兵頭龍樹研究員および玄田英典准教授の研究成果が、The Astrophysical Journal Lettersに掲載されました。(2018年4月2日)
論文タイトル: Implantation of Martian Materials in the Inner Solar System by a Mega Impact on Mars
Observations and meteorites indicate that the Martian materials are enigmatically distributed within the inner solar system. A mega impact on Mars creating a Martian hemispheric dichotomy and the Martian moons can potentially eject Martian materials. A recent work has shown that the mega-impact-induced debris is potentially captured as the Martian Trojans and implanted in the asteroid belt. However, the amount, distribution, and composition of the debris has not been studied. Here, using hydrodynamic simulations, we report that a large amount of debris (~1% of Mars' mass), including Martian crust/mantle and the impactor's materials (~20:80), are ejected by a dichotomy-forming impact, and distributed between ~0.5-3.0 au. Our result indicates that unmelted Martian mantle debris (~0.02% of Mars' mass) can be the source of Martian Trojans, olivine-rich asteroids in the Hungarian region and the main asteroid belt, and some even hit the early Earth. The evidence of a mega impact on Mars would be recorded as a spike of 40Ar-39Ar ages in meteorites. A mega impact can naturally implant Martian mantle materials within the inner solar system.
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