存在非同步转动的双星演化模型

通过计算双星演化中的角动量转移,研究了潮汐作用下双星系统自转与公转周期的变化以及潮汐作用对双星演化的影响.结果表明,密近双星系统在主序演化时,潮汐摩擦会在较短的时间内使自转与公转达到比较接近的状态,此后经过一个较长时间的调整才能使自转与公转达到同步转动.物质交换阶段开始后,半相接双星系统更容易出现非同步转动,而相接双星系统物质交换很难破坏系统的同步状态.同时比较了非同步双星模型与同步双星模型演化曲线在赫罗图上的不同,结果表明非同步模型在物质交换阶段主星演化曲线向赫罗图光度和有效温度高的方向移动.最后通过对统计的观测数据进行分析后发现,采用该模型可以解释观测上双星超过潮汐锁定时标后仍然存在非同步转动的现象.

A Binary Evolution Model with Non-synchronization Rotation

The spin and orbital periods are calculated by considering the angular momentum exchange during the evolution of binary systems.The influence of tidal effect is also considered.The calculation results indicate that the spin and orbital periods can be reached near synchronization in a short time,but it takes a long time to reach a complete synchronization.As mass exchange starts,the synchronization rotation can be changed into non-synchronization rotation for the semi-detached binaries.But for the contact binaries, mass exchange is not strong enough to break synchronization.The evolution tracks in the HR diagram of synchronization and non-synchronization models are also compared with each other.The results show that the model considering non-synchronization moves to high luminosity and high temperature during the mass exchange stage.Finally,the results are compared with the observational data,and the non-synchronization after the tidal-lock timescale in binaries can be explained with this model.