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Radio recombination line observations of the C II region NGC 2023The reflection nebula NGC 2023 has been observed at four frequencies in a study of its carbon recombination line emission. The observations show the recombination line region to be about 2 pc in diameter, with an average electron density of about 0.2 per cu cm and electron temperature of about 20 K. The electron density increases exponentially near the B1.5 star HD 37903, the illuminating star of NGC 2023. The most reasonable interpretation of the observational results is that the carbon emission lines arise in a cold C II region surrounding HD 37903. The coexistence of the C II region with a region of enhanced CO emission suggests that the CO in NGC 2023 may be excited by electron collisions.
Document ID
19750040241
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Knapp, G. R.
(Owens Valley Radio Observatory Pasadena, Calif., United States)
Brown, R. L.
(National Radio Astronomy Observatory Charlottesville, Va., United States)
Kuiper, T. B. H.
(California Institute of Technology, Jet Propulsion Laboratory, Pasadena Calif., United States)
Date Acquired
August 8, 2013
Publication Date
February 15, 1975
Publication Information
Publication: Astrophysical Journal
Volume: 196
Subject Category
Astrophysics
Accession Number
75A24313
Funding Number(s)
CONTRACT_GRANT: NSF GP-27503
CONTRACT_GRANT: NSF GP-30400-X1
CONTRACT_GRANT: NAS7-100
CONTRACT_GRANT: N00014-67-A-0094-0019
Distribution Limits
Public
Copyright
Other

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