Iron and nickel isotope compositions of presolar silicon carbide grains from supernovae
Iron and nickel isotope compositions of presolar silicon carbide grains from supernovae
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DOI：
10.1016/j.gca.2017.05.029
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发表时间：
2018-01
影响因子：
5
通讯作者：
J. Kodolányi;T. Stephan;R. Trappitsch;P. Hoppe;M. Pignatari;A. Davis;M. Pellin
中科院分区：
文献类型：
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作者：
J. Kodolányi;T. Stephan;R. Trappitsch;P. Hoppe;M. Pignatari;A. Davis;M. Pellin
我们报告的碳，硅，铁，镍同位素组成的25 presolar主要是超新星（SN）起源的SiC颗粒。铁和镍同位素组成的测量与新的芝加哥激光电离仪，辣椒，它允许所有的铁和镍同位素的分析没有同量异位素干扰困扰以前的测量与NanoSIMS。尽管有陆地铁和镍污染，在9个SN颗粒（X型）中检测到显著的54 Fe/56 Fe，57 Fe/56 Fe，60 Ni/58 Ni，61 Ni/58 Ni，62 Ni/58 Ni和64 Ni/58 Ni同位素异常。将三种具有最大镍同位素异常（至少一种同位素比值>100‰或<−100‰，当表示为与太阳值的偏差时）的颗粒的组合多同位素数据与两种SN模型的预测进行比较，一种在SN爆炸之前在He壳中有氢摄入，另一种没有。一个颗粒的碳-硅-铁-镍同位素组成与模型的预测一致，没有氢摄入，而其他两个颗粒的同位素异常不能使用任何SN模型再现。测得的同位素组成和模型预测之间的差异可能表明元素分馏的SN喷出物之前或期间的颗粒冷凝，并重申需要三维SN模型。
We report the carbon, silicon, iron, and nickel isotope compositions of twenty-five presolar SiC grains of mostly supernova (SN) origin. The iron and nickel isotope compositions were measured with the new Chicago Instrument for Laser Ionization, CHILI, which allows the analysis of all iron and nickel isotopes without the isobaric interferences that plagued previous measurements with the NanoSIMS. Despite terrestrial iron and nickel contamination, significant isotopic anomalies in54Fe/56Fe,57Fe/56Fe,60Ni/58Ni,61Ni/58Ni,62Ni/58Ni, and64Ni/58Ni were detected in nine SN grains (of type X). Combined multi-isotope data of three grains with the largest nickel isotope anomalies (>100‰ or <−100‰ in at least one isotope ratio, when expressed as deviation from the solar value) are compared with the predictions of two SN models, one with and one without hydrogen ingestion in the He shell prior to SN explosion. One grain’s carbon-silicon-iron-nickel isotope composition is consistent with the prediction of the model without hydrogen ingestion, whereas the other two grains’ isotope anomalies could not be reproduced using either SN models. The discrepancies between the measured isotope compositions and model predictions may indicate element fractionation in the SN ejecta prior to or during grain condensation, and reiterate the need for three-dimensional SN models.