Astrophysics Group, Keele University,
2 SUPA, School of Physics and Astronomy, University of St. Andrews, North Haugh, Fife KY16 9SS, UK
3 Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, 1290 Sauverny, Switzerland
4 Las Cumbres Observatory, 6740 Cortona Dr. Suite 102, Santa Barbara, CA 93117, USA
5 Department of Physics and Astronomy, University of Leicester, Leicester LE1 7RH, UK
6 Institut d’Astrophysique et de Géophysique, Université de Liège, Allée du 6 Août 17, Bat. B5C, Liège 1, Belgium
7 Astrophysics Research Centre, School of Mathematics & Physics, Queen’s University, University Road, Belfast BT7 1NN, UK
Received: 25 November 2010
Accepted: 18 May 2011
We report the discovery of the low-density, transiting giant planet WASP-31b. The planet is 0.48 Jupiter masses and 1.55 Jupiter radii. It is in a 3.4-day orbit around a metal-poor, late-F-type, V = 11.7 dwarf star, which is a member of a common proper motion pair. In terms of its low density, WASP-31b is second only to WASP-17b, which is a more highly irradiated planet of similar mass.
Key words: binaries: eclipsing / planetary systems / stars: individual: WASP-31
Based in part on observations made with the HARPS spectrograph on the 3.6-m ESO telescope (proposal 085.C-0393) and with the CORALIE spectrograph and the Euler camera on the 1.2-m Euler Swiss telescope, both at the ESO La Silla Observatory, Chile.
The photometric time-series and radial-velocity data used in this work are available at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (126.96.36.199) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/531/A60
© ESO, 2011