Publication Date:
2011-08-27
Description:
A single grain (~3 micrograms) returned by the Hayabusa spacecraft was analyzed by neutron activation analysis. This grain is mainly composed of olivine with minor amounts of plagioclase, troilite, and metal. Our results establish that the Itokawa sample has similar chemical characteristics (iron/scandium and nickel/cobalt ratios) to chondrites, confirming that this grain is extraterrestrial in origin and has primitive chemical compositions. Estimated iridium/nickel and iridium/cobalt ratios for metal in the Itokawa samples are about five times lower than CI carbonaceous chondrite values. A similar depletion of iridium was observed in chondrule metals of ordinary chondrites. These metals must have condensed from the nebular where refractory siderophile elements already condensed and were segregated.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ebihara, M -- Sekimoto, S -- Shirai, N -- Hamajima, Y -- Yamamoto, M -- Kumagai, K -- Oura, Y -- Ireland, T R -- Kitajima, F -- Nagao, K -- Nakamura, T -- Naraoka, H -- Noguchi, T -- Okazaki, R -- Tsuchiyama, A -- Uesugi, M -- Yurimoto, H -- Zolensky, M E -- Abe, M -- Fujimura, A -- Mukai, T -- Yada, Y -- New York, N.Y. -- Science. 2011 Aug 26;333(6046):1119-21. doi: 10.1126/science.1207865.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Chemistry, Tokyo Metropolitan University, Hachioji, Tokyo 192-0397, Japan. ebihara-mitsuru@tmu.ac.jp〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/21868669" target="_blank"〉PubMed〈/a〉
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
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Chemistry and Pharmacology
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Computer Science
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Medicine
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Natural Sciences in General
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Physics
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