Abstract
CaIrO3-type MgSiO3 is the planet-forming silicate stable at pressures and temperatures beyond those of Earth's core-mantle boundary. First-principles quasiharmonic free-energy computations show that this mineral should dissociate into CsCl-type MgO + cotunnite-type SiO2 at pressures and temperatures expected to occur in the cores of the gas giants and in terrestrial exoplanets. At ∼10 megabars and ∼10,000 kelvin, cotunnite-type SiO2 should have thermally activated electron carriers and thus electrical conductivity close to metallic values. Electrons will give a large contribution to thermal conductivity, and electronic damping will suppress radiative heat transport.
Original language | English (US) |
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Pages (from-to) | 983-986 |
Number of pages | 4 |
Journal | Science |
Volume | 311 |
Issue number | 5763 |
DOIs | |
State | Published - Feb 17 2006 |