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

TL;DR

This study uses VLT photometry to analyze CoRoT-1b, confirming its low density and thermal emission characteristics, and providing refined planetary parameters through combined observational and modeling approaches.

Contribution

First detailed VLT transit and occultation photometry for CoRoT-1b, refining its physical and atmospheric properties with new observational data.

Findings

Confirmed low planetary density of CoRoT-1b.

Measured significant thermal emission at 2.09 microns.

Supported atmospheric model with no heat redistribution.

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 microns. 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 microns (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.