Hyperon stars in the Brueckner-Bethe-Goldstone theory - art. no. 055801

In the framework of the Brueckner-Bethe-Goldstone theory, we determine a fu lly microscopic equation of state for asymmetric and beta-stable nuclear ma tter containing Sigma(-) and Lambda hyperons. We use the Paris and the new Argonne Au-18 two-body nucleon interaction, whereas the nucleon-hyperon int eraction is described by the Njimegen soft-core model. We stress the role p layed by the three-body nucleon interaction, which produces a strong repuls ion at high densities. This enhances enormously the hyperon population, and produces a strong softening of the equation of state, which turns out almo st independent on the nucleon-nucleon interaction. We use the new equation of state in order to calculate the structure of static neutron stars. We ob tain a maximum mass configuration with M-max = 1.26 (1.22) when the Paris ( Au-18) nucleon potential is adopted. Central densities are about 10 times n ormal nuclear matter density. Stellar rotations, treated within a perturbat ive approach, increase the value of the limiting mass by about 12%.