撞击太阳系行星和月球的小行星。III. 已知天体的真实撞击与LSST发现预测
Asteroids Impacting the Solar System Planets and the Moon. III. Real Impacts from Known Objects and LSST Discovery Predictions
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中文总结 AI 辅助
本研究评估LSST发现撞击前小行星的能力，预测可发现7个木星撞击体及多个地球撞击体，为检验撞击率模型差异提供新观测途径。
中文摘要 AI 辅助
使用撞击前源种群模型预测的撞击率与根据观测推断的撞击率，在太阳系各行星和月球上相差约2倍到约200倍。一个令人兴奋的额外观测约束机会是在小行星撞击前发现它们并跟踪直至撞击。我们基于已知天体和Vera C. Rubin天文台时空遗产调查（LSST）的预测来评估这一前景。首先，我们识别已知天体的撞击，确认了多个过去的案例，并预测了两次即将发生的撞击：2015 FK488，一颗约1.8公里的半人马小行星，其名义轨道预测约200年后与木星相撞；以及2022 KG1，一颗小于10米的近地天体，最近已从撞击风险列表中移除，但其名义轨迹导致约260年后撞击地球。这两条轨道都约束不佳。其次，假设基于模型的撞击率，我们预测LSST将发现我们先前分析中量化的59个合成撞击体中的7个。所有被发现的撞击体都将撞击木星，其尺寸范围约为200-2000米，预期发现到碰撞的提前时间为1.94-257.4年。其中两个在木星希尔球内部被发现，提供了在撞击发生前观察从临时束缚轨道到撞击转变的罕见机会。如果我们改为假设观测推断的撞击率，LSST最多将发现约20个未来的地球撞击体（大于10米）和约300个未来的木星撞击体（大于10米），发现到碰撞的提前时间两端范围更宽。这些结果表明，LSST可以在碰撞前数年至数百年识别出一部分行星撞击体，为测试源种群模型和撞击率不匹配提供新的观测途径。
英文摘要
Impact rates predicted using pre-impact source-population models and those inferred from observations disagree by a factor of a few to $\sim200$ across the Solar System planets and the Moon. An exciting opportunity for an additional observational constraint is the discovery of asteroids before impact and their tracking until impact. We evaluate this prospect based on both known objects and forecasts of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST). First, we identify impacts from known objects, confirming multiple past cases and predicting two coming impacts: 2015 FK488, a $\sim1.8$ km Centaur whose nominal orbit predicts an impact with Jupiter in $\sim200$ yr, and 2022 KG1, a $<10$ m NEO recently removed from the impact-risk lists but whose nominal trajectory leads to an Earth impact in $\sim260$ yr. Both orbits are poorly constrained. Second, assuming the model-based impact rate, we predict that LSST will discover 7 of the 59 synthetic impactors quantified in our previous analysis. All of the discovered impactors will impact Jupiter, and they have a size range of $\sim200-2000$ m and expected discovery-to-collision lead times of $1.94-257.4$ yr. Two of them are discovered inside Jupiter's Hill sphere, offering rare opportunities to observe the transition from a temporary bound orbit to impact before it happens. If instead we assume the observation-inferred impact rates, LSST will at most discover $\sim20$ future Earth impactors ($>10$ m) and $\sim300$ future Jupiter impactors ($>10$ m), with a wider range on both ends for discovery-to-collision lead times. These results demonstrate that LSST can identify a subset of planetary impactors years to centuries before collision, providing a new observational pathway for testing source-population models and the impact-rate mismatch.
发表机构
- Duke University（杜克大学）
机构由 AI 辅助整理，请以论文原文为准。
