Neutron Star Evolutionary Sequences.
Abstract
We have calculated evolutionary sequences for a non-rotating, non-magnetic 0.503 M(,(CIRCLE)) and 1.33 M(,(CIRCLE)) neutron star using a fully general relativistic, spherically symmetric, quasi-static stellar evolution code. The equation of state used in the present set of calculations is for "warm" neutron star matter. It consists of a finite temperature formulation in the outer crust of the neutron star and a zero-temperature formulation supplemented by finite temperature corrections in the inner crust and core. The crustal matter was found to go through a first order phase transition at a value of (GAMMA) (TURNEQ) 155, where (GAMMA) is the ratio of Coulomb to thermal energy. Thus crystallization with the subsequent release of latent heat, was expected to occur, and was included in our equation of state calculations. The effects of superfluidity on the heat content of the star was included, as well as the effects superfluidity has on the neutrino rates due to the modified URCA and nucleon-nucleon bremsstrahlung processes. In agreement with previous calculations, we find that emission of neutrinos from a postulated pion condensate utterly dominates the cooling of the stars. The timescales for the interior to cool to 10('7)(DEGREES)K from an initial temperature of 10('9)(DEGREES)K is (TURN) 300 years for the 1.33 M(,(CIRCLE)) star and (TURN) 150 years for the 0.503 M(,(CIRCLE)) star. The timescales for the crust to solidify (TURN) 1 year for the 1.33 M(,(CIRCLE)) star and (TURN) 30 years for the 0.503 M(,(CIRCLE)) star.
- Publication:
-
Ph.D. Thesis
- Pub Date:
- 1980
- Bibcode:
- 1980PhDT.........6R
- Keywords:
-
- Physics: Astronomy and Astrophysics;
- Consecutive Events;
- Equations Of State;
- Neutrinos;
- Neutron Stars;
- Stellar Evolution;
- Stellar Mass;
- Bremsstrahlung;
- Cooling;
- Nucleon-Nucleon Interactions;
- Pions;
- Stellar Temperature;
- Astrophysics