BANYAN. XIII. A First Look at Nearby Young Associations with Gaia Data Release 2

TL;DR

This study uses Gaia DR2 data and Bayesian analysis to identify nearly 900 new candidate members of nearby young stellar associations, including brown dwarfs and systems, enhancing understanding of low-mass populations.

Contribution

First comprehensive analysis of Gaia DR2 data to discover new members of young associations, especially low-mass stars and brown dwarfs, using Bayesian classification.

Findings

898 new high-likelihood candidate members identified

Includes 104 co-moving systems and 111 brown dwarfs

Sample extends to the Galactic plane, reducing previous contamination issues

Abstract

In this paper we examine the nearest 100 pc entries in the data release 2 of Gaia to identify previously unrecognized candidate members in young associations. We analyze 695 952 stars with the BANYAN {\Sigma} Bayesian classification software and discover 898 new high-likelihood candidate members that span a wide range in properties, from spectral types B9 to L2, including 104 co-moving systems, 111 brown dwarfs and 31 new bona fide members. Our sample is mostly composed of highly active M dwarfs and will be crucial to examine the low-mass end of the initial mass function of young associations. Our sample includes new candidate members near the Galactic plane where previous surveys suffered from a high rate of contamination. This paper represents the first step towards a full reassessment of young associations in the Solar neighborhood with the second data release of the Gaia mission.