标题： 后渐近巨星分支双星HD 213985中的盘相互作用及随机尘埃遮蔽现象 显示英文标题

标题： Circumbinary disc interactions and stochastic dust obscuration in the post-asymptotic-giant-branch binary HD 213985

摘要： HD 213985 是一个具有偏心轨道的双星系统，主星是一颗后渐近巨星支（post-AGB）星，次级星是一颗喷流发射星。 我们确认该系统的光变特性很可能是由围绕双星盘内边缘的遮挡引起，类似于RVb型RV Tau星。 该系统在光学测光带中显示出轨道变异性幅度增加，并伴随形状的不规则变化，这些变化常常开始呈现偏斜。 Na D线的变化表明这种行为可能由围绕双星盘与通过L2拉格朗日点的外流之间的相互作用驱动。 此外，HD 213985还表现出短期波动现象，其出现与轨道相位无严格相关性。 这种变异性与瞬态尘埃结构的遮挡一致，导致类似天气的变异性模式。 显示英文摘要

摘要： HD 213985 is an eccentric binary system with a post-AGB primary and a jet-launching secondary star. We confirm that the system photometric variability is likely due to obscuration by the inner edge of a circumbinary disc, similar to RVb-type RV Tau stars. The system has shown an increase in the orbital variability amplitude in optical photometric bands, along with irregular changes in its shape that often started to appear skewed. Variability in the Na D lines suggests that this behaviour may be driven by interactions between the circumbinary disc and outflows through the L2 Lagrange point. Moreover, HD 213985 has exhibited episodes of short-term fluctuations whose appearance is not strictly related to the orbital phase. This variability is consistent with obscuration by transient dust structure leading to weather-like variability patterns.