Relationship between carbon monoxide abundance and visual extinction in interstellar clouds

Journal Article · Mon Nov 15 04:00:00 EST 1982 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/160451· OSTI ID:5637334

Frerking, M A; Langer, W D; Wilson, R W

Carbon monoxide column densities are compared to visual extinctions toward field stars in the rho Oph and Taurus molecular cloud complexes. The relationship of C/sup 18/O column density to A/sub v/ is established, and new determinations for /sup 13/CO column densities are given for a range of visual extinctions extended to beyond 20 mag. A prescription for determining hydrogen column densities and masses of molecular clouds from observations of CO isotopes is presented and discussed critically. These measurements agree well with the predictions of gas phase chemistry models which include chemical fractionation and selective isotopic photodestruction. The functional dependence of the C/sup 18/O column density on A/sub v/ is characterized by two different regimes separated by a distinct transition observed to occur at 4 mag in both molecular cloud complexes, whereas the functional dependence of /sup 13/CO is quite different in the two regions. We find that some saturation occurs for C/sup 18/O emission at high visual extinction and use the rarer isotopic species C/sup 17/O and /sup 13/C/sup 18/O to correct for it.

• Research Organization: Crawford Hill Laboratory, Bell Laboratories
• OSTI ID: 5637334
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 262:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CARBON COMPOUNDS
CARBON ISOTOPES
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
COSMIC DUST
COSMIC GASES
DUSTS
ELEMENTS
FLUIDS
FRACTIONATION
FUNCTIONS
GASES
HYDROGEN
INTERSTELLAR GRAINS
ISOTOPES
NONMETALS
OXIDES
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
PARTICLES
SEPARATION PROCESSES
SPECTRA
SPECTRAL DENSITY
SPECTRAL FUNCTIONS