Portal de Periódicos da CAPES

Itokawa Dust Particles: A Direct Link Between S-Type Asteroids and Ordinary Chondrites

2011; American Association for the Advancement of Science; Volume: 333; Issue: 6046 Linguagem: Inglês

10.1126/science.1207758

1095-9203

Tomoki Nakamura, T. Noguchi, Masahiko Tanaka, M. E. Zolensky, Makoto Kimura, A. Tsuchiyama, Aiko Nakato, T. Ogami, H. Ishida, Masayuki Uesugi, Toru Yada, K. Shirai, Akio Fujimura, Ryuji Okazaki, Scott A. Sandford, Yukihiro Ishibashi, Masanao Abe, Tatsuaki Okada, Munetaka Ueno, Toshifumi Mukai, Makoto Yoshikawa, Jun’ichiro Kawaguchi,

High-pressure geophysics and materials

The Hayabusa spacecraft successfully recovered dust particles from the surface of near-Earth asteroid 25143 Itokawa. Synchrotron-radiation x-ray diffraction and transmission and scanning electron microscope analyses indicate that the mineralogy and mineral chemistry of the Itokawa dust particles are identical to those of thermally metamorphosed LL chondrites, consistent with spectroscopic observations made from Earth and by the Hayabusa spacecraft. Our results directly demonstrate that ordinary chondrites, the most abundant meteorites found on Earth, come from S-type asteroids. Mineral chemistry indicates that the majority of regolith surface particles suffered long-term thermal annealing and subsequent impact shock, suggesting that Itokawa is an asteroid made of reassembled pieces of the interior portions of a once larger asteroid.