Sign on
ADS Classic is now deprecated. It will be completely retired in October 2019. Please redirect your searches to the new ADS modern form or the classic form. More info can be found on our blog.

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Full Refereed Journal Article (PDF/Postscript)
· Full Refereed Scanned Article (GIF)
· References in the article
· Citations to the Article (117) (Citation History)
· Refereed Citations to the Article
· SIMBAD Objects (3)
· Associated Articles
· Reads History
· Translate This Page
The energetics of molecular clouds. I - Methods of analysis and application to the S255 molecular cloud [ Erratum: 1978ApJ...221..382E ]
Evans, N. J., II; Blair, G. N.; Beckwith, S.
AA(California Institute of Technology, Pasadena, Calif.), AB(California Institute of Technology, Pasadena, Calif.)
Astrophysical Journal, Part 1, vol. 217, Oct. 15, 1977, p. 448-451, 453-463. (ApJ Homepage)
Publication Date:
NASA/STI Keywords:
Carbon Monoxide, Infrared Astronomy, Interstellar Gas, Nebulae, Radio Sources (Astronomy), Astronomical Maps, Cosmic Dust, Formaldehyde, H Ii Regions, Hydrogen, Infrared Spectra, Line Spectra, Molecular Spectra, Thermodynamic Properties
Bibliographic Code:


Observations of the S255 molecular cloud in the radio lines of CO, (C-13)O, and H2O as well as in the IR region from 12 to 20 microns are presented. These results show that an extended molecular cloud is associated with the optically visible H II regions S255 - S257, both the kinetic temperature and molecular density are enhanced in an area centered on a compact near-IR source, this source is also coincident with an OH and an H2O maser (within the errors), and the IR source exhibits the silicon absorption feature. First-order techniques which allow physical properties of molecular clouds to be estimated and the energetics of the gas and dust in the clouds to be analyzed are developed and applied to S255. It is concluded that: (1) the gas cooling rate is much less than the dust cooling rate; (2) the primary energy flow is in the IR through dust emission over a range of temperatures; (3) the near-IR source is apparently responsible for the local peak in gas kinetic temperature; and (4) the exciting stars of nearby H II regions appear to be the primary heat sources for the overall molecular cloud.

Associated Articles

Main Paper     Part  2     Erratum     Part  3    

Printing Options

Print whole paper
Print Page(s) through

Return 600 dpi PDF to Acrobat/Browser. Different resolutions (200 or 600 dpi), formats (Postscript, PDF, etc), page sizes (US Letter, European A4, etc), and compression (gzip,compress,none) can be set through the Printing Preferences

More Article Retrieval Options

HELP for Article Retrieval

Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)

Find Similar Abstracts:

Use: Authors
Keywords (in text query field)
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
arXiv e-prints