大质量中子星PSR J0348+0432原生星的组成与结构

Composition and Structure of Massive Protoneutron Star PSR J0348+0432

在相对论平均场理论中考虑重子八重态,选取每重子熵S=1或S=2,集中研究讨论了熵效应对大质量中子星PSR J0348+0432原生星性质的影响.利用GL85核子耦合参数组计算了PSR J0348+0432的质量,将该参数组推广来计算每重子熵S=1或S=2时原生中子星的性质.结果发现原生中子星较零温中子星会有更多超子出现,且原生中子星的温度越往内部温度越高,超子的出现会降低内部温度.熵会增大大质量原生中子星的质量,这种增加效应超过超子出现减小大质量中子星质量的效应.熵会增加原生中子星的半径,即原生中子星的冷却是一个星体收缩的过程.

Considering the octet baryons in relativistic mean field （RMF） theory, the entropy per baryon is selected to be 1 or 2. We investigate the influence of the entropy per baryon for the massive protoneutron star corresponding to PSR J0348＋0432. One set of coupling constants GL85 in RMF are selected to reproduce the mass of PSR J0348＋0432 at zero temperature, and then extended to describe the massive protoneu- tron stars with the per baryon entropy S = 1 or S = 2. It is found that the massive protoneutron stars have more hyperons than the cold neutron stars, the temperature increases with the increase of the density from surface to interior, and the existence of hyperons leads to the decrease of the interior temperature. Entropy causes the increase of the mass of massive protoneutron star, and this effect is more obvious than that of the decreasing mass due to hyperons. The entropy per baryon brings on the increase of the radius of protoneutron star. In other words, the protoneutron star＇s cooling may be a contracting process.