J/A+A/622/A190 eps Tau intensity and RV time-series data (Arentoft+, 2019)
Asteroseismology of the Hyades red giant and planet host epsilon Tauri.
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., Palle P.L., Garcia R.A., Deng L., Hon M., Stello D.,
Jorgensen U.G.
<Astron. Astrophys. 622, A190 (2019)>
=2019A&A...622A.190A 2019A&A...622A.190A (SIMBAD/NED BibCode)
ADC_Keywords: Stars, giant ; Stars, variable ; Radial velocities
Keywords: asteroseismology - techniques: radial velocities -
techniques: photometric - stars: individual: HD28305 -
stars: oscillations - planetary systems
Abstract:
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.
Using asteroseismic techniques combined with other methods, we aim to
derive physical parameters and the evolutionary stage for the planet
hosting star epsilon Tau, which is one of the four red giants located
in the Hyades.
We analysed time-series data from both ground and space to perform the
asteroseismic analysis. By combining high signal-to-noise (S/N)
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 epsilon
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 epsilon Tau, and discuss its evolutionary
status. Along with other physical parameters, we derive an
asteroseismic mass for epsilon Tau of M=2.458±0.073M☉, 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±2.3ppm m/s,
which is higher than expected from scaling relations.
Description:
Time-series data for epsilon Tau; photometric time-series data from
the revised Kepler mission K2 and radial-velocity measurements from
SONG (Stellar Observations Network Group). The time series have been
filtered in order to remove variations and instrumental effects at low
frequencies.
Objects:
---------------------------------------------
RA (2000) DE Designation(s)
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04 28 37.00 +19 10 49.5 eps Tau = HD 28305
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
k2-ts.dat 28 3390 Photometric/intensity time-series (K2)
song-ts.dat 28 5401 Radial-velocity time-series (SONG)
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Byte-by-byte Description of file: k2-ts.dat
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Bytes Format Units Label Explanations
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1- 14 F14.6 d BJD Baryocentric Julian Date
18- 28 F11.6 ppm Int Low-frequency filtered intensity measurements
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Byte-by-byte Description of file: song-ts.dat
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Bytes Format Units Label Explanations
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1- 14 F14.6 d BJD Baryocentric Julian Date
19- 28 F10.6 m/s RV Low-frequency filtered radial-velocity
measurements
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Acknowledgements:
Torben Arentoft, toar(at)phys.au.dk
(End) Torben Arentoft [Aarhus University], Patricia Vannier [CDS] 18-Jan-2019