标题： SN 2011fe 的星云光谱和丰度断层扫描：具有稳定铁核的正常 Ia 型超新星 显示英文标题

标题： Nebular spectra and abundance tomography of the type Ia supernova SN 2011fe: a normal SN Ia with a stable Fe core

摘要： 展示并分析了覆盖SN 2011fe第一年的光学和近红外星云光谱系列。 被证明最适合早期光学/紫外光谱的密度分布“rho-11fe”被扩展到更低的速度，以包括在星云期发射的区域。 模型rho-11fe介于快速燃烧模型W7和低能延迟点火模型之间。 如果最内部的喷出物主要由中子丰富的稳定铁族元素主导，则可以很好地拟合星云光谱，这些元素有助于冷却但不加热。 因此，可以达到正确的热平衡，从而用观测到的比例再现最强的[FeII]和[FeIII]线。 由此得到的56Ni质量为0.47 +/- 0.05 Mo。 大部分56Ni的质量外缘速度约为8500公里/秒。 稳定的铁的质量为0.23 +/- 0.03 Mo。 稳定的镍丰度较低，约为10^{-2} Mo。 这足以重现一条在7400 Å附近的观测到的发射线。 一个质量为1.02 Mo且没有中心稳定铁的次临界爆炸模型无法再现观测到的线比。 显示了一个模拟模型，其中中子丰富的铁族元素位于56Ni之上，这是基于最近的建议，该模型产生的光谱与观测结果不太兼容。 从星云分析中获得的内层密度和丰度，结合之前获得的外层密度和丰度，用于计算合成的总光度曲线，该曲线与SN 2011fe的光度曲线比较吻合。 显示英文摘要

摘要： A series of optical and one near-infrared nebular spectra covering the first year of the Type Ia supernova SN 2011fe are presented and modelled. The density profile that proved best for the early optical/ultraviolet spectra, "rho-11fe", was extended to lower velocities to include the regions that emit at nebular epochs. Model rho-11fe is intermediate between the fast deflagration model W7 and a low-energy delayed-detonation. Good fits to the nebular spectra are obtained if the innermost ejecta are dominated by neutron-rich, stable Fe-group species, which contribute to cooling but not to heating. The correct thermal balance can thus be reached for the strongest [FeII] and [FeIII] lines to be reproduced with the observed ratio. The 56Ni mass thus obtained is 0.47 +/- 0.05 Mo. The bulk of 56Ni has an outermost velocity of ~8500 km/s. The mass of stable iron is 0.23 +/- 0.03 Mo. Stable Ni has low abundance, ~10^{-2} Mo. This is sufficient to reproduce an observed emission line near 7400 A. A sub-Chandrasekhar explosion model with mass 1.02 Mo and no central stable Fe does not reproduce the observed line ratios. A mock model where neutron-rich Fe-group species are located above 56Ni following recent suggestions is also shown to yield spectra that are less compatible with the observations. The densities and abundances in the inner layers obtained from the nebular analysis, combined with those of the outer layers previously obtained, are used to compute a synthetic bolometric light curve, which compares favourably with the light curve of SN 2011fe.