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

Hellier; Smalley; Maxted

Abstract

We report the discovery of an eclipsing binary system with mass-ratio q ~ 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 ± 4 MJup (0.081 M?) and a radius of 0.84+ 0.14-0.04RJup (0.084 R?) that is comparable to that of Saturn. EBLM J0555-57Ab has a surface gravity log?g2 =5.50+ 0.03-0.13 and is one of the densest non-stellar-remnant objects currently known. These measurements are consistent with models of low-mass stars.

Citation

Hellier, Smalley, & Maxted. (2017). The EBLM project - III. A Saturn-size low-mass star at the hydrogen-burning limit. Astronomy & Astrophysics, L6 -L6. https://doi.org/10.1051/0004-6361/201731107

• Acceptance Date: Jun 12, 2017
• Publication Date: Aug 1, 2017
• Journal: Astronomy & Astrophysics
• Print ISSN: 0004-6361
• Publisher: EDP Sciences
• Pages: L6 -L6
• DOI: https://doi.org/10.1051/0004-6361/201731107
• Keywords: binaries, eclipsing, spectroscopic, stars, low-mass, techniques, spectroscopic, photometric, EBLM J0555-57Ab
• Publisher URL: https://doi.org/10.1051/0004-6361/201731107