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

A. von Boetticher, A.~H.~M.~J. Triaud, Didier Queloz, S. Gill, M. Lendl, L. Delrez, D.~R. Anderson, A. Collier Cameron, F. Faedi, Michael Gillon, Y. Gómez Maqueo Chew, L. Hebb, C. Hellier, E. Jehin, P.~F.~L. Maxted, D.~V. Martin, F. Pepe, D. Pollacco, D. Ségransan, B. SmalleyS. Udry, R. West

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)


We report the discovery of an eclipsing binary system with mass-ratio q tilde 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 plusmn 4 M$_Jup$ (0.081 M$_⊙$) and a radius of 0.84$^+ 0.14$$_-0.04$R$_Jup$ (0.084 R$_⊙$) that is comparable to that of Saturn. EBLM J0555-57Ab has a surface gravity log g$_2$ =5.50$^+ 0.03$$_-0.13$ and is one of the densest non-stellar-remnant objects currently known. These measurements are consistent with models of low-mass stars. The photometry tables and radial velocities are only available at the CDS and on demand via anonymous ftp to ( or via
Original languageEnglish
Pages (from-to)L6
JournalAstronomy and Astrophysics
Publication statusPublished - 1 Aug 2017


  • stars: individual: EBLM J0555-57Ab
  • binaries: eclipsing
  • binaries: spectroscopic
  • stars: low-mass
  • techniques: spectroscopic
  • techniques: photometric


Dive into the research topics of 'The EBLM project. III. A Saturn-size low-mass star at the hydrogen-burning limit'. Together they form a unique fingerprint.

Cite this