A Gaia Survey for Young Stars Associated with the Lupus Clouds

TL;DR

This study uses Gaia DR2 data to identify and characterize young stars in the Lupus clouds, providing a more complete catalog and insights into their age and initial mass function, distinct from other Sco-Cen populations.

Contribution

It presents a new, comprehensive catalog of Lupus members using Gaia data, improving membership discrimination and analyzing their age and mass distribution.

Findings

Lupus stars are ~0.4 mag brighter than Upper Sco, indicating an age of ~6 Myr.

The initial mass function in Lupus resembles that of other nearby star-forming regions.

The catalog is complete for spectral types earlier than M7 at A_K<0.2.

Abstract

I have used high-precision photometry and astrometry from the second data release of the Gaia mission to perform a survey for young stars associated with the Lupus clouds, which have distances of ~160 pc and reside within the Sco-Cen OB association. The Gaia data have made it possible to distinguish Lupus members from most of the stars in other groups in Sco-Cen that overlap with the Lupus clouds, which have contaminated previous surveys. The new catalog of candidate Lupus members should be complete for spectral types earlier than M7 at A_K<0.2 within fields encompassing clouds 1--4. I have used that catalog to characterize various aspects of the Lupus stellar population. For instance, the sequence of low-mass stars in Lupus is ~0.4 mag brighter than the sequence for Upper Sco, which implies an age of ~6 Myr based an adopted age of 10-12 Myr for Upper Sco and the change in luminosity with age predicted by evolutionary models. I also find that the initial mass function in Lupus is similar to that in other nearby star-forming regions based on a comparison of their distributions of spectral types.