An in-depth study of brown dwarfs with TESS

TL;DR

The study addresses the BD desert—the paucity of brown dwarfs in close orbits around main-sequence stars—by leveraging TESS Cycle 6 2-minute cadence photometry to search for transiting BDs and precisely measure their radii, which constrain BD ages through contraction. Using TLS on PDCSAP light curves, the authors analyze ~3300 targets, identifying 366 significant variable sources that include BD candidates, hot Jupiters, and eclipsing binaries, and they contribute these light curves to the Villanova TESS EB catalog. The work establishes a pipeline for BD transit detection in the TESS era and outlines follow-up analyses, such as asteroseismology of host stars and TTV/ETV studies, to refine BD demographics and formation channels. Overall, the results lay groundwork for improved BD radius–age constraints and population studies, informing theories of substellar formation and evolution in close-in orbits.

Abstract

The existence of a deficit of brown dwarfs (BDs) in close orbit around main-sequence stars is one of the most intriguing questions in stellar physics. This so-called BD desert may result from the transition between two different dominant formation processes occurring for different mass regimes. While the BD mass derived from radial-velocity measurements helps confirm the nature of the analyzed objects, the BD radius obtained from transits is important to better constrain the BD age, as BDs are believed to contract with age. Such objects with well-constrained parameters, although in small number, are of prime interest for deeper investigations of BD structure and chemical composition. The present document aims at presenting the first results of a search for BD transits among a sample of approximately 3300 host star candidates observed by the Transiting Exoplanet Survey Satellite during Cycle 6.