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Recent volcanic activity has long been considered a distinct possibility that would place major constraints on the evolution of Mars’ interior. Volcanic activity would result in the outgassing of sulfur-bearing species. As part of our multi-band search for active release of volcanic gases on Mars, we looked for carbonyl sulfide (OCS) at its combination band (ν1+ν3) at 3.42 µ m (2924 cm−1), and sulfur...
Mars Reconnaissance Orbiter Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) hyperspectral image data have been acquired in an along-track oversampled (ATO) mode with the intent of processing the data to better than the nominal ∼18m/pixel ground resolution. We have implemented an iterative maximum log-likelihood method (MLM) that utilizes the instrument spectral and spatial transfer functions...
Pluto’s lower atmosphere has been observed to evolve since the first definitive occultation detection in 1988. Possibilities for explaining the lower atmospheric structure include a steep thermal gradient and/or extinction, the latter of which can be characterized as a dependence between occultation flux and wavelength. On 2011 June 23, a 14.43 UCAC magnitude star (R=13.64) was occulted by Pluto as...
Is Mars actively releasing organic and other minor gases into the atmosphere? We present a comprehensive search for trace species on Mars, targeting multiple volatile organic species (CH 4 , CH 3 OH, H 2 CO, C 2 H 6 , C 2 H 2 , C 2 H 4 ), hydroperoxyl (HO 2 ), several nitrogen compounds (N 2 O, NH 3 , HCN),...
The reflectance spectra of 15 CK chondrites have been measured as part of an ongoing study of carbonaceous chondrite reflectance spectra. The available sample suite includes multiple grain sizes and samples with petrologic grades varying from CK4 to CK6. CK reflectance spectra are all characterized by an olivine-associated absorption band in the 1.05μm region. Compared to pure olivine, CK spectra...
We have analyzed reflectance spectra (0.3–2.5μm) of a number of ungrouped or tentatively grouped carbonaceous chondrites (CCs), possible CC-type xenoliths in an aubrite (Cumberland Falls) and a howardite (PRA 04401), a CH chondrite (PCA 91467), a CC polymict breccia (Kaidun), and some R chondrites. The best approach to analysis relies largely on characterizing spectrally active phases – i.e., those...
Multiple reflectance spectra of 11 CV chondrites have been measured to determine spectral–compositional 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 0.56μm, and ∼5% to 15% at the 0.7μm region local reflectance maximum. Overall slopes range from slightly blue to red for powders, while...
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 experienced varying degree of thermal metamorphism,...
We examined the spectral reflectance properties of 26 carbonaceous chondrites (CCs) that show evidence of aqueous alteration and subsequent thermal metamorphism (termed ATCCs). We also reviewed the thermal and aqueous alteration history of these meteorites and searched for trends between spectral parameters and temperature histories in order to uncover spectral–compositional relationships. Aqueous...
We observed Comet C/2009 P1 (Garradd) on UT 2011 September 8th and 9th at a large heliocentric distance of 2.1AU upon its entry to the inner Solar System. The observations were performed using high-resolution infrared spectrometers (NIRSPEC at Keck II and CSHELL at IRTF), allowing us to obtain strong detections of H 2 O, CO, CH 4 and HCN and sensitive upper-limits for C 2 H...
Powdered samples of a suite of 14 CR and CR-like chondrites, ranging from petrologic grade 1 to 3, were spectrally characterized over the 0.3–2.5μm interval as part of a larger study of carbonaceous chondrite reflectance spectra. Spectral analysis was complicated by absorption bands due to Fe oxyhydroxides near 0.9μm, resulting from terrestrial weathering. This absorption feature masks expected absorption...
We have examined the spectral reflectance properties and available modal mineralogies of 39 CM carbonaceous chondrites to determine their range of spectral variability and to diagnose their spectral features. We have also reviewed the published literature on CM mineralogy and subclassification, surveyed the published spectral literature and added new measurements of CM chondrites and relevant end...
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 viewing geometry effects have not previously...
Surface features observed on Mars and evidence from martian meteorites both suggest that hydrothermal systems have operated in the crust of the planet. Hydrothermal systems are a potential habitat for living organisms and identifying these on Mars is, therefore, important in the search for life beyond the Earth. One of the surface expressions of hydrothermal systems on Earth are silica sinters, deposited...
We present quantitative laboratory studies that simulate the effect of redeposition of impact-ejecta on mineral surfaces. We produced deposits of natural olivine (Fo90) and forsterite on olivine and forsterite powder samples by ns-pulsed laser ablation. The deposits produce changes in the optical reflectance (0.66–2.5 μm). We show that significant darkening and reddening of the surface occurs when...
We have used HST/NICMOS to observe approximately 57% of the martian surface in 7 narrow band filters (0.97, 1.08, 1.13, 1.66, 1.90, 2.12, and 2.15 μm) during the 2003 opposition (Ls∼250°) and at a resolution of ∼12 km/pixel. Principal components analysis (PCA) of the dataset has identified regional variability on scales of hundreds of kilometers associated with differences in the near-infrared spectrum...
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