Astron. J., 155, 114-114 (2018)
HAT-TR-318-007: a double-lined M dwarf binary with total secondary eclipses discovered by HATNet and observed by K2.
HARTMAN J.D., QUINN S.N., BAKOS G.A., TORRES G., KOVACS G., LATHAM D.W., NOYES R.W., SHPORER A., FULTON B.J., ESQUERDO G.A., EVERETT M.E., PENEV K., BHATTI W. and CSUBRY Z.
Abstract (from CDS):
We report the discovery by the HATNet survey of HAT-TR-318-007, a P=3.34395390±0.00000020day period detached double-lined M dwarf binary with total secondary eclipses. We combine radial velocity (RV) measurements from TRES/FLWO 1.5 m and time-series photometry from HATNet, FLWO 1.2 m, BOS 0.8 m, and NASA K2 Campaign 5, to determine the masses and radii of the component stars: MA=0.448±0.011 M☉N, MB=0.2721–0.0042+0.0041 M☉N, RA=0.4548–0.0036+0.0035 R☉N, and RB=0.2913–0.0024+0.0023 R☉N. We obtained a FIRE/Magellan near-infrared spectrum of the primary star during a total secondary eclipse, and we use this to obtain disentangled spectra of both components. We determine spectral types of STA=M3.71±0.69 and STB=M5.01±0.73 and effective temperatures of Teff,A=3190±110K and Teff,B=3100±110K for the primary and secondary star, respectively. We also measure a metallicity of [Fe/H] =+0.298±0.080 for the system. We find that the system has a small, but significant, nonzero eccentricity of 0.0136±0.0026. The K2 light curve shows a coherent variation at a period of 3.41315–0.00032+0.00030 days, which is slightly longer than the orbital period, and which we demonstrate comes from the primary star. We interpret this as the rotation period of the primary. We perform a quantitative comparison between the Dartmouth stellar evolution models and the seven systems, including HAT-TR-318-007, that contain M dwarfs with 0.2 M☉N< M< 0.5 M☉N, have metallicity measurements, and have masses and radii determined to better than 5% precision. Discrepancies between the predicted and observed masses and radii are found for three of the systems.
© 2018. The American Astronomical Society. All rights reserved.
binaries: eclipsing - stars: fundamental parameters - stars: individual: (HAT-TR-318-007, EPIC 211432946) - stars: late-type
VizieR on-line data:
<Available at CDS (J/AJ/155/114): table2.dat table4.dat table6.dat table9.dat table10.dat table11.dat table12.dat>
Cl NGC 2682 FBC 6558 is a misprint for Cl NGC 2682 FBC 2136.
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