Determination of cooling rates in the interstellar medium.
Abstract
The cooling in most interstellar 'clouds' is due to fine-structure line emission by C(+). An estimate of the cooling rate can be obtained from the measurement, in the ultraviolet, of the column density N(C(+) 2 P 3/2) relative to N(H(0) + H(+)). The measurement of these column densities for eight interstellar 'clouds' is discussed. In equilibrium the cooling rate equals the heating rate. The rate obtained is too high to be explained either by the ionization of C by the interstellar radiation field or by ionization of H by low-energy cosmic rays. Photoelectric emission from 'dust' could explain the observed heating rate.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- May 1979
- Bibcode:
- 1979A&A....74L..15P
- Keywords:
-
- Energy Dissipation;
- Hydrogen Clouds;
- Interstellar Gas;
- Radiant Cooling;
- Radiative Heat Transfer;
- Carbon;
- Cosmic Dust;
- Cosmic Rays;
- Gas Heating;
- Ion Density (Concentration);
- Ultraviolet Spectra;
- Astrophysics;
- Interstellar Dust;
- Interstellar Matter:Cooling