Abundance of atomic carbon near the ionization fronts in M17 and S140

Journal Article · Sun Dec 01 04:00:00 EST 1985 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/163763· OSTI ID:5446010

Keene, J; Blake, G A; Phillips, T G; Huggins, P J; Beichman, C A

The 492 GHz ground-state line of atomic carbon in the edge-on ionization fronts in M17 and S140 were observed. It was found that, contrary to expectation, the C I emission peaks farther into the molecular cloud from the ionization front than does the CO. In fact the peak C I abundance in M17 occurs more than 60 mag of visual extinction into the cloud from the ionization front. Calculations of the ratio of C I to CO column densities yield values of 0.1-0.2. These observations do not support chemical models which predict that neutral atomic carbon should be found only near the edges of molelcular clouds. Other models are discussed which may explain the observations. 79 references.

• Research Organization: California Institute of Technology, Pasadena; New York Univ., NY
• OSTI ID: 5446010
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 299; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BASIC INTERACTIONS
CARBON
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL COMPOSITION
CHEMISTRY
COSMIC GASES
COSMOCHEMISTRY
ELECTROMAGNETIC INTERACTIONS
ELEMENTS
FLUIDS
GASES
INTERACTIONS
MOLECULES
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PARTICLE PRODUCTION
PHOTOPRODUCTION
TIME DEPENDENCE