Models for Zero-Temperature Stars.

The equation of state derived in the preceding paper is applied to models for zero-temperature stars Models are evaluated numerically for stars consisting of He,4 C'2, Mg?4, Si", S , or Fe06 For the same central density, p , our models have smaller values of radius R and mass M than the simpler Chandrasekhar models These deviations are most marked at the lowest densities (of order 20 per cent for p 10'gm/ 01 Mo). For models with high density the most important effects are due to inverse beta decays in the interior of the star. Instead of the Chandrasekhar limiting mass (1.46 Mo for He4) as p H one obtains a maximum value of mass M for a fmite value of p The value of this maximum mass depends on initial chemical composition. The lowest possible value is 1.01 Mo for the optimum chemical composition, the value of this maximum mass for Fe'0 is 111 Mo and is largest for C'2 (1.40 Mo). The values of p for the maximum mass are in the range 10'-10" gm/cc. Models are constructed for zero-temperature stars which contain a hydrogen envelope. The presence of such an envelope increases the radius of the star but has little effect on the mass For the more massive stars (M > 0.7 Mo), only small hydrogen envelopes are possible Models are constructed for neutron stars (p > 10") containing a neutron core and an envelope consisting of electrons and ions For p <3 X 10' the envelope contains most of the mass (M > 0 5 Mo). A sharp minimum mass of about 0 OS Mo is obtained at p 3 5 X 10' , and for larger p the envelope is unimportant.

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