We report on the discovery of a new extremely short period transiting extra-solar planet , WASP-19b .
The planet has mass , M _ { pl } = 1.15 \pm 0.08 Â M _ { J } , radius , R _ { pl } = 1.31 \pm 0.06 Â R _ { J } , and orbital period , P = 0.7888399 \pm 0.0000008 Â days .
Through spectroscopic analysis , we determine the host star to be a slightly super-solar metallicity ( [ M / H ] = 0.1 \pm 0.1 Â dex ) G-dwarf with T _ { eff } = 5500 \pm 100 Â 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 \pm 0.2 Â days .
The relatively short stellar rotation period suggests that either WASP-19 is somewhat young ( \sim 600 Â 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 } ^ { \prime } , if a more precise age is determined .