HR: 11:35h
AN: MR22A-06    [Abstracts]
TI: Phase transformation in CaIrO3-type MgSiO3 at ultra-high PTs: implications for the solar giants and terrestrial exoplanets
AU: * Umemoto, K
EM: umemoto@cems.umn.edu
AF: Department of Chemical Engineering and Materials Science and Minnesota Supercomputing Institute, University of Minnesota, 421 Washington Ave SE, Minneapolis, MN 55455 United States
AU: Wentzcovitch, R M
EM: wentzcov@cems.umn.edu
AF: Department of Chemical Engineering and Materials Science and Minnesota Supercomputing Institute, University of Minnesota, 421 Washington Ave SE, Minneapolis, MN 55455 United States
AU: Allen, P B
EM: philip.allen@stonybrook.edu
AF: Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794-3800 United States
AB: CaIrO₃-type MgSiO₃ is the abundant planet-forming silicate, stable at pressures and temperatures (PTs) at and beyond those of Earth's core-mantle boundary (CMB). We have found using first principles quasiharmonic free energy computations that this mineral should undergo a phase transformation at PTs expected to occur in the cores of the gas giants. The transformation should also affect the thermal-chemical structure of the massive dense core of the Saturn-like exoplanet HD149026 and perhaps the mantle of Earth-like GJ876. At ~10 Mbar and ~ 10,000 K the resulting aggregate should have thermally activated carriers, causing electrical conductivity close to metallic values, and a correspondingly large electronic contribution to thermal conductivity, while simultaneously shutting down radiative heat transport because of electronic damping.
DE: 3924 High-pressure behavior
DE: 5100 PHYSICAL PROPERTIES OF ROCKS
DE: 5410 Composition (1060, 3672)
DE: 5709 Composition (1060)
SC: Mineral and Rock Physics [MR]
MN: Fall Meeting 2005