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arXiv 0910.4236nucl-th
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密度相关相对论Hartree-Fock理论中的中子星性质

Neutron star properties in density-dependent relativistic Hartree-Fock theory

Bao Yuan Sun, Wen Hui Long, Jie Meng, U. Lombardo

摘要:

利用新近发展的密度相关相对论Hartree-Fock(DDRHF)强子物质物态方程,首次研究了无超子的静态和$β$平衡中子星的性质,并与相对论平均场(RMF)模型的预言和最近的观测数据进行了比较.详细讨论了Fock项对高密度非对称核物质性质的影响。由于$σ$ -和$ω$ -交换项对对称性能量的重要贡献,DDRHF计算预测了中子星中的大质子分数,这强烈地影响了恒星的冷却过程.利用DDRHF方法计算了中子星发生直接Urca过程的有效相互作用PKO 2和PKO 3的临界质量约为1.45 $M_\odot$,接近于现代软X射线数据分析确定的极限值1.5 $M_\odot$. DDRHF计算的中子星最大质量在2.45 M $_\odot$和2.49 M $_\odot$之间,这与PSR B 1516 + 02 B的高脉冲星质量$2.08 \pm 0.19 M_\odot$相当一致。DDRHF得到的中子星质量-半径关系与孤立中子星RX J1856的热辐射测量结果、LMXB 4U 0614+09和4U 1636-536的QPO频率极限以及LMXB EXO 0748-676的红移值一致。

英文摘要:

With the equations of state provided by the newly developed density dependent relativistic Hartree-Fock (DDRHF) theory for hadronic matter, the properties of the static and $β$-equilibrium neutron stars without hyperons are studied for the first time, and compared to the predictions of the relativistic mean field (RMF) models and recent observational data. The influences of Fock terms on properties of asymmetric nuclear matter at high densities are discussed in details. Because of the significant contributions from the $σ$- and $ω$-exchange terms to the symmetry energy, large proton fractions in neutron stars are predicted by the DDRHF calculations, which strongly affect the cooling process of the star. The critical mass about 1.45 $M_\odot$, close to the limit 1.5 $M_\odot$ determined by the modern soft X-ray data analysis, is obtained by DDRHF with the effective interactions PKO2 and PKO3 for the occurrence of direct Urca process in neutron stars. The maximum masses of neutron stars given by the DDRHF calculations lie between 2.45 M$_\odot$ and 2.49 M$_\odot$, which are in reasonable agreement with high pulsar mass $2.08 \pm 0.19 M_\odot$ from PSR B1516+02B. It is also found that the mass-radius relations of neutron stars determined by DDRHF are consistent with the observational data from thermal radiation measurement in the isolated neutron star RX J1856, QPOs frequency limits in LMXBs 4U 0614+09 and 4U 1636-536, and redshift determined in LMXBs EXO 0748-676.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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