超子耦合常数对中子星性质的影响

Influences of Hyperon Coupling Constant on the Properties of Neutron Star

采用相对论平均场理论(RMFT)下的GL85参数组,在考虑超子(Λ,Σ+,Σ0,Σ-,Ξ0,Ξ-)自由度下,研究超子耦合常数的选取对中子星内粒子数密度分布、状态方程及质量-半径关系的影响.结果表明:随着超子耦合常数的增大,超子Σ-的出现密度增大,其他超子(Λ,Σ+,Σ0,Ξ0,Ξ-)的出现密度变小,状态方程变硬,中子星的引力质量变大而半径变小;当超子耦合常数从0.4增大到1.0时,中子星质量从1.36M⊙(M⊙=1.99×1030kg为太阳质量)增大到1.97M⊙,相应的半径由12.1km减小到11.3km.并得到与中子星质量下限(1.4M⊙)对应的超子耦合常数值.

The influences of hyperon coupling constant on the properties of neutron star were studied by making use of GL85 parameter set in the framework of the relativistic mean field theory （RMFT） and taking freedoms of hyperons into consideration.Numerical results indicate that with the increase of the hyperon coupling constant,the onset density of hyperon Σ-increases and those of other hyperons （Λ,Σ ＋,Σ 0,Ξ0,Ξ-） decrease,the equations of state soften,the maximum mass of the star increases and the corresponding radius decreases.The maximum mass of the star increases from 1.36M⊙（M⊙=1.99 × 1030 kg is the solar mass） to 1.97M⊙ and corresponding radius changes from 12.1 km to 11.3 km with the increase of the coupling constant from 0.4 to 1.0.We also found out the minimum coupling constant for this parameter set corresponding to lower limit of neutron star mass （1.4M⊙）.