A Distributed Population of Low Mass Pre-Main Sequence Stars near the Taurus Molecular Clouds

Abstract

We present a drift scan survey covering a ~5 deg by 50 deg region toward the southern portion of the Taurus-Auriga molecular cloud. Data taken in the B,R,I filters with the Quest-2 camera on the Palomar 48-inch telescope were combined with 2MASS near-infrared photometry to select candidate young stars. Follow-up optical spectroscopy of 190 candidates led to identification of 42 new low mass pre-main sequence stars with spectral types M4-M8, of which approximately half exhibit surface gravity signatures similar to known Taurus stars while the other half exhibit surface gravity signatures similar to members of the somewhat older Upper Sco, TW Hya and Beta Pic associations. The pre-main sequence stars are spread over ~35 deg, and many are located well outside of previously explored regions. From assessment of the spatial and proper motion distributions, we argue that the new pre-main sequence stars identified far from the clouds cannot have originated from the vicinity of the 1-2 Myr-old subclusters which contain the bulk of the identified Taurus members, but instead represent a newly-identified area of recent star-formation near the clouds.Comment: Accepted for publication in AJ. 13 pages including 9 figures (2 in color) and 1 table. A separate file tabA1.ps contains a hard copy of a second table which will be published in electronic form onl