Kiro Miyazaki Properties and evolution of protoneutron stars within the extended Zimanyi-Moszkowski model (364K, PDF) ABSTRACT. We have investigated the properties of protoneutron stars (PNSs) in three different stages during its evolution. Their equations-of-state (EOSs) are derived by the extended Zimanyi-Moszkowski (EZM) model of the relativistic mean-field theory. We have taken into account the isovector-scalar meson and the NSC97f hyperon-hyperon interactions are implemented in terms of appropriate strange-meson coupling constants. The EOSs of the neutrino-trapped PNSs are stiffer than the neutrino-free neutron stars (NSs), while the EOSs of early and late stage of PNSs and of deleptonized hot and cold NSs are nearly the same. As a result, the evolution of NS mass proceeds mostly during the deleptonization. However, the minimum mass is determined in the lepton-rich PNS at the earliest stage of evolution while the maximum mass is determined in the hot deleptonized NS before the final cooling process. The resultant allowed gravitational NS mass between 1.06M_{\odot} and 1.604M_{\odot} is consistent with the observed masses within 1.3\pm0.27M_{\odot}.