论文标题
现实中子星的分析I-LOVE-C关系
Analytic I-Love-C relations for realistic neutron stars
论文作者
论文摘要
对中子恒星（NS）的最新观察，带有无线电，X射线和引力波已经开始限制核物质以外的核物质的状态方程（EOS）。令人惊讶的是，存在近似的普遍关系，将NS的某些批量性质连接起来，这些特性对基础EO不敏感，并且在探测基本物理学（包括核和引力物理学）上具有重要的应用。迄今为止，缺乏关于现实NSS的普遍关系的分析作品，这可能会更好地理解普遍性的起源。在这里，我们关注紧凑性（C），惯性矩（i）和潮汐变形（与爱数相关）之间的普遍关系，并得出了分析，近似I-love-c关系。为了实现这一目标，我们从分析上构建了缓慢旋转/潮汐化的NS溶液，从扩展的Tolman VII模型开始，该模型准确地描述了非旋转现实的NSS，从而使我们能够提取惯性矩和紧凑度顶部的潮汐变形。我们通过扩展牛顿限制并在恒星紧凑型中扩展到第六阶，从而分析了场方程。基于这些分析解决方案，我们可以数学上证明I-C和Love-C关系中的O（10％）EOS变异以及I-Love关系中的O（1％）变化，这些变化以前已经在数值上找到。我们的新分析关系与现实的NSS（尤其是I-C和Love-C结构）的数值结果更准确地一致，而不是先前工作中得出的恒定恒星的分析关系。基于这些分析发现，我们将I-C和Love-C关系的普遍性的可能起源归因于以下事实：逼真的NSS的能量密度可以近似为二次函数，就像Tolman VII解决方案一样。
Recent observations of neutron stars (NS) with radio, X-rays and gravitational waves have begun to constrain the equation of state (EoS) for nuclear matter beyond the nuclear saturation density. To one's surprise, there exist approximate universal relations connecting certain bulk properties of NSs that are insensitive to the underlying EoS and having important applications on probing fundamental physics including nuclear and gravitational physics. To date, analytic works on universal relations for realistic NSs are lacking, which may lead to a better understanding of the origin of the universality. Here, we focus on the universal relations between the compactness(C), moment of inertia (I), and tidal deformability(related to the Love number), and derive analytic, approximate I-Love-C relations. To achieve this, we construct slowly-rotating/ tidally-deformed NS solutions analytically starting from an extended Tolman VII model that accurately describes non-rotating realistic NSs, allowing us to extract the moment of inertia and the tidal deformability on top of the compactness. We solve the field equations analytically by expanding them about the Newtonian limit and keeping up to 6th order in the stellar compactness. Based on these analytic solutions, we can mathematically demonstrate the O(10%) EoS variation in the I-C and Love-C relations and the O(1%) variation in the I-Love relation that have previously been found numerically. Our new analytic relations agree more accurately with numerical results for realistic NSs(especially the I-C and Love-C ones) than the analytic relations for constant density stars derived in previous work. Based on these analytic findings, we attribute a possible origin of the universality for the I-C and Love-C relations to the fact that the energy density of realistic NSs can be approximated as a quadratic function, as is the case for the Tolman VII solution.
