Atmosphere Loss in Oblique Super-Earth Collisions
Atmosphere Loss in Oblique Super-Earth Collisions
复制标题
倾斜超级地球碰撞中的大气层损失
DOI：
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发表时间：
2022
影响因子：
4.8
通讯作者：
P. Carter
中科院分区：
文献类型：
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作者：
Thomas R Denman;Z. Leinhardt;P. Carter
利用光滑粒子流体力学，我们模拟了超地球质量岩石行星在无大气抛射体和富大气目标之间的巨大碰撞。在这项工作中，我们给出了从迎头碰撞到掠过碰撞的结果。模拟的结果分为两大类：1)主要的碰撞后残留物，包含来自目标和弹丸的材料；2)两个主要的碰撞后残留物，由侵蚀性的打了就跑的碰撞产生。与目标质量不变的理想肇事逃逸定义形成对比的是，所有碰撞都至少移除了部分目标大气。我们发现，在预测的最接近点，打了就跑的碰撞和导致射弹和目标增长/合并的碰撞之间的边界与相互逃逸速度密切相关。我们的工作表明，一次巨大的撞击不太可能消除所有的大气。对于要消除的所有大气层，迎头撞击大约需要灾难性破坏的能量(即系统总质量的一半永久抛射)，并导致地幔的严重侵蚀。我们发现，更常见的高撞角碰撞在去除大气方面的效率低于迎头碰撞。因此，在行星形成过程中，预计不会发生单次碰撞，在不显著扰乱行星的情况下消除所有大气层。
Using smoothed particle hydrodynamics we model giant impacts of Super-Earth mass rocky planets between an atmosphere-less projectile and an atmosphere-rich target. In this work we present results from head-on to grazing collisions. The results of the simulations fall into two broad categories: 1) one main post-collision remnant containing material from target and projectile; 2) two main post-collision remnants resulting from ‘erosive hit-and-run’ collisions. All collisions removed at least some of the target atmosphere, in contrast to the idealised hit-and-run definition in which the target mass is unchanged. We find that the boundary between ‘hit-and-run’ collisions and collisions that result in the projectile and target accreting/merging to be strongly correlated with the mutual escape velocity at the predicted point of closest approach. Our work shows that it is very unlikely for a single giant impact to remove all of the atmosphere. For all the atmosphere to be removed, head-on impacts require roughly the energy of catastrophic disruption (i.e. permanent ejection of half the total system mass) and result in significant erosion of the mantle. We show that higher impact angle collisions, which are more common, are less efficient at atmosphere removal than head-on collisions. Therefore, single collisions that remove all the atmosphere without substantially disrupting the planet are not expected during planet formation.