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Seminars at FGG

Origin of meteorites including the Almahata-Sitta meteorite and the 2008 TC3 asteroid.

Speaker: Marco Delbo (UNS.CNRS)

Date and time: 2012-03-09 11:00

2008 TC3 was a Near Earth Asteroid (NEA) that impacted the Earth on October 7, 2008. Meteorites were produced by the break up of 2008 TC3 in the high atmosphere and at present, about 600 meteorites - called Almahata Sitta - coming from 2008 TC3 have been recovered. A mineralogical study of Almahata Sitta fragments shows that the asteroid 2008 TC3 was made of meteorites of different types (ureilites, H, L, and E chondrites). Understanding the origin of this body and how it was put together remain a challenge. Here we show that asteroids with spectroscopic classes that can be associated with the different meteorite types of Almahata Sitta are present in the region of the inner Main Belt. We also discuss a plausible explanation of how asteroid 2008 TC3 was formed by low velocity collisions between asteroids of different mineralogies. This mechanism might also explain the mixing of different mineralogies during regolith gardening and the presence of foreign clasts observed - albait rarely - in some other meteorites such as Kaidun and the CB/CH-like meteorite Isheyevo.