X-RAY ABSORPTION SPECTROSCOPIC STUDY OF
CARBONACEOUS MATERIALS FROM HAYABUSARETURNED SAMPLES.
H. Yabuta1, M. Uesugi2, H. Naraoka3, M. Ito4, D. Kilcoyne5, S. A.
Sandford6, F. Kitajima3, H. Mita7, Y. Takano4, T. Yada2, Y.
Karouji2, Y. Ishibashi2, T. Okada2, and M. Abe2. 1Osaka
University, Japan. 2 JAXA/ISAS. 3Kyushu University, Japan.
4
JAMSTEC. 5Advanced Light Source, LBNL, USA. 6NASA
Ames, USA. 7Fukuoka Inst. Tech. Japan.
E-mail: hyabuta@ess.sci.osaka-u.ac.jp
Introduction: At the Planetary Material Sample Curation
Facility of JAXA (PMSCF/JAXA), several tens of carbonaceous
particles of unknown origin have been collected from the sample
catcher and classified as Category 3, in addition to the asteroid
particles investigated (Categories 1 and 2) [1, 2]. In order todetermine whether the materials are terrestrial or extraterrestrial,
we have analyzed the functional group compositions of theCategory 3 particles by a scanning transmission X-ray
microscope (STXM) using X-ray absorption near edge structure(XANES) spectroscopy.
Samples and methods: In this study, four Category 3
carbonaceous samples, RA-QD02-0120, RA-QD02-0180-02,
RB-QD04-0037-01-02, RB-QD04-0047-02, were investigated.
RA-QD02-0120 and RB-QD04-0047-02 were also analyzed by
FE-SEM-EDS [1], micro-Raman, micro-FTIR, NanoSIMS [3],ToF-SIMS, and TEM [2]. The ultra-thin sections (100 nm thick)of the four samples were were fixed by pressing on gold (Au)plates, extracted by focused ion beam (FIB), and analyzed by
STXM, at beamline 5.3.2.2, Advanced Light Source (ALS),LBNL. Two different sections of RA-QD02-0120 before andafter TEM were analyzed by STXM.
Results and discussion: RA-QD02-0120 and RB-QD040047-02 show C-XANES spectra with the typical spectral
patterns of heterogeneous organic macromolecules: the set ofpeaks corresponding to aromatic/olefinic carbon, heterocyclic
nitrogen and/or nitrile, and carboxyl carbon. N-XANES spectraof the samples include the developed peak of heterocyclic
nitrogen and/or nitrile. Differences in C- and N-XANES spectraof RA-QD02-0120 before and after TEM were observed,
demonstrating that the carbonaceous materials are electron beam
sensitive. On the other hand, C-XANES spectrum of RB-QD040037-01-02 has the well-resolved three peaks of amide, carboxyls,
and urea/ether, in addition to an aromatic peak shifted to lower
energy (284.8 eV) by 0.3 eV from the two other samples (285.1eV). Its N-XANES shows a unusually high abundance ofheterocyclic nitrogen including R-NH-(C=O)-R’ as a peak at 401
eV. C-XANES spectrum of RA-QD02-0180-02 is very similar tothat of epoxy resin. N-XANES spectrum of this sample shows adeveloped peak at 401 eV.
Ca-XANES spectrum and mapping identified a calcium
carbonate grain from RA-QD02-0120 and RA-QD02-0180-02.
Ti- and Cl-XANES detected titanium and chloride grains fromRA-QD02-0180-02. Any fluorine-containing molecular species
are not detected from F-XANES of the particles. As one ofpossibilities, it is implied that the Category 3 functional groupfeatures may be reflected by degradation of polymer materials
used or contaminated in the Hayabusa spacecraft. Further
investigation will be necessary for identification of their sources.
References: [1] Yada et al. 2013. Meteoritics & Planetary
Science 49:135-153. [2] Uesugi et al. 2014. Earth Planets. Spacein press. [3] Ito et al. 2014. Earth Planets. Space 66:91.