Transiting exoplanets from the CoRoT space mission XXVIII. CoRoT-33b, an object in the brown dwarf desert with 2:3 commensurability with its host star

TL;DR

This paper reports the discovery of CoRoT-33b, a rare transiting brown dwarf in the brown dwarf desert with a 5.82-day eccentric orbit, providing insights into brown dwarf occurrence and tidal evolution.

Contribution

It presents the detection and characterization of a new brown dwarf in a unique orbital resonance, expanding understanding of brown dwarf demographics.

Findings

CoRoT-33b has a mass of 59 M_Jup and radius of 1.1 R_Jup.

The orbit is eccentric with e=0.07 and period of 5.82 days.

Brown dwarfs with P < 10 days are about six times less frequent than hot Jupiters.

Abstract

We report the detection of a rare transiting brown dwarf with a mass of 59 M_Jup and radius of 1.1 R_Jup around the metal-rich, [Fe/H] = +0.44, G9V star CoRoT-33. The orbit is eccentric (e = 0.07) with a period of 5.82 d. The companion, CoRoT-33b, is thus a new member in the so-called brown dwarf desert. The orbital period is within 3% to a 3:2 resonance with the rotational period of the star. CoRoT-33b may be an important test case for tidal evolution studies. The true frequency of brown dwarfs close to their host stars (P < 10 d) is estimated to be approximately 0.2% which is about six times smaller than the frequency of hot Jupiters in the same period range. We suspect that the frequency of brown dwarfs declines faster with decreasing period than that of giant planets.