The Transit Light Curve project. XIV. Confirmation of Anomalous Radii for the Exoplanets TrES-4b, HAT-P-3b, and WASP-12b

TL;DR

This study refines the parameters of three exoplanets, confirming the bloated nature of TrES-4b and WASP-12b and revealing a metal-rich composition for HAT-P-3b, with no significant transit timing variations.

Contribution

The paper provides improved system parameters and confirms the anomalously large radii of TrES-4b and WASP-12b, and identifies a metal-enriched composition for HAT-P-3b.

Findings

TrES-4b and WASP-12b are confirmed as bloated planets.

HAT-P-3b has a smaller, metal-rich core.

Transit timings show no significant deviations.

Abstract

We present transit photometry of three exoplanets, TrES-4b, HAT-P-3b, and WASP-12b, allowing for refined estimates of the systems' parameters. TrES-4b and WASP-12b were confirmed to be "bloated" planets, with radii of 1.706 +/- 0.056 R_Jup and 1.736 +/- 0.092 R_Jup, respectively. These planets are too large to be explained with standard models of gas giant planets. In contrast, HAT-P-3b has a radius of 0.827 +/- 0.055 R_Jup, smaller than a pure hydrogen-helium planet and indicative of a highly metal-enriched composition. Analyses of the transit timings revealed no significant departures from strict periodicity. For TrES-4, our relatively recent observations allow for improvement in the orbital ephemerides, which is useful for planning future observations.