Improved radius determinations for the transiting brown dwarf population in the era of Gaia and TESS

TL;DR

This paper updates the mass-radius diagram for 11 transiting brown dwarfs using Gaia DR3 data, revealing significant radius measurement improvements for most and refining the understanding of old and young substellar objects.

Contribution

It reanalyzes previous brown dwarf data with Gaia DR3 parallaxes, improving radius estimates and impacting substellar evolutionary model testing.

Findings

7 BDs show significant radius estimate changes with Gaia data

Some of the smallest known BDs are larger than previously thought

The mass-radius region for old BDs remains sparsely populated

Abstract

I report updates to the substellar mass-radius diagram for 11 transiting brown dwarfs (BDs) and low-mass stars published before the third data release from the Gaia mission (Gaia DR3). I reanalyse these transiting BD systems whose physical parameters were published between 2008 and 2019 and find that when using the parallax measurements from Gaia DR3, 7 BDs show significant differences in their radius estimate or an improvement in the radius uncertainty. This has important implications for how these BDs are used to test substellar evolutionary models in the mass-radius diagram. The remaining 4 BDs show mass-radius estimates that are consistent with their previous pre-Gaia DR3 measurements. The 7 BDs that show significant deviation from the original mass-radius measurements are AD 3116b, CoRoT-3b, CoRoT-15b, EPIC 201702477b, Kepler-39b, KOI-205b, and KOI-415b. Of these, AD 3116b is a known member of the Praesepe cluster at an age of 600 Myr. Additionally, some of the previously smallest known transiting BDs, KOI-205b and KOI-415b, are not as small as once thought, leaving the mass-radius region for the very oldest BDs relatively sparse as a result of this work.