Electron densities in gaseous nebulae.
Abstract
Electron densities derived from new observations of forbidden-line ratios of [S II] and [Cl III] obtained with the Wampler-Robinson image tube scanner at the Cassegrain focus of the 3 m Lick reflector are compared with previously obtained [0 II] densities. In general the red [S II] lines indicate higher densities than do either the [0 II] or [Cl III] lines by average factors of roughly 3.4 and 1.6 respectively, although there is considerable scatter. It is suggested that the concentrations wherein the singly ionized sulfur radiation is produced are dense, cool regions, while the [0 II] and [Cl III] emission may be produced in extended regions as well as in discrete clouds. Subject heading: nebulae: planetary
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1976
- DOI:
- 10.1086/154188
- Bibcode:
- 1976ApJ...204..445A