H-band thermal emission from the 19-h period planet WASP-19b

摘要

We present the first ground-based detection of thermal emission from an exoplanet in the H-band.Using HAWK-I on the VLT, we observed an occultation of WASP-19b by itsG8V-type host star. WASP-19b is a Jupiter-mass planet with an orbitalperiod of only 19h, and thus, being highly irradiated, isexpected to be hot. We measure an H-band occultation depth of 0.259+0.046-0.044%, whichcorresponds to an H-band brightness temperature of K. A cloud-free model of the planet's atmosphere, with no redistribution of energy from day-side to night-side, under predicts the planet/star flux density ratio by a factor of two. As the stellar parameters, and thus the level of planetary irradiation, are well-constrained by measurement, it is likely that our model of the planet's atmosphere is too simple. Key words: planets and satellites: atmospheres - planetary systems - stars: individual: WASP-19b - techniques: photometric