Six High-Precision Transits of OGLE-TR-113b

TL;DR

This study presents six new high-precision transits of OGLE-TR-113b, refines its system parameters, and investigates potential orbital period variations that could indicate tidal decay or external perturbations.

Contribution

It provides updated system parameters, places limits on perturber masses, and suggests possible orbital decay, offering new insights into the dynamics of close-in exoplanets.

Findings

No significant transit timing variations detected.

Hints of a decreasing orbital period over two years.

Potential evidence for orbital decay or external perturbation.

Abstract

We present six new transits of the hot Jupiter OGLE-TR-113b observed with MagIC on the Magellan Telescopes between January 2007 and May 2009. We update the system parameters and revise the planetary radius to R_p=1.084 pm 0.029 R_J, where the error is dominated by stellar radius uncertainties. The new transit midtimes reveal no transit timing variations from a constant ephemeris of greater than 13 pm 28 seconds over two years, placing an upper limit of 1-2 M_Earth on the mass of any perturber in a 1:2 or 2:1 mean-motion resonance with OGLE-TR-113b. Combining the new transit epochs with five epochs published between 2002 and 2006, we find hints that the orbital period of the planet may not be constant, with the best fit indicating a decrease of dP/dt=-60 pm 15 milliseconds per year. If real, this change in period could result from either a long-period (more than 8 years) timing variation due to a massive external perturber, or more intriguingly from the orbital decay of the planet. The detection of a changing period is still tentative and requires additional observations, but if confirmed it would enable direct tests of tidal stability and dynamical models of close-in planets.