标题： Be星+He星双星作为质量转移阶段的指示器 显示英文标题

标题： Be star + He star binary as an indicator of binary mass transfer phase

摘要： 人们认为，Be星的快速自转主要源于双星演化。近年来，越来越多带有氦（He）星伴星的Be星被发现，这为研究双星相互作用物理提供了重要的机会。在这项工作中，我们使用更新后的双星质量转移稳定性判据进行了双星群体综合模拟，并尝试通过构建一系列Be星+He星（BeHe）双星群体来理解质量转移过程的细节。我们发现，模拟结果和观测数据可以根据组分的质量分为两组，分别对应于质量转移过程中两种不同的演化过程。特别是，我们发现BeHe双星的质量比可以作为原始双星初始质量比的探针。此外，结果表明，较高的质量转移效率（$\gtrsim 0.5$）更能支持观测结果。模拟预测了太多经历B型质量转移的Be星双星，这与观测结果相冲突。原因可能是观测选择效应或不清楚的物理因素。 显示英文摘要

摘要： The rapid rotation of Be stars is supposed to mainly originate from binary evolution. In recent years, more and more Be stars with helium (He) star companions have been discovered, which provides a significant opportunity to study binary interaction physics. In this work, we perform binary population synthesis with an updated binary mass transfer stability criterion and try to understand the details of mass transfer processes by constructing a series of Be star + He star (BeHe) binary populations. We found that the simulations and the observations can be divided into two groups according to the masses of components, corresponding to the two distinct evolutionary processes during the mass transfer. In particular, we found that the mass ratios of BeHe binaries may be taken as a probe of the initial mass ratios of the primordial binaries. Moreover, the results suggest that a higher mass transfer efficiency ($\gtrsim 0.5$) supports the observations better. The simulations predicted too many Be star binaries experiencing Case B mass transfer, which conflicts with the observations. The reason is due to either observational selection effects or unclear physical factors.