Icy Satellites

The moons of the gas giants (Jupiter, Saturn, Uranus, Neptune) are composed mainly of ice, and are geologically fascinating. For instance, Europa has features which look similar to plate tectonic features on Earth, while tiny Enceladus has a giant geyser blasting off into space. The Galileo spacecraft provided a good look at the satellites of Jupiter, while Cassini just finished doing the same for those of Saturn.

I was a Participating Scientist on the Cassini mission. This yielded good gravity measurements for both Titan and Enceladus. The results suggest that Titan’s ice shell is not convecting, and that Enceladus has an ocean beneath its icy shell. I then got distracted by the New Horizons observations of Pluto and Charon, icy bodies similar to the Galilean and Saturnian satellites. But now I am back to thinking about Europa, as a team member on three instruments for the forthcoming Europa Clipper mission. Part of the reason that Europa is so interesting is the possible detection of cryovolcanic “plumes”, similar to the plumes seen on Enceladus.


Cryovolcanic plumes detected on Europa (left) and Enceladus (right).


Publications on icy satellites

Below are some recent highlights; you can get a full listing here:

·  Ocean worlds in the outer solar system, F. Nimmo, R.T. Pappalardo J. Geophys. Res. , 121 1378-1399, 2016 Reprint .

·  Tidally-modulated eruptions on Enceladus: Cassini ISS observations and models F. Nimmo, C. Porco, C. Mitchell, Astron. J. 148 46, 2014 Reprint.

·  The gravity field and interior structure of Enceladus, L. Iess, D.J. Stevenson, M. Parisi, D. Hemingway, R.A. Jacobson, J.I. Lunine, F. Nimmo, J.W. Armstrong, S.W. Asmar, M. Ducci, P. Tortora Science 344, 78-80, 2014.

·  Transient water vapor at Europa's South pole, L. Roth, J. Saur, K.D. Retherford, D.F. Strobel, P.D. Feldman, M.A. McGrath, F. Nimmo Science 343, 171-174, 2014

·  Tidal heating in icy satellite oceans, E.M.A. Chen, F. Nimmo, G.A. Glatzmaier, Icarus 229, 11-30, 2014 Reprint.

·  Late-stage impacts and the orbital and thermal evolution of Tethys, K. Zhang, F. Nimmo, Icarus 218, 348-355, 2012 Reprint



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Last Modified: 20th Nov 2017.