标题： 广义相对论双中子星的拟平衡模型 显示英文标题

标题： General Relativistic Models of Binary Neutron Stars in Quasiequilibrium

摘要： 我们对处于共转、圆轨道上的双中子星系统进行了完全相对论的计算。 虽然牛顿引力允许严格的平衡状态，但一个相对论双星系统会发射引力辐射，导致系统失去能量并缓慢螺旋内移。然而，由于螺旋过程发生在远远长于轨道周期的时间尺度上，我们可以将双星视为准平衡态。在此近似下，我们整合爱因斯坦方程的一个子集（与相对论静水压平衡方程耦合），以解决任意分离度双星系统的初值问题。 我们采用多态性方程状态来确定近距双星中中子星的结构和最大质量，多态性指数 n 分别取 1、1.5 和 2。 我们构建了恒定静止质量的序列，并沿能量平衡曲线定位转折点，以识别轨道不稳定性的开始。特别是，我们定位了最内稳定圆轨道 (ISCO) 及其角速度。 我们在完整的广义相对论框架下构造了首次接触的双星系统。这些系统总是出现在方程状态足够软（>= 1.5）的情况下。径向稳定性分析表明，近距离双星中的中子星在合并之前没有塌缩成黑洞的趋势。 显示英文摘要

摘要： We perform fully relativistic calculations of binary neutron stars in corotating, circular orbit. While Newtonian gravity allows for a strict equilibrium, a relativistic binary system emits gravitational radiation, causing the system to lose energy and slowly spiral inwards. However, since inspiral occurs on a time scale much longer than the orbital period, we can treat the binary to be in quasiequilibrium. In this approximation, we integrate a subset of the Einstein equations coupled to the relativistic equation of hydrostatic equilibrium to solve the initial value problem for binaries of arbitrary separation. We adopt a polytropic equation of state to determine the structure and maximum mass of neutron stars in close binaries for polytropic indices n=1, 1.5 and 2. We construct sequences of constant rest-mass and locate turning points along energy equilibrium curves to identify the onset of orbital instability. In particular, we locate the innermost stable circular orbit (ISCO) and its angular velocity. We construct the first contact binary systems in full general relativity. These arise whenever the equation of state is sufficiently soft >= 1.5. A radial stability analysis reveals no tendency for neutron stars in close binaries to collapse to black holes prior to merger.