Title: Rummaging inside the Eskimo's parka: Variable asymmetric PN fast wind and a binary nucleus? Show Chinese title

Title: 翻找爱斯基摩人的斗篷：可变的不对称PN快速风和双核？

Abstract: We report on high-resolution optical time-series spectroscopy of the central star of the `Eskimo' planetary nebula NGC~2392. Datasets were secured with the ESO 2.3m in 2006 March and CFHT 3.6m in 2010 March to diagnose the fast wind and photospheric properties of the central star. The HeI and HeII recombination lines reveal evidence for clumping and temporal structures in the fast wind that are erratically variable on timescales down to ~ 30 min. (i.e. comparable to the characteristic wind flow time). We highlight changes in the overall morphology of the wind lines that cannot plausibly be explained by line-synthesis model predictions with a spherically homogeneous wind. Additionally we present evidence that the UV line profile morphologies support the notion of a high-speed, high-ionization polar wind in NGC~2392. Analyses of deep-seated, near-photospheric absorption lines reveals evidence for low-amplitude radial velocity shifts. Fourier analysis points tentatively to a ~ 0.12-d modulation in the radial velocities, independently evident in the ESO and CFHT data. We conclude that the overall spectroscopic properties support the notion of a (high inclination) binary nucleus in NGC~2392 and an asymmetric fast wind. Show Chinese abstract

Abstract: 我们报告了对“雪人”行星状星云NGC~2392中心恒星的高分辨率光学时序光谱观测。 数据于2006年3月用ESO 2.3米望远镜和2010年3月用CFHT 3.6米望远镜获取，以诊断中心恒星的快速星风和光球特性。 HeI和HeII复合线显示出快速星风中存在团块和时间结构的证据，这些结构在时间尺度上变化不定，最短可达约30分钟。 （即，与特征星风流动时间相当）。 我们强调了星风线的整体形态变化，这些变化无法合理地通过球对称星风的线合成模型预测来解释。 此外，我们提供了证据，表明紫外线轮廓形态支持NGC~2392中存在高速、高电离极向星风。 对深层、接近光球的吸收线的分析显示有低振幅径向速度变化的证据。 傅里叶分析初步指向径向速度中约0.12天的调制，在ESO和CFHT数据中独立显现。 我们得出结论，整体光谱特性支持NGC~2392中存在（高倾角）双星核和不对称快速星风。