Two New Hyperon Coupling Models in the Light of the Massive Neutron Star PSR J0348+0432

In the context of the relativistic mean field theory,we propose two new hyperon coupling models,namely the limitation model and the potential well depth model,in the light of the observed data for the massive neutron PSR J0348+0432.The radius of PSR J0348+0432 given by the limitation model is found to be 12.52 km^12.97 km,while the radius given by the potential well depth model is found to be 12.19 km^12.89 km.We also calculate the gravitational redshift of PSR J0348+0432 within these two models,for which the limitation model gives 0.346~0.391 and the potential well depth model gives 0.350~0.409.Further exploration of these two models shows that,these two models are almost degenerate for neutron stars lighter than 1.85 M⊙,and start to give different results for massive neutron stars heavier than 1.85 M⊙.Therefore,the studies of massive neutron stars could be crucial for discriminating these two models and help deepen our understanding of hyper-nuclear interactions.

Effects of σ*and φ on the proto-neutron star PSR J0348+0432

The influence ofσ＊andφon the proto-neutron star（PNS）PSR J0348＋0432 is described by the relativistic mean field theory（RMFT）through choosing effective coupling constants.We use an entropy per baryon S=1 to describe the thermal effects on PSR J0348＋0432 in this work and compare this PNS with and withoutσ＊,φ.These effects include the particle number distribution,mass-radius relation,moment of inertia and surface gravitational redshift.The PNS PSR J0348＋0432 withσ＊andφhas more nucleons and will push forward the threshold for the appearance of the hyperons.The mass-radius relations are（2.010M,12.6520 km）withσ＊andφand（2.010M,12.6170 km）withoutσ＊andφ.The moments of inertia corresponding to PNS PSR J0348＋0432are（2.010M,1.510×10^45g·cm^2）and（2.010M,1.559×10^45g·cm^2）respectively,and the surface gravitational redshifts are（2.010M,0.3747）and（2.010M,0.3701）respectively.With the help of these calculations,we study the restriction ofσ~＊andφon the interactions between baryons in the PNS core.

Influence of Entropy on Composition and Structure of Massive Protoneutron Stars

Adjusting the suitable coupling constants in relativistic mean field(RMF) theory and focusing on thermal effect of an entropy per baryon(S) from 0 to 3, we investigate the composition and structure of massive protoneutron stars corresponding PSR J1614-2230 and PSR J0348+0432. It is found that massive protoneutron stars(PNSs) have more hyperons than cold neutron stars. The entropy per baryon will stiffen the equation of state, and the influence on the pressure is more obvious at low density than high density, while the influence on the energy density is more obvious at high density than low density. It is found that higher entropy will give higher maximum mass, higher central temperature and lower central density. The entropy per baryon changes from 0 to 3, the radius of a PNS corresponding PSR J0348+0432 will increase from 12.86 km to 19.31 km and PSR J1612-2230 will increase from 13.03 km to 19.93 km.The entropy per baryon will raise the central temperature of massive PNSs in higher entropy per baryon, but the central temperature of massive PNSs maybe keep unchanged in lower entropy per baryon. The entropy per baryon will increase the moment of inertia of a massive protoneutron star, while decrease gravitational redshift of a massive neutron star.