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arXiv 1610.08770astro-ph.HEastro-ph.SRnucl-th
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关于统一状态方程的快自旋中子星的注记

Note on fast spinning neutron stars with unified equations of states

A. Li, N. B. Zhang, B. Qi, G. F. Burgio

摘要:

为了将最新的脉冲星观测结果与已发展的中子星状态方程(EoS)相对应,我们采用了核壳统一的四种EoS,即BCPM、BSK 20、BSK 21和Shen-TM 1,以及文献中广泛使用的两种非统一EoS,即APR和GM 1,它们通常与Negele-Vautherin和Baym-Pethick-Sutherland地壳EoS相匹配。所有的核心Eos都满足最近对两颗质量被精确测量的大质量恒星的观测约束。我们发现,NS质量赤道半径的关系略有影响的平滑核壳匹配界面。此外,在地壳EoS和匹配接口的不确定性带来微不足道的变化,即使在最大旋转(开普勒)配置。我们还发现,对于所有四个统一的EOS,旋转可以增加恒星的引力质量高达$18\%-19\%$和赤道半径的$29\%-36\%$,这是与以前的计算使用非统一的EOS一致。对于质量为1.4 M $_{\odot}$的恒星,半径增加更为明显,达到$41\%-43\%$,即$5-6$ km。此外,通过面对的结果,使用统一的EOS,这给出了正确的经验值在饱和密度,两个有争议的确定半径的快速旋转4U 1608-52,我们解决了一个小的半径可能是更好地证明了这个源。

英文摘要:

For the propose of confronting updated pulsar observations with developed neutron star equation of states (EoSs), we employ four unified EoSs for both the core and the crust, namely BCPM, BSk20, BSk21, Shen-TM1, as well as two non-unified EoSs widely used in the literature, i.e. APR and GM1 EoS, which are commonly matched with the Negele-Vautherin and the Baym-Pethick-Sutherland crust EoS. All the core EoSs satisfy the recent observational constraints of the two massive pulsars whose masses are precisely measured. We show that the NS mass-equatorial radius relations are slightly affected by the smoothness at the core-crust matching interface. Moreover, the uncertainties in the crust EoS and the matching interface bring insignificant changes, even at maximally rotating (Keplerian) configurations. We also find that for all four unified EoSs, rotation can increase the star's gravitational mass up to $18\%-19\%$ and the equatorial radius by $29\%-36\%$, which are consistent with the previous calculations using non-unified EoSs. For stars as heavy as 1.4 M$_{\odot}$, the radius increase is more pronounced, reaching $41\%-43\%$, i.e. $5-6$ km. Moreover, by confronting the results using unified EoSs, which give the correct empirical values at saturation density, with two controversial determinations of the radius for the fast rotator 4U 1608-52, we address that a small radius may be better justified for this source.

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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