The `666' collaboration on OGLE transits: I. Accurate radius of the planets OGLE-TR-10b and OGLE-TR-56b with VLT deconvolution photometry

TL;DR

This study uses high-precision VLT photometry and deconvolution algorithms to accurately measure the radii of exoplanets OGLE-TR-10b and OGLE-TR-56b, confirming them as inflated hot Jupiters.

Contribution

It provides precise radius measurements of OGLE-TR-10b and OGLE-TR-56b using advanced photometry, resolving previous discrepancies and confirming their inflated nature.

Findings

OGLE-TR-10b radius: 1.22 R_J

OGLE-TR-56b radius: 1.30 R_J

Both planets are confirmed as inflated hot Jupiters.

Abstract

Transiting planets are essential to study the structure and evolution of extra-solar planets. For that purpose, it is important to measure precisely the radius of these planets. Here we report new high-accuracy photometry of the transits of OGLE-TR-10 and OGLE-TR-56 with VLT/FORS1. One transit of each object was covered in Bessel V and R filters, and treated with the deconvolution-based photometry algorithm DECPHOT, to ensure accurate millimagnitude light curves. Together with earlier spectroscopic measurements, the data imply a radius of 1.22 +0.12-0.07 R_J for OGLE-TR-10b and 1.30 +- 0.05 R_J for OGLE-TR-56b. A re-analysis of the original OGLE photometry resolves an earlier discrepancy about the radius of OGLE-TR-10. The transit of OGLE-TR-56 is almost grazing, so that small systematics in the photometry can cause large changes in the derived radius. Our study confirms both planets as inflated hot Jupiters, with large radii comparable to that of HD 209458$b$ and at least two other recently discovered transiting gas giants.