Nothing to Hide: An X-ray Survey for Young Stellar Objects in the Pipe Nebula
Abstract
We have previously analyzed sensitive mid-infrared observations to establish that the Pipe Nebula (PiN) has a very low star formation efficiency. That study focused on young stellar objects (YSOs) with excess infrared emission (i.e., protostars and pre-main-sequence stars with disks), however, and could have missed a population of more evolved pre-main-sequence stars or Class III objects (i.e., young stars with dissipated disks that no longer show excess infrared emission). Evolved pre-main-sequence stars are X-ray bright, so we have used ROSAT All-Sky Survey data to search for diskless pre-main-sequence stars throughout the PiN. We have also analyzed archival XMM-Newton observations of three prominent areas within the Pipe: Barnard 59 (B 59), containing a known cluster of YSOs; Barnard 68, a dense core that has yet to form stars; and the Pipe molecular ring, a high-extinction region in the bowl of the Pipe. We also characterize the X-ray properties of YSOs in B 59. The ROSAT and XMM-Newton data provide no indication of a significant population of more evolved pre-main-sequence stars within the Pipe, reinforcing our previous measurement of the Pipe's very low star formation efficiency.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 2010
- DOI:
- 10.1088/0004-637X/719/1/691
- arXiv:
- arXiv:1006.3556
- Bibcode:
- 2010ApJ...719..691F
- Keywords:
-
- stars: pre-main sequence;
- X-rays: stars;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Accepted for publication in ApJ