Variations in the HCN/HNC abundance ratio in the Orion molecular cloud

Journal Article · Sat Nov 01 04:00:00 EST 1986 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/164692· OSTI ID:6696042

Goldsmith, P F; Irvine, W M; Hjalmarson, A; Ellder, J

Observations of the rare isotopes of HCN and HNC have been used to determine the relative abundance of these two chemical isomers along the central ridge of the Orion molecular cloud. The abundance ratio HCN/HNC decreases by more than an order of magnitude from the relatively warm plateau and hot core sources toward the KL nebula to the colder, more quiescent clouds to the north and south. Even in the cooler regions, however, the ratio is an order of magnitude larger than that found in previous investigations of cold dark clouds. The kinetic temperature in the regions studied is determined from new observations of methylacetylene (CH3CCH), together with other recent estimates of the gas temperature near KL. The results suggest that the warmer portions of the cloud are dominated by different chemical pathways that those in the general instellar cloud material. 22 references.

• Research Organization: Massachusetts Univ., Amherst; Onsala Rymdobservatorium, Sweden
• OSTI ID: 6696042
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 310; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640105* -- Astrophysics & Cosmology-- Galaxies
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
CHEMICAL COMPOSITION
COSMIC GASES
CYANIDES
DATA PROCESSING
FLUIDS
GASES
HYDROCYANIC ACID
HYDROGEN COMPOUNDS
INORGANIC ACIDS
INTERSTELLAR SPACE
ISOMERS
MOLECULES
PROCESSING
SPACE
VARIATIONS