Hyperon-hyperon interactions and properties of neutron matter

We present results from Brueckner-Hartree-Fock calculatons for beta stable neutron star matter with nucleonic and hyperonic degress degrees of freedom, employing the most recent parametrizations of the baryon-baryon interaction of the Nijmegen group. It is found that the only strange baryons emergin in beta stable matter up to total barionic densities of 1.2 fm^-3 are $\Sigma^-$ and $\Lambda$. The corresponding equations of state are then used to compute properties of neutron stars such as masses and radii.