  We calculate properties of neutron stars such as mass and radius using a
relativistic Dirac-Brueckner-hartree-Fock apprach for asymmetric nuclear
matter. For pure neutron matter we find the maximum mass to be 2.4 solar masses
with a radius of 12 km. For a proton fraction of 30% we find a max mass of 2.1
solar masses and a radius of 10.5 km. The implications are discussed.
