Search Publications
Macromolecular organic compound s from the depths of Enceladus
Postberg, Frank; Trieloff, Mario; Schmidt, Jürgen +18 more
Saturn's moon Enceladus harbours a global water ocean, which lies under an ice crust and above a rocky core. Through warm cracks in the crust a cryo-volcanic plume ejects ice grains and vapour into space that contain materials originating from the ocean. Hydrothermal activity is suspected to occur deep inside the porous core, powered by tidal diss…
Saturn's magnetic field revealed by the Cassini Grand Finale
Cao, Hao; Dougherty, Michele K.; Hunt, Gregory J. +10 more
During 2017, the Cassini fluxgate magnetometer made in situ measurements of Saturn's magnetic field at distances ~2550 ± 1290 kilometers above the 1-bar surface during 22 highly inclined Grand Finale orbits. These observations refine the extreme axisymmetry of Saturn's internal magnetic field and show displacement of the magnetic equator northward…
Chemical interactions between Saturn's atmosphere and its rings
Kurth, W. S.; Mitchell, D. G.; Wahlund, J. -E. +25 more
The Pioneer and Voyager spacecraft made close-up measurements of Saturn's ionosphere and upper atmosphere in the 1970s and 1980s that suggested a chemical interaction between the rings and atmosphere. Exploring this interaction provides information on ring composition and the influence on Saturn's atmosphere from infalling material. The Cassini Io…
Titan's Meteorology Over the Cassini Mission: Evidence for Extensive Subsurface Methane Reservoirs
Le Mouélic, S.; Rodriguez, S.; Sotin, C. +15 more
Cassini observations of Titan's weather patterns over >13 years, almost half a Saturnian year, provide insight into seasonal circulation patterns and the methane cycle. The Imaging Science Subsystem and the Visual and Infrared Mapping Spectrometer documented cloud locations, characteristics, morphologies, and behavior. Clouds were generally mor…
In situ collection of dust grains falling from Saturn's rings into its atmosphere
Postberg, Frank; Schmidt, Jürgen; Spahn, Frank +16 more
Saturn's main rings are composed of >95% water ice, and the nature of the remaining few percent has remained unclear. The Cassini spacecraft's traversals between Saturn and its innermost D ring allowed its cosmic dust analyzer (CDA) to collect material released from the main rings and to characterize the ring material infall into Saturn. We rep…
Atmospheric structure and helium abundance on Saturn from Cassini/UVIS and CIRS observations
Guerlet, S.; Koskinen, T. T.
We combine measurements from stellar occultations observed by the Cassini Ultraviolet Imaging Spectrograph (UVIS) and limb scans observed by the Composite Infrared Spectrometer (CIRS) to create empirical atmospheric structure models for Saturn corresponding to the locations probed by the occultations. The results cover multiple locations at low to…
Study of Titan's fall southern stratospheric polar cloud composition with Cassini/CIRS: Detection of benzene ice
de Kok, R.; Flasar, F. M.; Bézard, B. +5 more
We report the detection of a spectral signature observed at 682 cm-1 by the Cassini Composite Infrared Spectrometer (CIRS) in nadir and limb geometry observations of Titan's southern stratospheric polar region in the middle of southern fall, while stratospheric temperatures are the coldest since the beginning of the Cassini mission. In …
In situ measurements of Saturn’s ionosphere show that it is dynamic and interacts with the rings
Gurnett, D. A.; Persoon, A. M.; Kurth, W. S. +10 more
The ionized upper layer of Saturn’s atmosphere, its ionosphere, provides a closure of currents mediated by the magnetic field to other electrically charged regions (for example, rings) and hosts ion-molecule chemistry. In 2017, the Cassini spacecraft passed inside the planet’s rings, allowing in situ measurements of the ionosphere. The Radio and P…
Bathymetry and composition of Titan's Ontario Lacus derived from Monte Carlo-based waveform inversion of Cassini RADAR altimetry data
Lorenz, R. D.; Lunine, J. I.; Hayes, A. G. +8 more
Recently, the Cassini RADAR was used to sound hydrocarbon lakes and seas on Saturn's moon Titan. Since the initial discovery of echoes from the seabed of Ligeia Mare, the second largest liquid body on Titan, a dedicated radar processing chain has been developed to retrieve liquid depth and microwave absorptivity information from RADAR altimetry of…
Dust grains fall from Saturn's D-ring into its equatorial upper atmosphere
Persoon, A. M.; Kurth, W. S.; Mitchell, D. G. +12 more
The sizes of Saturn's ring particles range from meters (boulders) to nanometers (dust). Determination of the rings' ages depends on loss processes, including the transport of dust into Saturn's atmosphere. During the Grand Finale orbits of the Cassini spacecraft, its instruments measured tiny dust grains that compose the innermost D-ring of Saturn…