The Transiting Extrasolar Giant Planet around the Star OGLE-TR-113

We report the independent discovery of a new extrasolar transiting planet around OGLE-TR-113, a candidate star from the Optical Gravitational Lensing Experiment. Small radial velocity variations have been detected based on observations conducted with the MIKE spectrograph on the Magellan I (Baade) telescope at the Las Campanas Observatory (Chile) during 2003. We have also carried out a light-curve analysis incorporating new photometry and realistic physical parameters for the star. OGLE-TR-113b has an orbital period of only 1.43 days, a mass of (1.08 ± 0.28) M Jup , and a radius of (1.09 ± 0.10) R Jup . Similar parameters have been obtained very recently in an independent study by Bouchy et al., from observations taken a year later. The orbital period of OGLE-TR-113b and the previously announced planet OGLE-TR-56b ( P orb = 1.21 days)—the first two found photometrically—are much shorter than the apparent cutoff of close-in giant planets at 3-4 day periods found in high-precision radial velocity surveys. Along with a third case reported by Bouchy et al. (OGLE-TR-132b, P orb = 1.69 days), these objects appear to form a new class of "very hot Jupiters" that pose very interesting questions for theoretical study.