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Thermal conductivity of H 2 O‐CH 3 OH mixtures at high pressures: Implications for the dynamics of icy super‐Earths outer shells
Author(s) -
Hsieh WenPin,
Deschamps Frédéric
Publication year - 2015
Publication title -
journal of geophysical research: planets
Language(s) - English
Resource type - Journals
eISSN - 2169-9100
pISSN - 2169-9097
DOI - 10.1002/2015je004883
Subject(s) - thermal conductivity , thermal conduction , convection , heat transfer , heat flux , thermodynamics , thermal , chemistry , convective heat transfer , conductivity , analytical chemistry (journal) , materials science , physics , chromatography
Thermal conductivity of H 2 O‐volatile mixtures at extreme pressure‐temperature conditions is a key factor to determine the heat flux and profile of the interior temperature in icy bodies. We use time domain thermoreflectance and stimulated Brillouin scattering combined with diamond anvil cells to study the thermal conductivity and sound velocity of water (H 2 O)‐methanol (CH 3 OH) mixtures to pressures as high as 12 GPa. Compared to pure H 2 O, the presence of 5–20 wt % CH 3 OH significantly reduces the thermal conductivity and sound velocity when the mixture becomes ice VI‐CH 3 OH and ice VII‐CH 3 OH phases at high pressures, indicating that the heat transfer is hindered within the icy body. We then apply these results to model the heat transfer through the icy mantles of super‐Earths, assuming that these mantles are animated by thermal convection. Our calculations indicate that the decrease of thermal conductivity due to the presence of 10 wt % CH 3 OH induces a twofold decrease of the power transported by convection.