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

Journal Article · Thu Oct 15 04:00:00 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), Journal Name: Astrophys. J.; (United States) Vol. 249:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

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