The EBLM Project V. Physical properties of ten fully convective, very-low-mass stars

Abstract

Measurements of the physical properties of stars at the lower end of the main sequence are scarce. In this context we report masses, radii and surface gravities of ten very-low-mass stars in eclipsing binary systems, with orbital periods of the order of several days. The objects probe the stellar mass-radius relation in the fully convective regime, $M_{\star }\lesssim 0.35$ M${}_{\odot }$, down to the hydrogen burning mass-limit, $M_{\mathrm{HB}}\sim 0.07$ M${}_{\odot }$. The stars were detected by the WASP survey for transiting extra-solar planets, as low-mass, eclipsing companions orbiting more massive, F- and G-type host stars. We use eclipse observations of the host stars (TRAPPIST, Leonhard Euler, SPECULOOS telescopes), and radial velocities of the host stars (CORALIE spectrograph), to determine physical properties of the low-mass companions. Companion surface gravities are derived from the eclipse and orbital parameters of each system. Spectroscopic measurements of the host star effective temperature and metallicity are used to infer the host star mass and age from stellar evolution models. Masses and radii of the low-mass companions are then derived from the eclipse and orbital parameters of each system. The objects are compared to stellar evolution models for low-mass stars, to test for an effect of the stellar metallicity and orbital period on the radius of low-mass stars in close binary systems. Measurements are in good agreement with stellar models; an inflation of the radii of low-mass stars with respect to model predictions is limited to 1.6 $\pm$ 1.2% in the fully convective regime. The sample of ten objects indicates a scaling of the radius of low-mass stars with the host star metallicity. No correlation between stellar radii and orbital periods of the binary systems is determined. A combined analysis with comparable objects from the literature is consistent with this result.

19 pages

References in corpus (20)

• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• The Dartmouth Stellar Evolution Database
• Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• Improving PARSEC models for very low mass stars
• Evolution of low-mass star and brown dwarf eclipsing binaries
• Efficient identification of exoplanetary transit candidates from SuperWASP light curves
• Simulations of dynamo action in fully convective stars
• The Transit Light Curve Project. IX. Evidence for a Smaller Radius of the Exoplanet XO-3b
• KOI-126: A Triply-Eclipsing Hierarchical Triple with Two Low-Mass Stars
• Absolute properties of the low-mass eclipsing binary CM Draconis
• First Results from the CHARA Array. IV. The Interferometric Radii of Low-Mass Stars
• On Correlated-noise Analyses Applied To Exoplanet Light Curves
• WASP-42 b and WASP-49 b: two new transiting sub-Jupiters
• A method for the direct determination of the surface gravities of transiting extrasolar planets
• The EBLM Project IV. Spectroscopic orbits of over 100 eclipsing M dwarfs masquerading as transiting hot-Jupiters
• A photometric study of the hot exoplanet WASP-19b
• Bayesian mass and age estimates for transiting exoplanet host stars
• The EBLM project III. A Saturn-size low-mass star at the hydrogen-burning limit
• The EBLM project. II. A very hot, low-mass M dwarf in an eccentric and long period eclipsing binary system from SuperWASP

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• Spectral analysis of two directly imaged benchmark L dwarf companions at the stellar-substellar boundary
• NGTS-EB-8: A double-lined eclipsing M+M binary discovered by citizen scientists
• Evidence of Radius Inflation Based on 50 Transiting Brown Dwarfs and Low-mass Stellar Companions
• The M-dwarf Ultraviolet Spectroscopic Sample I. Determining Stellar Parameters for Field Stars