The Spectra of the Emission Nebulosities in Messier 33.
Abstract
The emission nebulosities in Messier 33 are similar in spectral characteristics to those of our own Gal- axy and to the low-excitation planetary IC 418. The ratio of A 5007/X 3727 is found to be the most re- liable excitation criterion for these nebulosities. The available evidence suggests that in most of these nebulosities the oxygen is predominantly in the singly ionized condition
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 1942
- DOI:
- 10.1086/144372
- Bibcode:
- 1942ApJ....95...52A