双星系统中的轨道偏心率分布

Orbital Eccentricity Distribution in Binary Systems

讨论了１４３颗早型和１２５个晚型双星系统轨道偏心率与轨道周期间的关系。结果表明：几乎所有Ｐ＜１７ｄ的早型主序双星都具有圆或近圆轨道（ｅ≤００５），即早型主序双星的圆轨道临界周期约为１７ｄ；而早型巨星、特殊星和晚型主序、晚型巨星组双星的圆轨道临界周期分别约为２０ｄ，７５ｄ，７ｄ和１０ｄ。比较理论预期与实测统计关系，动力学潮汐机制及粘滞理论与实测数据较好地吻合，而纯流体动力学理论与我们的统计不太一致。

In this paper, we discuss the orbital eccentricity distribution for 143 early-type and 125 late-type binary systems. By dividing these samples into main-sequence, giant and particular binary groups, we find that the degree of orbital circularization in giant binaries is averagely higher than that in corresponding main-sequence systems, and that there exists a limiting orbital period below which orbital circularization(e≤0 05) can be regarded as a rule in each group. The limiting P is about 1 7d in early-type main-sequence binaries, 2 0d and 7 5d respectively for early-type giant and particular binary systems, whereas the late-type main-sequence and giant binary systems have the limiting P of about 7 0d and 10 0d respectively. Analyzing the obtained statistical relations and theoretical predictions on circularization, we find that the predictions of dynamically and equilibrium tidal mechanisms fit observational data better than that by using the purely hydrodynamic theory.