H. Yabuta

Osaka University, Suika, Ōsaka, Japan

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Publications (84)208.77 Total impact

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    ABSTRACT: Three category 3 (organic) particles (RB-QD04-0001, RB-QD04-0047-02, and RA-QD02-0120) and so-called `white object' found in the sample container have been examined by micro-Raman and infrared (IR) spectroscopy. In addition, several artificial substances that could occur as possible contaminants and chondritic insoluble organic matter (IOM) prepared from the Murchison CM2 chondrite were analyzed. The Raman spectra of the particles show broad G-band and weak D-band. The G-band parameters plot in the disordered region and close to the artifact produced from a Viton glove after laser exposure rather than chondritic IOM. The particles were therefore originally at low maturity level, suggesting that they have not experienced strong heating and are therefore not related to the LL4-6 parent body. The IR spectra are not similar to that of chondritic IOM. Furthermore, the particles cannot be identified as some artificial carbonaceous substances, including the white object, which are the possible contaminants, examined in this investigation. Although it cannot be determined exactly whether the three category 3 particles are extraterrestrial, the limited IR and Raman results in this investigation strongly suggest their terrestrial origin. Although they could not be directly related to the artificial contaminants examined in this investigation, they may yet be reaction products from similar substances that flew on the mission. In particular, RB-QD04-0047-02 shows several infrared spectral absorption bands in common with the `white object.' This may relate to the degradation of a polyimide/polyamide resin.
    12/2015; 67(1). DOI:10.1186/s40623-015-0182-6
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    ABSTRACT: Three carbonaceous category 3 particles (RA-QD02-0180, RB-QD04-0037-01, and RB-QD04-0047-02) returned in the sample catcher from the Hayabusa spacecraft were analyzed by time of flight-secondary ion mass spectrometry (ToF-SIMS) to establish an analytical procedure for determination of their origins. By the different analytical schemes, the three particles gave distinct elemental and molecular ions, in which the organic carbons commonly appear to be associated with nitrogen, silicon, and/or fluorine. The particles could be debris of silicon rubber and fluorinated compounds and are therefore man-made artifacts rather than natural organic matter.
    12/2015; 67(1). DOI:10.1186/s40623-015-0224-0
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    ABSTRACT: We have investigated seven micrometeorites (MMs) from Antarctic snow collected in 2003 and 2010 by means of electron microscopy, X-ray diffraction, micro-Raman spectroscopy, transmission electron microscopy (TEM) observation, and noble-gas isotope analysis. Isotopic ratios of He and Ne indicate that the noble gases in these MMs are mostly of solar wind (SW). Based on the release patterns of SW 4He, which should reflect the degree of heating during atmospheric entry, the seven MMs were classified into three types including two least heated, three moderately heated, and two severely heated MMs. The heating degrees are well correlated to their mineralogical features determined by TEM observation. One of the least heated MMs is composed of phyllosilicates, whereas the other consists of anhydrous minerals within which solar flare tracks were observed. The two severely heated MMs show clear evidence of atmospheric heating such as partial melt of the uppermost surface layer in one and abundant patches of dendritic magnetite and Si-rich glass within an olivine grain in the other. It is noteworthy that a moderately heated MM composed of a single crystal of olivine has a 3He/4He ratio of 8.44 × 10-4, which is higher than the SW value of 4.64 × 10-4, but does not show a cosmogenic 21Ne signature such as 20Ne/21Ne/22Ne = 12.83/0.0284/1. The isotopic compositions of He and Ne in this sample cannot be explained by mixing of a galactic cosmic ray (GCR)-produced component and SW gases. The high 3He/4He ratio without cosmogenic 21Ne signature likely indicates the presence of a 3He-enriched component derived from solar energetic particles.
    11/2015; 67(1). DOI:10.1186/s40623-015-0261-8
  • Tetsuro Hirono · Yuka Maekawa · Hikaru Yabuta
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    ABSTRACT: To understand the mechanism of fault lubrication during the 1999 Taiwan Chi-Chi earthquake, we developed a new temperature proxy for carbonaceous materials by using infrared and Raman spectroscopies together with heating and friction experiments. We found marked anomalies in the infrared and Raman spectra of carbonaceous materials retrieved from the primary slip zone of the earthquake: the infrared spectra exhibited very weak aliphatic CH2 and CH3 peaks and aromatic C=C absorbance peaks, and the Raman spectra exhibited very weak disordered and graphitic bands and a high ratio of disordered band area to graphitic band area. Those weak peaks and bands and the band area ratio were reproduced by heating carbonaceous materials from the nearby host rock to 700 °C. These results suggest that the frictional heat in the slip zone reached approximately 700 °C. We characterized the host rock's carbonaceous materials by means of elemental analysis, pyrolysis–gas chromatography–mass spectrometry, and simultaneous thermogravimetry–differential scanning calorimetry and found that the H/C and O/C ratios were 0.108 and 0.400, respectively (which are close to the ratios for lignin) and that the volatile fraction was as high as 48 wt %. The pyrolysates obtained by heating from 100 to 400 °C were dominated by phenols, fatty alcohols, and n-alkanes. When the residue from pyrolysis at 100–400 °C was rapidly heated to 700 °C, the resulting pyrolysate was dominated by phenols, aromatic compounds, heterocyclic compounds, and n-alkenes. This information suggests that changes in the infrared and Raman spectra with increasing temperature may have been due to decomposition and aromatization reactions during pyrolysis. Rapid heating during earthquake slip may promote reactions of carbonaceous materials that are different from the reactions that occur during long-term metamorphism. This article is protected by copyright. All rights reserved.
    Geochemistry Geophysics Geosystems 04/2015; 16(5). DOI:10.1002/2014GC005622 · 3.05 Impact Factor
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    ABSTRACT: Tanpopo, a dandelion in Japanese, is a plant species whose seeds with floss are spread by wind. We propose this mission to examine possible interplanetary migration of microbes, and organic compounds at the Exposure Facility of Japan Experimental Module (JEM: KIBO) of the International Space Station (ISS). The Tanpopo mission consists of six subthemes: Capture of microbes in space (Subtheme 1), exposure of microbes in space (Subtheme 2), analysis of organic compounds in interplanetary dust (Subtheme 3), exposure of organic compounds in space (Subtheme 4), measurement of space debris at the ISS orbit (Subtheme 5), and evaluation of ultra low-density aerogel developed for the Tanpopo mission (Subtheme 6). “Sample Trays” for exposure of microbes and organic materials and “Sample Aerogel Panels” for aerogel will be launched. The trays and panels will be placed on the Exposed Experiment Handrail Attachment Mechanism (ExHAM) in the ISS. The ExHAM with trays and panels will be placed on the Exposure Facility of KIBO (JEM) with the Japanese robotic arms through the airlock of KIBO. The trays and panels will be exposed for more than one year and will be retrieved and returned to the ground for the analyses.
    Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan 12/2014; 12(ists29):Tk_49-Tk_55. DOI:10.2322/tastj.12.Tk_49
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    ABSTRACT: Analyses with a scanning transmission x-ray microscope (STXM) using x-ray absorption near edge structure (XANES) spectroscopy were applied for the molecular characterization of two kinds of carbonaceous particles of unknown origin, termed category 3, which were collected from the Hayabusa spacecraft sample catcher. Carbon-XANES spectra of the category 3 particles displayed typical spectral patterns of heterogeneous organic macromolecules; peaks corresponding to aromatic/olefinic carbon, heterocyclic nitrogen and/or nitrile, and carboxyl carbon were all detected. Nitrogen-XANES spectra of the particles showed the presence of N-functional groups such as imine, nitrile, aromatic nitrogen, amide, pyrrole, and amine. An oxygen-XANES spectrum of one of the particles showed a ketone group. Differences in carbon-and nitrogen-XANES spectra of the category 3 particles before and after transmission electron microscopic (TEM) observations were observed, which demonstrates that the carbonaceous materials are electron beam sensitive. Calcium-XANES spectroscopy and elemental contrast mapping identified a calcium carbonate grain from one of the category 3 particles. No fluorine-containing molecular species were detected in fluorine-XANES spectra of the particles. The organic macromolecular features of the category 3 particles were distinct from commercial and/or biological 'fresh (non-degraded)' polymers, but the category 3 molecular features could possibly reflect degradation of contaminant polymer materials or polymer materials used on the Hayabusa spacecraft. However, an extraterrestrial origin for these materials cannot currently be ruled out.
    Earth Planets and Space 12/2014; 66(1):156. DOI:10.1186/s40623-014-0156-0 · 3.06 Impact Factor
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    ABSTRACT: To estimate the slip parameters and understand the fault lubrication mechanism during the 1999 Taiwan Chi-Chi earthquake, we applied vitrinite reflectance geothermometry to samples retrieved from the Chelungpu fault. We found a marked reflectance anomaly of 1.30% ± 0.21% in the primary slip zone of the earthquake, whereas the reflectances in the surrounding deformed and host rocks were 0.45% to 0.77%. By applying a kinetic model of vitrinite thermal maturation together with a one-dimensional heat and thermal diffusion equation, we determined the shear stress and peak temperature in the slip zone during the earthquake to be 1.00 ± 0.04 MPa and 626°C ± 25°C, respectively. Taking into account the probable overestimation of the temperature owing to a mechanochemically enhanced reaction or flash heating at grain contacts, this temperature should be considered an upper limit. The lower limit was previously constrained to 400°C by studies of fluid-mobile trace-element concentrations and magnetic minerals. Therefore, we inferred that the peak temperature during the Chi-Chi earthquake was 400°C to 626°C, corresponding to an apparent friction coefficient of 0.01 to 0.06. Such low friction and the previous evidence of a high-temperature fluid suggest that thermal pressurization likely contributed to dynamic weakening during the Chi-Chi earthquake.
    Earth Planets and Space 11/2014; DOI:10.1186/1880-5981-66-28 · 3.06 Impact Factor
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    ABSTRACT: Preliminary results of the analyses of five carbonaceous materials (particle size of approximately 50 μm) from the Hayabusa spacecraft sample catcher, including their texture, chemistry, and chemical/isotopic compositions, are summarized. The carbonaceous particles underwent sequential analysis using a series of microanalytical instruments located at several research institutes and universities. Collected particles were initially classified into four categories: two categories containing extraterrestrial silicate particles, one category containing metal and quartz particles consistent with contamination from the sample catcher or sample manipulation tools, and a final category containing carbonaceous particles. Analysis of this final category was the main focus of this study. Through examination of the carbonaceous materials, the appropriate analytical processes for sample transportation and handling were optimized to minimize sample damage and terrestrial contamination. Particles were investigated by transmission electron microscopy/scanning transmission electron microscopy, and Ca-carbonate inclusions were found in one particle. In a different particle, a heterogeneous distribution of silicon in a uniform C, N, and O matrix was found. Though further analysis is required for a strict determination of particle origin, the differences in the microstructure and elemental distribution of the carbonaceous particles suggest multiple origins.
    11/2014; 66(1). DOI:10.1186/1880-5981-66-102
  • 77th Annual Meeting of the Meteoritical-Society; 09/2014
  • 77th Annual Meeting of the Meteoritical-Society; 09/2014
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    ABSTRACT: Preliminary results of the analyses of five carbonaceous materials (particle size of approximately 50 μm) from the Hayabusa spacecraft sample catcher, including their texture, chemistry, and chemical/isotopic compositions, are summarized. The carbonaceous particles underwent sequential analysis using a series of microanalytical instruments located at several research institutes and universities. Collected particles were initially classified into four categories: two categories containing extraterrestrial silicate particles, one category containing metal and quartz particles consistent with contamination from the sample catcher or sample manipulation tools, and a final category containing carbonaceous particles. Analysis of this final category was the main focus of this study. Through examination of the carbonaceous materials, the appropriate analytical processes for sample transportation and handling were optimized to minimize sample damage and terrestrial contamination. Particles were investigated by transmission electron microscopy/scanning transmission electron microscopy, and Ca-carbonate inclusions were found in one particle. In a different particle, a heterogeneous distribution of silicon in a uniform C, N, and O matrix was found. Though further analysis is required for a strict determination of particle origin, the differences in the microstructure and elemental distribution of the carbonaceous particles suggest multiple origins.
    Earth Planets and Space 08/2014; 66:102. · 3.06 Impact Factor
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    ABSTRACT: We are developing a silica-aerogel-based cosmic dust collector for use in the Tanpopo experiment to be conducted on the International Space Station. The mass production of simple two-layer hydrophobic aerogels was undertaken in a contamination-controlled environment, yielding more than 100 undamaged products. The collector, comprising an aerogel tile and holder panel, was designed to resist launch vibration and to conform to an exposure attachment. To this end, a box-framing aerogel with inner and outer densities of 0.01 and 0.03 g/cm$^3$, respectively, was fabricated. The aerogel mounted in the panel passed random vibration tests at the levels of the acceptance and qualification tests for launch. It also withstood the pressure changes expected in the airlock on the International Space Station.
    Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan 08/2014; 12(ists29):Pk_29-Pk_34. DOI:10.2322/tastj.12.Pk_29
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    ABSTRACT: Since isotopic ratios of H, C, and N are sensitive indicators for determining extraterrestrial organics, we have measured these isotopes of Hayabusa category 3 organic samples of RB-QD04-0047-02, RA-QD02-0120, and RB-QD04-0001 with ion imaging using a NanoSIMS ion microprobe. All samples have H, C, and N isotopic compositions that are terrestrial within errors (approximately ±50‰ for H, approximately ±9‰ for C, and approximately ±2‰ for N). None of these samples contain micrometer-sized hot spots with anomalous H, C, and N isotopic compositions, unlike previous isotope data for extraterrestrial organic materials, i.e., insoluble organic matters (IOMs) and nano-globules in chondrites, interplanetary dust particles (IDPs), and cometary dust particles. We, therefore, cannot conclude whether these Hayabusa category 3 samples are terrestrial contaminants or extraterrestrial materials because of the H, C, and N isotopic data. A coordinated study using microanalysis techniques including Fourier transform infrared spectrometry (FT-IR), time-of-flight secondary ion mass spectrometry (ToF-SIMS), NanoSIMS ion microprobe, Raman spectroscopy, X-ray absorption near edge spectroscopy (XANES), and transmission electron microscopy/scanning transmission electron microscopy (TEM/STEM) is required to characterize Hayabusa category 3 samples in more detail for exploring their origin and nature.
    Earth Planets and Space 08/2014; 66(1):102. DOI:10.1186/1880-5981-66-91 · 3.06 Impact Factor
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    ABSTRACT: We have proposed an experiment (the Tanpopo mission) to capture microbes on the Japan Experimental Module of the International Space Station. An ultra low-density silica aerogel will be exposed to space for more than 1 year. After retrieving the aerogel, particle tracks and particles found in it will be visualized by fluorescence microscopy after staining it with a DNA-specific fluorescence dye. In preparation for this study, we simulated particle trapping in an aerogel so that methods could be developed to visualize the particles and their tracks. During the Tanpopo mission, particles that have an orbital velocity of ~8 km/s are expected to collide with the aerogel. To simulate these collisions, we shot Deinococcus radiodurans-containing Lucentite particles into the aerogel from a two-stage light-gas gun (acceleration 4.2 km/s). The shapes of the captured particles, and their tracks and entrance holes were recorded with a microscope/camera system for further analysis. The size distribution of the captured particles was smaller than the original distribution, suggesting that the particles had fragmented. We were able to distinguish between microbial DNA and inorganic compounds after staining the aerogel with the DNA-specific fluorescence dye SYBR green I as the fluorescence of the stained DNA and the autofluorescence of the inorganic particles decay at different rates. The developed methods are suitable to determine if microbes exist at the International Space Station altitude.
    Origins of Life and Evolution of Biospheres 08/2014; 44(1):43-60. DOI:10.1007/s11084-014-9361-x · 1.77 Impact Factor
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    ABSTRACT: Because a megasplay fault branching from the deep subduction boundary megathrust in the Nankai Trough is thought to be the source of large tsunamis associated with past Tonankai earthquakes, investigation of the heat signal due to frictional slip recorded in the fault is important for estimating the earthquake slip parameters. We performed X-ray diffraction and infrared spectroscopic analyses of a megasplay fault-rock sample and re-examined previously reported trace-element and isotope compositions, but observed no specific change related to high temperature (>= 250 degrees C). In addition, although a qualitative increase of the illite content in illite/smectite mixed-layer minerals within the slip-zone sample was previously reported, our kinetic evaluation of illitization, taking into consideration the coseismic temperature change due to frictional heating and heat conduction, revealed that the illitization reaction hardly progresses at temperatures under 250 degrees C. Alternatively, we suggest that the illite content in mixed-layer minerals might increase progressively via a comminution-dissolution-recrystallization process during multiple past slips. Accurate assessment of the slip behavior of the megasplay fault could be efficiently obtained by drilling to penetrate the fault zone at a deeper depth of approximately 1.5 km, where records of high temperatures would be detectable.
    Tectonophysics 06/2014; 626. DOI:10.1016/j.tecto.2014.04.020 · 2.87 Impact Factor
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    ABSTRACT: Enceladus is the only icy satellite known to exhibits on-going geological activity of water-rich plumes derived from the interior ocean. Here, we propose a sample return and in-situ measurement mission for Enceladus' plume materials. Depending on the cost, mission duration, and propulsion system, we propose three types of missions to Enceladus; type 1: free-return trajectory, type 2: trajectory orbiting Saturn, and type 3: trajectory orbiting Enceladus. Type 2 and 3 are preferable to type 1 in order to achieve lower encountering velocity to the plumes (> 4 km/s and 0.2 km/s for type 2 and 3, respectively) and, thus, to collect multiple and intact samples. High resolution mass spectroscopy of the gas components will provide essential information to understand the physical and chemical conditions of both the interior ocean and the solar nebula. Furthermore, detailed onboard and onshore analyses of returned samples could provide geochemical, preboplogical, and, potentially, biological context in the interior ocean of Enceladus.
    Transactions of the Japan Society for Aeronautical and Space Sciences, Aerospace Technology Japan 01/2014; 12(ists29):Tk_7-Tk_11. DOI:10.2322/tastj.12.Tk_7
  • Kasumi Sakata · Hikaru Yabuta · Tadashi Kondo
    Geochemical journal GJ 01/2014; 48(2):219-230. DOI:10.2343/geochemj.2.0300 · 1.94 Impact Factor
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    ABSTRACT: In order to discuss the possibility of delivery of organic compounds from space, alteration of prebiotic compounds in space environments should be clear. Therefore, we will expose some organic compounds on the exposure facility at ISS-JEM.
    International Astrobiology Workshop 2013, Sagamihara, Japan; 11/2013
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    ABSTRACT: As the first Japanese astrobiology experiment in space, the Tanpopo will test key concepts of the quasi-panspermia hypothesis by sample returns of microbe and bio-organics exposure and micrometeoroid capture onboard ISS-Kibo Exposed Facility ExHAM.
    International Astrobiology Workshop 2013, Sagamihara, Japan; 11/2013
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    ABSTRACT: We found a micrometeorite with unique mineralogy. It is composed of an aggregate of sub-micrometer-sized almost Fe-free low-Ca pyroxene, Fe-poor olivine, Fe-Ni metal, Fe sulfide, with a small amount of amorphous silicate and carbonaceous material.

Publication Stats

1k Citations
208.77 Total Impact Points

Institutions

  • 2010–2015
    • Osaka University
      • • Department of Earth and Space Science
      • • Graduate School of Science
      Suika, Ōsaka, Japan
    • Arizona State University
      • Department of Chemistry and Biochemistry
      Mesa, AZ, United States
  • 2014
    • Kochi University
      • Center for Advanced Marine Core Research
      Kôti, Kōchi, Japan
  • 2011
    • Fukuoka Institute of Technology
      Hukuoka, Fukuoka, Japan
  • 2008–2010
    • Carnegie Institution for Science
      • Geophysical Laboratory
      Washington, WV, United States
  • 2005
    • Tokyo Metropolitan University
      Edo, Tōkyō, Japan
    • Okayama University
      • Department of Earth Science
      Okayama, Okayama, Japan