发表机构
Universidade Federal do Rio de Janeiro; Royal Observatory of Belgium; Universität Potsdam; Universidad Nacional Autónoma de México; Leopold–Franzens Universität Innsbruck; University of Warmia and Mazury; Aix-Marseille Univ.; Chalmers University of Technology; Universidad Central de Chile（里约热内卢联邦大学; 比利时皇家天文台; 波茨坦大学; 墨西哥国立自治大学; 因斯布鲁克大学; 瓦尔米亚和马祖里大学; 艾克斯-马赛大学; 查尔姆斯理工大学; 智利中央大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过VLT/FORS2光谱和NLTE模型，确认Sakurai天体中心星为[WR]型恒星，其温度低于理论预测，为快速演化阶段提供了关键约束。
AI 中文摘要
Sakurai天体提供了一个在人类时间尺度上观察恒星演化的罕见机会。自其1996年的“重生”事件及被发现以来，其演化过程已被广泛监测，近期光学光谱学已暗示[WR]型发射特征的出现。在本快报中，我们基于新的VLT/FORS2观测和非局部热力学平衡（NLTE）膨胀大气模型，对其中心恒星进行了可靠的光谱识别。若干观测到的发射线源于[WR]型恒星风，确立了该中心恒星为[WR]天体。最强的恒星特征由C II-III和He I产生。我们推导了Sakurai天体的恒星及风参数，并讨论了其演化状态。该[WR]恒星远比约80年前爆发的重生恒星V605 Aql（有效温度约95 kK）冷得多（有效温度约30.5 kK）。推断的温度低于在极晚期热脉冲（VLTP）期间抑制对流混合效率的模型预测值，但与涉及略低质量（小于约0.6太阳质量）残骸的更高时间分辨率计算一致。持续的光谱监测和大气建模对于追踪其再加热曲线和约束这一快速演化阶段的物理过程至关重要。
英文摘要
Sakurai's object provides a rare opportunity to observe stellar evolution on human timescales. Since its born-again event and detection in 1996, its evolution has been extensively monitored, and recent optical spectroscopy has suggested the emergence of [WR]-type emission features. In this Letter, we present a secure spectroscopic identification of its central star based on new VLT/FORS2 observations and NLTE expanding atmosphere models. Several observed emission lines arise in a [WR]-type stellar wind, establishing the central star as a [WR] object. The strongest stellar features are due to C II-III and He I. We derive the stellar and wind parameters of Sakurai's object and discuss its evolutionary status. The [WR] star is much cooler (Teff ~ 30.5 kK) than the born-again star V605 Aql (Teff} ~ 95 kK), which erupted about 80 years earlier. The inferred temperature is lower than predicted by models suppressing convective mixing efficiency during the VLTP, but is consistent with higher time-resolution calculations involving slightly lower-mass (<~ 0.6Msun) remnants. Continued spectroscopic monitoring and atmospheric modelling will be crucial for tracing its reheating curve and constraining the physics of this rapid evolutionary phase.
Journal refMNRAS, Volume 552, Issue 1, October 2026, stag1533
