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arXiv 2212.04892gr-qcastro-ph.HEastro-ph.SR
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缓慢旋转、分层中子星的 r-modes

The r-modes of slowly rotating, stratified neutron stars

Fabian Gittins, Nils Andersson

AI总结:

研究了分层中子星中 r-modes 的特性,发现除基本 $l = |m|$ 扰动外其余扰动在接近正压极限时变为惯性模式,且局部正压模型中 r-mode 泛音发散并入惯性模式,需引入完整广义相对论以确定现实情况。

摘要:

在全局正压、旋转的 Newtonian 恒星中,唯一存在的 r-modes 是基本的 $l = |m|$ 解,其中 $l$ 和 $m$ 是描述该模式角依赖性的球谐函数 $Y_l^m$ 的指标。这与内部整体非正压的恒星模型形成鲜明对比,后者包含所有 $l \geq |m|$ 的扰动,包括径向泛音。实际上,中子星是分层的,具有局部正压区域。因此,我们探讨了分层如何改变恒星维持 r-modes 的能力。我们考虑了全局分层的情况,并研究了当恒星接近正压状态时模式的行为。在此极限下,我们发现除了基本的 $l = |m|$ 扰动外,所有扰动都会改变特性并成为一般的惯性模式。将分析限制在 $l = |m|$ 扰动上,我们发展了 r-mode 方程,以考虑表现出局部正压性的恒星模型。我们对这类模型的结果表明,r-mode 泛音发生发散并并入惯性模式。为了观察哪些 r-modes 在现实的中子星中能够持续并保持其特性,这些计算需要引入完整的广义相对论。

英文摘要:

The only r-modes that exist in a globally barotropic, rotating, Newtonian star are the fundamental $l = |m|$ solutions, where $l$ and $m$ are the indices of the spherical harmonic $Y_l^m$ that describe the mode's angular dependence. This is in stark contrast to a stellar model that is non-barotropic throughout its interior, which hosts all the $l \geq |m|$ perturbations including radial overtones. In reality, neutron stars are stratified with locally barotropic regions. Therefore, we explore how stratification alters a star's ability to support r-modes. We consider the globally stratified case and examine the behaviour of the modes as the star gets close to barotropicity. In this limit, we find that all but the fundamental $l = |m|$ perturbations change character and become generic inertial modes. Restricting the analysis to $l = |m|$ perturbations, we develop the r-mode equations in order to consider stellar models that exhibit local barotropicity. Our results for such models show that the r-mode overtones diverge and join the inertial modes. In order to see which r-modes persist and retain their character in realistic neutron stars, these calculations will need to be brought into full general relativity.

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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