Specific Star Forming Regions -- Oral Presentation
Disks Around Brown Dwarfs and Low Mass Stars in the Orion Molecular
Clouds 2 and 3
Dawn Peterson, University of Virginia
T. Megeath (CfA), J. Pipher (Rochester), K. Luhman (CfA), L. Allen (CfA), P. Myers (CfA)
The Orion Molecular Clouds 2 and 3 (OMC 2/3) region is a very
active region of ongoing star formation. Submillimeter surveys have
found twenty-one protostellar cores in OMC 2/3 (Chini et al. 1997);
however it has not been studied as extensively and to similar depth in
the infrared as the neighboring Orion Nebula Cluster. Deep near-IR,
visible and now Spitzer observations of OMC 2/3 have been obtained and
analyzed to identify PMS stars and brown dwarfs. Spectroscopic follow-up
has confirmed as many as 17 bona fide brown dwarfs in this region.
Circumstellar disks are identified in many of these young objects
through infrared excess emission. Spitzer photometry is used to detect
mid-infrared excess emission in a dozen OMC 2/3 brown dwarfs, confirming
that they exhibit circumstellar disks. Using the ground-based near-IR
and Spitzer data, the population of protostars and young stars with
disks is identified, and the number and spatial distribution of young
stellar objects is presented. By combining this data with the near-IR
variabiliity study of Carpenter et al. (2001), a circumstellar disk
fraction is determined.