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[PPS08-11] Topographic degradation of craters on Phobos and the comparison with other small bodies
Keywords:Phobos, crater, Topographic degradation
We find that the distributions of κt are different between these small bodies. The medians of κt are estimated to be (1.4±0.1) ×105 m2 for Phobos, and (4.4±1.0) ×104 m2 for Eros, suggesting that the Phobos craters are more degraded than the Eros craters.
The observed high crater degradation rate of Phobos, which is about 3 times higher than that of Eros and the corrected that of Lutetia, implies that the ejecta re-accumulation has occurred throughout the geologic history of Phobos. To evaluate the effect of ejecta re-accumulation, we calculated the total number of craters generated by re-impacts of ejecta from all Phobos craters larger than 1 km in radius. The result shows that the total number of re-impact craters is 2–10 times of the primary impacts, suggests that the high crater degradation rate of Phobos can be explained by the ejecta re-accumulation.