6653 20240125101810.0 POSTER-2024-0012 Zhao, B. Physical Properties of Fe-S and Fe-C-S Alloys Under Planetary Core Conditions 2023 2023-12-14 MR43C-0105 The Fe-FeS binary is largely seen as the archetypal system to model the properties of the core of small to medium-sized telluric bodies. Noteworthy, while at the low pressures characteristic of the Moon the Fe-FeS is a simple binary eutectic, at the conditions relevant for planets such as such as Mercury, or satellite such as Ganymede, Io, and Europa, the Fe-S phase diagram is quite complex, with intermediate compounds of narrow stability field that incongruently melt. Fe-FeS compounds have thus been studied in the range 11-15 GPa, between room temperature to solidus, using in situ X-ray diffraction to assess stability and equation of state of the Fe3S2 solid phase. The stability field of FeS and Fe3S2 indicates that Fe3S2 is a potential crystallization product of S-rich telluric bodies and should be used as the end-member phase to model the properties of telluric planetary cores in the 12-20 GPa range together with, respectively, Fe or FeS depending on whether the S content is less than or grater than 27wt%. However, Fe3S2 is not expected to form in the cores of Europa, Io, or Ganymede, as they are too small, or in Mercury, as most likely too low in S. As C is another light element potentially present at a few wt% in the core of terrestrial planets, it is important to understand its effects on the properties of Fe-S alloys. Therefore, the local structure and density of ternary Fe-C-S liquid alloys have been studied in-situ by the combination of X-ray diffraction and absorption measurements between 1 and 5 GPa and 1600 to 1900 K. Obtained results allowed us to develop a thermodynamic model of the liquid Fe-C-S system that is used to correlate the densities proposed in recent models of the Moon with the S and C content within its core. 3PORODPLANINT/ 3PORODPLANINT/ 3PORODPLANINT NO Morard, G. Boulard, E. Boccato, S. Siersch, N. C. Rivoldini, A. Guignot, N. Henry, L. King, A. Zurkowski, C. Fei, Y. Antonangeli, D. AGU 2023 San Fransisco attilio.rivoldini@ksb-orb.be https://agu.confex.com/agu/fm23/meetingapp.cgi/Paper/1339710 3634251 http://publi2-as.oma.be/record/6653/files/zhao.pdf 14815 http://publi2-as.oma.be/record/6653/files/zhao.jpg?subformat=icon-180 icon-180 15767 http://publi2-as.oma.be/record/6653/files/zhao.gif?subformat=icon icon CPOSTER