Results from BASS, the BANYAN All-Sky Survey

TL;DR

The BASS survey systematically identified potential brown dwarf members in young moving groups using cross-matched sky catalogs and Bayesian analysis, leading to new discoveries of low-mass objects and companions with signs of youth.

Contribution

This work introduces the BASS catalog of over 300 candidate members of young moving groups, combining cross-matched data and Bayesian analysis, and reports new low-mass star and brown dwarf discoveries.

Findings

Identification of new low-mass stars and brown dwarfs with signs of low gravity.

Evidence for mass segregation in AB Doradus and Argus groups.

Discovery of a new 13 M_Jup co-moving companion with youth indicators.

Abstract

We present results from the BANYAN All-Sky Survey (BASS), a systematic all-sky survey for brown dwarf candidates in young moving groups. We describe a cross-match of the 2MASS and AllWISE catalogs that provides a list of 98 970 potential nearby dwarfs with spectral types later than M5 with measurements of proper motion at precisions typically better than 15 mas yr$^{-1}$, as well as the Bayesian Analysis for Nearby Young AssociatioNs II tool (BANYAN II) which we use to build the BASS catalog from this 2MASS-AllWISE cross-match, consisting of more than 300 candidate members of young moving groups. We present the first results of a spectroscopic follow-up of those candidates, which allowed us to identify several new low-mass stars and brown dwarfs displaying signs of low gravity. We use the BASS catalog to show tentative evidence for mass segregation in AB Doradus and Argus, and reveal a new $\sim$ 13 M$_{Jup}$ co-moving companion to a young low-mass star in BASS. We obtain a moderate-resolution near-infrared spectrum for the companion, which reveals typical signs of youth and a spectral type L4 $\gamma$.