AI 中文总结
发现首个双红巨星大陵五型系统，此为吸积星进入共包层前刚成红巨星时的半分离系统。通过光谱和光度观测分析其轨道参数等，并用双星演化模型支持，发现系统最终会合并成一颗恒星。
AI 中文摘要
双红巨星对于研究物质转移稳定性、共包层演化以及短轨道周期双白矮星的形成非常重要。然而，尚未发现正在经历物质转移的双红巨星系统。我们发现了一个由两颗红巨星组成的紧密大陵五型双星系统。这是首次在吸积星进入共包层阶段之前刚膨胀成红巨星的极短阶段观测到的半分离系统。Hα线表明该系统最近损失了一些物质，正朝我们移动。我们对该系统所有可用的光谱和光度观测进行了一致分析，确定了其轨道参数和各组成部分的基本性质。我们的发现得到了一个成功再现当前观测参数的双星演化模型的支持。该模型表明该系统最终将合并为一颗恒星。
英文摘要
Double red giant stars are very important for studies of the stability of mass transfer, common-envelope evolution, and the formation of double white dwarfs with short orbital periods. However, no double red giant system undergoing mass transfer has yet been found. We present the discovery of a close Algol-type binary system composed of two red giant stars. This is the first known semi-detached system observed during the very short phase when the accretor has expanded into a red giant just before entering the common envelope phase. The $H_α$ line suggests that the system has recently lost some material, which is now moving toward us. We present a consistent analysis of all the available spectroscopic and photometric observations of this system, constraining its orbital parameters and the fundamental properties of the components. Our findings are supported by a binary evolution model that successfully reproduces the currently observed parameters. The model suggests that the system will eventually merge into a single star.
CommentsAccepted in Astronomical Journal, wasn't considered interesting for Nature Astronomy
