Microscopic Nuclear Equation of State with Three-Body Forces and Neutron Star Structure

Abstract

We calculate static properties of non-rotating neutron stars (NS's) using a microscopic equation of state (EOS) for asymmetric nuclear matter. The EOS is computed in the framework of the Brueckner--Bethe--Goldstone many--body theory. We introduce three-body forces in order to reproduce the correct saturation point of nuclear matter. A microscopic well behaved EOS is derived. We obtain a maximum mass configuration with $M_{max} = 1.8 M_\odot$, a radius $R = 9.7$ km and a central density $n_c = 1.34~fm^{-3}$. We find the proton fraction exceeds the critical value $x^{Urca}$, for the onset of direct Urca processes, at densities $n \geq 0.45~fm^{-3}$. Therefore, in our model, NS's with masses above $M^{Urca} = 0.96 M_\odot$ can undergo very rapid cooling depending on whether or not nucleon superfluidity in the interior of the NS takes place. A comparison with other microscopic models for the EOS is done, and neutron star structure is calculated for these models too.