We report on the discovery of a new extremely short period transiting extrasolar planet, WASP-19b. The planet has mass Mpl = 1.15 \pm 0.08 MJ, radius Rpl = 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 slightly super-solar metallicity ([M/H] = 0.1 \pm 0.1 dex) G-dwarf with Teff = 5500 \pm 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 Prot = 10.5 \pm 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.
@article{arxiv.1001.0403,
title = {WASP-19b: the shortest period transiting exoplanet yet discovered},
author = {Leslie Hebb and A. Collier-Cameron and A. H. M. J. Triaud and T. A. Lister and B. Smalley and P. F. L. Maxted and C. Hellier and D. R. Anderson and D. Pollacco and M. Gillon and D. Queloz and R. G. West and S. Bentley and B. Enoch and C. A. Haswell and K. Horne and M. Mayor and F. Pepe and D. Segransan and I. Skillen and S. Udry and P. J. Wheatley},
journal= {arXiv preprint arXiv:1001.0403},
year = {2010}
}