The Evolution of low mass stars
The Evolution of low mass stars
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DOI：
10.1093/mnras/151.3.351
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发表时间：
1971-02
影响因子：
4.8
通讯作者：
P. Eggleton
中科院分区：
文献类型：
--
作者：
P. Eggleton
本文提出了一种计算低质量恒星从主星序到氦闪光演化的方法。许多这样的计算都受到这样一个事实的阻碍，即燃烧氢的壳源在演化的相对早期阶段变得非常薄，这意味着要么在红巨星分支上需要非常短的时间步长，要么必须引入一些特殊的方法。本方法既没有缺点：无论是否有薄壳，都使用相同的程序，并且可以选择时间步长，使得星形的整体结构每步以固定的小量变化。恒星演化成氦闪光大约需要100或150个步骤。该方法的基本特点是用非拉格朗日网格求解结构方程，使薄壳(如果存在)即使在质量坐标上快速移动也能缓慢通过网格；组合和网格与结构方程同时求解，具有更大的稳定性和自洽性。虽然这里描述的工作没有考虑成分的对流混合，但有人建议，如果对流和半对流混合发生的话，对这里使用的方程的简单推广将给出一个合理的处理。
This paper presents a method of computing the evolution of low mass stars from the main sequence to the helium flash. Many such computations are handicapped by the fact that the hydrogen burning shell source becomes very thin at a relatively early stage of evolution, and this means that either a very short time step is needed on the red giant branch, or else that some special method must be introduced. The present method has neither handicap: the same procedure is used whether there is a thin shell or not, and the time step can be chosen so that the overall structure of the star changes by a fixed small amount per step. About 100 or 150 steps are necessary to evolve a star to the helium flash. The basic features of the method are that the structure equations are solved using a non-Lagrangian mesh, so that a thin shell if it exists can move slowly through the mesh, even if it moves rapidly with respect to the mass coordinate; and that the composition and the mesh are solved simultaneously with the structure equations, giving greater stability and self-consistency. Although the work described here does not take account of convective mixing of composition, it is suggested that a simple generalization of the equations used here would give a reasonable treatment of both convective and semi-convective mixing, if they occur.