论文标题

倾斜超伊斯的大气损失影响

Atmosphere Loss in Oblique Super-Earth Impacts

论文作者

Denman, Thomas R., Leinhardt, Zoe M., Carter, Philip J.

论文摘要

使用平滑的颗粒流体动力学,我们对超级地球岩石行星的巨大影响建模,在大气中无弹丸和大气富含大气的目标之间。在这项工作中,我们提出了从正面到放牧碰撞的结果。模拟的结果分为两个广泛的类别:1)一个主要的后倒数残留物,其中包含来自目标和弹丸中的材料; 2)两次由“侵蚀性撞击”碰撞导致的两次主要碰撞残留物。与理想化的命中率定义相反,所有碰撞至少消除了目标大气,在该定义中,目标质量不变。我们发现,在最接近的方法的预测点,导致弹丸和目标积聚/合并的“撞击”碰撞与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,单个巨大的影响不太可能消除所有气氛。为了消除所有大气,正面的影响大致需要大约灾难性破坏的能量(即,总系统质量的一半的永久弹出),并导致地幔严重侵蚀。我们表明,更常见的较高的影响角碰撞在清除大气时的效率较低,而不是正面的碰撞。因此,在行星形成期间,没有预期的没有实质性破坏行星的无实质性破坏行星的单一碰撞。

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.

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