Search Publications
The Titan 14N/ 15N and 12C/ 13C isotopic ratios in HCN from Cassini/CIRS
Bézard, Bruno; Vinatier, Sandrine; Nixon, Conor A.
We report the detection of H 13CN and HC 15N in mid-infrared spectra recorded by the Composite Infrared Spectrometer (CIRS) aboard Cassini, along with the determination of the 12C/ 13C and 14N/ 15N isotopic ratios. We analyzed two sets of limb spectra recorded near 13-15° S (Tb flyb…
Valley formation on martian volcanoes in the Hesperian: Evidence for melting of summit snowpack, caldera lake formation, drainage and erosion on Ceraunius Tholus
Head, James W.; Fassett, Caleb I.
Ceraunius Tholus, a Hesperian-aged volcano in the Tharsis region, is characterized by small radial valleys on its flanks, and several larger valleys originating near its summit caldera. All of these large valleys drain from near the lowest present portion of the caldera rim and down the flanks of the volcano. The largest valley debauches into Rahe…
Assessing the limits of the Modified Gaussian Model for remote spectroscopic studies of pyroxenes on Mars
Mustard, John F.; Gendrin, Aline; Kanner, Lisa C.
We investigate the ability to refine pyroxene composition and modal abundance from laboratory and remotely acquired spectra. Laboratory data including the martian meteorites, Shergotty, Zagami, MIL03346, and ALH84001 as well as additional pyroxene-rich spectra obtained from the OMEGA (Observatoire pour la Minéralogie, l'Eau, les Glaces, et l'Activ…
Analysis of a giant lightning storm on Saturn
Gurnett, D. A.; Kurth, W. S.; Fischer, G. +5 more
On January 23, 2006, the Cassini/RPWS (Radio and Plasma Wave Science) instrument detected a massive outbreak of SEDs (Saturn Electrostatic Discharges). The following SED storm lasted for about one month and consisted of 71 consecutive episodes. It exceeded all other previous SED observations by Cassini as well as by the Voyagers with regard to num…
Saturn eddy momentum fluxes and convection: First estimates from Cassini images
West, Robert A.; Porco, Carolyn C.; Ingersoll, Andrew P. +5 more
We apply an automated cloud feature tracking algorithm to estimate eddy momentum fluxes in Saturn's southern hemisphere from Cassini Imaging Science Subsystem near-infrared continuum image sequences. Voyager Saturn manually tracked images had suggested no conversion of eddy to mean flow kinetic energy, but this was based on a small sample of <1…
Electrical properties of Titan's surface from Cassini RADAR scatterometer measurements
Cassini RADAR Team; Lorenz, Ralph D.; Ostro, Steven J. +4 more
We report regional-scale low-resolution backscatter images of Titan's surface acquired by the Cassini RADAR scatterometer at a wavelength of 2.18-cm. We find that the average angular dependence of the backscatter from large regions and from specific surface features is consistent with a model composed of a quasi-specular Hagfors term plus a diffus…
The orbit, mass, size, albedo, and density of (65489) Ceto/Phorcys: A tidally-evolved binary Centaur
Spencer, J. R.; Cruikshank, D. P.; Trilling, D. E. +6 more
Hubble Space Telescope observations of Uranus- and Neptune-crossing object (65489) Ceto/Phorcys (provisionally designated 2003 FX 128) reveal it to be a close binary system. The mutual orbit has a period of 9.554±0.011 days and a semimajor axis of 1840±48 km. These values enable computation of a system mass of (5.41±0.42)×10 kg. Spitzer…
Titan's corona: The contribution of exothermic chemistry
Johnson, R. E.; Waite, J. H.; Cravens, T. E. +4 more
The contribution of exothermic ion and neutral chemistry to Titan's corona is studied. The production rates for fast neutrals N 2, CH 4, H, H 2, 3CH 2, CH 3, C 2H 4, C 2H 5, C 2H 6, N( 4S), NH, and HCN are …
The spatial morphology of Europa's near-surface O 2 atmosphere
Johnson, R. E.; Cooper, J. F.; McGrath, M. A. +2 more
Results from a three-dimensional ballistic model of Europa's O 2 atmosphere are presented. Hubble Space Telescope (HST) ultraviolet observations show spatially non-uniform O 2 airglow from Europa. One explanation for this is that the O 2 atmosphere is spatially non-uniform. We show that non-uniform ejection of O
Variability in the H +3 emission of Saturn: Consequences for ionisation rates and temperature
Trafton, L. M.; Geballe, T. R.; Melin, Henrik +2 more
We present an analysis of observations of the auroral/polar regions of Saturn, carried out in 1999, 2004 and 2005, making use of the facility spectrometer, CGS4, on the United Kingdom Infrared Telescope (UKIRT), Mauna Kea, Hawaii. We obtain temperatures of 380(±70) K in 1999 and 420(±70) K in 2004. (The 2005 data has insufficient spectral resoluti…