von Boetticher, A, Triaud, AHMJ, Queloz, D, Gill, S, Lendl, M, Delrez, L, Anderson, DR, Collier Cameron, A, Faedi, F, Gillon, M, Gómez Maqueo Chew, Y, Hebb, L, Hellier, C, Jehin, E, Maxted, PFL, Martin, DV, Pepe, F, Pollacco, D, Ségransan, D, Smalley, B, Udry, S and West, R (2017) The EBLM project - III. A Saturn-size low-mass star at the hydrogen-burning limit. Astronomy & Astrophysics, 604. L6 -L6. ISSN 0004-6361

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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.

Item Type: Article
Additional Information: © EDP Sciences. This is the final published version of the article (version of record). It first appeared online via EDP Sciences at https://doi.org/10.1051/0004-6361/201731107 - please refer to any applicable terms of use of the publisher.
Uncontrolled Keywords: binaries, eclipsing, spectroscopic, stars, low-mass, techniques, spectroscopic, photometric, EBLM J0555-57Ab
Subjects: Q Science > QB Astronomy > QB460 Astrophysics
Divisions: Faculty of Natural Sciences > School of Chemical and Physical Sciences
Depositing User: Symplectic
Date Deposited: 05 Sep 2017 11:22
Last Modified: 19 Mar 2019 12:32
URI: https://eprints.keele.ac.uk/id/eprint/3990

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