双简并并合遗迹WD J005311的超快线驱动风
The Ultrafast Line-Driven Wind from the Double-Degenerate Merger Remnant WD J005311
AI总结：
本研究构建双简并并合遗迹的稳态风解，将其应用于WD J005311，结合观测与历史记录确定其风的演化阶段，验证了其未坍缩为中子星的状态。
AI中文摘要：
我们系统构建了由简并氧氖核心与碳壳燃烧驱动的光学厚膨胀包层组成的双简并并合遗迹的稳态风解，该风由包含线驱动的辐射压力加速。对于给定的包层成分，每个解由两个本征值表征：简并核心质量$M_{\rm WD}$以及包层与风的总质量$\Delta M$。我们发现当$M_{\rm WD} \gtrsim 1.0\\,M_\odot$时存在风解。对于给定的$M_{\rm WD}$，随着$\Delta M$减小，解从慢速的连续谱驱动风过渡到超快的线驱动风，形成可解释为并合遗迹时间演化的序列。我们将这些解应用于WD J005311，这是一个具有$v_{\rm w} \sim 0.05\\,c$超快风的银心双简并并合遗迹候选体。通过$M_{\rm WD} \sim 1.15-1.25\\,M_\odot$和$\Delta M \sim (1.8-5.7)\times 10^{-3}\\,M_\odot$，我们一致重现了它的光度、有效温度和质量损失率。结合演化分析与周围星云Pa 30的观测以及SN 1181的历史记录，我们认为WD J005311在假定的并合后400-650年开始发射连续谱驱动风，并在约100年前过渡到超快风阶段。该阶段预计还将持续约1000年，在此期间白矮星将保持低于钱德拉塞卡质量，避免坍缩为中子星。在连续谱驱动风阶段之前，遗迹可能经历过更膨胀、流体静力学的巨星阶段，具有更慢但质量更大的风。未来对风星云的观测可通过揭示慢速大质量风与超快风之间相互作用的特征来验证这一情景。
英文摘要：
We systematically construct steady-state wind solutions for double-degenerate merger remnants consisting of a degenerate oxygen-neon core and an optically thick expanding envelope powered by carbon-shell burning, with winds accelerated by radiation pressure including line driving. For a given envelope composition, each solution is characterized by two eigenvalues: the degenerate core mass, $M_{\rm WD}$, and the total envelope and wind mass, $ΔM$. We find that wind solutions exist for $M_{\rm WD} \gtrsim 1.0\,M_\odot$. For a given $M_{\rm WD}$, the solutions transition with decreasing $ΔM$ from slow, continuum-driven winds to ultrafast, line-driven winds, forming a sequence that can be interpreted as the temporal evolution of a merger remnant. We apply these solutions to WD J005311, a Galactic double-degenerate merger-remnant candidate with an ultrafast wind of $v_{\rm w} \sim 0.05\,c$. Its luminosity, effective temperature, and mass-loss rate are consistently reproduced with $M_{\rm WD} \sim 1.15-1.25\,M_\odot$ and $ΔM \sim (1.8-5.7)\times 10^{-3}\,M_\odot$. Combining our evolutionary analysis with observations of the surrounding nebula Pa 30 and historical records of SN 1181, we argue that WD J005311 began launching a continuum-driven wind $400-650$ yr after the putative merger and transitioned to the ultrafast-wind phase approximately $100$ yr ago. This phase is expected to continue for another $\sim 1000$ yr, during which the WD will remain below the Chandrasekhar mass and avoid collapse into a neutron star. Before the continuum-driven wind phase, the remnant may have passed through a more bloated, hydrostatic giant phase with a slower but more massive wind. Future observations of the wind nebula could test this scenario by revealing signatures of interactions between the slow, massive wind and the ultrafast wind.
