2018A&A...619L...8R -
Astronomy and Astrophysics, volume 619, L8-8 (2018/11-1)
New ultra-cool and brown dwarf candidates in Gaia DR2.
REYLE C.
Abstract (from CDS):
Context. The second Gaia data release (Gaia DR2) contains high-precision positions, parallaxes, and proper motions for 1.3 billion sources. The resulting Hertzsprung-Russel diagram reveals fine structures throughout the mass range.
Aims. This paper aims to investigate the content of Gaia DR2 at the low-mass end and to characterize ultra-cool and brown dwarfs.
Methods. We first retrieved the sample of spectroscopically confirmed ultra-cool and brown dwarfs in Gaia DR2. We used their locus in the precise Hertzsprung-Russel diagram to select new candidates and to investigate their properties.
Results. The number of spectroscopically confirmed objects recovered in Gaia DR2 corresponds to 61% and 74% of the expected number of objects with an estimated Gaia magnitude Gest≤21.5 and 20.3, respectively. This fills much of the gap to Gaia DR1. Furthermore, Gaia DR2 contains ∼13000≥M7 and 631 new L candidates. A tentative classification suggests that a few hundred of them are young or subdwarf candidates. Their distance distribution shows that the solar neighborhood census is still incomplete.
Conclusions. Gaia DR2 offers a great wealth of information on low-mass objects. It provides a homogeneous and precise catalog of candidates that is worthwhile to be further characterized with spectroscopic observations.
Abstract Copyright:
© ESO 2018
Journal keyword(s):
stars: low-mass - solar neighborhood - Galaxy: stellar content - surveys - catalogs
VizieR on-line data:
<Available at CDS (J/A+A/619/L8): table2.dat>
Simbad objects:
14916
View the references in ADS