激变双星的磁滞效应

Magnetic Braking in Cataclysmic Binary Systems

本文研究了激变双星中较冷次星的星风在磁场耦合作用下造成的角动量损失，以及对激变双星演化的影响。本文特别注意到双星成员的星风物质损失和角动量损失应该与单星情况明显不同，这就是：双星成员的星风物质损失受到潮汐效应和系统自转效应的影响而增大，同时双星成员的角动量是由轨道角动量和自转角动量所组成，并且轨道角动量远大于自转角动量。研究结果表明，由于次星的星风物质损失率很小，星风的速度也不大，因而磁滞效应造成的角动量损失极小，不能成为驱动周期大于３小时的激变双星演化的机制。

In this paper the angular momentum loss due to a magnetically coupled stellarwind of the cool secondaries and its effect on the evolution of the cataclysmic binaries are studied.Special attention is paid to the differences between the binary system & single star cases with regard to mass loss & angular momentum loss.The differences are:the stellar wind of a component of a binary will be enhanced by the tidal effect and rotation of the binary system,and the angular momentum of a member star of a binary consists of the rotational and the orbital components,in addition the orbital angular momentum is much greater than the rotational angular momentum.It is shown that owing to the small values of both the mass-loss rates and the velocities of the stellar winds of the cool secondaries,the angular momentum loss due to magnetic braking is far too insignificant to drive the evolution of cataclysmic binaries with periods longer than 3hr.