The EBLM project III. A Saturn-size low-mass star at the hydrogen-burning limit

Abstract

We report the discovery of an eclipsing binary system with mass-ratio q $\sim$ 0.07. After identifying a periodic photometric signal received by WASP, we obtained CORALIE spectroscopic radial velocities and follow-up light curves with the Euler and TRAPPIST telescopes. From a joint fit of these data we determine that EBLM J0555-57 consists of a sun-like primary star that is eclipsed by a low-mass companion, on a weakly eccentric 7.8-day orbit. Using a mass estimate for the primary star derived from stellar models, we determine a companion mass of $85\pm 4M_{\mathrm{Jup}}$ ($0.081M_{\odot }$) and a radius of $0.84_{-0.04}^{+0.14}{R}_{\mathrm{Jup}}$ ($0.084R_{\odot }$) that is comparable to that of Saturn. EBLM J0555-57Ab has a surface gravity $\log g_2=5.50_{-0.13}^{+0.03}$ and is one of the densest non-stellar-remnant objects currently known. These measurements are consistent with models of low-mass stars.

Accepted for publication in A&A, 6 pages, 5 figures

References in corpus (14)

• A grid of MARCS model atmospheres for late-type stars I. Methods and general properties
• Gaia Data Release 1. Summary of the astrometric, photometric, and survey properties
• 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
• Determining stellar atmospheric parameters and chemical abundances of FGK stars with iSpec
• The Solar Neighborhood XVII: Parallax Results from the CTIOPI 0.9m Program -- Twenty New Members of the RECONS 10 Parsec Sample
• Efficient identification of exoplanetary transit candidates from SuperWASP light curves
• The Transit Light Curve Project. IX. Evidence for a Smaller Radius of the Exoplanet XO-3b
• Steady-state planet migration by the Kozai-Lidov mechanism in stellar binaries
• WASP-42 b and WASP-49 b: two new transiting sub-Jupiters
• A photometric study of the hot exoplanet WASP-19b
• Bayesian mass and age estimates for transiting exoplanet host stars
• 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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