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Internal structures of the Galilean satellites

Schubert, G. and Stevenson, D. J. and Ellsworth, K. (1981) Internal structures of the Galilean satellites. Icarus, 47 (1). pp. 46-59. ISSN 0019-1035.

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New models for the interiors of Io, Ganymede, and Callisto are proposed. The model of Io consists of a thin, high-rigidity outer layer separated from a solid interior by a thin, molten or partially molten shell. The modulus of rigidity of the outer layer must be at least 100 times larger than that of the underlying partially molten shell. These layers have thicknesses of order 100 km or less. The near-surface partially molten layer was most likely produced early in Io's history as a consequence of accretional heating; enhanced tidal heating in the outer rigid layer has kept the underlying region partially molten to the present day. The model of Ganymede consists of an ice outer layer, a shell of undifferentiated, primordial ice-silicate mixture, and a rock core. Accretional heating is responsible for melting the ice in the outer layers of Ganymede's initially homogeneous ice-silicate interior. Most of the rock in this outer layer accumulates in a shell on top of Ganymede's early cold and rigid central region; the water in the outer layer quickly refreezes. Heating of the undifferentiated region by the decay of radioactive elements in the silicate fraction would gradually warm it and reduce its viscosity. The rock layer would become gravitationally unstable and sink through the undifferentiated materials to form a rock core. Callisto's heavily cratered surface strongly suggests that relatively little, if any, ice-rock differentiation has occured in its interior.

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Stevenson, D. J.0000-0001-9432-7159
Additional Information:© 1981 by Academic Press, Inc. Received June 30, 1980; revised April 28, 1981. We thank our colleagues P. Cassen and R. T. Reynolds for helpful discussions. This research was supported by NASA Grants NSG 7315 and NGL-05-007-002.
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Official Citation:G. Schubert, D.J. Stevenson, K. Ellsworth, Internal structures of the Galilean satellites, Icarus, Volume 47, Issue 1, July 1981, Pages 46-59, ISSN 0019-1035,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:39095
Deposited By: Tony Diaz
Deposited On:26 Jun 2013 17:29
Last Modified:03 Oct 2019 05:03

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