Carbon monoxide isotope fractionation in the dust cloud Lynds 134

Journal Article · Thu Nov 15 04:00:00 EST 1979 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/157476· OSTI ID:5543205

Dickman, R L; McCutcheon, W H; Shuter, W L.H.

Prior observations of isotopically substituted CO in Lynds 134 are used to discuss the spatial behavior of the (CO)/(/sup 13/CO) abundance ratio as a function of visual extinction in the cloud. (CO)/(/sup 13/CO) is determined from both LTE and non-LTE evaluations of the double ratio (/sup 13/CO)/: C/sup 18/O) by subsequent application of an assumed constant, terrestrial oxygen isotope ratio. It is found that (CO)/(/sup 13/CO) is roughly terrestrial toward the central regions of L134 where A/sub ..nu../> or approx. =7 mag, and decreases in the cloud periphery where A/sub ..nu../ is lower. These results are in qualitative agreement with theoretical expectation for a low-temperature, chemically fractionated dark cloud, in which preferential /sup 13/CO enhancement is driven in low-extinction regions by the charge exchange /sup 13/C/sup +/+/sup 12/CO..-->../sup 12/C+/sup 13/CO. The impact of this result on previous studies of the carbon isotope ratio (/sup 12/C)/(/sup 13/C) in the sense interstellar medium is discussed.

• Research Organization: Rensselaer Polutechnic Institute/The Aerospace Corporation
• OSTI ID: 5543205
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 233:4; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
CARBON 12
CARBON 13
CARBON COMPOUNDS
CARBON ISOTOPES
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL COMPOSITION
CHEMISTRY
COSMOCHEMISTRY
ENERGY SPECTRA
EQUILIBRIUM
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FRACTIONATION
FUNCTIONS
INTERSTELLAR SPACE
ISOTOPE RATIO
ISOTOPES
LIGHT NUCLEI
LTE
MOLECULES
NEBULAE
NUCLEI
OXIDES
OXYGEN COMPOUNDS
SEPARATION PROCESSES
SPACE
SPECTRA
SPECTRAL DENSITY
SPECTRAL FUNCTIONS
STABLE ISOTOPES