A&A 493, L31-L34 (2009)
DOI: 10.1051/0004-6361:200811268

Letter

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

D. K. Sing¹ and M. López-Morales<sup>2

1</sup>  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 2718⁺¹²⁷_-107 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.

Key words: binaries: eclipsing -- planetary systems -- stars: individual: OGLE-TR-56 -- techniques: photometric

© ESO 2009

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