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

Abstract

We report the discovery by the WASP transit survey of two new highly irradiated giant planets. WASP-64 b 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-circle dot, 1.058 +/- 0.025 R-circle dot, T-eff = 5500 +/- 150 K). Its size is typical of hot Jupiters with similar masses. WASP-72 b 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-circle dot, 1.98 +/- 0.24 R-circle dot, T-eff = 6250 +/- 100 K). Despite its extreme irradiation (similar to 5.5 x 10(9) erg s(-1) cm(-2)), WASP-72 b 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.