Search Publications

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…

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…

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…

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…

A radiation belt of energetic protons located between Saturn and its rings

Livi, S.; Krupp, N.; Jones, G. H. +21 more

Saturn has a sufficiently strong dipole magnetic field to trap high-energy charged particles and form radiation belts, which have been observed outside its rings. Whether stable radiation belts exist near the planet and inward of the rings was previously unknown. The Cassini spacecraft's Magnetosphere Imaging Instrument obtained measurements of a …