Young Stars with SALT

TL;DR

This study spectroscopically and kinematically analyzes 79 nearby M dwarfs, identifying 44 young stars, including new members of known moving groups and potential new populations, using SALT observations and literature data.

Contribution

First comprehensive spectroscopic and kinematic analysis of nearby M dwarfs using SALT, identifying new young star members and suggesting a new population of young stars.

Findings

44 young stars identified, including 12 new members

Multiple known and new moving group members found

Evidence for a new population of nearby young stars

Abstract

We present a spectroscopic and kinematic analysis of 79 nearby M dwarfs in 77 systems. All are low-proper-motion southern hemisphere objects and were identified in a nearby star survey with a demonstrated sensitivity to young stars. Using low-resolution optical spectroscopy from the Red Side Spectrograph (RSS) on the South African Large Telescope (SALT), we have determined radial velocities, H-alpha, Lithium 6708\AA, and Potassium 7699\AA~equivalent widths linked to age and activity, and spectral types for all our targets. Combined with astrometric information from literature sources, we identify 44 young stars. Eighteen are previously known members of moving groups within 100 parsecs of the Sun. Twelve are new members, including one member of the TW Hydra moving group, one member of the 32 Orionis moving group, nine members of Tucana-Horologium, one member of Argus, and two new members of AB Doradus. We also find fourteen young star systems that are not members of any known groups. The remaining 33 star systems do not appear to be young. This appears to be evidence of a new population of nearby young stars not related to the known nearby young moving groups.