Microscopic study of neutrino trapping in hyperon stars

Employing the most recent parametrization of the baryon-baryon interaction of the Nijmegen group, we investigate, in the framework of the Brueckner--Bethe--Goldstone many-body theory at zero temperature, the influence of neutrino trapping on the composition, equation of state, and structure of neutron stars, relevant to describe the physical conditions of a neutron star immediately after birth (protoneutron star). We find that the presence of neutrinos changes significantly the composition of matter delaying the appearance of hyperons and making the equation of state stiffer. We explore the consequences of neutrino trapping on the early evolution of a neutron star and on the nature of the final compact remnant left by the supernova explosion.