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Detailed Reference Information |
Squyres, S.W., Reynolds, R.T., Summers, A.L. and Shung, F. (1988). Accretional heating of the satellites of Saturn and Uranus. Journal of Geophysical Research 93: doi: 10.1029/88JB00420. issn: 0148-0227. |
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We consider the heating of the larger satellites of Saturn and Uranus (with the exception of Titan) by deposition of impactor kinetic energy during satellite accretion. Satellite growth takes place from cisplanetary and transplanetary planetesimal swarms, proceeding until the planetesimal reservoirs are exhausted. Impact velocities are controlled by the initial orbital eccentricities of the planetesimals, and by gravitational focusing by the planet and the growing satellite. Heat is deposited below the satellite's surface by dissipation of impact-generated shocks. An effective thermal diffusivity produced by impact mixing provides most of the energy transport within the satellite during accretion. A number of parameters that go into the calculation are poorly constrained. The ones that can have an important influence on the results are the Safronov parameter describing the mean orbital eccentricity of bodies in the cisplanetary impactor swarm, the exponent in the power law size distribution of impacting bodies, and the fraction of the impactor kinetic energy partitioned into subsurface heat. Typical postaccretion thermal profiles show temperature maxima several tens of kilometers beneath the surface. The maximum temperature reached is in all cases insufficient to melt H2O ice. However, if NH3 or CH4 is present within the satellites, accretional heating can produce a zone of relatively warm, mobile, and buoyant material tens of kilometers below the surface. Cooling of the outer regions of the satellite immediately following accretion will produce thermal stresses sufficient to fracture surface materials, perhaps producing conduits that will allow the mobilized material to ascend to the surface. Accretional heating therefore may have been responsible for some of the resurfacing and tectonism that has taken place on many of the Saturnian and Uranian satellites. ¿ American Geophysical Union 1988 |
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Abstract |
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Keywords
Planetology, Solid Surface Planets, Interiors, Planetology, Solid Surface Planets, Origin and evolution, Planetology, Solid Surface Planets, Tectonics, Planetology, Solid Surface Planets, Volcanism |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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