眩目光芒：关于 terrestrial 巨行星撞击作为天文可观测事件的模拟证据
Blinding Lights: Simulation-Based Evidence for Terrestrial Giant Impacts as Astronomically Observable Events
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中文总结 AI 辅助
本文提出一种后处理SPH模拟的方法，以模拟巨行星撞击的低密度喷射物，发现撞击后数日的热辐射可与M矮星相当，从而可作为天文观测事件，为未来巡天提供约束。
中文摘要 AI 辅助
巨行星撞击（行星大小天体之间的碰撞）是剧烈事件，从根本上改变行星的性质和行星系统的结构。对这些事件的观测为巨行星撞击在行星系统形成中的作用提供了重要约束。然而，将此类观测与造成撞击的具体细节联系起来具有挑战性，因为数值模拟难以解析正在进行的撞击结构边缘处可观测物质的预期极端低密度。特别是，在SPH代码中，为了计算效率，通常强制设定密度的下限。在这里，我们提出了一种对巨行星撞击的平滑粒子流体动力学（SPH）模拟输出进行后处理的方法，该方法模拟多相和多材料碰撞中的真实物理特性，以更好地理解这些低密度外部区域。我们应用我们新颖的后处理流程来确定巨行星撞击的直接热辐射和潜在的观测特征，并针对一系列分辨率和代码参数模拟的示例撞击获得一致的光球表面几何形状。我们发现，在这次terrestrial巨行星撞击事件后的最初几天内，来自炽热的、未束缚的喷射物的辐射在温度和光度上可以与M矮星相当，因此可以作为天文可观测事件。我们的工作开始弥合观测与理论模型之间的差距，并可能使高节奏、大天区巡天（如维拉·鲁宾天文台即将进行的巡天）能够对本地邻域内巨行星撞击的频率和性质施加约束。
英文摘要
Giant impacts (collisions between planet-sized bodies) are violent events that fundamentally alter the properties of planets and the structure of planetary systems. Observations of these events provide important constraints on the role of giant impacts in the formation of planetary systems. However, relating such observations to the specifics of the impact responsible is challenging, since numerical simulations struggle to resolve the expected extreme low densities of observable material at the edge of ongoing impact structures. In particular, lower limits on density are often enforced in SPH codes for computational efficiency. Here, we present a method of post-processing output from smoothed particle hydrodynamics (SPH) simulations of giant impacts, that emulates realistic physical properties in multi-phase and multi-material collisions, in order to better understand these low-density outer regions. We apply our novel post-processing pipeline to determine the direct thermal emission and potential observational signatures of giant impacts, and obtain consistent photic surface geometries for an example impact simulated for a range of resolutions and code parameters. We find that during the first days after this terrestrial giant impact event, the emission from hot, unbound ejecta can be comparable in temperature and luminosity to that of an M-Dwarf star, and as such can be astronomically observable. Our work begins to bridge the gap between observations and theoretical models, and could allow high cadence, large-sky surveys, such as that to be carried out by the Vera C. Rubin Observatory, to place constraints on the frequency and properties of giant impacts in our local neighbourhood.
发表机构
- University of Bristol（布里斯托大学）
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