Incipient space weathering observed on the surface of itokawa dust particles

T. Noguchi, T. Nakamura, M. Kimura, M. E. Zolensky, M. Tanaka, T. Hashimoto, M. Konno, A. Nakato, T. Ogami, A. Fujimura, M. Abe, T. Yada, T. Mukai, M. Ueno, T. Okada, K. Shirai, Y. Ishibashi, R. Okazaki

Research output: Contribution to journalArticle

169 Citations (Scopus)

Abstract

The reflectance spectra of the most abundant meteorites, ordinary chondrites, are different from those of the abundant S-type (mnemonic for siliceous) asteroids. This discrepancy has been thought to be due to space weathering, which is an alteration of the surfaces of airless bodies exposed to the space environment. Here we report evidence of space weathering on particles returned from the S-type asteroid 25143 Itokawa by the Hayabusa spacecraft. Surface modification was found in 5 out of 10 particles, which varies depending on mineral species. Sulfur-bearing Fe-rich nanoparticles exist in a thin (5 to 15 nanometers) surface layer on olivine, low-Ca pyroxene, and plagioclase, which is suggestive of vapor deposition. Sulfur-free Fe-rich nanoparticles exist deeper inside (<60 nanometers) ferromagnesian silicates. Their texture suggests formation by metamictization and in situ reduction of Fe 2+.

Original languageEnglish
Pages (from-to)1121-1125
Number of pages5
JournalScience
Volume333
Issue number6046
DOIs
Publication statusPublished - Aug 26 2011

All Science Journal Classification (ASJC) codes

  • General

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