Determination of the HNC to HCN abundance ratio in giant molecular clouds

Journal Article · Thu Oct 15 00:00:00 EDT 1981 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/159312· OSTI ID:5652331

Goldsmith, P F; Langer, W D; Ellder, J; Irvine, W; Kollberg, E

We have used the rare isotopes of HCN and HNC to measure the relative abundance of these two chemical isomers in four giant molecular clouds. The lines of H/sup 13/CN, HC/sup 15/N, HN/sup 13/C, and H/sup 15/NC are all sufficiently weak to be little affected by saturation. A comparison of intensities measured with different beamsizes indicates that the sources are not resolved even with the 42'' beamsize used in the present work. The abundance ratio (HNC)/(HCN) varies by more than an order of magnitude, ranging from 0.015 to 0.40. These low values (which are similar to those found in warm sources from the common isotopes by Wootten et al.) are not consistent with HNC and HCN production solely from various sources of the precursor ion H/sub 2/CN/sup +/, and they indicate that another source of HCN is required in warm, giant molecular clouds. We suggest that neutral atom-molecule reactions may make an important contribution to the HCN production rate in such regions.

• Research Organization: Five College Radio Astronomy Observatory, University of Massachusetts
• OSTI ID: 5652331
• Journal Information: Astrophys. J.; (United States), Vol. 249:2
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
HYDRIDES
ABUNDANCE
HYDROCYANIC ACID
INTERSTELLAR SPACE
CARBIDES
CARBON ISOTOPES
ENERGY SPECTRA
ISOTOPE RATIO
MOLECULES
NITRIDES
NITROGEN ISOTOPES
RECOMBINATION
CARBON COMPOUNDS
CYANIDES
HYDROGEN COMPOUNDS
INORGANIC ACIDS
ISOTOPES
NITROGEN COMPOUNDS
PNICTIDES
SPACE
SPECTRA
640105* - Astrophysics & Cosmology- Galaxies