Narrow Results

The role of the Coulomb and isovector effects in dense stellar matter with neutrino trapping in the region of perturbative momentum q ≤ 0.6 fm^-1 has been investigated. The result might have an impact on the neutrino transport in stellar matter.

Protoneutron stars are hot and lepton rich objects formed in type II supernovae. It is natural to regard the evolution of these stars as taking place in several stages. This paper describes results of analysis of protoneutron star evolution for models incorporating an strangeness-rich, neutrino opaque matter equation of state. Of special interest in this paper is the comparison of protoneutron star models for two different phases. One characterized by neutrino trapping and by the value of entropy s=1 and the other, formed when neutrinos leak out of the system, described as a hot deleptonized star. The equation of state adequate for the protoneutron star has been constructed. It has been shown that the maximum stable protoneutron star mass is close to 1.44 M_⊙.

We address nuclear liquid-gas instablitities in the mean-field framework, using a Skyrme-like density functional. These instabilities lead to the clusterization of nuclear and compact-star matter at sub-saturation density. In this contribution, we study the extension of the spinodal region, how it affects star matter at β-equilibrium and how it is affected by the choice of different Skyrme forces. The dynamics of cluster formation is also characterized, comparing a semi-classical approach to a quantal one.

We investigate the composition and the equation of state of the kaon condensed phase in neutrino-free and neutrino-trapped star matter within the framework of the Brueckner-Hartree-Fock approach with three-body forces. We find that neutrino trapping shifts the onset density of kaon condensation to a larger baryon density and reduces considerably the kaon abundance. As a consequence, when kaons are allowed, the equation of state of neutrino-trapped star matter becomes stiffer than the one of neutrino free matter. The effects of different three-body forces are compared and discussed. Neutrino trapping turns out to weaken the role played by the symmetry energy in determining the composition of stellar matter and thus reduces the difference between the results obtained by using different three-body forces.