J/A+A/648/A113 Kepler red giants in eclipsing binaries RVs (Benbakoura+, 2021)
Spectroscopic and seismic analysis of red giants in eclipsing binaries
discovered by Kepler.
Benbakoura M., Gaulme P., McKeever J., Sekaran S., Beck P.G., Spada F.,
Jackiewicz J., Mathis S., Mathur S., Tkachenko A., Garcia R.A.
<Astron. Astrophys. 648, A113 (2021)>
=2021A&A...648A.113B 2021A&A...648A.113B (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing ; Binaries, spectroscopic ; Stars, giant ;
Radial velocities
Keywords: asteroseismology - binaries: eclipsing - binaries: spectroscopic -
stars: fundamental parameters - stars: oscillations - stars: evolution
Abstract:
Eclipsing binaries (EBs) are unique targets for measuring accurate
stellar properties and constraining stellar evolution models. In
particular, it is possible to measure masses and radii at the few
percent level for both components of a double-lined spectroscopic EB
(SB2-EB). On the one hand, detached EBs hosting at least one star with
detectable solar-like oscillations constitute ideal test objects to
verify the ability of ensemble asteroseismology to derive stellar
properties. On the other hand, the oscillations and surface activity
of stars that belong to EBs offer unique information about the
evolution of binary systems. This paper builds upon previous works
dedicated to red giant stars (RG) in EBs; so far 20 known systems have
been discovered by the NASA Kepler mission. We report the discovery of
16 RGs in EBs, which are also from the Kepler data, leading to a total
of 36 confirmed RG stars in EBs from the original Kepler mission. This
new sample includes three SB2-EBs with oscillations, resulting in a
total of 14 known SB2-EBs with an oscillating RG component. This
sample also includes six close systems in which the RG display a clear
surface activity and complete oscillation suppression. Based on
dedicated high-resolution spectroscopic observations (Apache Point
Observatory, Observatoire de Haute Provence), we focus on three main
aspects. Firstly, from the extended sample of 14 SB2-EBs, we confirm
that the simple application of the asteroseismic scaling relations to
RGs overestimates masses and radii of RGs by about 15% and 5 %. This
bias can be reduced by employing either new asteroseismic reference
values for RGs or model-based corrections of the asteroseismic
parameters. Secondly, we confirm that close binarity leads to a high
level of photometric modulation (up to 10%) and a suppression of
solar-like oscillations. In particular, we show that it reduces the
lifetime of radial modes by a factor of up to 10. Thirdly, we use our
16 new systems to complement previous observational studies that aimed
to constrain tidal dissipation in interacting binaries. We confirm the
important role of the equilibrium tide in binary evolution, but we
also identify systems with circular orbits despite relatively young
ages, which suggests the need to explore complementary tidal
dissipation mechanisms in the future. Finally, as a by-product, we
report the measurements of mass, radius, and age of three M-dwarf
companion stars.
Description:
Radial velocity data corresponding to the spectra obtained for the
present paper. Dates are mid-exposure times expressed in Kepler Julian
dates (KJD), which are barycentric Julian dates BJD with an offset:
KJD=BJD-2454833-days. The first spectrum was taken on March 25, 2016
(KJD=2639.9), and the last on November 15, 2020 (KJD=4336.5). The
least significant digit in brackets after the value indicates the
statistical uncertainty arising from the position of the peaks in the
BF. For the APO data, the dispersion of the data point with respect to
the best-fit models indicate that the actual RV uncertainties are
actually about 0.5km/s for the giant component and 1km/s for the
companion. The statistical error on the BF does not include
instrumental effect and atmospheric seeing. The empirical error bars
were used to model our data. Dates with a * symbol correspond with
data taken at OHP.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 61 16 List of studied stars
tabled1.dat 57 251 Radial velocity data corresponding to the
spectra obtained for the present paper
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See also:
V/133 : Kepler Input Catalog (Kepler Mission Team, 2009)
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 3 A3 --- --- [KIC]
5- 12 I8 --- KIC Star KIC number
15- 16 I2 h RAh Simbad right ascension (J2000)
18- 19 I2 min RAm Simbad right ascension (J2000)
21- 25 F5.2 s RAs Simbad right ascension (J2000)
27 A1 --- DE- Simbad declination sign (J2000)
28- 29 I2 deg DEd Simbad declination (J2000)
31- 32 I2 arcmin DEm Simbad declination (J2000)
34- 37 F4.1 arcsec DEs Simbad declination (J2000)
39- 49 F11.6 d Per Period (from dynamical modeling with JKTEBOP,
from table1 of the paper)
51- 58 F8.6 d e_Per rms uncertainty on Per
60- 61 I2 --- NRV Number of RV observations in tabled1.dat
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Byte-by-byte Description of file: tabled1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 8 I8 --- KIC Star KIC number
12- 20 F9.4 d Date Barycentric Julian date (BJD-2454833)
21 A1 --- n_Date [*] * for data taken at OHP
24- 31 F8.4 km/s RV1 Radial velocity of primary
34- 39 F6.4 km/s e_RV1 rms uncertainty on RV1
42- 49 F8.4 km/s RV2 ?=- Radial velocity of secondary
52- 57 F6.4 km/s e_RV2 ?=- rms uncertainty on RV2
--------------------------------------------------------------------------------
Acknowledgements:
Patrick Gaulme, gaulme(at)mps.mpg.de
(End) Patricia Vannier [CDS] 18-Mar-2021