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Far-infrared spectroscopy of the DR 21 star formation regionFar-IR line and continuum observations of the DR 21 star formation region are presented. It is shown that the extended emission in the 63 micron forbidden O I, 35 micron forbidden Si II, and 158 micron forbidden C II lines is most likely produced in dense, warm photodissociation regions on the surfaces of atomic and molecular clumps of size smaller than 0.6 pc. The gas temperatures in these photoelectrically heated, predominantly atomic layers are 250-500 K and are maintained by FUV fluxes 10,000 or more times the average interstellar radiation field. Gas densities in the surface layers are in the range 10,000-50,000/cu cm. The gas phase abundance of Si(+) is inferred to be about 5 x 10 to the -6th relative to hydrogen, or about 0.15 of its solar abundance. The mass of atomic gas is at least 200 solar masses.
Document ID
19900061860
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Lane, Adair P.
(Boston University MA, United States)
Haas, M. R.
(Boston Univ. Boston, MA, United States)
Hollenbach, D. J.
(Boston Univ. Boston, MA, United States)
Erickson, E. F.
(NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
August 14, 2013
Publication Date
September 20, 1990
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 361
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
90A48915
Distribution Limits
Public
Copyright
Other

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