J = 4-3 HCN observations of M17 SW, DR 21/OH/, W51 and NGC 6334
Abstract
We report observations of NGC 6334N, Ml7 5W, W 51 and DR2l(OH) in the J = 4→3 transition of HCN at 354GHz. These results are combined with previously obtained J=1→0HCN data to determine molecular abundances X(HCN) ∼4 × 10-11 -4 × 10-12, and characteristic line excitation zone densities n(H2)∼106 cm-3. These results are at variance with previous analyses based on J=1→0 results alone, and the predictions of certain models of the cloud chemistry. The reasons for these discrepancies are discussed.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- April 1982
- DOI:
- 10.1093/mnras/199.2.375
- Bibcode:
- 1982MNRAS.199..375W
- Keywords:
-
- Abundance;
- Electron Transitions;
- Gas Density;
- Hydrocyanic Acid;
- Hydrogen Clouds;
- Molecular Clouds;
- Molecular Spectra;
- Astronomical Models;
- Bolometers;
- Carbon;
- Cosmochemistry;
- Hydrogen;
- Hyperfine Structure;
- Line Spectra;
- Molecular Collisions;
- Molecular Excitation;
- Nitrogen;
- Astrophysics