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Licensed Unlicensed Requires Authentication Published by De Gruyter October 30, 2018

Liquid properties in the Fe-FeS system under moderate pressure: Tool box to model small planetary cores

Guillaume Morard, Johann Bouchet, Attilio Rivoldini, Daniele Antonangeli, Mathilde Roberge, Eglantine Boulard, Adrien Denoeud and Mohamed Mezouar
From the journal American Mineralogist


Physical properties of liquid Fe-S alloys (from 10 to 50 at%S) under high pressure were investigated by in situ X‑ray diffraction (up to 5 GPa and 1900 K) and by ab initio calculations. The local structure of Fe-S liquid alloys clearly shows how S modifies the local arrangement of the Fe atoms. Density has been extracted from the diffuse scattering by minimization of the oscillation in the short distance of the radial distribution function g(r). Two different formalisms for the P-V-T-X equation of state are presented to model density and sound velocity as a function of pressure, temperature, and sulfur content. Based on these results, Moon’s core composition is discussed. This coherent data set will serve as a thermodynamically consistent ground for modeling the core of small telluric planets and large icy satellites.


The authors thank Stany Bauchau (ESRF) for his help with the X‑ray experiments. This work was supported by the Planetlab program of the French National Research Agency (ANR), grant No. ANR-12-BS04-001504. A.R. is supported by the Belgian PRODEX program managed by the European Space Agency in collaboration with the Belgian Federal Science Policy Office

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Received: 2017-11-23
Accepted: 2018-07-06
Published Online: 2018-10-30
Published in Print: 2018-11-27

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