined with other methods, we aim to derive physical
parameters and the evolutionary stage for the planet hosting star
ɛ Tau, which is one of the four red giants located in the
Hyades. Methods: We analysed time-series data from both ground
and space to perform the asteroseismic analysis. By combining high
signal-to-noise radial-velocity data from the ground-based SONG network
with continuous space-based data from the revised Kepler mission K2, we
derive and characterize 27 individual oscillation modes for ɛ
Tau, along with global oscillation parameters such as the large
frequency separation Δν and the ratio between the amplitude of
the oscillations measured in radial velocity and intensity as a function
of frequency. The latter has been measured previously for only two
stars, the Sun and Procyon. Combining the seismic analysis with
interferometric and spectroscopic measurements, we derive physical
parameters for ɛ Tau, and discuss its evolutionary status. Results: Along with other physical parameters, we derive an
asteroseismic mass for ɛ Tau of M = 2.458 ± 0.073
M⊙, which is slightly lower than previous estimates, and
which leads to a revised minimum mass of the planetary companion. Noting
that the SONG and K2 data are non-simultaneous, we estimate the
amplitude ratio between intensity and radial velocity to be 42.2
± 2.3 ppm m-1 s, which is higher than expected from
scaling relations.
Time-series data are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr
(ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/622/A190Based
on observations made with the SONG telescopes operated on the Spanish
Observatorio del Teide (Tenerife) and at the Chinese Delingha
Observatory (Qinghai) by the Aarhus and Copenhagen Universities, by the
Instituto de Astrofísica de Canarias and by the National
Astronomical Observatories of China, and with NASA's K2 mission.
Related projects
Helio and Astero-Seismology and Exoplanets Search
The principal objectives of this project are: 1) to study the structure and dynamics of the solar interior, 2) to extend this study to other stars, 3) to search for extrasolar planets using photometric methods (primarily by transits of their host stars) and their characterization (using radial velocity information) and 4) the study of the planetary
Savita
Mathur