2010ApJ...708..224H

We report on the discovery of a new extremely short period transiting extrasolar planet, WASP-19b. The planet has mass M_pl= 1.15±0.08 M_J , radius R_pl= 1.31±0.06 R_J, and orbital period P = 0.7888399±0.0000008 days. Through spectroscopic analysis, we determine the host star to be a slightly super-solar metallicity ([M/H] = 0.1±0.1 dex) G-dwarf with T_eff = 5500±100 K. In addition, we detect periodic, sinusoidal flux variations in the light curve which are used to derive a rotation period for the star of P_rot= 10.5±0.2 days. The relatively short stellar rotation period suggests that either WASP-19 is somewhat young (∼ 600 Myr old) or tidal interactions between the two bodies have caused the planet to spiral inward over its lifetime resulting in the spin-up of the star. Due to the detection of the rotation period, this system has the potential to place strong constraints on the stellar tidal quality factor, Q'_s, if a more precise age is determined.