J/AJ/168/253 RVs of TIC 56913729 & TIC 97729372 from LAMOST DR10 (Pan+, 2024)
Starspot coverage on two new K-type low-mass eclipsing binaries with radius
inflation.
Pan Y., Frasca A., Wang J.-X., Fu J.-N., Zhang X.-B.
<Astron. J., 168, 253 (2024)>
=2024AJ....168..253P 2024AJ....168..253P
ADC_Keywords: Radial velocities ; Binaries, eclipsing ; Spectroscopy ;
Optical ; Stars, K-type
Keywords: Low mass stars ; Eclipsing binary stars ; Starspots
Abstract:
Utilizing data from the Transiting Exoplanet Survey Satellite (TESS)
and LAMOST, we present a photometric and spectroscopic investigation
of two new K-type low-mass eclipsing binaries, TIC 56913729 and
TIC 97729372. Our analysis yields masses and radii for TIC 56913729,
M1=0.7822±0.0054M☉, R1=0.7891±0.0021R☉, and
M2=0.7532±0.0052M☉, R2=0.7648±0.0021R☉.
For TIC 97729372, the results are M1=0.6410±0.0058M☉,
R1=0.6537±0.0069R☉ and M2=0.6480±0.0058M☉,
R2=0.6418±0.0062R☉. In addition, by analyzing the
out-of-eclipse starspot light variations, the lower limit of starspot
coverage varies in different TESS sectors from 2% to 12%. We observed
a clear radius inflation in the mass-radius diagram for both stars,
when plotted against PARSEC and SPOT isochrones with 1Gyr. Yet, this
apparent discrepancy disappears when the comparison is made with
either an older PARSEC isochrone (12Gyr) or a SPOT isochrone (250Myr)
with high starspot coverage (Fspot ∼85%), which is significantly
higher than the typical starspot coverage deduced from light curves.
Due to the lack of strong age constraints, we cannot firmly exclude
that the observed radius inflation may be the result of a
post-main-sequence evolutionary effect, although the spectral and
kinematic properties of these stars are hardly compatible with
10-12Myr old (Pop II) stars. It is more likely that the radius
inflation is produced by the strong magnetic activity in these rapidly
rotating stars, even if it is impossible to infer the actual total
spot coverage, due to the age uncertainties.
Description:
The targets were observed by the Large Sky Area Multi-Object Fiber
Spectroscopic Telescope (LAMOST), located in Xinglong Station of the
national Astronomical Observatory, China, in time-domain
medium-resolution survey (R∼7500). The wavelength coverage of red-arm
and blue-arm are 495-535 and 630-680nm, respectively.
The medium-resolution spectra from LAMOST DR10, with observations
from 2011 October 24 to 2022 June 30, were used to determine RVs and
stellar parameters.
Objects:
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RA (2000) DE Designation(s)
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09 17 42.90 +42 13 32.3 TIC 56913729 = Gaia DR3 816152092432271616
06 10 43.13 +34 38 50.1 TIC 97729372 = Gaia DR3 3452456065856186496
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table6.dat 54 100 Radial velocity measurements
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See also:
II/287 : Northern Sky Variability Survey (NSVS) (Wozniak+, 2004)
I/355 : Gaia DR3 Part 1. Main source (Gaia Collaboration, 2022)
IV/39 : TESS Input Catalog v8.2 (TIC v8.2) (Paegert+, 2021)
V/156 : LAMOST DR7 catalogs (Luo+, 2019)
J/MNRAS/328/45 : Late-type stars members of young groups (Montes+, 2001)
J/A+A/454/301 : Radial velocities of 6 binaries (Frasca+, 2006)
J/ApJ/691/1400 : Absolute properties of CM Dra (Morales+, 2009)
J/other/A+ARV/18.67 : Accurate masses and radii of normal stars (Torres+, 2010)
J/AJ/153/95 : Catalog of Suspected Nearby Young Stars (Riedel+, 2017)
J/ApJ/893/67 : Smoothed amplitudes from Kepler, K2 & TESS phot. (Morris, 2020)
J/ApJS/251/15 : LAMOST-Kepler/K2 survey (LK-MRS) first year obs. (Zong+, 2020)
J/ApJS/256/14 : RVs from LAMOST MRS DR7 stellar spectra (Zhang+, 2021)
J/A+A/664/A78 : Kepler targets class based on LAMOST spectra (Frasca+, 2022)
J/ApJS/258/16 : TESS Eclipsing Binary stars. I. Sectors 1-26 (Prsa+, 2022)
J/ApJS/258/26 : Spectroscopic binaries from LAMOST MRS. I. (Zhang+, 2022)
Byte-by-byte Description of file:table6.dat
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Bytes Format Units Label Explanations
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1- 10 F10.5 d BJD [1421/2694] Time, Barycentric Julian Date
BJD-2457000
12- 17 F6.4 --- Phase [0.05/0.95] Orbital phase
19- 25 F7.2 km/s RVel1 [-159/132] Radial velocity of the primary
component
27- 31 F5.2 km/s e_RVel1 [1.3/21] Uncertainty in RVel1
33- 39 F7.2 km/s RVel2 [-168/131] Radial velocity of the secondary
component
41- 45 F5.2 km/s e_RVel2 [1.4/27] Uncertainty in RVel2
47- 54 I8 --- TIC TIC identifier
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History:
From electronic version of the journal
(End) Prepared by [AAS], Robin Leichtnam [CDS] 03-Jul-2025