The EBLM project. II. A very hot, low-mass M dwarf in an eccentric and long period eclipsing binary system from SuperWASP

Abstract

In this paper, we derive the fundamental properties of 1SWASPJ011351.29+314909.7 (J0113+31), a metal-poor (-0.40 +/- 0.04 dex), eclipsing binary in an eccentric orbit (~0.3) with an orbital period of ~14.277 d. Eclipsing M dwarfs orbiting solar-type stars (EBLMs), like J0113+31, have been identified from WASP light curves and follow-up spectroscopy in the course of the transiting planet search. We present the first binary of the EBLM sample to be fully analysed, and thus, define here the methodology. The primary component with a mass of 0.945 +/- 0.045 Msun has a large radius (1.378 +/- 0.058 Rsun) indicating that the system is quite old, ~9.5 Gyr. The M-dwarf secondary mass of 0.186 +/- 0.010 Msun and radius of 0.209 +/- 0.011 Rsun are fully consistent with stellar evolutionary models. However, from the near-infrared secondary eclipse light curve, the M dwarf is found to have an effective temperature of 3922 +/- 42 K, which is ~600 K hotter than predicted by theoretical models. We discuss different scenarios to explain this temperature discrepancy. The case of J0113+31 for which we can measure mass, radius, temperature and metallicity, highlights the importance of deriving mass, radius and temperature as a function of metallicity for M dwarfs to better understand the lowest mass stars. The EBLM Project will define the relationship between mass, radius, temperature and metallicity for M dwarfs providing important empirical constraints at the bottom of the main sequence.

13 pages, 7 figures. Accepted for publication in A&A

References in corpus (15)

• The Dartmouth Stellar Evolution Database
• The Transiting Circumbinary Planets Kepler-34 and Kepler-35
• Evolution of low-mass star and brown dwarf eclipsing binaries
• Efficient identification of exoplanetary transit candidates from SuperWASP light curves
• Tidal friction in close-in satellites and exoplanets. The Darwin theory re-visited
• KOI-126: A Triply-Eclipsing Hierarchical Triple with Two Low-Mass Stars
• WASP-3b: a strongly-irradiated transiting gas-giant planet
• A fast hybrid algorithm for exoplanetary transit searches
• Absolute properties of the low-mass eclipsing binary CM Draconis
• The effect of activity on stellar temperatures and radii
• First Results from the CHARA Array. IV. The Interferometric Radii of Low-Mass Stars
• WASP-1: A lithium- and metal-rich star with an oversized planet
• The SDSS-HET Survey of Kepler Eclipsing Binaries: Spectroscopic Dynamical Masses of the Kepler-16 Circumbinary Planet Hosts
• A new detached K7 dwarf eclipsing binary system
• Photometry and spectroscopy of the newly discovered eclipsing binary GSC 4589-2999

Cited by in corpus (20)

• Tidal Locking of Habitable Exoplanets
• The EBLM Project IV. Spectroscopic orbits of over 100 eclipsing M dwarfs masquerading as transiting hot-Jupiters
• The BEBOP radial-velocity survey for circumbinary planets I. Eight years of CORALIE observations of 47 single-line eclipsing binaries and abundance constraints on the masses of circumbinary planets
• The EBLM Project V. Physical properties of ten fully convective, very-low-mass stars
• The EBLM project III. A Saturn-size low-mass star at the hydrogen-burning limit
• The EBLM Project VI. The mass and radius of five low-mass stars in F+M binaries discovered by the WASP survey
• Discovery and Precise Characterization by the MEarth Project of LP 661-13, an Eclipsing Binary Consisting of Two Fully Convective Low-mass Stars
• The EBLM project -- VIII. First results for M-dwarf mass, radius and effective temperature measurements using CHEOPS light curves
• Detection of a very low mass star in an Eclipsing Binary system
• TOI 694 b and TIC 220568520 b: Two Low-Mass Companions Near the Hydrogen Burning Mass Limit Orbiting Sun-like Stars
• A refined analysis of the low-mass eclipsing binary system T-Cyg1-12664
• Fundamental Properties of Late-Type Stars in Eclipsing Binaries
• The EBLM project X. Benchmark masses, radii and temperatures for two fully convective M-dwarfs using K2
• Orbital and physical parameters of eclipsing binaries from the All-Sky Automated Survey catalogue - X. Three high-contrast systems with secondaries detected with IR spectroscopy
• An eclipsing M-dwarf close to the hydrogen burning limit from NGTS
• Fundamental effective temperature measurements for eclipsing binary stars -- III. SPIRou near-infrared spectroscopy and CHEOPS photometry of the benchmark G0V star EBLM J0113+31
• The TESS light curve of the eccentric eclipsing binary 1SWASP J011351.29+314909.7 -- no evidence for a very hot M-dwarf companion
• TIC-320687387 B: a long-period eclipsing M-dwarf close to the hydrogen burning limit
• The SDSS-HET Survey of Kepler Eclipsing Binaries. Description of the Survey and First Results
• NGTS-EB-7, an eccentric, long-period, low-mass eclipsing binary