STXM-XANES analyses of Murchison meteorite samples captured by aerogel after hypervelocity impacts: A potential implication of organic matter degradation for micrometeoroid collection experiments

Journal Article · 01 January 2019 · Geochemical Journal

DOI: https://doi.org/10.2343/geochemj.2.0549 · OSTI ID:1542351

Kebukawa, Yoko ^[1]; Okudaira, Kyoko ^[2]; Yabuta, Hikaru ^[3]; Hasegawa, Sunao ^[4]; Tabata, Makoto ^[5]; Furukawa, Yoshihiro ^[6]; Ito, Motoo ^[7]; Nakato, Aiko ^[4]; Kilcoyne, A. L. David ^[8]; Kobayashi, Kensei ^[1]; Yokobori, Shin-ichi ^[9]; Imai, Eiichi ^[10]; Kawaguchi, Yuko ^[9]; Yano, Hajime ^[4]; Yamagishi, Akihiko ^[9]

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1. Yokohama National Univ., Yokohama (Japan)
2. Univ. of Aizu, Fukushima (Japan)
3. Hiroshima Univ., Hiroshima (Japan)
4. Japan Aerospace Exploration Agency, Sagamihara, Kanagawa (Japan). Inst. of Space and Astronautical Science (ISAS)
5. Chiba Univ., Chiba (Japan)
6. Tohoku Univ., Sendai (Japan)
7. Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Kochiu (Japan). Kochi Inst. for Core Sample Research
8. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Advanced Light Source (ALS)
9. Tokyo Univ. of Science, Tokyo (Japan). Dept. of Applied Life Sciences
10. Nagaoka Univ. of Technology, Nagaoka (Japan)

The Tanpopo mission is an astrobiology space experiment at the Japanese Experiment Module (JEM) 'Kibo' on the International Space Station (ISS). One of the sub-divided themes of the Tanpopo mission is for the intact capture of organic bearing micrometeoroids in low Earth orbit using ultralow density silica aerogel (0.01 g/cm³). In order to evaluate damage to organic matter in micrometeoroids during hyper velocity impacts into the aerogel, Murchison meteorite powdered samples, analogs of organic bearing micrometeoroids, were fired into flight-grade silica aerogel (0.01 g/cm³) using a two-stage light-gas gun with velocities of 4.4 and 5.9 km/s. The recovered Murchison grains were analyzed using scanning transmission X-ray microscopy/X-ray absorption near edge structure (STXM/XANES), transmission electron microscopy (TEM) and nanoscale secondary ion mass spectrometry (NanoSIMS). TEM observation did not show significant modifications of the recovered Murchison grains. Carbon-XANES spectra, however, showed a large depletion of the organic matter after the 5.9 km/s impact, but no such effects nor any significant hydrogen isotopic fractionation were observed after the 4.4 km/s impact.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• Grant/Contract Number: AC02-05CH11231
• OSTI ID: 1542351
• Journal Information: Geochemical Journal, Vol. 53, Issue 1; ISSN 0016-7002
• Publisher: Geochemical Society of JapanCopyright Statement
• Country of Publication: United States
• Language: English