On the temperatures of diffuse interstellar clouds
Abstract
It is proposed that the ratio of the column densities of HD and OH be used to estimate the kinetic temperatures of diffuse interstellar clouds. Ten reactions which govern the abundances of HD and OH in diffuse interstellar clouds are identified, and the ratio of the column densities of these two species is related to kinetic temperature. The method is employed to determine the kinetic temperatures toward Zeta Oph and Omicron Per; agreement with the temperatures inferred from the rotational excitation of H2 toward these stars is indicated. Column densities of OH are predicted from observed HD column densities and kinetic temperatures toward Epsilon Per, Gamma Ara, 139 Tau, Xi Per, Alpha Cam, and 10 Lac.
- Publication:
-
The Observatory
- Pub Date:
- June 1978
- Bibcode:
- 1978Obs....98..115T
- Keywords:
-
- Gas Density;
- Gas Temperature;
- Interstellar Gas;
- Atomic Energy Levels;
- Deuterium;
- Hydrogen;
- Hydroxyl Radicals;
- Interstellar Chemistry;
- Molecular Excitation;
- Astrophysics