Three-axial shape distributions of pebbles, cobbles and boulders smaller than a few meters on asteroid Ryugu
Three-axial shape distributions of pebbles, cobbles and boulders smaller than a few meters on asteroid Ryugu
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Ryugu 小行星上小于几米的卵石、鹅卵石和巨石的三轴形状分布
DOI：
10.1016/j.icarus.2022.115007
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发表时间：
2022
期刊：
影响因子：
3.2
通讯作者：
et al.
中科院分区：
文献类型：
--
作者：
Michikami Tatsuhiro;Hagermann Axel;Morota Tomokatsu;et al.
在一个广泛的尺寸范围内，灾难性破裂的冲击碎片的形状分布在平均轴比2：10：2：1附近，与实验条件和靶材料无关。虽然小行星上的大多数块体很可能是撞击碎片，但没有足够的定量数据来可靠地统计它们的三轴长度和/或比率，因为很难精确估计块体的高度。在这项研究中，我们评估的高度块小行星龙谷通过测量他们的阴影。利用隼鸟2号航天器第二次着陆前立即获得的在500米以下高度拍摄的8幅较窄地点的特写图像（分辨率<5.4厘米/像素），研究了龙宫赤道区约4，100个直径从5.0厘米到7.6米的小块的三轴比。这项研究的目的是调查块的形状分布，这对了解小行星Ryugu的地质历史很重要。具体而言，形状分布进行了比较，实验室的影响碎片。我们的观察结果表明，小于1米的块体的形状分布与实验室的影响碎片的形状分布是一致的，这意味着主要的形状决定过程中的块体在Ryugu是影响破碎。在赤道地区，几米大小的块体似乎比其他块体稍平坦，这表明有些块体部分被埋在风化层中。总之，小行星Ryugu赤道区域几厘米到几米大小的块体的形状分布表明，这些块体主要是其母体灾难性破裂和（或）后来撞击产生的碎片。
Over a broad size range, the shapes of impact fragments from catastrophic disruptions are distributed around the mean axial ratio 2: √2: 1, irrespective of experimental conditions and target materials. Although most blocks on asteroids are likely to be impact fragments, there is not enough quantitative data for reliable statistics on their three-axial lengths and/or ratios because it is difficult to precisely estimate the heights of the blocks. In this study, we evaluate the heights of blocks on asteroid Ryugu by measuring their shadows. The three-axial ratios of ~4100 small blocks with diameters from 5.0 cm to 7.6 m in Ryugu's equatorial region are investigated using eight close-up images of narrower localities taken at altitudes below 500 m, i.e. at <5.4 cm/pixel resolution, obtained immediately before the second touch-down of the Hayabusa2 spacecraft. The purpose of this study is to investigate the block shape distribution, which is important for understanding the geological history of asteroid Ryugu. Specifically, the shape distribution is compared to laboratory impact fragments. Our observations indicate that the shape distributions of blocks smaller than 1 m on Ryugu are consistent with laboratory impact fragment shape distributions, implying that the dominant shape-determining process for blocks on Ryugu was impact fragmentation. Blocks several meters in size in the equatorial region seem to be slightly flatter than the rest, suggesting that some blocks are partly buried in a bed of regolith. In conclusion, the shape distributions of blocks from several-cm to several-m in the equatorial region of asteroid Ryugu suggest that these are mainly fragments originating from the catastrophic disruption of their parent body and/or from a later impact.
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Kadono T、Kikuchi K 等人：“cologa 病中碱性生长因子的血清浓度”（出版中）。
DOI：
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发表时间：
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期刊：
影响因子：
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作者：
通讯作者：
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影响因子：
18.3
作者：
K. Walsh;E. Jawin;R. Ballouz;O. Barnouin;E. Bierhaus;H. Connolly;J. Molaro;T. Mccoy;M. Delbo’;C. Hartzell;M. Pajola;S. Schwartz;D. Trang;E. Asphaug;K. Becker;C. Beddingfield;C. Bennett;W. Bottke;K. Burke;B. Clark;M. Daly;D. DellaGiustina;J. Dworkin;C. Elder;D. Golish;A. Hildebrand;R. Malhotra;J. Marshall;P. Michel;M. Nolan;M. Perry;B. Rizk;A. Ryan;S. Sandford;D. Scheeres;H. Susorney;F. Thuillet;D. Lauretta;the OSIRIS-REx Team
通讯作者：
K. Walsh;E. Jawin;R. Ballouz;O. Barnouin;E. Bierhaus;H. Connolly;J. Molaro;T. Mccoy;M. Delbo’;C. Hartzell;M. Pajola;S. Schwartz;D. Trang;E. Asphaug;K. Becker;C. Beddingfield;C. Bennett;W. Bottke;K. Burke;B. Clark;M. Daly;D. DellaGiustina;J. Dworkin;C. Elder;D. Golish;A. Hildebrand;R. Malhotra;J. Marshall;P. Michel;M. Nolan;M. Perry;B. Rizk;A. Ryan;S. Sandford;D. Scheeres;H. Susorney;F. Thuillet;D. Lauretta;the OSIRIS-REx Team
DOI：
--
发表时间：
1986
期刊：
影响因子：
--
作者：
F. Capaccioni;P. Cerroni;M. Coradini;M. Martino;P. Farinella;E. Flamini;G. Martelli;P. Paolicchi;P. N. Smith;A. Woodward;V. Zappalá
通讯作者：
V. Zappalá
影响因子：
64.8
作者：
Lauretta, D. S.;DellaGiustina, D. N.;Marty, B.
通讯作者：
Marty, B.
小行星上巨石的大小和形状：爱神、糸川和龙宫的比较研究
影响因子：
3.2
作者：
Michikami Tatsuhiro;Hagermann Axel
通讯作者：
Hagermann Axel