A transiting extrasolar giant planet around the star OGLE-TR-10

We report a transiting extrasolar giant planet around the star OGLE-TR-10 (orbital period = 3.1 days), which was uncovered as a candidate by the OGLE team in their photometric survey towards the Galactic center (Udalski, 2002a). We observed OGLE-TR-10 spectroscopically over a period of two years (2002-2004) using the HIRES instrument with an iodine cell on the Keck I telescope, and measured small radial velocity variations that are consistent with the presence of a planetary companion. This confirms our earlier identification of OGLE-TR-10b as a possible planet. Additionally, in this paper we are able to rule out a blend scenario as an alternative explanation. From an analysis combining all available radial velocity measurements with the OGLE light curve we find that OGLE-TR-10b has a mass of 0.57 +/- 0.12 M_Jup and a radius of 1.24 +/- 0.09 R_Jup. These parameters bear close resemblance to those of the first known transiting extrasolar planet, HD209458b