X-ray Fluorescence Spectrometry of Asteroid Itokawa by Hayabusa
Abstract
X-ray fluorescence spectrometry of asteroid 25143 Itokawa was performed by the x-ray spectrometer onboard Hayabusa during the first touchdown on 19 November 2005. We selected those data observed during relatively enhanced solar activity and determined average elemental mass ratios of Mg/Si = 0.78 ± 0.09 and Al/Si = 0.07 ± 0.03. Our preliminary results suggest that Itokawa has a composition consistent with that of ordinary chondrites, but primitive achondrites cannot be ruled out. Among ordinary chondrites, LL- or L-chondrites appear to be more likely than H-chondrites. No substantial regional difference was found on the asteroid surface, indicating its homogeneity in composition.
Get full access to this article
View all available purchase options and get full access to this article.
Already a Subscriber?Sign In
Supplementary Material
File (okada.som.pdf)
References and Notes
1
R. P. Binzel, A. S. Rivkin, S. J. Bus, J. M. Sunshine, T. H. Burbine, Meteorit. Planet. Sci.36, 1167 (2001).
2
M. J. Gaffey et al., Icarus106, 573 (1993).
3
J. Kawaguchi, H. Kuninaka, A. Fujiwara, K. T. Uesugi, Proc. 5th IAA Int. Conf. Low-Cost Planetary Missions, Noordwijk, Netherlands, 24 to 26 September 2003, ESA SP-542 25 (2003).
4
A. Fujiwara et al., Science312, 1330 (2006).
5
T. Okada, M. Kato, A. Fujimura, H. Tsunemi, S. Kitamoto, Adv. Space Res.23, 345 (1999).
6
T. Okada et al., Adv. Geosci., in press.
7
I. J. Adler, J. I. Trombka, Phys. Chem. Earth10, 10 (1977).
8
J. I. Trombka et al., Science289, 2101 (2000).
9
M. Grande et al., Planet. Space Sci.51, 427 (2003).
10
T. Okada, M. Kato, A. Fujimura, H. Tsunemi, S. Kitamoto, Adv. Space Res.25, 1833 (2000).
11
S. Solomon et al., Planet. Space Sci.49, 1445 (2001).
12
R. Grard, A. Balogh, Planet. Space Sci.49, 1395 (2001).
13
K. Miyaguchi et al., Nucl. Instrum. MethodsA436, 24 (1999).
14
I. J. Adler, J. I. Trombka, P. Gorenstein, Anal. Chem.44, 28a (1972).
15
J. I. Trombka et al., J. Geophys. Res.102, 23729 (1997).
16
Y. Yamamoto, T. Arai, T. Okada, K. Shirai, M. Kato, Proc. ISAS Lunar Planet. Symp.36, 286 (2003).
17
T. Arai, Y. Yamamoto, T. Okada, K. Shirai, M. Kato, Proc. ISAS Lunar Planet. Symp.36, 282 (2003).
18
T. Okada et al., Lunar Planet. Sci Conf.36, 1175 (2005).
19
The solar geophysical database (www.sec.noaa.gov/ftpmenu/plots.html) shows that the solar x-ray flux was faint, classified as “very low,” from mid-September to early November. During almost all of that period, it was equal to or below the lower limit of detection.
20
Y. Kuwada, T. Okada, H. Mizutani, Proc. 30th ISAS Lunar Planet. Symp.30, 212 (1997).
21
M. Kaasalainen et al., Astron. Astrophys.405, L29 (2003).
22
J. Saito et al., Science312, 1341 (2006).
23
H. Demura et al., Science312, 1347 (2006).
24
E. Masuda, thesis, Tokyo Institute of Technology (2002).
25
L. Nittler et al., Meteorit. Planet. Sci.36, 1673 (2001).
26
E. Jarosewich, Meteoritics25, 332 (1990).
27
M. Abe et al., Science312, 1334 (2006).
28
P. A. Abell, F. Vilas, K. S. Jarvis, M. J. Gaffey, M. S. Kelley, Lunar Planet. Sci Conf.37, 1513 (2006).
29
T. J. McCoy et al., Meteorit. Planet. Sci.36, 1661 (2001).
30
We thank R. P. Binzel and the anonymous reviewer for constructive comments and fruitful discussions. The Hayabusa mission was organized by the Institute of Space and Astronautical Sciences, Japan Aerospace Exploration Agency. The XRS was manufactured by Meisei Electric Co. in Japan.
Information & Authors
Information
Published In
Science
Volume 312 | Issue 5778
2 June 2006
2 June 2006
Copyright
American Association for the Advancement of Science.
Submission history
Received: 2 February 2006
Accepted: 20 April 2006
Published in print: 2 June 2006
Authors
Metrics & Citations
Metrics
Article Usage
Altmetrics
Citations
Export citation
Select the format you want to export the citation of this publication.
Cited by
- Heavy Metal and Rock in Space: Cluster RAPID Observations of Fe and Si, Journal of Geophysical Research: Space Physics, 126, 3, (2021).https://doi.org/10.1029/2020JA028852
- Retraction, Science, 345, 6202, (1254-1254), (2021)./doi/10.1126/science.345.6202.1254-a
- Itokawa Dust Particles: A Direct Link Between S-Type Asteroids and Ordinary Chondrites, Science, 333, 6046, (1113-1116), (2021)./doi/10.1126/science.1207758
- Irradiation History of Itokawa Regolith Material Deduced from Noble Gases in the Hayabusa Samples, Science, 333, 6046, (1128-1131), (2021)./doi/10.1126/science.1207785
- Neutron Activation Analysis of a Particle Returned from Asteroid Itokawa, Science, 333, 6046, (1119-1121), (2021)./doi/10.1126/science.1207865
- Near-Infrared Spectral Results of Asteroid Itokawa from the Hayabusa Spacecraft, Science, 312, 5778, (1334-1338), (2021)./doi/10.1126/science.1125718
- Touchdown of the Hayabusa Spacecraft at the Muses Sea on Itokawa, Science, 312, 5778, (1350-1353), (2021)./doi/10.1126/science.1126164
- The Rubble-Pile Asteroid Itokawa as Observed by Hayabusa, Science, 312, 5778, (1330-1334), (2021)./doi/10.1126/science.1125841
- Adventures in Near-Earth Object Exploration, Science, 312, 5778, (1328-1329), (2021)./doi/10.1126/science.1128496
- Mass and Local Topography Measurements of Itokawa by Hayabusa, Science, 312, 5778, (1344-1347), (2021)./doi/10.1126/science.1126272
Loading...
View Options
Get Access
Log in to view the full text
AAAS login provides access to Science for AAAS Members, and access to other journals in the Science family to users who have purchased individual subscriptions.
- Become a AAAS Member
- Activate your AAAS ID
- Purchase Access to Other Journals in the Science Family
- Account Help
Log in via OpenAthens.
Log in via Shibboleth.
More options
Purchase digital access to this article
Download and print this article for your personal scholarly, research, and educational use.
Buy a single issue of Science for just $15 USD.
View options
PDF format
Download this article as a PDF file
Download PDF