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A study of Jupiter's UV Great Dark Spot and tropopause to stratosphere winds in the high northern latitudes as seen by Cassini imaging
West, R. A.; Sinclair, J. A.; Del Genio, A. D. +1 more
Images of Jupiter taken during the year 2000 Cassini flyby revealed the early stages and evolution of a high northern-latitude UV Great Dark Spot over a three-month period. They also provided a window on the circulation of Jupiter's polar stratosphere. Jupiter's rarely-detected UV Great Dark Spot (UVGDS) is unusual in several respects. It is an ep…
Particle sizes in Saturn's rings from UVIS stellar occultations 2. Outlier Populations in the C ring and Cassini Division
Colwell, J. E.; Esposito, L. W.; Jerousek, R. G. +1 more
The Cassini Ultraviolet Imaging Spectrograph (UVIS) included a High-Speed Photometer (HSP), which observed hundreds of stellar occultations by Saturn's ring system across a range of viewing geometries (Colwell et al. 2010). The unocculted time series data from the HSP follow Poisson counting statistics, such that the second and third central momen…
Saturn's atmospheric response to the large influx of ring material inferred from Cassini INMS measurements
Fletcher, Leigh N.; Guerlet, Sandrine; Moses, Julianne I. +12 more
During the Grand Finale stage of the Cassini mission, organic-rich ring material was discovered to be flowing into Saturn's equatorial upper atmosphere at a surprisingly large rate. Through a series of photochemical models, we have examined the consequences of this ring material on the chemistry of Saturn's neutral and ionized atmosphere. We find …
Microwaving Mimas, Enceladus, Tethys, Dione, Rhea, Iapetus and Phoebe: Insights into the regolith properties and geological history of Saturn's icy satellites
Lellouch, Emmanuel; Wall, Stephen; Le Gall, Alice A. +4 more
While Saturn's main airless moons are all composed largely of water ice, their respective thermal histories and near environments have led to different regolith compositions and structures. Part of this history is recorded in their subsurface which can be probed by microwaves. Using a combined thermal and radiative transfer model, we here investig…
The Bolometric Bond Albedo of Enceladus
West, Robert A.; Nixon, Conor A.; Fry, Patrick M. +13 more
The bolometric Bond albedo is a fundamental parameter of planets and moons. Here, combined observations from the Cassini spacecraft and the Hubble Space Telescope are used to determine the bolometric Bond albedo of Enceladus. We provide the full-disk reflectance of Enceladus across all phase angles (0° -180°) from 150 nm to 5131 nm, a spectral ran…
The complex shape of the outer edge of Saturn's B ring, as observed in Cassini occultation data
Nicholson, Philip D.; French, Richard G.; Hedman, Matthew M. +9 more
We determine the time-variable shape of the outer edge of Saturn's B ring using the complete set of Cassini radio and stellar occultation data obtained between mid-2005 and the End-of-Mission in late 2017, considerably expanding the range and number of individual ring edge measurements used in previous analyses (Spitale and Porco, 2010; Nicholson …
The case for an ocean-bearing Mimas from tidal heating analysis
Rhoden, Alyssa Rose; Walker, Matthew E.
Cassini measurements of Mimas' physical libration can be explained by either a non-hydrostatic core or a global, liquid water ocean beneath a 24-31 km thick ice shell. An ocean within Mimas would be surprising, given the lack of comparable geologic activity to that observed on other ocean-bearing moons like Europa and Enceladus, and thus has impor…
Polar and mid-latitude vortices and zonal flows on Jupiter and Saturn
Yadav, Rakesh K.; Featherstone, Nicholas A.; Aurnou, Jonathan M. +1 more
Zonal flow on Jupiter and Saturn consists of equatorial super-rotation and alternating East-West jet streams at higher latitudes. Interacting with these zonal flows, numerous vortices occur with various sizes and lifetimes. The Juno mission and Cassini's grand finale have shown that the zonal jets of Jupiter and Saturn extend deeply into their mol…
Modeling the complete set of Cassini's UVIS occultation observations of Enceladus' plume
Esposito, Larry W.; Portyankina, Ganna; Aye, Klaus-Michael +2 more
The Cassini Ultraviolet Imaging Spectrograph (UVIS) observed a plume of water vapor spewing out from the south polar regions of Enceladus via occultations 7 times during the Cassini mission. Five of them yielded spatially resolved data that allowed fits to a set of individually modeled jets. We created a direct simulation Monte Carlo (DSMC) model …
Molecular hydrogen in the upper atmospheres of Saturn and Titan
Strobel, Darrell F.
Molecular hydrogen is the third most abundant species in Titan's atmosphere with a tropospheric/lower stratospheric mole fraction of 0.001 derived from Voyager and Cassini measurements and the major species in Saturn's atmosphere. The motivation for this paper is to explore the hypothesis that the corrected H2 density measurements repor…