Ammonia in the Kleinmann-Low nebula.
Abstract
Ammonia is observed toward the Kleinmann-Low nebula via the microwave radiation from the inversion doublets of the six lowest metastable rotational states. Hyperfine structures were detected in the three lowest transitions, from which optical depths of the order of 1 to 2 are derived. Assuming usual values for density and temperature, this implies that the ammonia molecules must be 'clumped' with a filling factor of less than 0.04 with respect to a 1.4-arcmin beam. The effect of radiative trapping is to lower the upper limit on the filling factor. A low-velocity feature is detected at 3.8 km/s, less by a factor of 4 in line intensity than the 8 km/s main feature, in the (1, 1) line. This feature appears to be present in all six transitions observed.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 1977
- DOI:
- 10.1086/182338
- Bibcode:
- 1977ApJ...211L..39B
- Keywords:
-
- Ammonia;
- Hyperfine Structure;
- Interstellar Matter;
- Molecular Spectra;
- Nebulae;
- Electron Transitions;
- Metastable State;
- Microwave Emission;
- Molecular Energy Levels;
- Optical Thickness;
- Astrophysics