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  • Article
  • Open Access

Density distribution in medium-sized icy satellites of giant planets

Earth, Planets and Space200759:BF03352045

  • Received: 4 September 2006
  • Accepted: 8 July 2007
  • Published:


We discuss processes that determine the distribution of density in the medium-sized icy satellites (MIS). Gravitational differentiation, porosity and phase transitions lead to a spherical distribution, while thermal convection, large impacts and tidal deformation can result in a non-spherical distribution. According to our previous research, convective patterns in MIS can consist of one or two convective cells for radiogenic and tidal heating. The shift of the center of mass ΔrCM and the ratio of moments of inertia IZ/IXY are calculated using a numerical model of convection. A new dimensionless number C is introduced to describe the deformation of the surface. We found that ΔrCM can reach ≈0.5% of the satellite radius for the one-cell pattern. With the two-cell pattern the moment of inertia, IZ, can be reduced by ≈0.4%. The impact cratering could be one cause of significant changes in ΔrCM and IZ /IXY but only for the smallest of the MIS. Tidal deformation could result in the enhancement of mass redistribution caused by other mechanisms.

Key words

  • Icy satellites
  • density distribution
  • convection
  • tidal heating
  • moments of inertia