Neutron activation analysis of a particle returned from asteroid Itokawa

M. Ebihara; S. Sekimoto; N. Shirai; Y. Hamajima; M. Yamamoto; K. Kumagai; Y. Oura; T. R. Ireland; F. Kitajima; K. Nagao; T. Nakamura; H. Naraoka; T. Noguchi; R. Okazaki; A. Tsuchiyama; M. Uesugi; H. Yurimoto; M. E. Zolensky; M. Abe; A. Fujimura; T. Mukai; Y. Yada

doi:10.1126/science.1207865

Neutron activation analysis of a particle returned from asteroid Itokawa

M. Ebihara^*, S. Sekimoto, N. Shirai, Y. Hamajima, M. Yamamoto, K. Kumagai, Y. Oura, T. R. Ireland, F. Kitajima, K. Nagao, T. Nakamura, H. Naraoka, T. Noguchi, R. Okazaki, A. Tsuchiyama, M. Uesugi, H. Yurimoto, M. E. Zolensky, M. Abe, A. FujimuraT. Mukai, Y. Yada

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

58 Citations (Scopus)

Abstract

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.

Original language	English
Pages (from-to)	1119-1121
Number of pages	3
Journal	Science
Volume	333
Issue number	6046
DOIs	https://doi.org/10.1126/science.1207865
Publication status	Published - 26 Aug 2011

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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., ... Yada, Y. (2011). Neutron activation analysis of a particle returned from asteroid Itokawa. Science, 333(6046), 1119-1121. https://doi.org/10.1126/science.1207865

@article{23e165322c88458ea496cec15aa3d172,

title = "Neutron activation analysis of a particle returned from asteroid Itokawa",

abstract = "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.",

author = "M. Ebihara and S. Sekimoto and N. Shirai and Y. Hamajima and M. Yamamoto and K. Kumagai and Y. Oura and Ireland, {T. R.} and F. Kitajima and K. Nagao and T. Nakamura and H. Naraoka and T. Noguchi and R. Okazaki and A. Tsuchiyama and M. Uesugi and H. Yurimoto and Zolensky, {M. E.} and M. Abe and A. Fujimura and T. Mukai and Y. Yada",

year = "2011",

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doi = "10.1126/science.1207865",

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Ebihara, M, Sekimoto, S, Shirai, N, Hamajima, Y, Yamamoto, M, Kumagai, K, Oura, Y, Ireland, TR, Kitajima, F, Nagao, K, Nakamura, T, Naraoka, H, Noguchi, T, Okazaki, R, Tsuchiyama, A, Uesugi, M, Yurimoto, H, Zolensky, ME, Abe, M, Fujimura, A, Mukai, T & Yada, Y 2011, 'Neutron activation analysis of a particle returned from asteroid Itokawa', Science, vol. 333, no. 6046, pp. 1119-1121. https://doi.org/10.1126/science.1207865

TY - JOUR

T1 - Neutron activation analysis of a particle returned from asteroid Itokawa

AU - Ebihara, M.

AU - Sekimoto, S.

AU - Shirai, N.

AU - Hamajima, Y.

AU - Yamamoto, M.

AU - Kumagai, K.

AU - Oura, Y.

AU - Ireland, T. R.

AU - Kitajima, F.

AU - Nagao, K.

AU - Nakamura, T.

AU - Naraoka, H.

AU - Noguchi, T.

AU - Okazaki, R.

AU - Tsuchiyama, A.

AU - Uesugi, M.

AU - Yurimoto, H.

AU - Zolensky, M. E.

AU - Abe, M.

AU - Fujimura, A.

AU - Mukai, T.

AU - Yada, Y.

PY - 2011/8/26

Y1 - 2011/8/26

N2 - 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.

AB - 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.

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U2 - 10.1126/science.1207865

DO - 10.1126/science.1207865

M3 - Article

SN - 0036-8075

VL - 333

SP - 1119

EP - 1121

JO - Science

JF - Science

IS - 6046

ER -

Neutron activation analysis of a particle returned from asteroid Itokawa

Abstract

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