Abstract

For the first time, abundances of the main xenon components (Xe-P3, Xe-P3(fr), Xe-P6 and Xe-pr instead Xe-HL) in the nanodiamonds of Orgueil (CI), Tieschitz (H3.6) and Indarch (EH3-4) meteorites have been calculated. The Xe-pr component is the excess fraction of xenon isotopes in the Xe-HL component relative to Xe-P3 (fr) and mainly consists of the ^{124, 126, 134, 136}Хе isotopes formed in p- and r-processes of nucleosynthesis in a type II supernova explosion. Analysis of the data has shown the following. (1) The main nanodiamond component of Xe is Xe-P3 (fr), and its maximum during pyrolysis, like Xe-pr and Xe-P6, is high-temperature (>1000°C), irrespectively of the petrological type of meteorites. (2) The relative abundance of the Xe-pr component in the nanodiamonds of Indarch meteorite, which is most enriched in anomalous xenon components, is about 15% of the total xenon abundance in the diamond of this meteorite, which is significantly lower than the abundance of the Xe-HL component – about 87%. (3) The xenon components are contained in the individual populations of the diamond grains with different thermo-oxidative stability. The data we obtained and in (Huss, Lewis, 1994b) on the abundances and the yield kinetics of xenon components in meteoritic nanodiamonds, based on the Xe-pr and Xe-HL isotope compositions, respectively, most likely show their limiting values. Тhe real properties of xenon components are assumed to be similar to those obtained when using Xe-pr component for calculations, taking into account the data on the carbon isotope composition in the nanodiamond grains of the Allende meteorite (Lewis et al., 2019).

中文翻译：

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陨石纳米金刚石：氙组分的替代组成

摘要

首次在Orgueil（CI），Tieschitz（H3.6）纳米金刚石中发现主要氙成分（Xe-P3，Xe-P3（fr），Xe-P6和Xe-pr代替Xe-HL）已经计算出了Indarch（EH3-4）陨石。Xe-pr组分是Xe-HL组分中氙同位素相对于Xe-P3（fr）的过量部分，主要由^{124、126、134、136}组成II型超新星爆炸在核合成的p和r过程中形成的Х同位素。数据分析显示如下。（1）Xe的主要纳米金刚石成分是Xe-P3（fr），并且像Xe-pr和Xe-P6一样，其在热解过程中的最大值是高温（> 1000°C），而与陨石的岩石类型无关。（2）在异常陨石中含量最高的Indarch陨石纳米金刚石中Xe-pr组分的相对丰度约为该陨石钻石中氙总含量的15％，远低于该陨石的氙含量。 Xe-HL组分的丰度–约87％。（3）氙组分包含在具有不同热氧化稳定性的金刚石晶粒的各个族群中。我们获得的数据（Huss，Lewis，1994b）分别基于Xe-pr和Xe-HL同位素组成，研究了陨石纳米金刚石中氙组分的丰度和产率动力学，最有可能显示其极限值。考虑到阿连德陨石纳米金刚石晶粒中碳同位素组成的数据，假设氙组分的实际性质与使用Xe-pr组分进行计算时获得的性质相似（Lewis等人，2019）。