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。AI 中文总结
本研究比较太阳系各天体的观测与模拟撞击率，发现数量级差异，并分析其来源，提出彗星建模和尺寸外推改进方向。
AI 中文摘要
仅凭观测难以推断行星撞击率，因为撞击事件稀少，观测记录依赖于目标天体，且将观测到的闪光、火流星和陨石坑转换为固有撞击率取决于不确定的选择效应和转换参数。基于论文I中的模拟，我们检验观测系统性是否能解释地球上观测与模拟撞击率之间数量级的差异，以及类似的差异是否也存在于其他太阳系天体。我们将地球、月球、火星和木星的12条观测撞击记录转换为D>10 m的共同大气层前撞击率，在转换链中传播不确定性，并将所得撞击率与论文I中推导的固有撞击率进行比较。我们发现地球（观测与模型的中位比值为2.2-21.0）、月球（3.4-132.1）、火星（14.2-118.6）和木星（2.6-47.7）存在差异，且差异的主要来源因天体而异。模拟的木星族彗星（JFC）贡献显著减小了地球的差异，表明额外的动力学来源可能有助于解释这一差距。月球记录彼此相差两个数量级，差异主要由尺寸外推不确定性主导。火星的不匹配主要由陨石坑到撞击体的转换主导。木星的比较主要取决于推断的束缚撞击体数量和观测完备性阈值的不确定性。进一步研究这一不匹配需要纳入彗星建模，并对尺寸外推标度和改进的观测完备性进行更严格的约束。
英文摘要
Planetary impact rates are difficult to infer from observations alone because impacts are rare, observational records are target-dependent, and converting observed flashes, bolides, and craters to an intrinsic impact rate depends on uncertain selection effects and conversion parameters. Building on the simulations in Paper I, we examine whether observational systematics can explain the order-of-magnitude mismatch between observed and modeled impact rates on Earth, and whether comparable discrepancies extend to other Solar System bodies. We convert 12 observed impact records for Earth, the Moon, Mars, and Jupiter to a common pre-atmospheric impact rate for $D>10$ m, propagate uncertainties through the conversion chain, and compare the resulting rates with the intrinsic rates derived in Paper I. We find discrepancies for Earth (observation-to-model median ratio $2.2-21.0$), the Moon ($3.4-132.1$), Mars ($14.2-118.6$), and Jupiter ($2.6-47.7$), with the dominant source of the discrepancy differing by body. The simulated Jupiter-family comet (JFC) contribution substantially reduces the Earth discrepancy, suggesting that an additional dynamical source may help explain the gap. The lunar records disagree with each other by two orders of magnitude, with the discrepancy dominated by size-extrapolation uncertainties. The Mars mismatch is dominated by crater-to-impactor conversion. The Jupiter comparison depends mainly on uncertainties in the inferred number of bound impactors and in the observational completeness thresholds. Further investigation of this mismatch requires incorporating cometary modeling and tighter constraints on size-extrapolation scaling and improved observational completeness.
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