论文标题
建模CERES和VESTA CRATERS的时间表和尺寸分布
Modeling the chronologies and size distributions of Ceres and Vesta craters
论文作者
论文摘要
我们从小行星撞击器的自洽动力学模型中推断出CERES和VESTA的火山口按年表。该模型在太阳系历史记录早期说明了行星迁移/不稳定，并跟踪了4.56 Gy的小行星轨道。它在小行星带的当前人群上进行了校准。该模型在整个太阳系历史上的任何时候都提供了对不同世界的小行星影响。我们将结果与撞击界的缩放关系结合在一起，以确定CERES和VESTA的火山口分布，并将这些理论预测与观察结果进行比较。我们发现：（i）CERES和VESTA的时间顺序相似，而它们与月球年表显着差异。因此，与以前的出版物中经常这样做一样，将月球年表用于主带小行星是不正确的。 （ii）模型结果与Vesta上观察到的大型（直径> 90 $ km）的大号（直径> 90 $ km）的数量和尺寸分布相匹配，但高估了CERES上的大口号的数量。这意味着CERES需要大量的火山口擦除。 （iii）在一个模型中，行星迁移/不稳定性发生早期发生，在最后1 Gy期间，在Vesta上形成Rheasilvia盆地的可能性为10 \％，$ \ sim1.5 $的因子比晚期不稳定案例高，而SIM2.5 $ \ sim2.5 $ $ \ sim2.5 $ $ $ \ sim2.5 $倍。因此，虽然$ \ sim1 $ gy（ga）的Rheasilvia的形成是不寻常的，但它不能以超过$ \simeq1.5σ$排除。在更广泛的背景下，我们的工作提供了一个自洽的框架，用于建模小行星弹口记录。
We infer the crater chronologies of Ceres and Vesta from a self-consistent dynamical model of asteroid impactors. The model accounts for planetary migration/instability early in the solar system history and tracks asteroid orbits over 4.56 Gy. It is calibrated on the current population of the asteroid belt. The model provides the number of asteroid impacts on different worlds at any time throughout the solar system history. We combine the results with an impactor-crater scaling relationship to determine the crater distribution of Ceres and Vesta and compare these theoretical predictions with observations. We find that: (i) The Ceres and Vesta chronologies are similar, whereas they significantly differ from the lunar chronology. Therefore, using the lunar chronology for main belt asteroids, as often done in previous publications, is incorrect. (ii) The model results match the number and size distribution of large (diameter $>90$ km) craters observed on Vesta, but overestimate the number of large craters on Ceres. This implies that large crater erasure is required for Ceres. (iii) In a model where planetary migration/instability happens early, the probability to form the Rheasilvia basin on Vesta during the last 1 Gy is 10\%, a factor of $\sim1.5$ higher than for the late instability case and $\sim2.5$ times higher than found in previous studies. Thus, while the formation of the Rheasilvia at $\sim1$ Gy ago (Ga) would be somewhat unusual, it cannot be ruled out at more than $\simeq1.5σ$. In broader context, our work provides a self-consistent framework for modeling asteroid crater records.
