发表机构
University of Bristol（布里斯托大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过三维模拟发现巨大撞击优先剥离低质量大气，提出包含大气质量的新标度律，并应用于太阳系形成模拟，揭示了撞击随机性对行星大气多样性的关键塑造作用。
AI 中文摘要
撞击驱动的大气损失在塑造行星大气的多样性中起着关键作用。然而，现有的根据给定撞击计算损失的方案忽略了大气质量对损失的关键作用，因此常常严重错误地估计损失程度。利用三维光滑粒子流体动力学模拟，我们量化了质量分数为1%-20%的大气层行星在巨大撞击过程中的大气损失，并表明质量较小（气压较低）的大气层明显更容易被剥离。我们推导了一个新的关于大气损失的标度律，该标度律包含大气质量的影响，适用于从贫挥发物行星胚胎到超级地球和亚海王星的碰撞。将我们的标度律应用于太阳系形成的N体模拟，我们表明，考虑大气质量与损失效率之间的耦合会导致显著更多的大气被剥离。对于较小的行星（小于约0.6个地球质量），显著的大气损失事件很常见，而即使是大约地球质量的星体，也会通过多次撞击损失其大气的30%-100%。我们还表明，月球形成撞击期间的大气损失强烈依赖于撞击前的大气质量和撞击方式。对于代表性的约100巴的撞击前大气，地球可能已经损失了其大气的20%-80%。在任何经历巨大撞击阶段的系统中，宿主行星的大气将不可避免地受到撞击随机性的塑造。我们的新标度律可以很容易地纳入行星形成和系统范围演化的模型中，为行星多样性的起源提供新的见解。
英文摘要
Impact-driven atmospheric loss plays a key role in shaping the diversity of planetary atmospheres. However, existing prescriptions for calculating loss from a given impact neglect the critical role of atmospheric mass on loss, and thus often severely miscalculate the extent of loss. Using 3D smoothed particle hydrodynamics simulations, we quantify atmospheric loss during giant impacts onto planets with 1-20% mass fraction atmospheres and show that less massive (lower-pressure) atmospheres are significantly easier to remove. We derive a new scaling law for atmospheric loss that includes the effects of atmospheric mass and is applicable to collisions between volatile-poor planetary embryos through to super-Earths and sub-Neptunes. Applying our scaling law to $N$-body simulations of solar system formation, we show that including the coupling between atmospheric mass and loss efficiency results in significantly more atmosphere removal. Substantial atmospheric loss events are common for smaller planets ($\lesssim$0.6 M$_{\oplus}$), whilst even roughly Earth mass bodies lose 30-100% of their atmospheres through multiple impacts. We also show that atmospheric loss during the Moon-forming impact strongly depends on both the pre-impact atmospheric mass and impact style. For a representative $\sim$100 bar pre-impact atmosphere, Earth could have lost between 20-80% of its atmosphere. In any system that undergoes a phase of giant impacts, the atmospheres of its host planets will be unavoidably shaped by the stochasticity of impacts. Our new scaling law can be readily incorporated into models of planet formation and system-wide evolution, offering new insights into the origins of planetary diversity.
Comments11 pages, 5 figures
