Hiroshi Naraoka
A5008740529- Astro and Planetary Science
- Isotope Analysis in Ecology
- Planetary Science and Exploration
- Geology and Paleoclimatology Research
- Geological and Geochemical Analysis
- Mass Spectrometry Techniques and Applications
- Methane Hydrates and Related Phenomena
- Hydrocarbon exploration and reservoir analysis
- High-pressure geophysics and materials
- Paleontology and Stratigraphy of Fossils
- Nuclear Physics and Applications
- Origins and Evolution of Life
- Geochemistry and Elemental Analysis
- Astrophysics and Star Formation Studies
- Geochemistry and Geologic Mapping
- Atmospheric chemistry and aerosols
- Analytical Chemistry and Chromatography
- Marine and coastal ecosystems
- Geological and Geophysical Studies
- Geomagnetism and Paleomagnetism Studies
- Space Exploration and Technology
- Toxic Organic Pollutants Impact
- Atmospheric Ozone and Climate
- Stellar, planetary, and galactic studies
- Radioactive element chemistry and processing
Kyushu University
2016-2025
The University of Queensland
2024
Japan Aerospace Exploration Agency
2004-2022
Nishikyushu University
2022
Kyushu Institute of Information Sciences
2022
Planetary Science Institute
2014
Okayama University
2004-2011
Institute of Space and Astronautical Science
2004-2009
Tokyo Metropolitan University
1997-2008
Pennsylvania State University
2008
Laboratory analysis of samples returned from an asteroid establishes a direct link between asteroids and meteorites provides clues to the complex history its surface.
Abstract C-type asteroids 1 are considered to be primitive small Solar System bodies enriched in water and organics, providing clues the origin evolution of building blocks life. asteroid 162173 Ryugu has been characterized by remote sensing 2–7 on-asteroid measurements 8,9 with Hayabusa2 (ref. 10 ). However, ground truth provided laboratory analysis returned samples is invaluable determine fine properties other planetary bodies. We report preliminary results analyses on from particle size...
Carbonaceous meteorites are thought to be fragments of C-type (carbonaceous) asteroids. Samples the asteroid (162173) Ryugu were retrieved by Hayabusa2 spacecraft. We measured mineralogy and bulk chemical isotopic compositions samples. The samples mainly composed materials similar those carbonaceous chondrite meteorites, particularly CI (Ivuna-type) group. consist predominantly minerals formed in aqueous fluid on a parent planetesimal. primary altered fluids at temperature 37° ± 10°C, about...
The Hayabusa2 spacecraft collected samples from the surface of carbonaceous near-Earth asteroid (162173) Ryugu and brought them to Earth. were expected contain organic molecules, which record processes that occurred in early Solar System. We analyzed molecules extracted samples. identified a variety containing atoms CHNOS, formed by methylation, hydration, hydroxylation, sulfurization reactions. Amino acids, aliphatic amines, carboxylic polycyclic aromatic hydrocarbons, nitrogen-heterocyclic...
The Hayabusa2 spacecraft investigated the C-type (carbonaceous) asteroid (162173) Ryugu. mission performed two landing operations to collect samples of surface and subsurface material, latter exposed by an artificial impact. We present images second touchdown site, finding that ejecta from impact crater was at sample location. Surface pebbles both sites show morphological variations ranging rugged smooth, similar Ryugu's boulders, shapes quasi-spherical flattened. were returned Earth on 6...
Abstract The lack of pyrimidine diversity in meteorites remains a mystery since prebiotic chemical models and laboratory experiments have predicted that these compounds can also be produced from precursors found meteorites. Here we report the detection nucleobases three carbonaceous using state-of-the-art analytical techniques optimized for small-scale quantification down to range parts per trillion (ppt). In addition previously detected purine such as guanine adenine, identify various...
Samples of the carbonaceous asteroid (162173) Ryugu were collected and brought to Earth by Hayabusa2 spacecraft. We investigated macromolecular organic matter in samples found that it contains aromatic aliphatic carbon, ketone, carboxyl functional groups. The spectroscopic features are consistent with those chemically primitive chondrite meteorites experienced parent-body aqueous alteration (reactions liquid water). morphology carbon includes nanoglobules diffuse associated phyllosilicate...
The pristine sample from the near-Earth carbonaceous asteroid (162173) Ryugu collected by Hayabusa2 spacecraft enabled us to analyze extraterrestrial material without uncontrolled exposure Earth's atmosphere and biosphere. initial analysis team for soluble organic matter reported detection of wide variety molecules including racemic amino acids in samples. Here we report uracil, one four nucleobases ribonucleic acid, aqueous extracts In addition, nicotinic acid (niacin, a B3 vitamer), its...
Organic matter in meteorites reveals clues about early Solar System chemistry and the origin of molecules important to life, but terrestrial exposure complicates interpretation. Samples returned from B-type asteroid Bennu by Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer mission enabled us study pristine carbonaceous astromaterial without uncontrolled Earth's biosphere. Here we show that samples are volatile rich, with more carbon, nitrogen ammonia than...
Meteorite studies suggest that each solar system object has a unique oxygen isotopic composition. Chondrites, the most primitive of meteorites, have been believed to be derived from asteroids, but compositions asteroids themselves not established. We measured, using secondary ion mass spectrometry, rock particles asteroid 25143 Itokawa returned by Hayabusa spacecraft. Compositions are depleted in (16)O relative terrestrial materials and indicate Itokawa, an S-type asteroid, is one sources LL...
Noble gas isotopes were measured in three rocky grains from asteroid Itokawa to elucidate a history of irradiation cosmic rays and solar wind on its surface. Large amounts helium (He), neon (Ne), argon (Ar) trapped various depths the observed, which can be explained by multiple implantations particles into grains, combined with preferential He loss caused frictional wear space-weathered rims grains. Short residence time less than 8 million years was implied for an estimate...
The occurrence of extraterrestrial organic compounds is a key for understanding prebiotic synthesis in the universe. In particular, amino acids have been studied carbonaceous meteorites almost 50 years. Here we report ten new identified Murchison meteorite, including family nine hydroxy acids. discovery mostly C3 and C4 structural isomers provides insight into mechanisms compounds. A complementary experiment suggests that these could be produced from aldehydes ammonia on meteorite parent...
The synthesis of nucleobases in natural environments, especially interstellar molecular clouds, is the focus a long-standing debate regarding prebiotic chemical evolution. Here we report simultaneous detection all three pyrimidine (cytosine, uracil and thymine) purine (adenine, xanthine hypoxanthine) ice analogues composed simple molecules including H2O, CO, NH3 CH3OH after exposure to ultraviolet photons followed by thermal processes, that is, conditions simulate processes accompanying star...
The near-Earth carbonaceous asteroid (162173) Ryugu is expected to contain volatile chemical species that could provide information on the origin of Earth's volatiles. Samples were retrieved by Hayabusa2 spacecraft. We measured noble gas and nitrogen isotopes in samples found they are dominated presolar primordial components, incorporated during Solar System formation. Noble concentrations higher than those Ivuna-type (CI) chondrite meteorites. Several host phases isotopically distinct have...
Little is known about the origin of spectral diversity asteroids and what it says conditions in protoplanetary disk. Here, we show that samples returned from Cb-type asteroid Ryugu have Fe isotopic anomalies indistinguishable Ivuna-type (CI) chondrites, which are distinct all other carbonaceous chondrites. Iron isotopes, therefore, demonstrate CI chondrites formed a reservoir was different source regions asteroids. Growth migration giant planets destabilized nearby planetesimals ejected some...
The extraterrestrial materials returned from asteroid (162173) Ryugu consist predominantly of low-temperature aqueously formed secondary minerals and are chemically mineralogically similar to CI (Ivuna-type) carbonaceous chondrites. Here, we show that high-temperature anhydrous primary in chondrites exhibit a bimodal distribution oxygen isotopic compositions: 16O-rich (associated with refractory inclusions) 16O-poor chondrules). Both the probably inner solar protoplanetary disk were...
Chondrule-like objects and Ca-Al-rich inclusions (CAIs) are discovered in the retuned samples from asteroid Ryugu. Here we report results of oxygen isotope, mineralogical, compositional analysis chondrule-like CAIs. Three dominated by Mg-rich olivine 16O-rich -poor with Δ17O (=δ17O - 0.52 × δ18O) values ~ -23‰ -3‰, resembling what has been proposed as early generations chondrules. The likely to be melted amoeboid aggregates that escaped incorporation into 16O-poor chondrule precursor dust....
Samples from the carbonaceous asteroid (162173) Ryugu provide information on chemical evolution of organic molecules in early solar system. Here we show element partitioning major component ions by sequential extractions salts, carbonates, and phyllosilicate-bearing fractions to reveal primordial brine composition primitive asteroid. Sodium is dominant electrolyte salt fraction extract. Anions NH4+ are more abundant than carbonate phyllosilicate fractions, with molar concentrations order...
Polycyclic aromatic hydrocarbons (PAHs) contain ≲20% of the carbon in interstellar medium. They are potentially produced circumstellar environments (at temperatures ≳1000 kelvin), by reactions within cold (~10 kelvin) clouds, or processing carbon-rich dust grains. We report isotopic properties PAHs extracted from samples asteroid Ryugu and meteorite Murchison. The doubly-13C substituted compositions (Δ2×13C values) naphthalene, fluoranthene, pyrene 9 to 51‰ higher than values expected for a...
Abstract Transmission electron microscopy analyses of Hayabusa2 samples show that Ryugu organic matter exhibits a range morphologies, elemental compositions, and carbon functional chemistries consistent with those carbonaceous chondrites have experienced low‐temperature aqueous alteration. Both nanoglobules diffuse are abundant. Non‐globular particles also present, including some contain nanodiamond clusters. Diffuse is finely distributed in around phyllosilicates, forms coatings on other...