随机晚期积累到地球,月球和火星
William F Bottke1, Richard J Walker, James M D Day
1Southwest Research Institute, 1050 Walnut Street, Suite 400, Boulder, CO 80302, USA. bottke@boulder.swri.edu
概括
行星体的晚期积累解释了陆地天体中高度 siderophile 元素 (HSEs) 的丰富性. 剩余种群中的巨大弹药将这些元素送到了地球,火星和月球.
科学领域:
- 行星科学 行星科学
- 地质化学 地质化学
- 天文学 天文学
背景情况:
- 预计核心形成将从行星地幔中去除高度 siderophile 元素 (HSEs).
- 陆地行星 (地球,月球,火星) 呈现出意想不到的高HSE丰度,尽管核心形成.
研究的目的:
- 为了研究晚期积累假说作为解释在陆地行星地幔中升高的HSE.
- 确定向地球,火星和月球传递HSE所需的小行星种群的特征.
主要方法:
- 剩余的行星小人口的建模,由巨大的弹子主导.
- 推断撞击器尺寸分布与来自小行星带内部,火星撞击盆地和行星积累模型的分布进行比较.
主要成果:
- 宽泛的冠状体行星体的晚期积累可以解释观察到的HSE丰度.
- 需要积累的质量:地球的质量≥0.5%,火星的质量≥10倍,月球的质量≥1200倍.
- 最大的撞击体 (25003000公里) 可能改变了地球的斜率;较小的撞击体 (250300公里) 可能将水送到月球.
结论:
- 大质量行星体的晚期积聚为陆地物体中HSE枯竭提供了统一的解决方案.
- 推断的冲击体大小分布与独立的地质和积累模型保持一致.
- 后期冲击对行星进化产生了重大影响,包括斜度变化和供水.
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