Transiting exoplanets from the CoRoT space mission. XV. CoRoT-15b: a brown dwarf transiting companion

TL;DR

This paper reports the discovery of CoRoT-15b, a transiting brown dwarf with a 3.06-day orbit around an F7V star, highlighting its unique properties and implications for brown dwarf evolution.

Contribution

It presents the first detailed characterization of CoRoT-15b, a brown dwarf transiting companion, including its mass, radius, and potential evolutionary state, expanding knowledge of substellar objects.

Findings

CoRoT-15b has a mass of 63.3 Mjup and radius of 1.12 Rjup.

The system's spin period is between 2.9 and 3.1 days.

CoRoT-15b is either very young or inflated compared to models.

Abstract

We report the discovery by the CoRoT space mission of a transiting brown dwarf orbiting a F7V star with an orbital period of 3.06 days. CoRoT-15b has a radius of 1.12 +0.30 -0.15 Rjup, a mass of 63.3 +- 4.1 Mjup, and is thus the second transiting companion lying in the theoretical mass domain of brown dwarfs. CoRoT-15b is either very young or inflated compared to standard evolution models, a situation similar to that of M-dwarfs stars orbiting close to solar-type stars. Spectroscopic constraints and an analysis of the lightcurve favors a spin period between 2.9 and 3.1 days for the central star, compatible with a double-synchronisation of the system.