Search results for: Nancy J. Chanover
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Here we present new ultraviolet–visible spectra of irradiated ammonium hydrosulfide (NH4SH), a reported jovian atmospheric cloud component, for a range of temperatures and radiation doses and make assignments to the spectral features. We show that the combination of radiolysis and thermal annealing of NH4SH causes the originally featureless ultraviolet–visible reflectance spectrum to evolve into one...
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Here we present our recent studies of proton-irradiated and unirradiated ammonium hydrosulfide, NH4SH, a compound predicted to be an important tropospheric cloud component of Jupiter and other giant planets. We irradiated both crystalline and amorphous NH4SH at 10–160K and used IR spectroscopy to observe and identify reaction products in the ice, specifically NH3 and long-chained sulfur-containing...
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We present analysis of high spectral resolution NIR spectra of CO and H 2 O in Comet C/2009 P1 (Garradd) taken during its 2011–2012 apparition with the CSHELL instrument on NASA’s Infrared Telescope Facility (IRTF). We also present analysis of observations of atomic oxygen in Comet Garradd obtained with the ARCES echelle spectrometer mounted on the ARC 3.5-m telescope at Apache Point Observatory...
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A balloon-borne Acousto-Optic Tunable Filter (AOTF) hyperspectral imager is ideally suited to address numerous outstanding questions in planetary science. The spectral agility, narrowband wavelength selection, tolerance to the near-space environment, and spectral coverage afforded by AOTFs would enable investigations not feasible from ground-based facilities. A notional AOTF imager design includes...
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We discuss the development of a portable NIR reflectance point spectrometer based on acousto-optic tunable filter (AOTF) technology for future in situ geologic investigations of planetary surfaces. AOTFs are low power devices that operate on the principle of diffraction in a birefringent crystal. We have demonstrated the efficacy of this technique in extreme subterranean environments using the Portable...
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We demonstrate the biosignature detection capabilities of several classes of instruments, including a compact laser desorption/ionization time-of-flight mass spectrometer, an acousto-optic tunable filter IR point spectrometer, a laser-induced breakdown spectrometer, and a scanning electron microscope. We collected biotic and abiotic calcite, gypsum, and manganese oxide samples from Fort Stanton Cave...
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We present analysis of high spectral resolution optical spectra of Comet 103P/Hartley taken during its Fall 2010 apparition. These spectra include transitions belonging to CN, C2, CH, NH2, and OI. We measure production rates and mixing ratios from these spectra. We find evidence for large changes in production rates (factors of a few) over the course of a nucleus rotation, in agreement with other...
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We present analysis of observations of the forbidden oxygen lines in Comet 103P/Hartley, the target of the Deep Impact Extended Investigation (DIXI), during its Fall 2010 apparition. We obtained the observations using the ARCES echelle spectrometer mounted on the Astrophysical Research Consortium (ARC) 3.5-m telescope at Apache Point Observatory. We detected the 5577, 6300, and 6364Å lines on all...
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We present observations and analysis of the forbidden oxygen lines in Comets C/2006 W3 (Christensen) and C/2007 Q3 (Siding Spring) at heliocentric distances of 3.13 and 2.96AU, respectively. We obtained the observations using the ARCES echelle spectrometer, which is mounted on the Astrophysical Research Consortium 3.5-m telescope at Apache Point Observatory. We detected the 5577, 6300, and 6364Å atomic...
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The oxygen green line is one of the most characteristic features in the terrestrial visible nightglow; it can be seen in the Venus nightglow, but with much greater intensity variation than in the terrestrial case. Here we synthesize our current understanding of the green line in the Venus nightglow and discuss what might be expected observationally in the rising phase of solar cycle 24.
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Space Science Reviews > 2012 > 167 > 1-4 > 93-140
NASA’s LCROSS (Lunar Crater Observation and Sensing Satellite) mission was designed to explore the nature of previously detected enhanced levels of hydrogen near the lunar poles. The LCROSS mission impacted the spent upper stage of the launch vehicle into a permanently shadowed region of the lunar surface to create an ejecta plume. The resultant impact crater and plume were then observed by the LCROSS...
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The chromophores responsible for coloring the jovian atmosphere are embedded within Jupiter’s vertical aerosol structure. Sunlight propagates through this vertical distribution of aerosol particles, whose colors are defined by ϖ 0 (λ), and we remotely observe the culmination of the radiative transfer as I/F(λ). In this study, we employed a radiative transfer code to retrieve ϖ 0 (λ)...
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We present a novel method of constructing streamlines to derive wind speeds within jovian vortices and demonstrate its application to Oval BA for 2001 pre-reddened Cassini flyby data, 2007 post-reddened New Horizons flyby data, and 1998 Galileo data of precursor Oval DE. Our method, while automated, attempts to combine the advantages of both automated and manual cloud tracking methods. The southern...
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Jupiter's remaining White Oval changed color in late 2005 and became noticeably red in early 2006, as reported by amateur observers. We present wind and color analyses from high spatial resolution images taken with the Hubble Space Telescope Advanced Camera for Surveys in April 2006. These images suggest that the recent color change was tied to a strengthening of this storm, as implied by increased...
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High spatial resolution images of Mars were acquired with the Advanced Electro-Optical System (AEOS) 3.63-meter telescope at the Maui Space Surveillance System (MSSS) during both the 2001 and 2003 Mars apparitions. Comparisons are made of the surface albedo patterns obtained from these AEOS images to the surface albedo maps constructed from the Mars Global Surveyor (MGS) Thermal Emission Spectrometer...
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Schmider et al. (Schmider, F.-X., B. Mosser, and E. Fossat 1991. Astron. Astrophy. 248, 281-291) and Mosser et al. (Mosser, B., D. Mekarnia, J.P. Maillard, J. Gay, D. Gautier, and P. Delache 1993. Astron. Astrophys. 267, 604-622) report detection of Doppler shifts in reflected solar radiation from Jupiter purportedly induced by p-mode oscillations of the planet. We consider the possibility that these...
