Nonradial oscillations of neutron stars with a solid crust - Analysis in the relativistic Cowling approximation
Nonradial oscillations of neutron stars with a solid crust - Analysis in the relativistic Cowling approximation
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具有固体地壳的中子星的非径向振荡 - 相对论考林近似的分析
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
U. Lee
中科院分区：
文献类型：
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作者：
Shijun Yoshida;U. Lee
在忽略度规扰动的相对论Cowling近似下，计算了具有固体壳的相对论中子星的非径向振荡。对于模态分析，我们采用三分量相对论中子星星模型与固体地壳，流体核心，和流体海洋。作为相对论效应对振荡模的测量，我们计算了相对频率差，定义为δσ/σ R（σGR − σN）/σGR，其中σGR和σR分别是相对论振荡频率和牛顿振荡频率。中子星星模型的不同振荡模式的相对差δσ/σ取不同的值，对于给定的振荡模式，δσ/σ的值取决于模型的物理性质。我们发现|δσ/σ|对于我们计算的大多数振荡模式，尽管有少数例外，例如地壳中的基本（无节点）环形扭转模式，限制在表面海洋中的表面重力模式，以及被困在流体核中的核重力模式，但都小于0.1。我们还发现，模态特性，所代表的本征函数，并没有强烈的影响，通过引入广义相对论。然而，它示出的模式特性的两个界面模式，与核/壳和壳/洋界面，已互换两者之间通过避免交叉时，我们从牛顿动力学的广义相对论动力学。
Nonradial oscillations of relativistic neutron stars with a solid crust are computed in the relativistic Cowling approx- imation, in which all metric perturbations are ignored. For the modal analysis, we employ three-component relativistic neutron star models with a solid crust, a fluid core, and a fluid ocean. As a measure for the relativistic effects on the oscillation modes, we calculate the relative frequency difference defined as δσ/σ ≡ (σGR − σN)/σGR ,w hereσGR and σR are, respectively, the relativistic and the Newtonian oscillation frequencies. The relative difference δσ/σ takes various values for different oscillation modes of the neutron star model, and the value of δσ/σ for a given mode depends on the physical properties of the models. We find that |δσ/σ| is less than ∼0.1 for most of the oscillation modes we calculate, although there are a few exceptions such as the fundamental (nodeless) toroidal torsional modes in the crust, the surface gravity modes confined in the surface ocean, and the core gravity modes trapped in the fluid core. We also find that the modal properties, represented by the eigenfunctions, are not strongly affected by introducing general relativity. It is however shown that the mode characters of the two interfacial modes, associated with the core/crust and crust/ocean interfaces, have been interchanged between the two through an avoided crossing when we move from Newtonian dynamics to general relativistic dynamics.