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Coronal Activity in Low-Mass Pre-Main Sequence Stars: NGC 2264We present the preliminary results of an analysis of ROSAT images in the region of the populous young (age approx. 3 Myr) star-forming region NGC 2264. The cluster was imaged with the ROSAT HRI in two sets of pointings -- one set near the central region of the cluster, centered on the star LW Mon, and the other set in the southern part of the cluster, centered near the star V428 Mon, just south of the Cone Nebula. In total 113 unique X-ray sources have been identified in the ROSAT images with signal-to-noise ratios greater than 3. The limiting luminosities (log Lx(ergs/sec)) for 3-sigma detections are estimated to be 30.18, 30.23, and 30.08 for the northern field, southern field, and overlap region between the two fields respectively. Extensive optical photometry, classification spectroscopy, and proper motions, obtained from recent ground-based surveys of this region, were used to identify the most likely optical counterpart to each X-ray source. Although most of our X-ray selected sample appears to be associated with NGC 2264 members, we find that the vast majority of the cluster membership was undetected in the ROSAT HRI survey. The X-ray cumulative luminosity function for solar-mass stars in NGC 2264 shows that most of the low-mass members probably have X-ray luminosities similar to those seen for the X-ray brightest members of older clusters such as IC 2391/IC 2602 (age approx. 50 Myr) and the Pleiades (age approx. 100 Myr). This research was funded in part by the SAO Summer Intern Program and NASA grant NAG5-8120.
Document ID
20040034214
Acquisition Source
Headquarters
Document Type
Conference Paper
Authors
Tebbe, H. J.
(Missouri Univ. MO, United States)
Patten, B. M.
(Harvard-Smithsonian Center for Astrophysics Cambridge, MA, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2000
Subject Category
Astronomy
Meeting Information
Meeting: AAS 195th Meeting
Country: Unknown
Start Date: January 1, 2000
Sponsors: American Astronomical Society
Funding Number(s)
CONTRACT_GRANT: NAG5-8120
Distribution Limits
Public
Copyright
Other

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