9:30 AM - 9:45 AM
[PPS07-03] Collisional stripping of the rock mantle on the differentiated asteroid
Keywords:Small bodies, Impacts
The collisional event on asteroids is important to consider the debris producing many kinds of meteorites. The origin of the iron meteorites is thought to be made by impact-induced debris on a differentiated asteroid like Vesta. Those iron meteorites reaccumulate by their self-gravity and make rabble pile meteorites. The iron-rich rabble pile meteorite is considered an M-type asteroid (e.g., Psyche), formed from the differentiated asteroid that loses the rock material by the collision. The origin of iron meteorites is an important material for the formation history of planets with large iron cores. The differentiated asteroid is thought to have been formed by heating radiatively decayed elements. After the asteroid is differentiated, iron meteorites are ejected by the impact when the differentiated asteroid loses its rock material and iron core. However, the impact condition for the rock material loss or iron material ejection is unknown. In this study, we performed the smoothed particle hydrodynamical simulation of the impact event on the differentiated asteroid to determine the escaping mass of the rock and the iron material and calculated the impact simulation to consider the catastrophic disruption threshold. We find the total escaping mass can be represented by the specific impact energy normalized by the catastrophic disruption energy of the differentiated asteroid. On the other hand, the escaping rock or iron material can be normalized the catastrophic disruption energy of the rock mantle of the differentiated asteroid. The iron material begins to escape when the specific impact energy is larger than the catastrophic disruption energy of the rock because the rock material prevents the escaping of the iron material. Our finding suggests that the collisional stripping of the rock mantle of the differentiated asteroid keeps the iron material selectively.