A5091868992- Astro and Planetary Science
- Planetary Science and Exploration
- Isotope Analysis in Ecology
- Geological and Geochemical Analysis
- Geology and Paleoclimatology Research
- Stellar, planetary, and galactic studies
- Nuclear Physics and Applications
- High-pressure geophysics and materials
- Geomagnetism and Paleomagnetism Studies
- Space Exploration and Technology
- Space Science and Extraterrestrial Life
- Paleontology and Stratigraphy of Fossils
- Geochemistry and Geologic Mapping
- Historical Astronomy and Related Studies
- Spacecraft and Cryogenic Technologies
- Astrophysics and Star Formation Studies
- Space Satellite Systems and Control
- X-ray Spectroscopy and Fluorescence Analysis
- Geological Studies and Exploration
- Astronomical and nuclear sciences
- Advanced X-ray Imaging Techniques
- earthquake and tectonic studies
- Archaeology and ancient environmental studies
- Astronomical Observations and Instrumentation
- X-ray Diffraction in Crystallography
Mount Holyoke College
2014-2024
Planetary Science Institute
1992-2024
Bates College
2008-2010
Centre National de la Recherche Scientifique
2006
Université de Bretagne Occidentale
2006
The Open University
2006
Sorbonne Université
2006
Goddard Space Flight Center
2000-2005
Smithsonian Institution
2000-2003
National Museum of Natural History
2000-2002
Abstract The following discussion is divided into seven major sections. first section outlines the scientific background and justification for asteroid studies in context of understanding formation early evolution solar system. second briefly reviews nature distribution population. third discusses several unresolved issues meteorite science which can potentially be addressed by remote sensing investigations. fourth definition taxonomic classes. fifth summarizes existing asteroidal spectral...
A number of distinct methodologies are available for determining the oxygen isotope composition minerals and rocks, these include laser-assisted fluorination, secondary ion mass spectrometry (SIMS) UV laser ablation. In this review we focus on which currently achieves highest levels precision analysis. particular, examine how results using method have furthered our understanding early-formed differentiated meteorites. Due to its rapid reaction times low blank levels, fluorination has now...
Meteorites provide a unique insight into early Solar System processes. However, to fully interpret this record requires that these meteorites are related back their source asteroids and ultimately the original planetesimal population formed in history. As first step process an assessment has been undertaken of likely number distinct sampled by extraterrestrial materials. The results survey indicate there between 95 148 parent bodies represented our sample collections. This steadily...
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...
Abstract— Near‐Earth asteroid (25143) 1998 SF36 is a planned target for the Japanese MUSES‐C sample return mission. High signal‐to‐noise and relatively high‐resolution (50 Å) visible near‐infrared spectroscopic measurements obtained during this asteroid's favorable 2001 apparition reveal it to have red‐sloped S(IV)‐type spectrum with strong 1 2 μm absorption bands analogous those measured ordinary chondrite meteorites. This red slope, which primary spectral difference between meteorites,...
Although ordinary chondrite (OC) meteorites dominate observed falls, the identification of near-Earth and main-belt asteroid sources has remained elusive. Telescopic measurements 35 asteroids ( approximately3 kilometers in diameter) revealed six that have visible wavelength spectra similar to laboratory OC meteorites. Near-Earth were found spectral properties span range between previously separated domains most common (S class) asteroids, suggesting a link. This could arise through diversity...
Asteroidal material, delivered to Earth as meteorites, preserves a record of the earliest stages planetary formation. High-precision oxygen isotope analyses for two major groups stony-iron meteorites (main-group pallasites and mesosiderites) demonstrate that each group is from distinct asteroidal source. Mesosiderites are isotopically identical howardite-eucrite-diogenite clan and, like them, probably derived asteroid 4 Vesta. Main-group represent intermixed core-mantle material single...
Abstract— We have calculated pyroxene mineralogies of seven near‐Earth asteroids (NEAs) with reflectance spectra similar to HEDs (howardites, eucrites, and diogenites). Two different sets formulas (Gaffey et al. 2002; Burbine 2007) are used calculate the NEAs from their Band I II centers. The band centers been adjusted compensate for low temperatures on asteroid surfaces. All derived Gaffey (2002) (2007) overlap. wollastonite (Wo) contents very differences being only approximately 1 mol%....
We report major element composition ratios for regions of the asteroid 433 Eros imaged during two solar flares and quiet sun conditions period May to July 2000. Low aluminum abundances all argue against global differentiation Eros. Magnesium/silicon, aluminum/silicon, calcium/silicon, iron/silicon are best interpreted as a relatively primitive, chondritic composition. Marked depletions in sulfur possible calcium depletions, relative ordinary chondrites, may represent signatures limited...
Abstract— We investigate the possibility that Mercury's crust is very reduced with FeO concentrations of less than ˜0.1 wt%. believe such a surface could have composition enstatite, plagioclase, diopside, and sulfide, similar to mineral assemblages found in aubritic meteorites. To test this hypothesis, we investigated spectra aubrites their constituent minerals as analogs for Mercury. some sulfides distinctive absorption features shortwards ˜0.6 μm may be apparent spectrum an object....
Visible and near-infrared spectroscopic observations of the asteroid 1459 Magnya indicate that it has a basaltic surface. is at 3. 15 astronomical units (AU) from sun no known dynamical link to any family, nearby large asteroid, or 4 Vesta 2.36 AU, which only other asteroid. We show region belt around densely filled by mean-motion resonances, generating slow orbital diffusion processes providing potential mechanism for removing fragments may have been created on same parent body as Magnya....
Abstract— We report major element ratios determined for the S‐class asteroid 433 Eros using remote‐sensing x‐ray fluorescence spectroscopy with near‐Earth rendezvous Shoemaker spectrometer (XRS). Data analysis techniques and systematic errors are described in detail. acquired during five solar flares two extended “quiet Sun” periods presented; these results sample a representative portion of asteroid's surface. Although uncertainties potentially large, most internally consistent plausible...
Abstract— The complete (or near complete) differentiation of a chondritic parent body is believed to result in an object with Fe‐Ni core, thick olivine‐dominated mantle and thin plagioclase/pyroxene crust. Compositional groupings iron meteorites give direct evidence that at least 60 bodies have been differentiated subsequently destroyed. A long standing problem has our meteorite collections, apparently asteroid observations as well, show great absence metal‐free material. While the basaltic...
Abstract— The near‐Earth asteroid rendezvous (NEAR) mission carried x‐ray/gamma‐ray spectrometers and multi‐spectral imager/near‐infrared spectrometer instrument packages which gave complementary information on the chemistry mineralogy, respectively, of target 433 Eros. Synthesis these two data sets provides not available from either alone, including abundance non‐mafic silicates, metal sulfide minerals. We have utilized four techniques to synthesize sets. Venn diagrams, examine overlapping...