VLT transit and occultation photometry for the bloated planet CoRoT-1b

Abstract

We present VLT eclipse photometry for the giant planet CoRoT-1b. We observed a transit in the R-band filter and an occultation in a narrow filter centered on 2.09 μm. Our analysis of this new photometry and published radial velocities, in combination with stellar-evolutionary modeling, leads to a planetary mass and radius of 1.07-0.18+0.13 M Jup and 1.45-0.13+0.07 RJup, confirming the very low density previously deduced from CoRoT photometry. The large occultation depth that we measure at 2.09 μm (0.278 -0.066+0.043%) is consistent with thermal emission and is better reproduced by an atmospheric model with no redistribution of the absorbed stellar flux to the night side of the planet. © ESO 2009.