WASP-64b and WASP-72b: two new transiting highly irradiated giant planets

astro-ph.EP

/ Authors

M. Gillon, D. R. Anderson, A. Collier-Cameron, A. P. Doyle, A. Fumel, C. Hellier, E. Jehin, M. Lendl, P. F. L. Maxted, J. Montalban

and 10 more authors

F. Pepe, D. Pollacco, D. Queloz, D. Segransan, A. M. S. Smith, B. Smalley, J. Southworth, A. H. M. J. Triaud, S. Udry, R. G. West

/ Abstract

We report the discovery by the WASP transit survey of two new highly irradiated giant planets transiting moderately bright stars. WASP-64b is slightly more massive (1.271+-0.068 M_Jup) and larger (1.271+-0.039 R_Jup) than Jupiter, and is in very-short (a=0.02648+-0.00024 AU, P=1.5732918+-0.0000015 days) circular orbit around a V=12.3 G7-type dwarf (1.004+-0.028 M_Sun, 1.058+-0.025 R_Sun, Teff=5500+-150 K). Its size is typical of hot Jupiters with similar masses. WASP-72b has also a mass a bit higher than Jupiter's (1.461-0.056+0.059 M_Jup) and orbits very close (0.03708+-0.00050 AU, P=2.2167421+-0.0000081 days) to a bright (V=9.6) and moderately evolved F7-type star (1.386+-0.055 M_Sun, 1.98+-0.24 R_Sun, Teff=6250+-100 K). Despite its extreme irradiation (about 5.5 10^9 erg/s/cm^2), WASP-72b has a moderate size (1.27+-0.20 R_Jup) that could suggest a significant enrichment in heavy elements. Nevertheless, the errors on its physical parameters are still too high to draw any strong inference on its internal structure or its possible peculiarity.