Ba星星风吸积机制的再检验

Reexamination of the Wind Accretion Scenario for Ba Stars

考虑双星之间距离的改变，用整个系统的角动量守恒条件代替切向动量守恒条件，推导了轨道参量变化方程，在此基础上，将星风吸积方程同内禀AGB星核合成模型结合起来计算Ba星的重元素超丰，并将计算结果与观测值进行比较。各参量按标准情况取值时，计算结果不太理想。取Bomdi－hoyle吸积率的0．2倍或取较大的星风速率，对于较长轨道周期（P＞1500d）的Ba星，计算结果与观测值基本符合；而较短轨道周期（P＜1500d）的Ba星，其重元素超车机制可能是盘吸积。

Taking account of distance variation between stars,the paper re-deduced the orbital parameter equations on the mass exchange by considering the equation of conservation of orbital angular mometum. The paper also calculated s-process enrichments of Ba stars by combing wind accretion scenarios with calculations of nucleosynthesis for intrinsic AGB stars, and made comparisons between the predictions of calculations and the observations. It is found that predictions from the model for the standard case are an upper limit to the observations. Better agreements are obtained either by increasing the wind velocity or reducing the accretion rate.