A 4.6-year period brown-dwarf companion interacting with the hot-Jupiter CoRoT-20 b

TL;DR

This paper reports the discovery of a second substellar companion in the CoRoT-20 system, revealing a unique eccentric hot Jupiter with a massive companion, providing insights into planetary migration mechanisms.

Contribution

It presents the first identification of a system with an eccentric hot Jupiter and a massive eccentric companion, suggesting a possible Lidov-Kozai migration process.

Findings

Discovery of a second substellar companion with 17 M_Jup

The companion orbits in 4.59 years with high eccentricity

Implication of Lidov-Kozai effect in hot Jupiter migration

Abstract

We report the discovery of an additional substellar companion in the CoRoT-20 system based on six years of HARPS and SOPHIE radial velocity follow-up. CoRoT-20 c has a minimum mass of 17 $\pm$ 1 $M_{Jup}$ and it orbits the host star in 4.59$\pm 0.05$ years, with an orbital eccentricity of 0.60 $\pm$ 0.03. This is the first identified system with an eccentric hot Jupiter and an eccentric massive companion. The discovery of the latter might be an indication of the migration mechanism of the hot Jupiter, via Lidov-Kozai effect. We explore the parameter space to determine which configurations would trigger this type of interactions.