FORS2 and HAWKI photometry of CoRoT-1

We observed a transit in the R-band filter and an occultation in a narrow filter centered on 2.09{mu}m. 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^+0.13^_-0.18_M_{Jup}_ and 1.45^+0.07^_-0.13_R_{Jup}, confirming the very low density previously deduced from CoRoT photometry.

The large occultation depth that we measure at 2.09{mu}m (0.278^0.043^_-0.066_% ) 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.