The radius anomaly in the planet/brown dwarf overlapping mass regime

TL;DR

This paper investigates the radius anomaly in massive substellar objects, exploring how combined observational data and advanced tidal evolution models can distinguish between brown dwarfs and planets in the overlapping mass regime.

Contribution

It introduces methods to constrain the nature of massive substellar objects using combined Radial Velocity and Photometry data, and discusses recent developments in tidal evolution modeling relevant to the radius anomaly.

Findings

Constraints on object nature from combined observables

Implications of tidal evolution models for radius anomaly

Analysis of high-eccentricity and inclined orbit systems

Abstract

The recent detection of the transit of very massive substellar companions (CoRoT-3b, Deleuil et al. 2008; CoRoT-15b, Bouchy et al. 2010; WASP-30b, Anderson et al. 2010; Hat-P-20b, Bakos et al. 2010) provides a strong constraint to planet and brown dwarf formation and migration mechanisms. Whether these objects are brown dwarfs originating from the gravitational collapse of a dense molecular cloud that, at the same time, gave birth to the more massive stellar companion, or whether they are planets that formed through core accretion of solids in the protoplanetary disk can not always been determined unambiguously and the mechanisms responsible for their short orbital distances are not yet fully understood. In this contribution, we examine the possibility to constrain the nature of a massive substellar object from the various observables provided by the combination of Radial Velocity and Photometry measurements (e.g. M_p, R_p, M_s, Age, a, e...). In a second part, developments in the modeling of tidal evolution at high eccentricity and inclination - as measured for HD 80 606 with e=0.9337 (Naef et al. 2001), XO-3 with a stellar obliquity >37.3+-3.7 deg (H\'ebrard et al. 2008; Winn et al. 2009) and several other exoplanets - are discussed along with their implication in the understanding of the radius anomaly problem of extrasolar giant planets.