发表机构
MIT Kavli Institute for Astrophysics and Space Research; Department of Astronomy & Astrophysics, University of California San Diego; Department of Astronomy and Theoretical Astrophysics Center, University of California, Berkeley; Department of Physics and Astronomy, University of Rochester; University of Florida, Department of Astronomy, Bryant Space Science Center; Christian-Albrechts-Universität zu Kiel, Institut für Theoretische Physik und Astrophysik（麻省理工学院卡弗里天体物理与空间研究所; 加州大学圣地亚哥分校天文与天体物理系; 加州大学伯克利分校天文与理论天体物理中心; 罗切斯特大学物理与天文系; 佛罗里达大学天文系布莱恩特空间科学中心; 基尔大学理论与天体物理研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究探测到并合后巨星TYC 4144-329-2的X射线和远紫外辐射及Hα谱线变化，表明其存在弱冕活动和持续吸积，并推测该星并合较晚，可作为研究并合后系统早期演化的独特探针。
AI 中文摘要
双星是超新星和引力波源等奇异天体的前身。然而，一些系统在主序星寿命末期，当主星膨胀为巨星并导致其伴星向内旋进时，会更早地发生并合。TYC 4144-329-2 是一颗候选的并合后首次上升巨星，具有在红外（IR）波段可见的星周盘。我们探测到来自 TYC 4144-329-2 的微弱 X 射线和远紫外（FUV）辐射，并将其解释为弱冕活动特征。我们还发现了 Hα 谱线轮廓和光学光变曲线的变化，并提出了一种中间几何结构，其中视线穿过具有时变柱密度的外翘盘的上层。虽然 X 射线必定来自冕层，但 Hα 谱线轮廓指向持续且变化的吸积。我们认为 TYC 4144-329-2 的并合比该类其他恒星更晚发生，且它尚未有时间发展出深厚的对流区。如果这一情景成立，TYC 4144-329-2 将成为研究并合后系统演化最早阶段的独特探针。
英文摘要
Binary stars are the progenitors of exotic objects, such as supernovae and gravitational wave sources. However, some systems merge earlier when the primary expands into a giant star at the end of its lifetime on the main sequence and causes its companion to spiral in. TYC 4144-329-2 is a candidate post-merger first ascent giant star with a circumstellar disk seen in the infrared (IR). We detect weak X-ray and far ultraviolet (FUV) emission from TYC 4144-329-2, which we interpret as a signature of weak coronal activity. We also find variability in Ha line profiles and in the optical light curves and we suggest an intermediate geometry where the line-of-sight passes through the upper layers of a flared disk with a time variable column density. While the X-rays must be coronal, the Ha line profiles point to ongoing and variable accretion. We suggest that TYC 4144-329-2's merger was more recent than other stars in this class and that it did not yet have time to develop a deep convection zone. If this scenario holds, TYC 4144-329-2 would be a unique probe of the earliest stages in the evolution of post-merger systems.
Comments16 pages (incl. references), 9 figures. Interactive figures not included in this version but will be in the journal version
