The Transit Light Curve Project. XII. Six Transits of the Exoplanet XO-2b

TL;DR

This study presents detailed photometric observations of six transits of exoplanet XO-2b, refining its physical parameters and analyzing transit timing to assess orbital stability and potential additional bodies.

Contribution

The paper provides new high-precision transit data for XO-2b and refines its planetary parameters, also examining transit timing for signs of orbital variations.

Findings

Planetary radius is approximately 1 Jupiter radius.

Planetary mass is about 0.565 Jupiter masses.

Transit times are consistent with a constant period, but slight discrepancies suggest further investigation.

Abstract

We present photometry of six transits of the exoplanet XO-2b. By combining the light-curve analysis with theoretical isochrones to determine the stellar properties, we find the planetary radius to be 0.996 +0.031/-0.018 rjup and the planetary mass to be 0.565 +/- 0.054 mjup. These results are consistent with those reported previously, and are also consistent with theoretical models for gas giant planets. The mid-transit times are accurate to within 1 min and are consistent with a constant period. However, the period we derive differs by 2.5 sigma from the previously published period. More data are needed to tell whether the period is actually variable (as it would be in the presence of an additional body) or if the timing errors have been underestimated.