WASP-12b: The hottest transiting planet yet discovered

TL;DR

WASP-12b is the hottest, largest, and most heavily irradiated transiting exoplanet discovered to date, with a very short orbital period around a metal-rich F-type star.

Contribution

This paper reports the discovery and detailed characterization of WASP-12b, the hottest and largest transiting exoplanet known, including its host star properties and orbital parameters.

Findings

WASP-12b has the largest radius among transiting planets.

It is the most heavily irradiated exoplanet with a very short orbital period.

The host star is a super-solar metallicity, late-F type star.

Abstract

We report on the discovery of WASP-12b, a new transiting extrasolar planet with $R_{\rm pl}=1.79 \pm 0.09 R_J$ and $M_{\rm pl}=1.41 \pm 0.1 M_J$. The planet and host star properties were derived from a Monte Carlo Markov Chain analysis of the transit photometry and radial velocity data. Furthermore, by comparing the stellar spectrum with theoretical spectra and stellar evolution models, we determined that the host star is a super-solar metallicity ([M/H]$=0.3^{+0.05}_{-0.15}$), late-F (T$_{\rm eff}=6300^{+200}_{-100}$ K) star which is evolving off the zero age main sequence. The planet has an equilibrium temperature of T$_{\rm eq}$=2516 K caused by its very short period orbit ($P=1.09$ days) around the hot, 12th magnitude host star. WASP-12b has the largest radius of any transiting planet yet detected. It is also the most heavily irradiated and the shortest period planet in the literature.