The Geometry, Composition, and Mass of the Crab Nebula
Abstract
Interference filter images and long-slit spectroscopy are presented which show that much of the brighter filamentary gas in the Crab Nebula is involved in large structures consisting of a nearly pure helium band or torus across the neutron star and bipolar, helium-rich lobes. It is inferred that the SN precursor may have initially had a mass of 20-30 solar masses, and that the strongest forbidden Ni II emission coincides with regions of relatively low helium abundance in the north-east part of the nebula. The results support a scenario in which interaction and mixing occurs between an ambient interstellar cloud and material produced in the SN.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 1989
- DOI:
- 10.1086/167598
- Bibcode:
- 1989ApJ...342..364M
- Keywords:
-
- Abundance;
- Astronomical Spectroscopy;
- Crab Nebula;
- Interstellar Chemistry;
- Neutron Stars;
- Stellar Composition;
- Forbidden Transitions;
- H Beta Line;
- Helium;
- Nickel;
- Stellar Mass;
- Astrophysics;
- NEBULAE: ABUNDANCES;
- NEBULAE: CRAB NEBULA;
- NEBULAE: SUPERNOVA REMNANTS