HCN hyperfine anomalies in dark clouds.
Abstract
We invesitgate the effects of cloud density structure and cloud kinematics on the intensity of the HCN J = 1-0 hyperfine lines in interstellar molecular dark clouds. Our numerical code treats the line overlap effects among the hyperfine components of the different rotational levels. Our results show the importance of the density and velocity structure of molecular clouds in explaining the emergent line profiles in dark clouds with temperature around 10 K. We suggest that a core-envelope structure and a negative velocity gradient of the gas in the core are required to explain the large hyperfine anomalies observed in TMC1.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- November 1993
- Bibcode:
- 1993A&A...279..506G
- Keywords:
-
- Anomalies;
- Astronomical Models;
- Hydrocyanic Acid;
- Hyperfine Structure;
- Interstellar Matter;
- Molecular Clouds;
- Molecular Spectra;
- Radiative Transfer;
- Radio Astronomy;
- Line Spectra;
- Mathematical Models;
- Molecular Excitation;
- Monte Carlo Method;
- Radio Spectra;
- Velocity Distribution;
- Astronomy