RY Sct is a unique massive binary star system in a short transitional evolutionary phase. It is an eclipsing binary where both stars have overfilled their Roche cavities, so that the system is in an “overcontact” state. It is surrounded by a young circumstellar nebula. The binary is regarded as a rare progenitor of a type WR+OB system. RY Sct is close to the Eddington luminosity limit, so that radiative pressure plays an important role in mass loss. At least one of the components of the close binary may be associated with a rare class of LBV stars or the so-called S Doradus variables. We have calculated the orbital elements using the old photometric data of Zakirov and Kumsiashvili and new spectral data, together with an analysis of HST observations. A model was examined according to which the components of RY Sct are in an overcontact state and fill their Roche cavities. The brighter primary component transfers mass to the more massive but less bright secondary. The binary system is surrounded by a common envelope. As initial parameters we, chose a mass ratio q = 4.42 and orbital period P = 11 d .12471, and used an orbital inclination of i = 75.6°.

中文翻译：

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大型二元系统 RY Sct – 光曲线的新解决方案

RY Sct 是一个独特的大质量双星系统，处于短暂的过渡演化阶段。这是一个食双星，两颗恒星都充满了它们的罗氏空腔，因此系统处于“过度接触”状态。它被一个年轻的星周星云包围着。该双星被认为是 WR+OB 型系统的罕见先驱。RY Sct 接近爱丁顿光度极限，因此辐射压力在质量损失中起着重要作用。近双星的至少一个组成部分可能与一类罕见的 LBV 恒星或所谓的 S Doradus 变星有关。我们使用 Zakirov 和 Kumsiashvili 的旧光度数据和新光谱数据以及对 HST 观测的分析计算了轨道元素。检查模型，根据该模型，RY Sct 的组件处于过度接触状态并填充其罗氏腔。较亮的主要成分将质量转移到质量较大但亮度较低的次要成分。二进制系统被一个公共信封包围。作为初始参数，我们选择质量比 q = 4.42 和轨道周期 P = 11 d .12471，并使用 i = 75.6° 的轨道倾角。