湍流压对中小质量恒星后期演化的影响(Ⅲ)红巨星和AGB星产生强大星风物质损失的机理研究

The Influence of Turbulent Pressure on the Later Stages of Evolution of Lowand Intermediatemass Stars (Ⅲ) On the Mechanism for Driving Strong Stellar Winds in Red Giant and AGB Stars

本文提供了一个判别红巨星和ＡＧＢ星对流外壳中是否会产生动力学非稳定性的条件．根据这个条件和对２８Ｍ及７Ｍ恒星从主序到巨星阶段和ＡＧＢ阶段的演化计算，可以证明，湍流压效应是导致红巨星和ＡＧＢ星靠近表面区域产生动力学非稳定性，从而造成物质向外喷流的原因．并认为它就是造成红巨星和ＡＧＢ星表面温度很低（因而辐射压很低）从而产生强大星风物质损失的物理原因．

n this paper a criterion is presented for judging the occurrence or absence of dynamical instability in the convective envelope of a red giant or an AGB star. According to this criterion and the calculations for the evolution of 28M and 7 M stars from the main sequence to the red giant stage and the AGB stage, itcan be shown that the effect of turbulent pressure can cause a dynamical instability in the regions close to the surface of a red giant or an AGB star, leading to mass ejection outwards. This may be the mechanism for driving the strong stellar winds in red giants and AGB stars with very low surface temperature and feeble radiation pressure.