Search Publications
A salt-water reservoir as the source of a compositionally stratified plume on Enceladus
Kempf, S.; Postberg, F.; Srama, R. +2 more
The discovery of a plume of water vapour and ice particles emerging from warm fractures (`tiger stripes') in Saturn's small, icy moon Enceladus raised the question of whether the plume emerges from a subsurface liquid source or from the decomposition of ice. Previous compositional analyses of particles injected by the plume into Saturn's diffuse E…
Flow of mass and energy in the magnetospheres of Jupiter and Saturn
Delamere, Peter A.; Bagenal, Fran
We present simple models of the plasma disks surrounding Jupiter and Saturn based on published measurements of plasma properties. We calculate radial profiles of the distribution of plasma mass, pressure, thermal energy density, kinetic energy density, and energy density of the suprathermal ion populations. We estimate the mass outflow rate as wel…
Rapid and Extensive Surface Changes Near Titan’s Equator: Evidence of April Showers
Barnes, J. W.; Lorenz, R. D.; West, R. A. +11 more
Although there is evidence that liquids have flowed on the surface at Titan’s equator in the past, to date, liquids have only been confirmed on the surface at polar latitudes, and the vast expanses of dunes that dominate Titan’s equatorial regions require a predominantly arid climate. We report the detection by Cassini’s Imaging Science Subsystem …
High heat flow from Enceladus' south polar region measured using 10-600 cm-1 Cassini/CIRS data
Spencer, J. R.; Howett, C. J. A.; Pearl, J. +1 more
Analysis of 2008 Cassini Composite Infrared Spectrometer (CIRS) 10 to 600 cm-1 thermal emission spectra of Encleadus shows that for reasonable assumptions about the spatial distribution of the emission and the thermophysical properties of the solar-heated background surface, which are supported by CIRS observations of background tempera…
Accretion of Saturn’s mid-sized moons during the viscous spreading of young massive rings: Solving the paradox of silicate-poor rings versus silicate-rich moons
Dones, Luke; Charnoz, Sébastien; Crida, Aurélien +7 more
The origin of Saturn’s inner mid-sized moons (Mimas, Enceladus, Tethys, Dione and Rhea) and Saturn’s rings is debated. Charnoz et al. [Charnoz, S., Salmon J., Crida A., 2010. Nature 465, 752-754] introduced the idea that the smallest inner moons could form from the spreading of the rings’ edge while Salmon et al. [Salmon, J., Charnoz, S., Crida, A…
Transient surface liquid in Titan's polar regions from Cassini
Lorenz, R. D.; Wye, L. C.; Zebker, H. A. +12 more
Cassini RADAR images of Titan's south polar region acquired during southern summer contain lake features which disappear between observations. These features show a tenfold increases in backscatter cross-section between images acquired one year apart, which is inconsistent with common scattering models without invoking temporal variability. The mo…
The composition and structure of the Enceladus plume
Hansen, C. J.; Hendrix, A. R.; West, R. A. +8 more
The Cassini Ultraviolet Imaging Spectrograph (UVIS) observed an occultation of the Sun by the water vapor plume at the south polar region of Saturn's moon Enceladus. The Extreme Ultraviolet (EUV) spectrum is dominated by the spectral signature of H2O gas, with a nominal line-of-sight column density of 0.90 ± 0.23 × 1016 cm
Plasma, plumes and rings: Saturn system dynamics as recorded in global color patterns on its midsize icy satellites
Johnson, Robert E.; Hamilton, Douglas P.; McKinnon, William B. +4 more
New global maps of the five inner midsize icy saturnian satellites, Mimas, Enceladus, Tethys, Dione, and Rhea, have been constructed in three colors (UV, Green and near-IR) at resolutions of 1 km/pixel. The maps reveal prominent global patterns common to several of these satellites but also three major color features unique to specific satellites …
Energy deposition and primary chemical products in Titan’s upper atmosphere
Lewis, G. R.; Coates, A. J.; Galand, M. +4 more
Cassini results indicate that solar photons dominate energy deposition in Titan's upper atmosphere. These dissociate and ionize nitrogen and methane and drive the subsequent complex organic chemistry. The improved constraints on the atmospheric composition from Cassini measurements demand greater precision in the photochemical modeling. Therefore,…
Dusty plasma in the vicinity of Enceladus
Gurnett, D. A.; Persoon, A. M.; Kurth, W. S. +7 more
We present in situ Cassini Radio Plasma Wave Science observations in the vicinity of Enceladus and in the E ring of Saturn that indicate the presence of dusty plasma. The four flybys of Enceladus in 2008 revealed the following cold plasma characteristics: (1) there is a large plasma density (both ions and electrons) within the Enceladus plume regi…