OGLE-TR-211 - a new transiting inflated hot Jupiter from the OGLE survey and ESO LP666 spectroscopic follow-up program

TL;DR

This paper reports the discovery and detailed characterization of OGLE-TR-211b, an inflated hot Jupiter with a 3.68-day orbit, confirmed through photometric and spectroscopic follow-up, challenging existing planetary models.

Contribution

First confirmation of OGLE-TR-211b as an inflated hot Jupiter with precise parameters derived from combined photometric and spectroscopic data.

Findings

OGLE-TR-211b has a mass of 1.03 M_Jup.

The planet's radius is 1.36 R_Jup, about 20% larger than typical hot Jupiters.

It belongs to the small group of inflated hot Jupiters with low density.

Abstract

We present results of the photometric campaign for planetary and low-luminosity object transits conducted by the OGLE survey in 2005 season (Campaign #5). About twenty most promising candidates discovered in these data were subsequently verified spectroscopically with the VLT/FLAMES spectrograph. One of the candidates, OGLE-TR-211, reveals clear changes of radial velocity with small amplitude of 82 m/sec, varying in phase with photometric transit ephemeris. Thus, we confirm the planetary nature of the OGLE-TR-211 system. Follow-up precise photometry of OGLE-TR-211 with VLT/FORS together with radial velocity spectroscopy supplemented with high resolution, high S/N VLT/UVES spectra allowed us to derive parameters of the planet and host star. OGLE-TR-211b is a hot Jupiter orbiting a F7-8 spectral type dwarf star with the period of 3.68 days. The mass of the planet is equal to 1.03+/-0.20 M_Jup while its radius 1.36+0.18-0.09 R_Jup. The radius is about 20% larger than the typical radius of hot Jupiters of similar mass. OGLE-TR-211b is, then, another example of inflated hot Jupiters - a small group of seven exoplanets with large radii and unusually small densities - objects being a challenge to the current models of exoplanets.