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arXiv 2101.09533astro-ph.EPcond-mat.soft
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球粒陨石母体的自重力原始孔隙结构

Primordial porous structure of chondrite parent bodies due to self-gravity

Tomomi Omura, Akiko M. Nakamura

摘要:

在研究我们的太阳系通过小天体的演变以及规划减缓战略以避免小行星撞击造成的灾害时,小行星的孔隙度很重要。我们对小行星孔隙度的了解很大程度上依赖于地球上的陨石样本。然而,建议对地球上的岩石样品按强度进行分类。在这项研究中,我们获得了最原始的“粒状”球粒陨石母体的多孔结构的球粒陨石组分类似物的压实行为的测量的基础上的估计。我们测量了粉尘和粉尘珠混合物样品的压实曲线。尘埃样品由直径约为10^0-10^1 $μ$ m的各种球形和不规则颗粒组成。混合物样品由具有不同粉尘体积分数(~0.2-1)的粉尘和珠粒组成。我们使用1.5和4.8 $μ$ m颗粒作为粉尘作为第一步,尽管基质中材料的典型尺寸可能小得多。我们用幂律形式近似了每个样品的压实曲线,并利用实验结果计算了原始球粒陨石母体的孔隙结构。我们的研究结果表明,原始母体可能具有较高的孔隙度比方解石。此外,相对较高的基质体积分数可能是大多数高孔隙度陨石是碳质陨石的原因之一。

英文摘要:

The porosity of an asteroid is important when studying the evolution of our solar system through small bodies and for planning mitigation strategies to avoid disasters due to asteroid impacts. Our knowledge of asteroid porosity largely relies on meteorites sampled on Earth. However, chondrites sampled on Earth are suggested to be sorted by strength. In this study, we obtained an estimate of the most porous structure of primordial "granular" chondrite parent bodies based on measurements of the compaction behavior of chondrite component analogs. We measured compaction curves of dust and dust-bead mixture samples. The dust sample consisted of various spherical and irregular particles with diameters on the order of 10^0-10^1 $μ$m. The mixture sample consisted of dust and beads with different dust volume fractions (~0.2-1). We used 1.5 and 4.8 $μ$m particles as dust as a first step, although the typical size of materials in matrix may be much smaller. We approximated the compaction curve of each sample with a power-law form and calculated the porosity structure of the primordial chondrite parent bodies using the experimental results. Our results show that the primordial parent bodies are likely to have higher porosity than the chondrites. Moreover, the relatively higher volume fraction of the matrix may be one of the reasons why most meteorites with high porosity are carbonaceous chondrites.

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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