A search for instability in two families of spherical stellar models
A search for instability in two families of spherical stellar models
复制标题
寻找两个球形恒星模型家族的不稳定性
DOI：
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发表时间：
1991
期刊：
影响因子：
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通讯作者：
M. Weinberg
中科院分区：
文献类型：
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作者：
M. Weinberg
矩阵本征方程技术在这里被用来确定两个常用的星系和集群的配置文件，国王和米吉模型，各向异性的速度分布的稳定性。在King模型的情况下，只有一个不稳定的模式被发现为l = 2，以前确定的径向轨道不稳定性。这种模式出现在很宽的中心浓度范围内。没有发现米吉模型的不稳定性。这些模型具有中等但不是极端的圆各向异性，这表明圆各向异性模型的任何不稳定性可能只发生在接近圆轨道的系统中。作为各向异性的函数，径向各向异性King模型的稳定边界与由主共振确定的相空间中的方向上的恒星分布的正梯度的出现相一致。这导致了一个潜在的有用的诊断不稳定性，它有一个简单的解析表达式。参考文献39篇。
A matrix-eigenequation technique is used here to determine the stability of two commonly used galaxy and cluster profiles, the King and Michie models, with anisotropic velocity distributions. In the case of the King models only one unstable mode is found for l = 2, the previously identified radial-orbit instability. This mode appears for a wide range of central concentrations. No instabilities were found for the Michie models. These models had moderate but not extreme circular anisotropy, suggesting that any instabilities for circularly anisotropic models may occur only for systems of nearly circular orbits. As a function of anisotropy, the stability boundary for the radial anisotropic King models coincides with the appearance of a positive gradient of the stellar distribution in a direction in phase space determined by the dominant resonance. This leads to a potentially useful diagnostic for instability which has a simple analytic expression. 39 refs.