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H2O heating in molecular clouds - Line transfer and thermal balance in a warm dusty mediumAn investigation is undertaken into the possibility of the heating of molecular gas through collisions with radiatively pumped H2O, in the context of the overall thermal balance of optically thick molecular clouds with embedded sources. In order to solve the line transfer equation, which includes warm dust grains, an extended method of escape probability approximation is developed in which the equilibrium gas temperature arises from the balance of heating by cosmic ray ionization of H2, and by collisions with warm dust grains and radiatively pumped H2O molecules against cooling by collisions with CO and C I. The equilibrium gas temperature for a given dust temperature strongly depends on the efficiency of the cooling species, and is therefore most sensitive to the cloud optical depth. It is less dependent, in decreasing order, on H2O abundance, gas density, and velocity dispersion.
Document ID
19840033429
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Takahashi, T.
(California Univ. Berkeley, CA, United States)
Silk, J.
(California, University Berkeley, CA, United States)
Hollenbach, D. J.
(NASA Ames Research Center Space Science Div., Moffett Field, CA, United States)
Date Acquired
August 12, 2013
Publication Date
December 1, 1983
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 275
ISSN: 0004-637X
Subject Category
Astrophysics
Accession Number
84A16216
Funding Number(s)
CONTRACT_GRANT: NSF AST-79-15244
Distribution Limits
Public
Copyright
Other

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