A5050183331- Astro and Planetary Science
- Planetary Science and Exploration
- Isotope Analysis in Ecology
- Geological and Geochemical Analysis
- High-pressure geophysics and materials
- Stellar, planetary, and galactic studies
- Geology and Paleoclimatology Research
- Nuclear Physics and Applications
- Astrophysics and Star Formation Studies
- Spacecraft and Cryogenic Technologies
- Astronomical and nuclear sciences
- Geomagnetism and Paleomagnetism Studies
- Solar and Space Plasma Dynamics
- Ion-surface interactions and analysis
- Paleontology and Stratigraphy of Fossils
- Geochemistry and Geologic Mapping
- Hydrocarbon exploration and reservoir analysis
- earthquake and tectonic studies
- Archaeology and ancient environmental studies
- Geochemistry and Elemental Analysis
- X-ray Spectroscopy and Fluorescence Analysis
- Space Exploration and Technology
- Mass Spectrometry Techniques and Applications
- Atmospheric Ozone and Climate
- Gamma-ray bursts and supernovae
University of Hawaiʻi at Mānoa
2015-2024
University of Hawaii System
2012-2024
Czech Academy of Sciences, Institute of Geophysics
2008-2023
NASA Astrobiology Institute
2012-2017
Ames Research Center
2011
Arizona State University
1999-2007
California Institute of Technology
1993-2006
University of Chicago
1990-2002
Fermi National Accelerator Laboratory
1990-2001
University of Minnesota
1988
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...
Shaking out water's dusty origin Where did Earth's water come from? Lavas erupting on Baffin Island, Canada, tap a part of mantle isolated from convective mixing. Hallis et al. studied hydrogen isotopes in the lavas that help to “fingerprint” what could be primordial reservoir. The isotope ratios for Island basalt suggest pre-solar Earth, probably delivered by adsorption onto dust grains. Science , this issue p. 795
Abstract— High‐purity separates of presolar diamond were prepared from 14 primitive chondrites 7 compositional groups. Their noble gases measured using stepped pyrolysis. Three distinct gas components are present in diamonds, HL, P3, and P6, each which is found to consist five gases. P3 , released between 200 °C 900 °C, has a “planetary” elemental abundance pattern roughly “normal” isotopic ratios. HL consisting isotopically anomalous Xe‐HL Kr‐H, Ar with high 38 Ar/ 36 Ar, most the making up...
A search was made for 26Mg (26Mg*) from the decay of 26Al (half-life = 0.73 million years) in Al-rich objects unequilibrated ordinary chondrites. Two Ca-Al-rich inclusions (CAIs) and two chondrules (not CAIs) were found that contained when they formed. Internal isochrons CAIs yielded an initial 26Al/27Al ratio [(26Al/27Al)0] 5 x 10(-5), indistinguishable most carbonaceous This result shows with this level are present throughout classes chondrites strengthens notion widespread early solar...
Ten samples of the Martian regolith have been analyzed by Viking lander X ray fluorescence spectrometers. Because high-stability electronics, inclusion calibration targets, and special data encoding within instruments quality analyses performed on Mars is closely equivalent to that attainable with same operated in laboratory. Determination absolute elemental concentrations requires gain drift adjustments, subtraction background components, use a mathematical response model adjustable...
Abstract From mid-Ordovician ∼470 Myr-old limestone >100 fossil L-chondritic meteorites have been recovered, representing the markedly enhanced flux of to Earth following breakup L-chondrite parent body. Recently one anomalous meteorite, Österplana 065 (Öst 65), was found in same beds that yield L chondrites. The cosmic-ray exposure age Öst 65 shows it may be a fragment impactor broke up Here we show chromium versus oxygen-isotope plot falls outside all fields encompassing known meteorite...
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...
60Fe, which decays to radiogenic 60Ni (60Ni*), is a now extinct radionuclide. 60Fe produced only in stars and thus provides constraint on the stellar contribution solar system radionuclides. Its short half-life [t1/2 = 1.49 × 106 yr (1.49 Myr)] makes it potential chronometer for early system. We found clear evidence 60Ni* troilite (FeS) grains from Bishunpur Krymka chondrites, two of least metamorphosed (LL3.1) ordinary chondrites. The weighted means inferred initial 60Fe/56Fe ratios...
Abstract— In order to investigate the distribution of 26 A1 in chondrites, we measured aluminum‐magnesium systematics four calcium‐aluminum‐rich inclusions (CAIs) and eleven aluminum‐rich chondrules from unequilibrated ordinary chondrites (UOCs). All CAIs were found contain radiogenic Mg ( Mg*) decay A1. The inferred initial Al/ 27 Al ratios for these objects (( Al) 0 ≅ 5 × 10 −5 ) are indistinguishable most carbonaceous chondrites. These observations, together with similarities mineralogy...
Abstract— Using the isotopic compositions derived in Huss and Lewis, 1994a (Paper I), abundances of P3, HL, P6 noble‐gas components were determined for 15 diamond separates from primitive chondrites 8 chondrite classes. Within a meteorite class, relative these correlate with petrologic subtype host meteorite, indicating that metamorphism is primarily responsible variations. Relative among samples can be understood terms thermal processing single mixture diamonds like those now found CI CM2...
On the basis of anomalous isotopic compositions oxygen and magnesium, 14 oxide grains from two primitive meteorites (Bishunpur Semarkona) have been identified as circumstellar condensates. One corundum grain has a high 18 O/ 16 O ratio calcium, titanium that are compatible with formation in ejecta type II supernova was about 15 times mass sun. The other oxygen, consistent around asymptotic giant branch (AGB) stars range initial composition. large aluminum/magnesium spinel is considered to...
Carbon dioxide well gases in Colorado, New Mexico, and South Australia show excesses of (124-128)Xe correlated with (129)I-derived (129)Xe (20)Ne/(22)Ne ratios that are higher than the atmospheric ratio. The xenon isotopic data indicate presence a solarlike component deep within Earth. this crustal upper mantle reservoirs may be explained by steady-state transport noble from lower mantle, which still retains much its juvenile volatile inventory. These measurements also source these carbon...
view Abstract Citations (120) References (29) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Extreme 26Mg and 17O Enrichments in an Orgueil Corundum: Identification of a Presolar Oxide Grain Hutcheon, I. D. ; Huss, G. R. Fahey, A. J. Wasserburg, A corundum (Al2O3) grain from the meteorite is greatly enriched O-17 (Mg-26)*. The measured O-16/O-17 1028 +/- 11 compared to solar(O-16/O-17) = 2610. This largest excess so far observed any meteoritic material....
60Fe decays to 60Ni with a half-life of 1.49 × 106 yr, so all the original atoms incorporated into solar system have decayed. Because is produced only in stars, its initial abundance provides constraint on stellar contribution radionuclides early and nature source. short half-life, also potential high-resolution chronometer early-solar-system events. The presence primitive meteorites has been confirmed sulfides, but loosely constrained because it uncertain when sulfides formed. We show that...