WASP-32b: A transiting hot Jupiter planet orbiting a lithium-poor, solar-type star

摘要

We report the discovery of a transiting planet orbiting the star TYC 2-1155-1. The star, WASP-32, is a moderately bright (V = 11:3) solar-type star (Teff = 6100 ± 100 K, [Fe=H] = -0:13 ± 0:10). The light curve of the star obtained with the WASP-South and WASP-North instruments shows periodic transitlike features with a depth of about 1% and a duration of 0.10 day every 2.72 days. The presence of a transitlike feature in the light curve is confirmed using z-band photometry obtained with Faulkes Telescope North. High-resolution spectroscopy obtained with the Coralie spectrograph confirms the presence of a planetary mass companion. From a combined analysis of the spectroscopic and photometric data, assuming that the star is a typical main-sequence star, we estimate that the planet has a mass Mp of 3:60 ± 0:07 MJup and a radius Rp = 1:19 ± 0:06 RJup. WASP-32 is one of a small group of hot Jupiters with masses greater than 3 MJup. We find that some stars with hot Jupiter companions and with masses M* ≈ 1:2 M?, including WASP-32, are depleted in lithium and that the majority of these stars have lithium abundances similar to field stars.