J/A+A/654/A17 TESS eclipsing binaries apsidal motion (Claret+, 2021)
Analysis of apsidal motion in eclipsing binaries using TESS data.
II. A test of internal stellar structure.
Claret A., Gimenez A., Baroch D., Ribas I., Morales J.C., Anglada-Escude G.
<Astron. Astrophys. 654, A17 (2021)>
=2021A&A...654A..17C 2021A&A...654A..17C (SIMBAD/NED BibCode)
ADC_Keywords: Binaries, eclipsing
Keywords: binaries: eclipsing - binaries: close - stars: evolution -
stars: interiors - stars: rotation
Abstract:
The measurement of apsidal motion rates in eccentric eclipsing
binaries is a unique way to gain insight into the internal structure
of stars through the internal density concentration parameter,k2.
High-quality physical parameters of the stellar components,together
with precise measurements of the advance of the periastron, are needed
for the comparison with values derived from models. As a product of
the TESS mission, high-precision light curves of a large number of
eclipsing binaries are now available. Using a selection of
well-studied, double-lined eccentric eclipsing binary systems, we aim
to determine their apsidal motion rates and place constraints on the
internal density concentration and compare with the predictions from
state-of-the-art theoretical models.
We compute times of minimum light using the TESS light curves of 34
eclipsing binaries with precise absolute parameters. We use the
changing difference over time between primary and secondary eclipse
timings to determine the apsidal motion rate. To extend the time
baseline, we combine the high-precision TESS timings with reliable
archival data. On the other hand, for each component of our sample of
double-lined eclipsing binaries we computed grids of evolutionary
stellar models for the observed stellar mass exploring ranges of
values of the overshooting parameter, fov, the mixing-length parameter
and the metallicity. To find the best solution for the two components
we adopt a chi-squared statistic to infer the optimal values of the
overshooting parameter and the mixing-length parameter. The
theoretical internal structure constants to be compared with the
observed values were calculated by integrating the differential
equations of Radau for each stellar model.
We have determined the apsidal motion rate of 27 double-lined
eclipsing binaries with precise physical parameters. The obtained
values, corrected for their relativistic contribution, yield precise
empirical parameters of the internal stellar density concentration.
The comparison of these results with the predictions based on new
theoretical models shows very good agreement. Small deviations are
identified but remain within the observational uncertainties and the
path for a refined comparison is indicated.
Description:
This table lists the time differences between primary and secondary
eclipses of 34 eclipsing binaries as computed from TESS photometry.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 37 34 List of studied stars
table2.dat 55 378 T2-T1 from TESS
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See also:
J/A+A/649/A64 : TESS time of eclipse of 15 eclipsing binaries (Baroch+, 2021)
Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Name of the system
12- 13 I2 h RAh Simbad Right ascension (J2000)
15- 16 I2 min RAm Simbad Right ascension (J2000)
18- 22 F5.2 s RAs Simbad Right ascension (J2000)
24 A1 --- DE- Simbad Declination sign (J2000)
25- 26 I2 deg DEd Simbad Declination (J2000)
28- 29 I2 arcmin DEm Simbad Declination (J2000)
31- 34 F4.1 arcsec DEs Simbad Declination (J2000)
36- 37 I2 --- N Number of measurements in table2.dat
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 10 A10 --- Name Name of the system
15- 26 F12.4 d t0 Reference time used to compute orbital cycle
31- 33 I3 --- N Orbital cycle
35- 43 F9.6 d T2-T1 Time difference between primary and secondary
eclipse
45- 52 F8.6 d e_T2-T1 rms uncertainty in T2-T1
54- 55 I2 --- dN [-2/1] Cycle difference between primary and
secondary eclipses
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Acknowledgements:
David Baroch, baroch(at)ice.cat
References:
Baroch et al., Paper I 2021A&A...649A..64B 2021A&A...649A..64B, Cat. J/A+A/649/A64
(End) David Baroch [ICE, CSIC, IEEC Spain], Patricia Vannier [CDS] 25-Jul-2021