The sub-Jupiter mass transiting exoplanet WASP-11b

Abstract

We report the discovery of a sub-Jupiter mass exoplanet transiting a magnitude V = 1.1.6 host star ISWASP J030928.54+304024.7. A. simultaneous fit to the transit photometry and radial-velocity measurements yield a planet mass Mp, = 0.53 ± 0.07 MJ, radius Rp, = 0.91+0.06-0.03 RJ and an orbital period of 3.722465+0.0000060.000008 days. The host star is an early to mid-K dwarf, with a spectral analysis yielding an effective temperature of 4800± 100 K and log g = 4.45 ±0.2. It is amongst the smallest, least massive and lowest luminosity stars known to harbour a transiting exoplanet. WASP-11b is the third least strongly irradiated transiting exoplanet discovered to date, experiencing an incident flux Fp = 1.9 x 10 8 erg s-1 cm-2 and having an equilibrium temperature Teql = 960 ± 70 K. © ESO 2009.