The massive semidetached binary with a long-term decreasing orbital period may involve a rapid mass-transfer phase in Case A, and thus, they are good astrophysical laboratories for investigating the evolution of massive binary stars. In this work, by using the long-term observational light curves from the Optical Gravitational Lensing Experiment project and other data in the low-metallicity Large Magellanic Cloud, four semidetached massive binaries with long-term decreases in the orbital periods are detected from 165 EB-type close binaries. It is found that the more massive component in S07798 is filling its Roche lobe, where the period decrease is caused by mass transfer from the primary to the secondary. However, the other three (S03065, S12631, S16873) are semidetached binaries with a lobe-filling secondary where the mass transfer between the components should cause the period to increase if the angular momentum is conservative. The long-term period decreases in these three systems may be caused by angular momentum loss. Additionally, the orbital periods of three systems (S03065, S07798, S16873) are detected to show cyclic variation with periods shorter than 11 yr, which can be plausibly explained by the presence of close-in third bodies in these massive binaries. Based on all of these results, it is suggested that the detected four semidetached binaries almost have multiplicity. The companion stars are crucial for the origin and evolution of these massive close binaries.

中文翻译：

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LMC 中四个轨道周期长期减小的大质量半分离双星的演化状态和三重性


在情况 A 中，轨道周期长期减小的大质量半分离双星可能涉及快速质量转移阶段，因此，它们是研究大质量双星演化的良好天体物理实验室。在这项工作中，利用光学引力透镜实验项目的长期观测光曲线和低金属丰度大麦哲伦星云中的其他数据，从 165 个 EB 型接近双星中探测到四个轨道周期长期减少的半分离大质量双星。研究发现，S07798 中质量更大的成分正在填充其罗氏叶，其中周期减少是由从初级到次级的质量传递引起的。然而，其他三个（S03065、S12631、S16873）是半分离的双元，具有一个充满叶的次级，如果角动量是保守的，则组件之间的质量传递应该会导致周期增加。这三个系统的长期周期减少可能是由角动量损失引起的。此外，三个系统（S03065、S07798、S16873）的轨道周期被检测到显示出周期短于 11 年的周期性变化，这可以通过在这些巨大的双星中存在近距离的第三天体来合理解释。基于所有这些结果，可以表明检测到的四个半分离二进制文件几乎具有多重性。伴星对于这些巨大的近距离双星的起源和演化至关重要。