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Accueil > Séminaires > Séminaires passés > Seminaires de 2012 > Tomoki Nakamura (Department of Earth and Planetary Materials Science - Faculty of Science - Tohoku University)

The First Recovery of Asteroidal Samples by the Japanese Hayabusa Mission — What comes to be known from the analysis of the returned samples

Tomoki Nakamura (Department of Earth and Planetary Materials Science - Faculty of Science - Tohoku University)

Lundi 11 juin 14h

Japanese spacecraft Hayabusa successfully returned many small particles from the surface of S-type Asteroid Itokawa. The sample return took 7 years from 2003 (launch of rocket) to 2010 (sample capsule return to the Earth). In addition, it further took another 6 months to identify asteroid particles in the capsule because of their small size. However, the outcome from the analysis of these small particles is very large. The mienral chemistry of the particles demostrates that S-type asteroids consist of rocks that are identical to primitive meteorites (ordinary chondrites), which provides a direct evidence connecting asteroids and meteorites. The mineral thermometry suggests that particles formed by prolonged heating at 800C. This indicates that asteroid Itokawa was once a larger asteroid more than 20Km in diameter but the parent asteroid was later disrupted by a heavy imapact. The rock fragments were reassembled into a small rubble-pile asteroid to form current Itokawa.