A SMALLER RADIUS FOR THE TRANSITING EXOPLANET WASP-10b

We present the photometry of WASP-10 during a transit of its short-period Jovian planet. We employed the novel point-spread function shaping capabilities of the Orthogonal Parallel Transfer Imaging Camera mounted on the UH 2.2 m telescope to achieve a photometric precision of 4.7 x 10(-4) per 1.3 minute sample. With this new light curve, in conjunction with stellar evolutionary models, we improve on existing measurements of the planetary, stellar, and orbital parameters. We find a stellar radius R(star) = 0.698 +/- 0.012 R(circle dot) and a planetary radius R(P) = 1.080 +/- 0.020 R(Jup). The quoted errors do not include any possible systematic errors in the stellar evolutionary models. Our measurement improves the precision of the planet's radius by a factor of 4, and revises the previous estimate downward by 16% (2.5 sigma, where sigma is the quadrature sum of the respective confidence limits). Our measured radius of WASP-10b is consistent with previously published theoretical radii for irradiated Jovian planets.