New X-ray Selected Pre-Main Sequence Members of the Serpens Molecular Cloud

Abstract

The study of young stars no longer surrounded by disks can greatly add to our understanding of how protoplanetary disks evolve and planets form. We have used VLT/FLAMES optical spectroscopy to confirm the youth and membership of 19 new young diskless stars in the Serpens Molecular Cloud, identified at X-ray wavelengths. Spectral types, effective temperatures and stellar luminosities were determined using the optical spectra and optical/near-IR photometry. Stellar masses and ages were derived based on PMS evolutionary tracks. The results yield remarkable similarities for age and mass distribution between the diskless and disk-bearing stellar populations in Serpens. We discuss the important impli- cations these similarities may have on the standard picture of disk evolution.