The influence of entropy and neutrinos on the properties of protoneutron stars

A neutron star is formed by the evolution of a protoneutron star, so the study of the properties of protoneutron stars can help in understanding the structure and composition of neutron stars. The mass and radius of a cold neutron star calculated by the selected parameters are consistent with various existing astronomical observations. This set of parameters is then extrapolated to study the properties of a protoneutron star. This paper considers the isentropic protoneutron star matter with hyperons to study the temperature, composition, and oscillation under different conditions. Entropy promotes the production of hyperons, while neutrinos inhibit it. The maximum mass increases as the entropy and neutrino proportion increase. The temperature and radius increase with entropy, while the radius decreases as the neutrino proportion increases. The linear relationship between the frequency and average density of the protoneutron star and temperature is fitted, which is important for future observations.