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New Cassini RADAR results for Saturn’s icy satellites
Lorenz, R. D.; Ostro, S. J.; West, R. D. +13 more
Cassini radar tracks on Saturn's icy satellites through the end of the Prime Mission in 2008 have increased the number of radar albedo estimates from 10 ( Ostro et al., 2006) to 73. The measurements sample diverse subradar locations (and for Dione, Rhea, and Iapetus almost always use beamwidths less than half the target angular diameters), thereby…
The opposition and tilt effects of Saturn’s rings from HST observations
French, Richard G.; Salo, Heikki
The two major factors contributing to the opposition brightening of Saturn's rings are (i) the intrinsic brightening of particles due to coherent backscattering and/or shadow hiding on their surfaces, and (ii) the reduced interparticle shadowing when the solar phase angle α → 0°. We utilize the extensive set of Hubble Space Telescope observations …
A long-lived cyclone in Saturn’s atmosphere: Observations and models
Hueso, R.; Sánchez-Lavega, A.; Pérez-Hoyos, S. +2 more
The atmospheres of the giant planets Jupiter and Saturn possess large numbers of vortices (closed circulation ovals). On the larger scale, above 2000 km, anticyclones on Jupiter and Saturn are generally long-lived coherent structures while cyclones survive a much shorter time and behave more chaotically. A long term survey of images of Saturn's at…
Far ultraviolet spectral properties of Saturn’s rings from Cassini UVIS
Colwell, Joshua E.; Cuzzi, Jeffrey N.; Esposito, Larry W. +3 more
Spectra taken by the Cassini Ultraviolet Imaging Spectrograph (UVIS) of Saturn’s C ring, B ring, Cassini Division, and A ring have been analyzed in order to characterize ring particle surface properties and water ice abundance in the rings. UVIS spectra sense the outer few microns of the ring particles. Spectra of the normalized reflectance (I/F) …
Observations of a stationary mid-latitude cloud system on Titan
Barnes, J. W.; de Pater, I.; Hartung, M. +1 more
We report the observation of a cloud system on Titan that remained localized near 40°S latitude and 60°W longitude for at least 34 h. Ground-based observations obtained with the SINFONI imaging spectrograph at the Very Large Telescope over four consecutive nights recorded the lifetime and altitude of the unresolved cloud system. Concomitant measur…
Constraints on Titan’s topography through fractal analysis of shorelines
Byrne, Shane; Sharma, Priyanka
Titan's north polar hydrocarbon lakes offer a unique opportunity to indirectly characterize the statistical properties of Titan's landscape. The complexity of a shoreline can be related to the complexity of the landscape it is embedded in through fractal theory. We mapped the shorelines of 290 of the north polar titanian lakes in the Cassini synth…
A multilayer model for thermal infrared emission of Saturn’s rings II: Albedo, spins, and vertical mixing of ring particles inferred from Cassini CIRS
Altobelli, Nicolas; Spilker, Linda; Ohtsuki, Keiji +3 more
Since the Saturn orbit insertion of the Cassini spacecraft in mid-2004, the Cassini composite infrared spectrometer (CIRS) measured temperatures of Saturn's main rings at various observational geometries. In the present study, we apply our new thermal model (Morishima, R., Salo, H., Ohtsuki, K. [2009]. Icarus 201, 634-654) for fitting to the early…
Far-infrared opacity sources in Titan’s troposphere reconsidered
Irwin, P. G. J.; Teanby, N. A.; de Kok, R.
We use Cassini far-infrared limb and nadir spectra, together with recent Huygens results, to shed new light on the controversial far-infrared opacity sources in Titan's troposphere. Although a global cloud of large CH 4 ice particles around an altitude of 30 km, together with an increase in tropospheric haze opacity with respect to the …
A bulk cloud parameterization in a Venus General Circulation Model
Read, Peter L.; Lewis, Stephen R.; Lee, Christopher
A condensing cloud parameterization is included in a super-rotating Venus General Circulation Model. A parameterization including condensation, evaporation and sedimentation of mono-modal sulfuric acid cloud particles is described. Saturation vapor pressure of sulfuric acid vapor is used to determine cloud formation through instantaneous condensat…
Observation of saturnian stream particles in the interplanetary space
Kempf, Sascha; Hsu, Hsiang-Wen; Jackman, Caitriona M.
In January 2004 the dust instrument on the Cassini spacecraft detected the first high-velocity grain expelled from Saturn - a so-called stream particle. Prior to Cassini's arrival at Saturn in July 2004 the instrument registered 801 faint impacts, whose impact signals showed the characteristic features of a high-velocity impact by a tiny grain. Th…