Far-infrared spectroscopy of the DR 21 star formation region

Journal Article · Sat Sep 01 04:00:00 EDT 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/169175· OSTI ID:6334466

Lane, A P; Haas, M R; Hollenbach, D J; Erickson, E F ^[1]

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1. Boston Univ., MA (USA) NASA, Ames Research Center, Moffett Field, CA (USA)

Far-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. 74 refs.

• OSTI ID: 6334466
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 361; ISSN ASJOA; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CARBON
COSMIC GASES
COSMIC RADIO SOURCES
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY-LEVEL TRANSITIONS
FAR INFRARED RADIATION
FINE STRUCTURE
FLUIDS
FORBIDDEN TRANSITIONS
GASES
H2 REGIONS
INFRARED RADIATION
INTERSTELLAR SPACE
NONMETALS
OXYGEN
RADIATIONS
SEMIMETALS
SILICON
SPACE
SPECTROSCOPY
STAR EVOLUTION