Characterizing the stellar-substellar limit: a step towards a better understanding of the ultra-cool dwarfs revealed by Gaia

A. Ficot , C. Reylé , Nadège Lagarde (1, 2) , R. L. Smart , A. J. Burgasser

1 LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac]
2 UTINAM - Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213)

Ultra-cool dwarfs (spectral type later than M7) serve as a link between stars and brown dwarfs which have not a sufficient mass to support the combustion of hydrogen. Although they are numerous in the Galaxy, they remain elusive due to their low luminosity and the modelling is still a chalenge. In this work we characterized 120 ultra-cool dwarfs revealed by Gaia for which spectroscopic monitoring have been obtained using various instruments of medium spectral resolution. Our results illustrate the impact of physics considered in atmospheric models on the characterization of these objects.

Mots clés: stars: low-mass; ultra-cool dwarfs; brown dwarfs; spectroscopy

Domaines: Astrophysique [astro-ph]

A. Ficot, C. Reylé, Nadège Lagarde, R. L. Smart, A. J. Burgasser. Characterizing the stellar-substellar limit: a step towards a better understanding of the ultra-cool dwarfs revealed by Gaia. SF2A-2021: Annual meeting of the French Society of Astronomy and Astrophysics., Jun 2021, En ligne, France. ⟨hal-03863145⟩