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Physical properties of the OMC-2 and OMC-3 cores from CS and C(18)O observationsWe have investigated the properties of the OMC-2 and OMC-3 cores in the Orion giant molecular cloud using high spatial spectral resolution observations of several transitions of the (13)CO, C(18)O, C(S-32) and C(S-34) molecules taken with the SEST telescope. The OMC-2 core consists of one clump (22 solar mass) with a radius of 0.11 pc surrounded by a cluster of 11 discrete infrared sources. The H2 column density and volume density in the center of this clump are 2 x 10(exp 22)/sq cm and 9 x 10(exp 5)/cu cm respectively. From a comparison between physical parameters derived from C(18)O and C(S-32) observations we conclude that the molecular envelope around the core has been completely removed by these sources and that only the very dense gas is left. OMC-3 shows a more complex elongated structure in C(18)O and CS than OMC-2. The C(S-32) and C(S-34) maps show that the denser region can be separated into at least sub-cores of roughly equal sizes (radius approximately equals 0.13 pc), with n(H2) = 6 x 10(exp 5)/cu cm, and a mass of 10 solar mass (from C(S-32)). The very different masses obtained for the central core from C(18)O and C(S-32) (55 and 12 solar mass respectively) indicate that a massive envelope is still present around the very dense sub-cores. We report the first detection of several molecular outflows in OMC-3. The presence of an IRAS source and the first detection of these outflows confirm that star formation is going on in OMC-3. Based on the different physical properties of these regions compared with OMC-1, OMC-2 appears to be in an intermediate evolutionary stage between OMC-1 and OMC-3.
Document ID
19950051554
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Castets, A.
(Observatorie de Grenoble Grenoble, France)
Langer, W. D.
(Jet Propulsion Lab. California Inst. of Tech., Pasadena, MD, United States)
Date Acquired
August 16, 2013
Publication Date
February 20, 1995
Publication Information
Publication: Astronomy and Astrophysics
Volume: 294
Issue: 3
ISSN: 0004-6361
Subject Category
Astrophysics
Accession Number
95A83153
Distribution Limits
Public
Copyright
Other

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