Mercury is notoriously difficult to form in Solar System simulations, due to its small mass and iron-rich composition. Smooth particle hydrodynamics simulations of collisions have found that a Mercury-like body could be formed by one or multiple giant impacts, but due to the chaotic nature of collisions, it is difficult to create a scenario where such impacts will take place. Recent work has found more success forming Mercury analogues by adding additional embryos near Mercury’s orbit. In this work, we aim to form Mercury by simulating the formation of the Solar System in the presence of the giant planets Jupiter and Saturn. We test out the effect of an inner disk of embryos added on to the commonly used narrow annulus of initial material. We form Mercury analogues with core-mass fractions (CMFs) > 0.4 in ∼10% of our simulations, and twice that number of Mercury analogues form during the formation process but are unstable and do not last to the end of the simulations. Mercury analogues form at similar rates for both disks with and without an inner component, and most of our Mercury analogues have lower CMFs than that of Mercury, ∼0.7, due to significant accretion of debris material. We suggest that a more in-depth understanding of the fraction of debris mass that is lost to collisional grinding is necessary to understand Mercury’s formation, or some additional mechanism is required to stop this debris from accreting.

中文翻译：

---

从激发的初始条件形成汞


众所周知，由于水星质量小且成分富含铁，因此在太阳系模拟中很难形成水星。碰撞的光滑粒子流体动力学模拟发现，一次或多次巨大碰撞可以形成类水星体，但由于碰撞的混沌性质，很难创建发生这种碰撞的场景。最近的研究发现，通过在水星轨道附近添加额外的胚胎，可以更成功地形成水星类似物。在这项工作中，我们的目标是通过在巨行星木星和土星存在的情况下模拟太阳系的形成来形成水星。我们测试了将胚胎内盘添加到常用的狭窄初始材料环上的效果。我们在约 10% 的模拟中形成了核心质量分数 (CMF) > 0.4 的汞类似物，并且在形成过程中形成的汞类似物数量是该数量的两倍，但不稳定，不会持续到模拟结束。对于有内部组件和没有内部组件的两个圆盘，汞类似物的形成速度相似，并且由于碎片材料的大量吸积，我们的大多数水星类似物的 CMF 低于水星的 CMF，约 0.7。我们建议，为了了解水星的形成，有必要更深入地了解碰撞研磨中损失的碎片质量分数，或者需要一些额外的机制来阻止这些碎片的积聚。