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Fig. 2(Color online) Experimental set up for X­ray diraction
analysis at SPring­8. The Gandol camera is modied tohave a long camera length for high resolution in diraction
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Fig. 3Electron­microscope image of a Itokawa particle RA_QD02_0013.

Fig. 4

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X­ray diraction pattern of a Itokawa particle RA_QD02_0013 taken at SPring­8.

Fig. 7(Color online) Average olivine and low­Ca pyroxene com­position of Itokawa dust particles 1). The composition iswithin the compositional range of LL chondrite meteorites.

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ÒÐîºq÷kåwåw@Éw¤È ³ö
tomokim.tohoku.ac.jp
êåFf¯ÈwÉú¾zni»wmªðn
1991Nåwåw@wn¤Èz¨wêUCmÛöC¹C1994Nmiw)B
1993NãBåwwn f¯ÈwÈèC2001N¯³öC2010Nkåwåw@w¤Èy³öðoÄC2012N 1
æè»EBcëFÆ§s­@l¨¿ÉÞ¿¤@\ÉåÈGWjA
masahikospring8.or.jpêåFX üñÜ@É»\¢ðÍmªðn
1992Nåwåw@wn¤Èz¨wêUmÛöC¹Cmiw)BGlM[¨w¤úËõÀ±{ÝèðoÄC2004N 4 æè»EBSynchrotron X­ray diraction analysis andelectron microscopy of Itokawa dust particles
recovered by the spacecraft Hayabusa
Tomoki NAKAMURADepartment of Earth and Planetary Material Sciences, Graduate School ofScience, Tohoku University
Aramaki, Aoba, Sendai, Miyagi 980_8578, Japan

Masahiko TANAKAWEBRAM, National Institute for Materials Science Synchrotron X­ray Stationat SPring­8
1_1_1 Kouto, Sayo, Hyogo, 679_5148, JapanAbstract

Hayabusa spacecraft has successfully recovered many dust particles from S­type asteroid Itoka­
wa. We performed analyses of these dust particles using synchrotron­radiation X­rays and elec­tron microscopes and found that the asteroid is a very primitive, chemically­unfractionated bodythat formed in the early solar system. After formation as a 20­km size body, the internal tempera­ture increased up to approximately 800C and slowly cooled down. The present Itokawa is anasteroid made of broken pieces of an inner part of the pre­existing larger asteroid.

úËõ Nov. 2012 Vol.25 No.6  341