Monday, February 08, 2010 at 4:00 PM

JILA Auditorium

Julie Castillo, Jet Propulsion Lab (JPL)

"Effect of Material Anelasticity on the Tidal Response of Outer-Planet Satellites"

Abstract:

Most of the models for the tidal response of planetary satellites have relied on the assumption that these objects behave as Maxwell bodies. However, the Maxwell model is inadequate for reproducing the response of planetary material to cyclic stressing because it does not account for anelasticity. The attenuation spectrum of silicates has been much studied by means of laboratory experiments and theoretical models of ice microphysics. These studies indicate that the Andrade model provides a better representation for the attenuation properties of silicates. Available literature also suggests that the Andrade model provides a good match to experimental measurement of ice attenuation properties. In order to constrain the input to the Andrade model for its application to planetary studies, we have undertaken a project to measure the anelasticity of a variety of icy compositions. This work is being carried out in the Planetary Tides Simulation Facility (PTSF – JPL). I will report on the progress and key results obtained so far with the PTSF. Then I will show that material anelasticity can become a major mechanism governing the deformation of outer planet satellites, and I will compare the tidal response expected for Enceladus, Europa, and Titan in this new framework.

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