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Differentiation, Planetary

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Encyclopedia of Astrobiology


Planetary differentiation is the separation of different constituents of planetary materials resulting in the formation of distinct compositional layers. Denser material tends to sink into the center and less dense material rises toward the surface. If internal differentiation of a terrestrial planet has run to completion, the interior would be subdivided into an iron-rich metallic core and a silicate mantle, overlain by a chemically distinct crust enriched in basalt.


The accretion of the terrestrial bodies from planetesimals provides the initial source of energy for subsequent planetary evolution. The amount of kinetic energy converted to heat during accretion is not well known because it is strongly dependent on specific formation timescales and environmental conditions. Heat sources, other than deposition of impact energy during accretion, are the release of energy through gravitational separation of light and dense constituents, the decay of radioactive heat...

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Correspondence to Frank Sohl .

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Sohl, F., Breuer, D. (2014). Differentiation, Planetary. In: Amils, R., et al. Encyclopedia of Astrobiology. Springer, Berlin, Heidelberg.

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