[U-06_28PM1] New Progress toward the Understanding of Small Solar System Bodies

[U06-16] Examination of the origin of carbonaceous particles in Hayabusa-returned samples

*Masayuki UESUGI¹, Hiroshi NARAOKA², Motoo ITO³, Hikaru YABUTA⁴, Fumio KITAJIMA², Yoshinori TAKANO³, Hajime MITA⁵, Yoko KEBUKAWA⁶, Toru YADA¹, Yuzuru KAROUJI¹, Yukihiro ISHIBASHI¹, Wataru SATAKE⁷, Tatsuaki OKADA¹, Masanao ABE¹ (1.Japan aerospace exploration agency, 2.Department of Earth and Planetary Sciences, Kyushu University, 3.Kochi Institute for Core Sample Research JAMSTEC, 4.Osaka University, Department of Earth and Space Science, 5.Fukuoka Institute of Technoology, Faculity of Engineering, Department of Life, Environment and Mater, 6.Department of Natural History Sciences Hokkaido University, 7.Department of Earth and Planetary Science, University of Tokyo)

Extraterrestrial Sample Curation Team (ESCuTe) recovered more than 50 carbonaceous particles from the sample catcher of the Hayabusa spacecraft. Those carbonaceous materials, named as category 3, were found in the form of particles with similar size range of the silicate particles those confirmed as Itokawa regolith particles. Initial description by the SEM-EDS analysis shows variable textures and chemical compositions of them, suggesting the multiple origins of the carbonaceous materials. Preliminary examinations of category 3 particles were carefully processed in parallel with those of silicate materials. However, we could not obtain the information for the origin of category 3 particles before the opening of international announcement of opportunity (A/O). The ESCuTe and preliminary examination team of category 3 particles have continued the investigations. In this paper, we report the several recent results obtained from the sequential analyses. Samples allocated for the preliminary examinations of category 3 are RA-QD02-0008, RA-QD02-0120, RA-QD02-0180, RB-QD04-0001, RB-QD04-0037-01 and RB-QD04-0047-02. RA-QD02-0008 was lost during the manipulation at first preliminary examination. Three samples, RA-QD02-0120, RB-QD04-0001, and RB-QD04-0047-02, were pressed on the Au plate and fixed without any adhesive materials. We analyzed H, C and N isotopic composition by nano-SIMS in the beginning of the sequential study, in order to investigate the isotopic anomaly which is a direct evidence of extraterrestrial origin of organic materials [8]. FT-IR and micro-Raman spectroscopy were also applied for the pressed samples [9]. After ToF-SIMS analysis of those particles, the samples were sliced by FIB in order to investigate the fine structure of the samples by XANES and TEM/STEM [10]. We performed those analyses with determining the effect on the subsequent analyses, such as sample damages and contaminations. The rest two particles, RA-QD02-0180 and RB-QD04-0037-01 were pressed on indium plates, because significant disturbance by Au on the ToF-SIMS analyses was found. We will also report the construction of the sequential analysis flow of tiny carbonaceous particles. In parallel with the Hayabusa-returned particles, we processed observation and analysis of insoluble organic matter (IOM) of A881458 (CM2) and several possible materials of the origin of the category 3 particles, such as viton, silicon rubber, vectran and particles collected from the Hayabusa2 clean room. We did not obtain any signature of extraterrestrial origin from category 3 particles so far. We are planning to continue the preliminary examination of category 3 by the end of March 2014. We are also planning to open the category 3 particles to the future International A/O, with the data of preliminary examinations before the end of 2014.References: [1] Yada et al. 2011. Meteoritics & Planetary Science 32:A74. [2] Nakamura et al. 2011. Science 333:1113-1116. [3] Yurimoto et al. 2011. Science 333:1116-1119. [4] Ebihara et al. 2011. Science 333:1119-1121. [5] Noguchi et al. (2011) Science 333:1121-1125. [6] Tsuchiyama et al. 2011. Science 333:1125-1128. [7] Nagao et al. 2011. Science 333:1128-1131. [8] Ito et al. 2013. Abstract of Hayabusa Symposium, [9] Kitajima et al., 2013 Abstract of Hayabusa Symposium, [10] Uesugi et al. 2013. Abstract of Hayabusa Symposium