WASP-19b: the shortest period transiting exoplanet yet discovered

摘要

We report on the discovery of a new extremely short period transitingextrasolar planet, WASP-19b. The planet has mass Mpl = 1.15 \pm 0.08 MJ, radiusRpl = 1.31 \pm 0.06 RJ, and orbital period P = 0.7888399 \pm 0.0000008 days.Through spectroscopic analysis, we determine the host star to be a slightlysuper-solar metallicity ([M/H] = 0.1 \pm 0.1 dex) G-dwarf with Teff = 5500 \pm100 K. In addition, we detect periodic, sinusoidal flux variations in the lightcurve which are used to derive a rotation period for the star of Prot = 10.5\pm 0.2 days. The relatively short stellar rotation period suggests that eitherWASP-19 is somewhat young (~ 600 Myr old) or tidal interactions between the twobodies have caused the planet to spiral inward over its lifetime resulting inthe spin-up of the star. Due to the detection of the rotation period, thissystem has the potential to place strong constraints on the stellar tidalquality factor, Q's, if a more precise age is determined.