Tidal Heating and Convection in the Medium Sized Icy Satellites

Surface features of some icy satellites indicate that the satellites are modified due to the internally driven tectonic activity. Convection could be one of the processes responsible for the formation of the surface features. The potential sources of energy inside the satellites are discussed. For the medium sized icy satellites the radiogenic and tidal heat sources seem to be of primary importance. To investigate the problem, a 3D model of convection is developed based on the Navier–Stokes equation, the equation of thermal conductivity, the equation of continuity, and the equation of state. The model includes both the tidal and the radiogenic heating. It can be applied to the homogeneous, non-differentiated medium sized satellites. The 3D formulae for tidal heat generation and stress tensor based on the results of Peale and Cassen (1978) and others are applied. A new dimensionless number C _t is introduced. It measures the relative importance of tidal and radiogenic heat sources. The systematic investigation of the steady-state convection is performed for different values of the Rayleigh number and for 0C _t 1. The results indicate that the convection pattern for low Rayleigh number driven by tidal heating in the medium sized icy satellites consists of two cells. The pattern of tidally driven convection is oriented, that is, the regions of downward motion are situated at the center of the near- and of the far-side of the satellite.     

The magmatic activity on asteroids

The tidal effects on a fractured asteroid are considered. The asteroid is assumed to consist of two parts. In gravitational field of another body the motion of one part of the asteroid in relation to second part may be initiated. The necessary conditions for this motion are determined and amount of heat that can be generated is calculated for some cases. It is suggested that metamorphic episodes found in some meteorites are the results of such heating.