Letter to the Editor

Ground-based secondary eclipse detection of the very-hot Jupiter OGLE-TR-56b^*

¹ Institut d'Astrophysique de Paris, CNRS/UPMC, 98bis boulevard Arago, 75014 Paris, France e-mail: sing@iap.fr
² Carnegie Institution of Washington, Dept. of Terrestrial Magnetism, 5241 Broad Branch Road NW, Washington, DC 20015, USA e-mail: mercedes@dtm.ciw.edu

Received: 31 October 2008
Accepted: 21 November 2008

Abstract

We report on the detection of the secondary eclipse of the very-hot Jupiter OGLE-TR-56b from combined z'-band time series photometry obtained with the VLT and Magellan telescopes. We measure a flux decrement of 0.0363 ± 0.0091% from the combined Magellan and VLT datasets, which indicates a blackbody brightness temperature of K, a very low albedo, and a small incident radiation redistribution factor, indicating a lack of strong winds in the planet's atmosphere. The measured secondary depth is consistent with thermal emission, but our precision is not sufficient to distinguish between a black-body emitting planet, or emission as predicted by models with strong optical absorbers such as TiO/VO. This is the first time that thermal emission from an extrasolar planet is detected at optical wavelengths and with ground-based telescopes.