Abstract

One of the possible bar formation mechanisms in the disks of galaxies was proposed by Lynden-Bell (1979). The presumed amplification of a weak seed oval stellar surface density perturbation in the central regions of the galaxy through the alignment of the major axes of precessing elliptical orbits underlies it. According to his qualitative reasoning, the orbits are aligned along the perturbation if the precession rate diminishes with decreasing angular momentum at a constant adiabatic invariant. Using a rigorous approach based on finding the system’s stable stationary points, we show that this condition is not the only one that determines the orbit alignment orientation. The orbit precession direction in the unperturbed potential and the rate of decrease of the bar potential amplitude with radius also turn out to be important. In some cases, the latter can even be more important.

中文翻译：

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银盘中的林登-贝尔棒形成机制

摘要

Lynden-Bell（1979）提出了星系盘中可能的条形形成机制之一。推测是通过进动椭圆轨道的主轴对准在银河系中心区域的弱种子椭圆形恒星表面密度扰动放大了。根据他的定性推论，如果进动率在恒定绝热不变下随角动量的减小而减小，则轨道沿扰动排列。使用基于找到系统的稳定静止点的严格方法，我们证明了这种条件并不是唯一确定轨道对准方向的条件。事实证明，在未受干扰的势中，轨道的进动方向和杆势的振幅随半径的减小率也很重要。在某些情况下，