A5016348206- Astro and Planetary Science
- Planetary Science and Exploration
- Isotope Analysis in Ecology
- Geological and Geochemical Analysis
- Space Exploration and Technology
- Spacecraft and Cryogenic Technologies
- Laser-induced spectroscopy and plasma
- Geochemistry and Geologic Mapping
- High-pressure geophysics and materials
- Geology and Paleoclimatology Research
- Space Science and Extraterrestrial Life
- Calibration and Measurement Techniques
- Stellar, planetary, and galactic studies
- Methane Hydrates and Related Phenomena
- Geomagnetism and Paleomagnetism Studies
- Space exploration and regulation
- Atmospheric Ozone and Climate
- Nuclear Physics and Applications
- Mineralogy and Gemology Studies
- Geophysics and Gravity Measurements
- Astronomical Observations and Instrumentation
- Solar and Space Plasma Dynamics
- Spaceflight effects on biology
- Ionosphere and magnetosphere dynamics
- GNSS positioning and interference
Brown University
2016-2025
John Brown University
2004-2024
University of Aizu
2023
Providence College
2018-2021
The Graduate University for Advanced Studies, SOKENDAI
2017
National Sagamihara Hospital
2017
National Institute of Polar Research
2011-2016
Chiba Institute of Technology
2012
Chiba University
2007
The University of Tokyo
1983-2006
The asteroid impact near the Russian city of Chelyabinsk on 15 February 2013 was largest airburst Earth since 1908 Tunguska event, causing a natural disaster in an area with population exceeding one million. Because it occurred era modern consumer electronics, field sensors, and laboratory techniques, unprecedented measurements were made event meteoroid that caused it. Here, we document account what happened, as understood now, using comprehensive data obtained from astronomy, planetary...
Hayabusa2 at the asteroid Ryugu Asteroids fall to Earth in form of meteorites, but these provide little information about their origins. The Japanese mission is designed collect samples directly from surface an and return them for laboratory analysis. Three papers this issue describe team's study near-Earth carbonaceous 162173 Ryugu, which spacecraft arrived June 2018 (see Perspective by Wurm). Watanabe et al. measured asteroid's mass, shape, density, showing that it a “rubble pile” loose...
Hayabusa2 at the asteroid Ryugu Asteroids fall to Earth in form of meteorites, but these provide little information about their origins. The Japanese mission is designed collect samples directly from surface an and return them for laboratory analysis. Three papers this issue describe team's study near-Earth carbonaceous 162173 Ryugu, which spacecraft arrived June 2018 (see Perspective by Wurm). Watanabe et al. measured asteroid's mass, shape, density, showing that it a “rubble pile” loose...
Samples of the carbonaceous asteroid Ryugu were brought to Earth by Hayabusa2 spacecraft. We analyzed 17 samples measuring 1 8 millimeters. Carbon dioxide-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent formed in outer Solar System. The contain low abundances materials at high temperatures, such as chondrules and calcium- aluminum-rich inclusions. rich phyllosilicates carbonates, which through aqueous alteration reactions temperature, pH,...
Collecting a sample of asteroid Ryugu The Hayabusa2 spacecraft recently traveled to the nearby carbonaceous collect samples and return them Earth for laboratory analysis. Morota et al. describe Hayabusa2's first collection, taken during brief touchdown on Ryugu's surface. Close-up images video sampling process allowed authors investigate surface colors morphology small scale. Relating these craters stratigraphy constrains evolution Ryugu. conclude that experienced prior period strong solar...
Abstract On September 24, 2023, NASA's OSIRIS‐REx mission dropped a capsule to Earth containing ~120 g of pristine carbonaceous regolith from Bennu. We describe the delivery and initial allocation this asteroid sample introduce its bulk physical, chemical, mineralogical properties early analyses. The is very dark overall, with higher‐reflectance inclusions particles interspersed. Particle sizes range submicron dust stone ~3.5 cm long. Millimeter‐scale larger stones typically have hummocky or...
A new type of carbonaceous chondrite, the Tagish Lake meteorite, exhibits a reflectance spectrum similar to spectra observed from D-type asteroids, which are relatively abundant in outer solar system beyond main asteroid belt and have been inferred be more primitive than any known meteorite. Until fall, these asteroids had no analog meteorite collections. The is carbon-rich (4 5 weight %), aqueously altered chondrite contains high concentrations presolar grains carbonate minerals, consistent...
Abstract Thermal metamorphism study of the C, G, B, and F asteroids has been revisited using their UV, visible, NIR, 3 μm reflectance spectra. High‐quality spectra seven selected have compared with for 29 carbonaceous chondrites, including thermally‐metamorphosed CI/CM meteorites. There are three sets spectral counterparts, among which 511 Davida B‐7904 most similar to each other in terms both shape brightness. By comparing 0.7 absorption strengths 21 heated Murchison samples, these grouped...
Doppler weather radar imaging enabled the rapid recovery of Sutter's Mill meteorite after a rare 4-kiloton TNT-equivalent asteroid impact over foothills Sierra Nevada in northern California. The recovered meteorites survived record high-speed entry 28.6 kilometers per second from an orbit close to that Jupiter-family comets (Tisserand's parameter = 2.8 ± 0.3). is regolith breccia composed CM (Mighei)-type carbonaceous chondrite and highly reduced xenolithic materials. It exhibits...
For the purpose of simulating surface alteration process called "space weathering", experiments pulse laser irradiation, proton implantation, and irradiation to implanted samples were performed reflectance spectra altered materials measured. To simulate impact heating by micrometeorite bombardments, we made a new apparatus using whose duration is 6–8 nanoseconds, comparable with timescale impacts. We find that degree space weathering, i.e., change spectrum should depend on mineral...
The near-infrared spectrometer on board the Japanese Hayabusa spacecraft found a variation of more than 10% in albedo and absorption band depth surface reflectance asteroid 25143 Itokawa. Spectral shape over 1-micrometer indicates that this body has an olivine-rich mineral assemblage potentially similar to LL5 or LL6 chondrites. Diversity physical condition Itokawa's appears be larger for other S-type asteroids previously explored by spacecraft, such as 433 Eros.
We present a new global survey of the purest anorthosite (PAN) rock using Spectral Profiler onboard Kaguya. found that PAN rocks are widely distributed over Moon, including Feldspathic Highland Terrain and south north polar regions. All sites associated with huge impact structures diameters larger than 100 km. Based on distributions olivine‐rich sites, we propose existence massive layer thickness ∼50 km below an uppermost mafic‐rich mixed ∼10 Below layer, lower crustal materials may be...
Abstract— Spectra of asteroid 4 Vesta and 21 small (estimated diameters less than 10 km) asteroids with Vesta‐like spectral properties (Vestoids) were measured at visible near‐infrared wavelengths (∼0.44 to ∼1.65 μm). All the (except for 2579 Spartacus) have reflectance spectra consistent surface compositions similar eucrites howardites all being derived from Vesta. None observed diogenites. We find no distinction between 15 objects tabulated as members dynamical family 6 7 sampled...
Reflectance spectra (0.3 to 2.6 micrometers) of 14 C, G, B, and F asteroids 21 carbonaceous chondrite powders are compared in detail. Only three thermally metamorphosed CM-Cl chondrites that have a weak ultraviolet absorption shown close counterparts among those asteroids. heated Murchison CM2 with the average C G type asteroid spectra. at 600° 1000°C exhibits similar provides best analog for Comparison strengths between 160 suggests surface minerals most temperatures around 1000°C.
The Spectral Profiler (SP) onboard the Japanese SELENE (KAGUYA) spacecraft is now providing global high spectral resolution visible‐near infrared continuous reflectance spectra of Moon. impact craters on farside Moon reveal lithologies that were not previously identified. achievements SP so far include: most definite detection crystalline iron‐bearing plagioclase with its characteristic 1.3 μ m absorption band Moon; a new interpretation lithology Tsiolkovsky crater central peaks, classified...