The low density transiting exoplanet WASP-15b

Abstract

We report the discovery of a low-density exoplanet transiting an 11th magnitude star in the Southern hemisphere. WASP-15b, which orbits its host star with a period P = 3.7520656 ± 0.0000028 d, has a mass Mp = 0.542 ± 0.050 MJ and radius Rp = 1.428 ± 0.077 RJ, and is therefore one of the least dense transiting exoplanets so far discovered (ρp = 0.247 ± 0.035 g cm -3). An analysis of the spectrum of the host star shows it to be of spectral type around F5, with an effective temperature Teff = 6300 ± 100 K and [Fe/H] = -0.17 ± 0.11. © 2009. The American Astronomical Society. All rights reserved.