SPIN-POLARIZED NUCLEAR-MATTER AND ITS APPLICATION TO NEUTRON-STARS

An equation of state (EOS) of nuclear matter with explicit inclusion o f a spin-isospin dependent force is constructed from a finite range, m omentum and density dependent effective interaction. This EOS is found to be in good agreement with those obtained from more sophisticated m odels for unpolarised nuclear matter. Introducing spin degrees of free dom, it is found that it is possible for neutron matter to undergo a f erromagnetic transition at densities realisable in the core of neutron stars. The maximum mass and the surface magnetic field of the neutron star can be fairly explained in this model. Since finding quark matte r rather than hadronic matter at the core of neutron stars is a possib ility, the proposed EOS is also applied to the study of hybrid stars. It is found using the bag model picture that one can in principle desc ribe both the mass as well as the surface magnetic field of hybrid sta rs satisfactorily. (C) 1997 Elsevier Science B.V.