Gravitational signals emitted by a point mass orbiting a neutron star: Effects of stellar structure
Gravitational signals emitted by a point mass orbiting a neutron star: Effects of stellar structure
复制标题
绕中子星运行的点质量发出的引力信号：恒星结构的影响
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
V. Ferrari
中科院分区：
文献类型：
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作者：
J. A. Pons;E. Berti;L. Gualtieri;G. Miniutti;V. Ferrari
在微扰状态和频域中研究中子星结构对双星系统引力发射的影响。假设中子星受到在紧密圆形轨道上运动的点质量的扰动，我们求解广义相对论中的恒星扰动方程，以评估系统在引力波中损失的能量。我们将不同恒星模型获得的能量输出与假设扰动物体是具有相同质量的黑洞所获得的能量输出进行了比较，并讨论了恒星模式激发所起的作用。我们的结果表明，当轨道速度为 $vensuremath{gtrsim}0.2 c$ $({ensuremath{
u}}_{mathrm{GW}}ensuremath{gtrsim}185 mathrm{Hz}$ 对于由两颗 ${1.4M}_{ensuremath{ igodot}}$ 中子星组成的双星系统）。我们表明，不同恒星模型和黑洞之间的差异主要是由于恒星准正规模式的激发。最后，我们讨论微扰方法可以在多大程度上和多大距离内用于描述恒星与点状大质量天体的相互作用。
The effects that the structure of a neutron star would have on the gravitational emission of a binary system are studied in a perturbative regime, and in the frequency domain. Assuming that a neutron star is perturbed by a point mass moving on a close, circular orbit, we solve the equations of stellar perturbations in general relativity to evaluate the energy lost by the system in gravitational waves. We compare the energy output obtained for different stellar models with that found by assuming that the perturbed object is a black hole with the same mass, and we discuss the role played by the excitation of the stellar modes. Our results indicate that the stellar structure begins to affect the emitted power when the orbital velocity is $vensuremath{gtrsim}0.2 c$ $({ensuremath{
u}}_{mathrm{GW}}ensuremath{gtrsim}185 mathrm{Hz}$ for a binary system composed of two ${1.4M}_{ensuremath{igodot}}$ neutron stars). We show that the differences between different stellar models and a black hole are due mainly to the excitation of the quasinormal modes of the star. Finally, we discuss to what extent and up to which distance the perturbative approach can be used to describe the interaction of a star and a pointlike massive body.