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arXiv 1208.4633astro-ph.EP
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H型球粒陨石母体的热历史模拟

Thermal history modeling of the H chondrite parent body

Stephan Henke, Hans-Peter Gail, Mario Trieloff, Winfried H. Schwarz, Thorsten Kleine

摘要:

个别陨石的冷却历史可以通过使用具有不同闭合温度的不同放射性同位素计时器的年龄来经验性地重建。对于一组来自单一母体的陨石,这些数据允许重建该主体的冷却历史和性质。特别适合的是H球粒陨石,因为可以在很大的闭合温度范围内获得精确的放射性年龄。利用至少有三种不同放射性年龄的H型球粒陨石,建立了H型球粒陨石母体的热演化模型。确定的热演化的H球粒陨石母体和未知的埋藏深度的H球粒陨石的几个关键参数是不同的,直到获得最佳的拟合。拟合由“进化算法”执行。八个样品的经验数据,其中放射性年龄可用于至少三个不同的封闭温度。一组参数的H球粒陨石母体的发现,产生良好的协议(误差范围内)之间的热演化模型和经验数据的六个检查八个球粒陨石。新的热模型约束了H球粒陨石母体(可能是(6)Hebe)的半径和形成时间、单个H球粒陨石的初始埋藏深度、该天体的平均地面温度、该天体增生来源的材料的平均初始孔隙度以及H球粒陨石母体的初始60 Fe含量。

英文摘要:

The cooling histories of individual meteorites can be empirically reconstructed by using ages from different radioisotopic chronometers with distinct closure temperatures. For a group of meteorites derived from a single parent body such data permit the reconstruction of the cooling history and properties of that body. Particularly suited are H chondrites because precise radiometric ages over a wide range of closure temperatures are available. A thermal evolution model for the H chondrite parent body is constructed by using all H chondrites for which at least three different radiometric ages are available. Several key parameters determining the thermal evolution of the H chondrite parent body and the unknown burial depths of the H chondrites are varied until an optimal fit is obtained. The fit is performed by an 'evolution algorithm'. Empirical data for eight samples are used for which radiometric ages are available for at least three different closure temperatures. A set of parameters for the H chondrite parent body is found that yields excellent agreement (within error bounds) between the thermal evolution model and empirical data of six of the examined eight chondrites. The new thermal model constrains the radius and formation time of the H chondrite parent body (possibly (6) Hebe), the initial burial depths of the individual H chondrites, the average surface temperature of the body, the average initial porosity of the material the body accreted from, and the initial 60Fe content of the H chondrite parent body.

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。

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