揭示AT 2025abao的本质：从前身到最终命运
Unravelling the Nature of AT 2025abao: From Precursor to Final Fate
- Chen-Ning Yang Institute for Advanced Study, Tsinghua University（清华大学杨振宁高等研究院）
- National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）
- Tsinghua University（清华大学）
- Yunnan Observatories, Chinese Academy of Sciences（中国科学院云南天文台）
- INAF – Osservatorio Astronomico di Padova（意大利国家天体物理研究所帕多瓦天文台）
- University of Chinese Academy of Sciences（中国科学院大学）
- University of Science and Technology of China（中国科学技术大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
通过模拟AT 2025abao从先驱到最终结果的完整演化，揭示其双星本质，表明主序伴星与AGB核心在公共包层演化后存活并形成紧密双星，填补观测空白。
AI中文摘要：
发光红新星（LRNe）是公共包层演化（CEE）的潜在特征，而公共包层演化是致密双星形成中一个关键但尚不为人所知的阶段。AT 2025abao是仙女座星系中的一颗发光红新星，起源于渐近巨分支（AGB）前身星，并表现出持续的前爆发瞬变。然而，由于缺乏对伴星的直接约束，该系统的演化命运仍不清楚。在此，我们通过模拟AT 2025abao从先驱阶段到最终结果的完整演化，揭示了其双星本质。我们表明，八年的红外先驱辐射源于一颗约1.4^{+0.2}_{-0.3}太阳质量的主序伴星，在约6.9太阳质量的AGB恒星风中螺旋内移。当公共包层演化开始时，伴星冲入包层并激发出激波。对该爆发的辐射流体动力学模拟将总抛射物质量限制在约0.92太阳质量，能量限制在约1.25×10^47尔格，揭示只有约0.57太阳质量成为非束缚态。随后的辐射传输模拟成功再现了演化的光谱能量分布。至关重要的是，我们的模型表明，主序伴星和AGB核心在公共包层演化开始后至少400天内以偏心轨道存活而未合并。因此，AT 2025abao可能是首个观测到的正在形成紧密双星的公共包层演化事件，填补了致密双星形成中一个长期存在的观测空白。
英文摘要：
Luminous red novae (LRNe) are potential signatures of common envelope evolution (CEE), a critical yet poorly understood phase in compact binary formation. AT 2025abao, an LRN in the Andromeda galaxy, originated from an asymptotic giant branch (AGB) progenitor and exhibited a prolonged pre-outburst transient. Lacking direct constraints on the companion, however, the system's evolutionary fate remains unclear. Here, we unravel the binary nature of AT 2025abao by modeling its complete evolution, from precursor to final outcome. We show that the eight-year infrared precursor arises from a $\approx1.4^{+0.2}_{-0.3}\,M_{\odot}$ main-sequence companion inspiralling through the wind of a $\approx 6.9\,M_{\odot}$ AGB star. As CEE commences, the companion plunges into the envelope and launches a shock. Radiation hydrodynamic modeling of this outburst constrains the total ejecta mass to $\approx 0.92\,M_{\odot}$ and energy to $\approx 1.25\times 10^{47}\,$erg, revealing that only $\approx 0.57\,M_{\odot}$ becomes unbound. Subsequent radiative transfer simulations successfully reproduce the evolving spectral energy distribution. Crucially, our models indicate the main-sequence companion and AGB core survive in an eccentric orbit without merging at least 400 days after CEE onset. AT 2025abao may therefore be the first observed CEE event caught forming a close compact binary, bridging a long-standing observational gap in compact binary formation.
