木星和土星冰卫星上的撞击坑分布:探寻外太阳系撞击体来源的钥匙
作者:
作者单位:

作者简介:

通讯作者:

中图分类号:

基金项目:

本文为澳门特别行政区科学技术发展基金资助成果。


Distributions of impact craters on Jovian and Saturnian icy satellites: implications to the impactor sources of the outer solar system
Author:
Affiliation:

Fund Project:

  • 摘要
  • |
  • 图/表
  • |
  • 访问统计
  • |
  • 参考文献
  • |
  • 相似文献
  • |
  • 引证文献
  • |
  • 资源附件
  • |
  • 文章评论
    摘要:

    充分认识外太阳系撞击体的来源类型和分布特征,对认识外太阳系固态天体上撞击过程,明确外太阳系天体上的撞击坑生成率和撞击坑定年等诸多方面具有重要的意义。得益于海量高质量探测数据的获取,如今我们对内太阳系主要天体表面的撞击分布和来源已经有了较为深入的了解,但对外太阳系天体的撞击分布和来源还知之甚少。不同大小频率的撞击体会在外太阳系冰卫星表面形成不同大小频率分布的撞击坑,不同飞行速度的撞击体也会在同步自转的冰卫星上留下程度不同的前导-后随半球不对称分布的撞击坑,因此,对外太阳系冰卫星上撞击坑的大小频率分布和前导-后随半球不对称性分布的观测,可以用于反推外太阳系的主要撞击来源。木星系统中大坑(D>10~30 km)的主要撞击来源是日心小天体(环绕太阳),但目前在木卫三和木卫四上观测到的前导-后随半球不对称性程度与黄道彗星引起的不对称性程度并不相符,更接近于近各向同性彗星(NICs)引起的不对称性,这与目前的天文观测和理论计算结果不一致;木卫二上的大坑稀少,小坑(D<1 km)则主要受一次坑的溅射物影响。对土星系统,土卫五和土卫八的大坑(D>20~30 km)分布更符合日心小天体来源;而土卫一、土卫四、土卫三上的分布则与行心碎屑物(以行星为中心)一致,尤其是小坑更可能来自以土星为中心的撞击体影响,例如大型盆地的溅射物或卫星碎片残骸。

    Abstract:

    A fully understanding of the sources and characteristics of the impactors in the outer solar system is vital to obtaining a more comprehensive understanding of the impact history of the outer solar system. Owing to the huge amounts of high-quality spacecraft data, we have obtained considerable knowledge about the impact cratering processes of planetary bodies in the inner solar system. However, our understanding about the outer solar system is still extremely limited. Impactors with different size-frequency will form craters with various size-frequency distributions on icy satellites, and impactors with a range of velocity will from craters with different degree of leading-trailing (apex-antapex) hemisphere asymmetry on synchronous rotating satellites. Conversely, the size-frequency distributions and leading-trailing hemisphere distributions of impact craters on icy satellites can be used to infer the impactor sources of the outer solar system. For Jovian system, most larger craters (diameter (D)>10~30 km) are formed from heliocentric impactors, but the degree of crater apex-antapex asymmetry observed on Ganymede and Callisto is much lower than that from theoretical estimation for ecliptic comets, which is inconsistent with current astronomical observations and theoretical computations. For Europa, most small craters (D<1 km) are formed from secondary impactors. For Saturnian system, the distributions of larger craters (D>20~30 km) on Rhea and Iapetus are more consistent with heliocentric impactors, while crater distributions on Mimas, Dione and Tethys are more consistent with planetocentric debris, especially for smaller craters, which are more likely to be influenced by the Saturn-orbiting impactors, such as escaped secondary ejecta from large basins and/or remnants of disrupted satellites.

    参考文献
    相似文献
    引证文献
引用本文

徐璐媛.2021.木星和土星冰卫星上的撞击坑分布:探寻外太阳系撞击体来源的钥匙[J].地质学报,95(9):2662-2677.
XU Luyuan.2021. Distributions of impact craters on Jovian and Saturnian icy satellites: implications to the impactor sources of the outer solar system[J]. Acta Geologica Sinica,95(9):2662-2677.

复制
分享
文章指标
  • 点击次数:
  • 下载次数:
  • HTML阅读次数:
  • 引用次数:
历史
  • 收稿日期:2021-05-07
  • 最后修改日期:2021-06-15
  • 录用日期:2021-08-08
  • 在线发布日期: 2021-08-10
  • 出版日期: