The influence of pressure-dependent viscosity on the thermal evolution of super-Earths
Stamenkovic, V. and Noack, L. and Breuer, D. and Spohn, T. (2012) The influence of pressure-dependent viscosity on the thermal evolution of super-Earths. The Astrophysical Journal, 748 (1/41), pp. 1-22. The American Astronomical Society. DOI: doi:10.1088/0004-637X/748/1/41. ISSN 0004-637X.
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Official URL: http://iopscience.iop.org/0004-637X/748/1/41/
We study the thermal evolution of super-Earths with a one-dimensional (1D) parameterized convection model that has been adopted to account for a strong pressure dependence of the viscosity. A comparison with a 2D spherical convection model shows that the derived parameterization satisfactorily represents the main characteristics of the thermal evolution of massive rocky planets. We find that the pressure dependence of the viscosity strongly influences the thermal evolution of super-Earths—resulting in a highly sluggish convection regime in the lower mantles of those planets. Depending on the effective activation volume and for cooler initial conditions, we observe with growing planetary mass even the formation of a conductive lid above the core-mantle boundary (CMB), a so-called CMB-lid. For initially molten planets our results suggest no CMB-lids but instead a hot lower mantle and core as well as sluggish lower mantle convection. This implies that the initial interior temperatures, especially in the lower mantle, become crucial for the thermal evolution—the thermostat effect suggested to regulate the interior temperatures in terrestrial planets does not work for massive planets if the viscosity is strongly pressure dependent. The sluggish convection and the potential formation of the CMB-lid reduce the convective vigor throughout the mantle, thereby affecting convective stresses, lithospheric thicknesses, and heat fluxes. The pressure dependence of the viscosity may therefore also strongly affect the propensity of plate tectonics, volcanic activity, and the generation of a magnetic field of super-Earths.
|Title:||The influence of pressure-dependent viscosity on the thermal evolution of super-Earths|
|Journal or Publication Title:||The Astrophysical Journal|
|In ISI Web of Science:||Yes|
|Page Range:||pp. 1-22|
|Publisher:||The American Astronomical Society|
|Keywords:||convection; Earth; planets and satellites: general; planets and satellites: interiors; planets and satellites: physical evolution; planets and satellites: tectonics|
|HGF - Research field:||Aeronautics, Space and Transport|
|HGF - Program:||Space|
|HGF - Program Themes:||W EW - Erforschung des Weltraums|
|DLR - Research area:||Space|
|DLR - Program:||W EW - Erforschung des Weltraums|
|DLR - Research theme (Project):||W - Vorhaben Exploration des Sonnensystems (old)|
|Institutes and Institutions:||Institute of Planetary Research > Planetary Physics|
Institute of Planetary Research
|Deposited By:||Lena Noack|
|Deposited On:||27 Jun 2012 14:42|
|Last Modified:||26 Mar 2013 13:39|
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