LHS6343C: A Transiting Field Brown Dwarf Discovered by the Kepler Mission

TL;DR

This paper reports the discovery of a transiting brown dwarf in the LHS6343 system using Kepler data, with detailed characterization confirming its mass and radius consistent with theoretical models.

Contribution

First detection of a transiting brown dwarf around a low-mass star using Kepler data, with detailed follow-up observations and characterization.

Findings

Brown dwarf mass: 62.8 +/- 2.3 Mjup

Brown dwarf radius: 0.832 +/- 0.021 Rjup

Consistent with theoretical models for >1 Gyr brown dwarfs

Abstract

We report the discovery of a brown dwarf that transits one member of the M+M binary system LHS6343AB every 12.71 days. The transits were discovered using photometric data from the Kelper public data release. The LHS6343 stellar system was previously identified as a single high-proper-motion M dwarf. We use high-contrast imaging to resolve the system into two low-mass stars with masses 0.45 Msun and 0.36 Msun, respectively, and a projected separation of 55 arcsec. High-resolution spectroscopy shows that the more massive component undergoes Doppler variations consistent with Keplerian motion, with a period equal to the transit period and an amplitude consistent with a companion mass of M_C = 62.8 +/- 2.3 Mjup. Based on an analysis of the Kepler light curve we estimate the radius of the companion to be R_C = 0.832 +/- 0.021 Rjup, which is consistent with theoretical predictions of the radius of a > 1 Gyr brown dwarf.