The first planet detected in the WTS: an inflated hot-Jupiter in a 3.35 day orbit around a late F-star

TL;DR

The paper reports the discovery of WTS-1b, an inflated hot Jupiter orbiting a late F-star with a 3.35-day period, using infrared transit survey data and spectroscopic follow-up, marking the first planet found by the WTS.

Contribution

This is the first detection of an exoplanet by the WFCAM Transit Survey, demonstrating its capability to discover transiting hot Jupiters.

Findings

WTS-1b has a mass of approximately 4 Mj.

WTS-1b has a radius of about 1.5 Rj.

WTS-1b exhibits a significant radius anomaly among hot Jupiters.

Abstract

We report the discovery of WTS-1b, the first extrasolar planet found by the WFCAM Transit Survey, which began observations at the 3.8-m United Kingdom Infrared Telescope. Light curves comprising almost 1200 epochs with a photometric precision of better than 1 per cent to J=16 were constructed for 60000 stars and searched for periodic transit signals. For one of the most promising transiting candidates, high-resolution spectra taken at the Hobby-Eberly Telescope allowed us to estimate the spectroscopic parameters of the host star, a late-F main sequence dwarf (V=16.13) with possibly slightly subsolar metallicity, and to measure its radial velocity variations. The combined analysis of the light curves and spectroscopic data resulted in an orbital period of the substellar companion of 3.35 days, a planetary mass of 4.01+-0.35 Mj and a planetary radius of 1.49+-0.17 Rj. WTS-1b has one of the largest radius anomalies among the known hot Jupiters in the mass range 3-5 Mj.