A spectroscopically confirmed Gaia-selected sample of 318 new young stars within $\sim$200 pc

TL;DR

This study identifies 318 new young stars within 200 parsecs using spectroscopic observations of Gaia-selected candidates, providing valuable age indicators and expanding the known nearby young stellar population.

Contribution

The paper presents a spectroscopic survey of Gaia-selected low-mass star candidates, discovering 318 new young stars and providing their age and kinematic data, which was previously unavailable.

Findings

318 new young stars identified via lithium absorption

Detection of stellar activity in 126 stars without lithium

Radial velocities measured with high precision

Abstract

In the Gaia era, the majority of stars in the Solar neighbourhood have parallaxes and proper motions precisely determined while spectroscopic age indicators are still missing for a large fraction of low-mass young stars. In this work we select 756 overluminous late K and early M young star candidates in the southern sky and observe them over 64 nights with the ANU 2.3m Telescope at Siding Spring Observatory using the Echelle (R=24,000) and Wide Field spectrographs (WiFeS, R=3000-7000). Our selection is kinematically unbiased to minimize the preference against low-mass members of stellar associations that dissipate first, and to include potential members of diffuse components. We provide measurements of H$\alpha$ and calcium H&K emission, as well as lithium absorption line, that enable identification of stars as young as $\sim$10-30 Myr which is a typical age of a stellar association. We report on 346 stars showing a detectable lithium line, 318 of which are not found in the known catalogs of young stars. We also report 126 additional stars in our sample which have no detectable lithium but signs of stellar activity indicating youth. Radial velocities are determined for WiFeS spectra with a precision of 3.2 $\mathrm{km\;s^{-1}}$ and 1.5 $\mathrm{km\;s^{-1}}$ for the Echelle sample.