RAMAN SPECTROSCOPICAL INVESTIGATIONS ON
RETRURNED PARTICLES FROM THE ASTEROID
ITOKAWA (JAXA HAYABUSA MISSION).
V.H. Hoffmann1,2; M. Kaliwoda3; R. Hochleitner3; T. Mikouchi4;
M. Komatsu5; K. Hagiya6; K. Ohsumi7; M. Zolensky8; J. Martinez9; Y. Terada7; N. Yagi7; M. Takata7; W. Satake4; Y. Aoyagi4;
A. Takenouchi4; Y. Karouji10; M. Uesugi10; T. Yada10. 1Fac.
Geosciences, Dep. Geo- and Environm. Sciences, Univ.
Muenchen; 2Dep. Geosciences, Univ. Tuebingen. Emaillavho@web.de; 3Mineralogical State Collection, Muenchen,
Germany; 4Dep. Earth and Planetary Science, The University ofTokyo, Japan; 5Waseda Inst. Advanced Study, Waseda Univ.,
Japan; 6School of Science, Univ. Hyogo, Japan; 7Japan Synchrotron Radiation Research Institute (JASRI), Japan; 8Astromaterials
Research and Exploration Science, NASA-JSC, USA; 9ESCG
Jacobs, USA; 10Inst. Space and Astronautical Science, Japan
Aerospace Exploration Agency (JAXA), Japan.
Introduction: Numerous particles of the asteroid Itokawa havebeen successfully returned by the Hayabusa mission of JAXA in2010. The recovered particles have been first studied by the preliminary examination (PE) team and the obtained results are providing unique information about the formation and evolution ofasteroids or other small bodies in our solar system [1, and publications in this issue]. The mineral compositions and oxygen isotopes of the Itokawa particles are close to those of LL chondrites[1]. The samples have been distributed by JAXA as international
AO study after the PE, and our team received 3 PE and 4 newparticles. We have performed detailed studies on mineralogy andcrystallography of these particles [2]. In this contribution we willreport detailed results of our experiments by Raman Spectroscopy on three selected Itokawa particles.
Results: We could identify the following phases by LASER Micro Raman Spectroscopy: (1) Particle RA-QD02-0036: olivine,plagioclase, troilite, chromite and a whitlockite-merrillite phase.
The sharp and well developed Raman pattern of the plagioclase
phase indicate a weak shock stage of S1-2. (2) Particle RAQD02-0041: olivine, plagioclase and minor chromite. This particle is generally characterized by a very high fluorescence background. Again, the features of the plagioclase Raman pattern indicate a quite low shock stage. (3) Particle RA-QD02-0133-01:
this particle is dominated by olivine and plagioclase, we could
not detect any other phases. The shock stage was estimated by theRaman pattern as quite similar to the other two particles.
Summarizing our Raman Spectroscopy results, one can state that
all obtained spectra are of high quality. The sample material fromasteroid Itokawa does not show any significant weathering or alteration effects. For the first time we have absolutely fresh andnon-altered material from the surface of an asteroid in our hands,best suited for scientific investigations towards a much better understanding of the origin and development of meteorite parentbodies.
References: [1] Nakamura T. et al. (2011) Science, 333, 1113–1116, and further Hayabusa-related publications in this ScienceIssue. [2] Mikouchi T., and the Hayabusa Sample Project Consortium (2014). Mineralogy and crystallography of some Itokawa
particles returned by the Hayabusa asteroidal sample return mission. Earth, Planets and Space, 66/82.