氢摄入闪光三维$4π$模拟中的全球非球形振荡
Global non-spherical oscillations in 3-D $4π$ simulations of the H-ingestion flash
摘要：
我们进行了3-D模拟富含质子的物质夹带到\czw丰富的氦壳闪光对流和随后的H-摄入闪光发生在后AGB明星樱井的对象。瞬态性质和异常丰度特征的观测可用于验证我们的方法和假设，目的是将它们应用于未来的极低金属丰度恒星。我们包括来自H燃烧的核能反馈，并覆盖壳层的全部$4π$几何形状。$768^3$和$1536^3$网格上的测试结果彼此一致，并已被$1500\mathrm{min}$和$1200\mathrm{min}$所遵循。经过一个$850\mathrm{min}$长的静止夹带阶段的模拟进入一个全球性的非球形振荡，启动和维持的个别点火事件的富氢流体口袋。快速的圆周流在对极碰撞，并导致下一个氢过剩口袋的形成和局部点火。这个循环重复了十几次，而它的振幅却在下降。在全球振荡期间，卷吸率暂时增加一个因子$\approx 100$。夹带熵抑制了上层的对流运动，直到夹带氢的燃烧建立了一个单独的对流区。低分辨率的运行暗示了另一场全球振荡的可能性，也许会更加激烈。H燃烧对流区的位置与1-D模型一致，其中混合效率被校准以再现光变曲线。模拟已经在NCSA的NSF Blue Waters超级计算机上进行。
英文摘要：
We performed 3-D simulations of proton-rich material entrainment into \czw-rich He-shell flash convection and the subsequent H-ingestion flash that took place in the post-AGB star Sakurai's object. Observations of the transient nature and anomalous abundance features are available to validate our method and assumptions, with the aim to apply them to very low metallicity stars in the future. We include nuclear energy feedback from H burning and cover the full $4π$ geometry of the shell. Runs on $768^3$ and $1536^3$ grids agree well with each other and have been followed for $1500\mathrm{min}$ and $1200\mathrm{min}$. After a $850\mathrm{min}$ long quiescent entrainment phase the simulations enter into a global non-spherical oscillation that is launched and sustained by individual ignition events of H-rich fluid pockets. Fast circumferential flows collide at the antipode and cause the formation and localized ignition of the next H-overabundant pocket. The cycle repeats for more than a dozen times while its amplitude decreases. During the global oscillation the entrainment rate increases temporarily by a factor $\approx 100$. Entrained entropy quenches convective motions in the upper layer until the burning of entrained H establishes a separate convection zone. The lower-resolution run hints at the possibility that another global oscillation, perhaps even more violent will follow. The location of the H-burning convection zone agrees with a 1-D model in which the mixing efficiency is calibrated to reproduce the light curve. The simulations have been performed at the NSF Blue Waters supercomputer at NCSA.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
