Détail de la notice
Titre du Document
Enceladus: Present internal structure and differentiation by early and long-term radiogenic heating
Auteur(s)
SCHUBERT Gerald ; ANDERSON John D. ; TRAVIS Bryan J. ; ...
Résumé
Pre-Cassini images of Saturn's small icy moon Enceladus provided the first indication that this satellite has undergone extensive resurfacing and tectonism. Data returned by the Cassini spacecraft have proven Enceladus to be one of the most geologically dynamic bodies in the Solar System. Given that the diameter of Enceladus is only about 500 km, this is a surprising discovery and has made Enceladus an object of much interest. Determining Enceladus' interior structure is key to understanding its current activity. Here we use the mean density of Enceladus (as determined by the Cassini mission to Saturn), Cassini observations of endogenic activity on Enceladus, and numerical simulations of Enceladus' thermal evolution to infer that this satellite is most likely a differentiated body with a large rock-metal core of radius about 150 to 170 km surrounded by a liquid water-ice shell. With a silicate mass fraction of 50% or more, long-term radiogenic heating alone might melt most of the ice in a homogeneous Enceladus after about 500 Myr assuming an initial accretion temperature of about 200 K, no subsolidus convection of the ice, and either a surface temperature higher than at present or a porous, insulating surface. Short-lived radioactivity, e.g., the decay of 26Al, would melt all of the ice and differentiate Enceladus within a few million years of accretion assuming formation of Enceladus at a propitious time prior to the decay of 26Al. Long-lived radioactivity facili
Editeur
Elsevier
Identifiant
ISSN : 0019-1035 CODEN : ICRSA5
Source
Icarus (New York, N.Y. 1962) A. 2007, vol. 188, n° 2, pp. 345-355 [11 pages] [bibl. : 1 p.]
Langue
Anglais
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