[P-PS03] 太陽系小天体：太陽系の形成と進化における最新成果と今後の展望

[PPS03-22] The discovery of the source of the EL meteorites.

*Chrysa Avdellidou¹、Marco Delbo¹、Alessandro Morbidelli¹、Kevin J. Walsh²、Edhah Munaibari¹、Joules Bourdelle de Micas³、Maxime Devogele⁴、Sonia Fornasier³、Matthiew Gounelle⁵、Gerard van Belle⁶ (1.Observatoire de la Cote dAzur、2.Southwest Research Institute、3.LESIA, Observatoire de Paris, MEUDON、4.Arecibo Observatory、5.Museum National dHistoire Naturelle、6.Lowell Observatory)

キーワード：asteroid families, enstatite meteorites, spectroscopy

The identification of meteorite parent bodies provides the context for understanding planetesimal formation and evolution as well as the key Solar System events they have witnessed. We identified that the asteroid family of Athor that is located in the inner main belt is the unique source of the rare EL enstatite chondrite meteorites. EL meteorites are closest meteorites to Earth in terms of their isotopic ratios. The Athor family was created by the collisional fragmentation of a parent body 3 Gyr ago in the inner main belt. We calculate that the diameter of the Athor family progenitor was 64 km in diameter, much smaller than the putative size of the EL original planetesimal. Therefore, we deduce that the EL planetesimal that accreted in the terrestrial planet region underwent a first catastrophic collision in that region, and one of its fragments suffered a more recent catastrophic collision in the main belt, generating the current source of the EL meteorites.