[P-PS06] 惑星科学

[PPS06-P08] セレスの衝突盆地を汚染した二次クレーター

*豊川 広晴^1,2、春山 純一^1,2、渡邊 広夢³、岩田 隆浩^1,2、三宅 亙³ (1.総合研究大学院大学、2.宇宙科学研究所、3.東海大学 工学部 航空宇宙学科 航空宇宙専攻)

キーワード：セレス、クレーター

The size distribution of projectiles onto Ceres is likely to be similar to that onto the lunar surface. The kilometer-scaled Crater Size Frequency Distributions (CSFDs) for floors of 18 impact basins on Ceres have been studied to examine their similarity. For 10 out of the 18 impact basins’ floors, the CSFDs are consistent with a crater production function (PF) that was modeled based on the lunar cratering record. For 8 floors, however, the CSFDs do not appear to be consistent with the PF model. We hypothesize that those floors are contaminated by secondary craters. We extracted secondary craters for the 8 floors and then investigated the direction of their distribution to identify the parent craters of their sources. In addition, we again plotted the CSFDs for the 8 basins’ floors after disregarding areas dominantly occupied by secondary craters. As a result, we identified the parent craters for the contaminating secondary craters. Furthermore, the deviations from the PF model got smaller for the replotted CSFDs than for the original CSFDs. In conclusion, the impact basins’ floors whose CSFDs deviate from the PF model are likely to be contaminated by secondary craters.