GROUND-BASED NEAR-INFRARED OBSERVATIONS OF THE SECONDARY ECLIPSE OF CoRoT-2b*

摘要

We present the results of a ground-based search for the secondary eclipse of the 3.3 M Jup transiting planet CoRoT-2b. We performed near-infrared photometry using the LIRIS instrument on the 4.2 m William Herschel Telescope, in the H and Ks filters. We monitored the star around two expected secondary eclipses in two nights under very good observing conditions. For the depth of the secondary eclipse, in the H band we found a 3σ upper limit of 0.17%, whereas we detected a tentative eclipse with a depth of 0.16% ± 0.09% in the Ks band. These depths can be translated into brightness temperatures of TH 2250 K and K, which indicate an inefficient re-distribution of the incident stellar flux from the planet's day side to its night side. Our results are in agreement with the CoRoT optical measurement (Alonso et al.) and with Spitzer 4.5 and 8 μm results (Gillon et al.).