Abstract

Variations in the orbital period of eclipsing binaries RY Aqr, AK Vir, and AX Vul are studied. It is shown these variations can be represented with equal accuracy in two ways: either in the form of a superposition of secular decrease and cyclic variations or only in the form of cyclic fluctuations. Cyclic variations in the periods of AK Vir and AX Vul can be fully explained by the light-time effect due to the presence of a third body in the system. Cyclic variations in the period of RY Aqr can be explained by both the light-time effect and magnetic cycles. The secular decrease in the periods can be caused by magnetic braking.

中文翻译：

---

渐进二进制RY Aqr，AK Vir和AX Vul的轨道周期变化

摘要

研究了月食​​双星RY Aqr，AK Vir和AX Vul轨道周期的变化。结果表明，这些变化可以两种方式以相同的精度表示：要么以长期下降和周期性变化的叠加形式出现，要么仅以周期性波动的形式出现。AK Vir和AX Vul周期中的周期性变化可以通过光时效应来充分解释，这是由于系统中存在第三体所致。RY Aqr周期中的循环变化可以通过光时间效应和磁循环来解释。周期的长期减少可能是由电磁制动引起的。