Some remarkable spectra in the outskirts of the Crab Nebula.
Abstract
Red and blue spectra of some very faint wisps of gas situated outside the shell of bright filaments in the Crab Nebula are examined. Helium is found to be overabundant in northern faint regions and to account for at least half of the mass in those regions. The results also indicate that: (1) gaseous oxygen, nitrogen, and neon in the northern faint regions cannot have abundances greater than the solar values; (2) gaseous nitrogen and oxygen are probably not seriously depleted by condensation; and (3) the faint outer regions may account for 10% of the total nebular mass.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- February 1978
- DOI:
- 10.1086/155894
- Bibcode:
- 1978ApJ...220..177D
- Keywords:
-
- Crab Nebula;
- Radio Sources (Astronomy);
- Supernova Remnants;
- Abundance;
- Helium;
- Hydrogen;
- Photoionization;
- Stellar Spectra;
- Astronomy;
- Crab Nebula:Spectra