I. Physical and orbital parameters, including spin-orbit angles, of two low-mass eclipsing binaries on opposite sides of the brown dwarf limit
Observatoire Astronomique de l’Université de Genève,
Chemin des Maillettes 51,
2 Department of Physics and Astronomy, Vanderbilt University, Nashville, TN37235, USA
3 Astrophysics Group, Keele University, Staffordshire, ST55 BG, UK
4 SUPA, School of Physics & Astronomy, University of St Andrews, North Haugh, KY16 9SS, St Andrews, Fife, Scotland, UK
5 Astrophysics Research Centre, School of Mathematics & Physics, Queens University, University Road, Belfast, BT71NN, UK
6 Institut d’Astrophysique et de Géophysique, Université de Liège, Allée du 6 Août 17, Bat. B5C, Liège 1, Belgium
7 Department of Physics and Astronomy, University of Leicester, Leicester, LE17 RH, UK
Received: 22 May 2012
Accepted: 27 September 2012
This paper introduces a series of papers aiming to study the dozens of low-mass eclipsing binaries (EBLM), with F, G, K primaries, that have been discovered in the course of the WASP survey. Our objects are mostly single-line binaries whose eclipses have been detected by WASP and were initially followed up as potential planetary transit candidates. These have bright primaries, which facilitates spectroscopic observations during transit and allows the study of the spin-orbit distribution of F, G, K+M eclipsing binaries through the Rossiter-McLaughlin effect.
Here we report on the spin-orbit angle of WASP-30b, a transiting brown dwarf, and improve its orbital parameters. We also present the mass, radius, spin-orbit angle and orbital parameters of a new eclipsing binary, J1219–39b (1SWAPJ121921.03–395125.6, TYC 7760-484-1), which, with a mass of 95 ± 2 Mjup, is close to the limit between brown dwarfs and stars. We find that both objects have projected spin-orbit angles aligned with their primaries’ rotation. Neither primaries are synchronous. J1219–39b has a modestly eccentric orbit and is in agreement with the theoretical mass-radius relationship, whereas WASP-30b lies above it.
Key words: binaries: eclipsing / stars: individual: WASP-30 / techniques: radial velocities / stars: individual: J1219-39 / stars: low-mass / brown dwarfs
Using WASP-South photometric observations (Sutherland, South Africa) confirmed with radial velocity measurement from the CORALIE spectrograph, photometry from the EulerCam camera (both mounted on the Swiss 1.2 m Euler Telescope), radial velocities from the HARPS spectrograph on the ESO’s 3.6 m Telescope (prog ID 085.C-0393), and photometry from the robotic 60 cm TRAPPIST telescope, all located at ESO, La Silla, Chile. The data is publicly available at the CDS Strasbourg and on demand to the main author.
Tables A.1–A.3 are available in electronic form at http://www.aanda.org
Photometry tables are only available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (188.8.131.52) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/549/A18
© ESO, 2012