Michael J Gaffey

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On 25 October 2000, the Near Earth Asteroid Rendevous (NEAR)-Shoemaker spacecraft executed a low-altitude flyover of asteroid 433 Eros, making it possible to image the surface at a resolution of about 1 meter per pixel. The images reveal an evolved surface distinguished by an abundance of ejecta blocks, a dearth of small craters, and smooth material(More)
Existing reflectance spectra of CI chondrites (18 spectra of 3 CIs) have been augmented with new (18 spectra of 2 CIs) reflectance spectra to ascertain the spectral variability of this meteorite class and provide insights into their spectral properties as a function of grain size, composition, particle packing, and viewing geometry. Particle packing and(More)
Absorption features having depths up to 5% are identified in high-quality, high-resolution reflectance spectra of 16 dark asteroids in the main belt and in the Cybele and Hilda groups. Analogs among the CM2 carbonaceous chondrite meteorites exist for some of these asteroids, suggesting that these absorptions are due to iron oxides in phyllosilicates formed(More)
Multispectral images (0.44 to 0.98 μm) of asteroid (4) Vesta obtained by the Dawn Framing Cameras reveal global color variations that uncover and help understand the north-south hemispherical dichotomy. The signature of deep lithologies excavated during the formation of the Rheasilvia basin on the south pole has been preserved on the surface. Color(More)
Spectra of near-Earth asteroids were compared to spectra of selected asteroids, planets, and satellites to determine possible source regions. The diversity of reflectance spectra of the near-Earth asteroids implies different mineralogical compositions and hence more than one source region. The presence of near-Earth asteroid spectral signatures similar to(More)
Powdered samples of a suite of 14 CR and CR-like chondrites, ranging from petrologic grade 1 to 3, were spectrally characterized over the 0.3–2.5 lm interval as part of a larger study of carbonaceous chondrite reflectance spectra. Spectral analysis was complicated by absorption bands due to Fe oxyhydroxides near 0.9 lm, resulting from terrestrial(More)
The surface of the asteroid Vesta has prominent near-infrared absorption bands characteristic of a range of pyroxenes, confirming a direct link to the basaltic howardite-eucrite-diogenite class of meteorites. Processes active in the space environment produce 'space weathering' products that substantially weaken or mask such diagnostic absorption on airless(More)
From February 13 to May 13, 2000, the Near Infrared Spectrometer (NIS) instrument on the Near Earth Asteroid Rendezvous (NEAR) mission obtained more than 200,000 spatially-resolved 800 to 2500 nm reflectance spectra of the S-type asteroid 433 Eros. An important subset of the spectra were obtained during a unique opportunity on February 13 and 14, when the(More)
We examined the spectral reflectance properties of 16 CO-type carbonaceous chondrites (CCs) in order to better understand their range of spectral properties, develop spectral–compositional correlations, and provide information that may aid in the search for CO parent bodies. As a group, our CO powder spectra have some similarities and differences. COs have(More)
Multiple reflectance spectra of 11 CV chondrites have been measured to determine spectral–composi-tional relationships for this meteorite class and to aid the search for CV parent bodies. The reflectance of CV chondrite spectra is variable, ranging from $5% to 13% at 0.56 lm, and $5% to 15% at the 0.7 lm region local reflectance maximum. Overall slopes(More)