Asymmetric nuclear matter and neutron star properties

In this work we calculate the total mass, radius, moment of inertia, and surface gravitational redshift for neutron stars using various equations of state (EOS). Modern meson-exchange potential models are used to evaluate the G-matrix for asymmetric nuclear matter. We have calculated both a nonrelativistic and a relativistic EOS for different proton fractions. Of importance here is the fact that relativistic Brueckner-Hartree-Fock calculations for symmetric nuclear matter fit the empirical data, which are not reproduced by nonrelativistic calculations. Relativistic effects are known to be important at high densities, giving an increased repulsion. This leads to a stiffer EOS compared to the EOS derived with a nonrelativistic approach. We also calculate the EOS for beta-stable matter. Both the nonrelativistic and the relativistic EOS yield moments of inertia and redshifts in agreement with the accepted values. The relativistic EOS yields, however, too large mass and radius. The implications are discussed.