J/A+A/668/A82 KIC4054905 radial velocities (Brogaard+, 2022)
Establishing the accuracy of asteroseismic mass and radius estimates of giant
stars.
III. KIC4054905, an eclipsing binary with two 10 Gyr thick disk RGB stars.
Brogaard K., Arentoft T., Slumstrup D., Grundahl F., Lund M.N., Arndt L.,
Grund S., Rudrasingam J., Theil A., Christensen K., Sejersen M., Vorgod F.,
Salmonsen L., Ortoft Endelt L., Dainese S., Frandsen S., Miglio A.,
Tayar J., Huber D.
<Astron. Astrophys. 668, A82 (2022)>
=2022A&A...668A..82B 2022A&A...668A..82B (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Radial velocities
Keywords: binaries: eclipsing - stars: evolution - stars: abundances -
stars: fundamental parameters - stars: oscillations -
stars: individual: KIC 4054905
Abstract:
Eclipsing binary stars with an oscillating giant component allow
accurate stellar parameters to be derived and asteroseismic methods to
be tested and calibrated. To this aim, suitable systems need to be
firstly identified and secondly measured precisely and accurately.
KIC 4054905 is one such system, which has been identified, but with
measurements of a relatively low precision and with some confusion
regarding its parameters and evolutionary state.
Our aim is to provide a detailed and precise characterisation of the
system and to test asteroseismic scaling relations.
Dynamical and asteroseismic parameters of KIC 4054905 were determined
from Kepler time-series photometry and multi-epoch high-resolution
spectra from FIES at the Nordic Optical Telescope.
KIC4054905 was found to belong to the thick disk and consist of two
lower red giant branch (RGB) components with nearly identical masses
of 0.95M☉ and an age of 9.9±0.6Gyr. The most evolved star with
R=8.4R☉ displays solar-like oscillations. These oscillations
suggest that the star belongs to the RGB, supported also by the
radius, which is significantly smaller than the red clump phase for
this mass and metallicity. Masses and radii from corrected
asteroseismic scaling relations can be brought into full agreement
with the dynamical values if the RGB phase is assumed, but a best
scaling method could not be identified.
The dynamical masses and radii were measured with a precision better
than 1.0%. We firmly establish the evolutionary nature of the system
to be that of two early RGB stars with an age close to 10Gyr, unlike
previous findings. The metallicity and Galactic velocity suggest that
the system belongs to the thick disk of the Milky Way. We investigate
the agreement between dynamical and asteroseismic parameters for
KIC 4054905 measured in various ways. This suggests that consistent
solutions exist, but the need to analyse more of these systems
continues in order to establish the accuracy of asteroseismic methods.
Description:
Radial velocity measurements of the components of the eclipsing binary
KIC4054905 exctracted from spectra from the FIES spectrograph at the
Nordic Optical Telescope. The primary component is defined as the
larger of the two stars.
Objects:
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RA (2000) DE Designation(s)
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19 23 40.54 +39 10 11.6 KIC 4054905 = TIC 122685666
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 36 11 Radial velocity measurements
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 13 F13.5 d BJD Barycentric Julian Day (TDB)
15- 19 F5.2 km/s RVp Radial velocity of primary component
21- 24 F4.2 km/s e_RVp Radial velocity uncertainty, primary component
26- 31 F6.2 km/s RVs Radial velocity of secondary component
33- 36 F4.2 km/s e_RVs Radial velocity uncertainty, secondary
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Acknowledgements:
Karsten Brogaar, dkfb(at)phys.au.dk
(End) Patricia Vannier [CDS] 24-Oct-2022