Letter to the Editor
Astrophysics Group, Keele University, Staffordshire ST5 5BG, UK e-mail: email@example.com
2 Institut d'Astrophysique et de Géophysique, Université de Liège, Allée du 6 Août 17, Bat. B5C, 4000 Liège, Belgium
3 Observatoire de Genève, Université de Genève, 51 Chemin des Maillettes, 1290 Sauverny, Switzerland
4 Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, AZ 86001, USA
5 School of Physics and Astronomy, University of St. Andrews, North Haugh, Fife KY16 9SS, UK
Accepted: 10 March 2010
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 its G8V-type host star. WASP-19b is a Jupiter-mass planet with an orbital period of only 19 h, and thus, being highly irradiated, is expected to be hot. We measure an H-band occultation depth of 0.259%, which corresponds to an H-band brightness temperature of TH = 2580 ± 125 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
Based on data collected with the VLT/HAWKI instrument at ESO Paranal Observatory, Chile (programs 083.C-0377(A)).
The photometric time-series used in this work are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (188.8.131.52) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/513/L3
© ESO, 2010