New Young Stars and Brown Dwarfs in the Upper Scorpius Association

TL;DR

This study enhances the census of the 11-million-year-old Upper Scorpius association by identifying and spectroscopically confirming 530 new members, significantly expanding the known population and setting the stage for future Gaia-based discoveries.

Contribution

It provides a comprehensive spectroscopic confirmation of 530 new members, including 377 previously unconfirmed, and compiles an updated list of 1631 members, improving the understanding of the association's population.

Findings

Confirmed 530 new members of Upper Sco.

Expanded the known member list to 1631 objects.

Highlighted the potential of Gaia data for future discoveries.

Abstract

To improve the census of the Upper Sco association (~11 Myr, ~145 pc), we have identified candidate members using parallaxes, proper motions, and color-magnitude diagrams from several wide-field imaging surveys and have obtained optical and infrared spectra of several hundred candidates to measure their spectral types and assess their membership. We also have performed spectroscopy on a smaller sample of previously known or suspected members to refine their spectral types and evidence of membership. We have classified 530 targets as members of Upper Sco, 377 of which lack previous spectroscopy. Our new compilation of all known members of the association contains 1631 objects. Although the census of Upper Sco has expanded significantly over the last decade, there remain hundreds of candidates that lack spectroscopy. The precise parallaxes and proper motions from the second data release of Gaia should extend down to substellar masses in Upper Sco, which will greatly facilitate the identification of the undiscovered members.