Nuclear-energy release in neutron-star envelopes, and sources of x-ray emission
Abstract
During the evolution of a hot neutron star, a shell with a nonequilibrium chemical composition is formed. Consequently, the nuclear energy stored therein may be radiated during shell decay. The decay of the nonequilibrium layer occurs as a result of neutron diffusion in the gravitational field at the neutron star's center. In this paper, the diffusion equations for a plane layer are considered. A computer numerical solution of the equations has been performed, and luminosity, chemical composition, and shell structure as functions of time are obtained. It is shown that the nuclear energy stored in the shell is sufficient to support a neutron star X-ray luminosity at a level of 10 to the 34th to 10 to the 36th power erg/sec over a period of 10,000 years. The relationship of the model to observed X-ray sources and pulsars is discussed. The proposed model is of particular significance for the heavy elements (A greater than 60) nucleosynthesis; to account for the formation of heavy elements, only 1 billion neutron stars in the Galaxy are required to explain such formation. Possible observational implications of the model are discussed.
- Publication:
-
Astronomicheskii Zhurnal
- Pub Date:
- October 1976
- Bibcode:
- 1976AZh....53..975B
- Keywords:
-
- Energy Dissipation;
- Neutron Stars;
- Nuclear Astrophysics;
- Nuclear Energy;
- Stellar Envelopes;
- X Ray Sources;
- Neutron Emission;
- Nonequilibrium Conditions;
- Nuclear Fusion;
- Pulsars;
- Stellar Luminosity;
- Stellar Models;
- Astrophysics