Composition and Structure of Massive Protoneutron Star of PSR J0348+0432

Considering the baryon octet in the framework of relativistic mean field (RMF) theory, and the entropy per baryon is selected to be 1 or 2, we investigate the entropy effect on the protostar properties of the massive neutron star PSR J0348+0432. One set of coupling constants GL85 in the RMF are selected to reproduce the mass of PSR J0348+0432 at zero temperature, and then the parameter set is extended to calculate the properties of the massive protoneutron star with the entropy per baryon S = 1 or S = 2. It is found that more hyperons will occur in the protoneutron star than that in the zero-temperature neutron star, the temperature in the protoneutron star increases with the increase of density from surface to interior, and the occurrence of hyperons will reduce the interior temperature. Meanwhile, the entropy causes the increase of the mass of massive protoneutron star, and this effect exceeds that of hyperons to decrease the mass of massive neutron star. The entropy also brings on the increase of the radius of protoneutron star. In other words, the cooling of protoneutron star is a contraction process of stellar object.