WDJ0914+1914周围的行星大气逃逸与原行星盘形成
Planetary atmospheric escape and disk formation around WDJ0914+1914
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中文总结 AI 辅助
本研究通过三维辐射流体动力学模拟与一维粘滞盘模型，证实轨道半径15个太阳半径的富气行星光蒸发形成的原行星盘，可匹配WDJ0914+1914的观测特征，支持蒸发行星场景并约束原行星盘结构。
中文摘要 AI 辅助
白矮星WD J091405.30+191412.25的光谱显示出氢、氧、硫等挥发性物质的吸收线与双峰发射线，这一独特特征被解读为该白矮星从原行星盘吸积物质的证据，而该原行星盘由一颗近距类海王星或超级泡芙（super-puff）质量行星的大气蒸发物质形成。不过，目前该行星的轨道间距及其质量损失率仅通过简单的解析近似估算得出。本研究采用受辐照氢大气的三维辐射流体动力学模拟，结合一维粘滞盘演化模型对该场景展开研究，计算类海王星行星与超级泡芙行星在不同轨道间距下受白矮星极紫外（XUV）辐射时的大气逃逸情况，并追踪逃逸气体形成原行星盘后的演化过程。模拟得到的行星质量损失率为$(1.8-4)×10^{12}$克/秒，注入物质形成的气态盘在不到$10^5$年的时间内达到准稳态，这一过程由持续的质量供给与向白矮星的粘滞吸积之间的平衡所决定，由此产生的吸积率与观测估算值一致。与此前的解读不同，本模型预测该原行星盘延伸至行星轨道之外。研究结论为，一颗轨道半径为15个太阳半径的富气行星会发生持续的光蒸发，自然形成的原行星盘能够重现WD J0914+1914的观测吸积率与光谱特征，这些结果为蒸发行星场景提供了有力支持，并为原行星盘的结构与范围提供了新的约束。
英文摘要
The spectrum of the white dwarf WD J091405.30+191412.25 displays the absorption and double-peaked emission lines of the volatiles hydrogen, oxygen, and sulfur. This unique characteristic has been interpreted as evidence of this white dwarf accreting mass from a circumstellar disk that had formed from atmospheric material evaporating off a close-in Neptune-like or super-puff mass planet. Thus far, however, the orbital separation of the planet and its mass-loss rate have only been estimated using simple analytical approximations. We investigate this scenario using 3D radiative-hydrodynamic simulations of irradiated hydrogen atmospheres together with 1D viscous disk evolution models. We compute atmospheric escape from Neptune-like and super-puff planets exposed to extreme ultraviolet (XUV) radiation of the white dwarf at different orbital separations and follow the evolution of the escaping gas after it forms a circumstellar disk. The simulations yield planetary mass-loss rates of $(1.8-4)x10^{12}$ g/s. The injected material forms a gaseous disk that reaches a quasi-steady state in less than $10^5$ through the balance between continuous mass supply and viscous accretion onto the white dwarf. The resulting accretion rates are consistent with observational estimates. In contrast to previous interpretations, our models predict that the disk extends beyond the planetary orbit. We conclude that a gas-rich planet orbiting at 15 solar radii undergoes sustained photoevaporation and naturally produces a circumstellar disk capable of reproducing the observed accretion rates and spectral signatures of WD J0914+1914. These results provide strong support for the evaporating-planet scenario and offer new constraints on the structure and extent of the circumstellar disk.
