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Gravity Field, Shape, and Moment of Inertia of Titan

Stevenson, David J.; Iess, Luciano; Jacobson, Robert A. +5 more

Precise radio tracking of the spacecraft Cassini has provided a determination of Titan’s mass and gravity harmonics to degree 3. The quadrupole field is consistent with a hydrostatically relaxed body shaped by tidal and rotational effects. The inferred moment of inertia factor is about 0.34, implying incomplete differentiation, either in the sense…

Cassini Finds an Oxygen-Carbon Dioxide Atmosphere at Saturn’s Icy Moon Rhea

Coates, A. J.; Tokar, R. L.; Jones, G. H. +10 more

The flyby measurements of the Cassini spacecraft at Saturn’s moon Rhea reveal a tenuous oxygen (O₂)-carbon dioxide (CO₂) atmosphere. The atmosphere appears to be sustained by chemical decomposition of the surface water ice under irradiation from Saturn’s magnetospheric plasma. This in situ detection of an oxidizing atmosphere…

An Evolving View of Saturn’s Dynamic Rings

Clark, R. N.; Nicholson, P. D.; Kempf, S. +20 more

We review our understanding of Saturn’s rings after nearly 6 years of observations by the Cassini spacecraft. Saturn’s rings are composed mostly of water ice but also contain an undetermined reddish contaminant. The rings exhibit a range of structure across many spatial scales; some of this involves the interplay of the fluid nature and the self-g…

Iapetus: Unique Surface Properties and a Global Color Dichotomy from Cassini Imaging

West, Robert A.; Porco, Carolyn C.; Burns, Joseph A. +8 more

Since 2004, Saturn’s moon Iapetus has been observed repeatedly with the Imaging Science Subsystem of the Cassini spacecraft. The images show numerous impact craters down to the resolution limit of ~10 meters per pixel. Small, bright craters within the dark hemisphere indicate a dark blanket thickness on the order of meters or less. Dark, equator-f…

Saturn: Atmosphere, Ionosphere, and Magnetosphere

Ingersoll, Andrew P.; Gombosi, Tamas I.

The Cassini spacecraft has been in orbit around Saturn since 30 June 2004, yielding a wealth of data about the Saturn system. This review focuses on the atmosphere and magnetosphere and briefly outlines the state of our knowledge after the Cassini prime mission. The mission has addressed a host of fundamental questions: What processes control the …