Search Publications
Connections between spectra and structure in Saturn’s main rings based on Cassini VIMS data
Clark, R. N.; Nicholson, P. D.; Hedman, M. M. +4 more
Saturn’s main rings exhibit variations in both their opacity and their spectral properties on a broad range of spatial scales, and the correlations between these parameters can provide insights into the processes that shape the composition and dynamics of the rings. The Visual and Infrared Mapping Spectrometer (VIMS) instrument onboard the Cassini…
Saturn’s Great Storm of 2010-2011: Evidence for ammonia and water ices from analysis of VIMS spectra
Baines, K. H.; Sromovsky, L. A.; Fry, P. M.
Our analysis of Cassini/VIMS near-infrared spectra of Saturn’s Great Storm of 2010-2011 reveals a multi-component aerosol composition comprised primarily of ammonia ice, with a significant component of water ice. The most likely third component is ammonium hydrosulfide or some weakly absorbing material similar to what dominates visible clouds outs…
Near-infrared spectral monitoring of Pluto's ices: Spatial distribution and secular evolution
Olkin, C. B.; Buie, M. W.; Young, E. F. +2 more
We report results from monitoring Pluto's 0.8 to 2.4 µm reflectance spectrum with IRTF/SpeX on 65 nights over the dozen years from 2001 to 2012. The spectra show vibrational absorption features of simple molecules CH4, CO, and N2 condensed as ices on Pluto's surface. These absorptions are modulated by the planet's 6.39 …
Observations of D/H ratios in H2O, HCl, and HF on Venus and new DCl and DF line strengths
Li, G.; Belyaev, D. A.; Krasnopolsky, V. A. +2 more
Intensities of the spectral lines in the fundamental bands of D35Cl and DF were calculated using the semi-empirical dipole moment functions derived from the most accurate and precise measurements of intensities of the ro-vibrational lines of H35Cl and HF. Values obtained in this way for the deuterated species are superior to …
Multiple working hypotheses for the formation of compositional stratigraphy on Mars: Insights from the Mawrth Vallis region
Baldridge, A. M.; Michalski, Joseph R.; Cuadros, J. +1 more
A unique aspect of martian geology is the presence of similar compositional stratigraphy observed in many locations throughout the surface. Where the Al-rich and Fe/Mg-rich clay minerals occur together, aluminous clays typically overly layered ferromagnesian clays, possibly indicating that precipitation-driven leaching occurred in a warmer, wetter…
Evidence for two modes of water release in Comet 103P/Hartley 2: Distributions of column density, rotational temperature, and ortho-para ratio
Villanueva, Geronimo L.; Mumma, Michael J.; Meech, Karen J. +5 more
This paper presents long-slit spectra of H2O emission from the inner coma of Comet 103P/Hartley 2, acquired with NIRSPEC/Keck 2 during the comet's close approach to Earth in 2010. On UT 19.6 October 2010 the slit was oriented nearly orthogonal to the projected (in the plane of the sky) Sun-comet line, and the H2O rotational t…
Impact basin relaxation on Rhea and Iapetus and relation to past heat flow
Schenk, Paul M.; White, Oliver L.; Dombard, Andrew J.
Evidence for relaxation of impact crater topography has been observed on many icy satellites, including those of Saturn, and the magnitude of relaxation can be related to past heat flow (e.g. Moore, J.M., Schenk, P.M., Bruesch, L.S., Asphaug, E., McKinnon, W.B. [2004]. Icarus 171, 421-443; Dombard, A.J., McKinnon, W.B. [2006]. J. Geophys. Res. 111…
Crater topography on Titan: Implications for landscape evolution
Lorenz, R. D.; Kirk, R. L.; Cassini Radar Team +7 more
We present a comprehensive review of available crater topography measurements for Saturn’s moon Titan. In general, the depths of Titan’s craters are within the range of depths observed for similarly sized fresh craters on Ganymede, but several hundreds of meters shallower than Ganymede’s average depth vs. diameter trend. Depth-to-diameter ratios a…
Processes forming and sustaining Saturn's proton radiation belts
Krupp, N.; Roussos, E.; Paranicas, C. +2 more
Saturn's proton radiation belts extend over the orbits of several moons that split this region of intense radiation into several distinct belts. Understanding their distribution requires to understand how their particles are created and evolve. High-energy protons are thought to be dominantly produced by cosmic ray albedo neutron decay (CRAND). Th…
Wind driven capillary-gravity waves on Titan's lakes: Hard to detect or non-existent?
Lorenz, R. D.; Lunine, J. I.; Hayes, A. G. +13 more
Saturn's moon Titan has lakes and seas of liquid hydrocarbon and a dense atmosphere, an environment conducive to generating wind waves. Cassini observations thus far, however, show no indication of waves. We apply models for wind wave generation and detection to the Titan environment. Results suggest wind speed thresholds at a reference altitude o…