Effect of Hydrogen on the Sulfur-rich Martian Core

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Studies of Mars over the past twenty years have determined that early in its history the climate was warm enough for water to flow on its surface. Liquid water is not found on the surface of Mars today, because the surface is too cold and the atmosphere too thin. The cause of this change might be the loss of the planet’s global magnetic field, allowing the solar radiation to strip the atmosphere. This would imply a major change took place in the planet’s core, shutting off the dynamo responsible for the magnetic field. The role of hydrogen in the dynamics and structure of the Martian core is poorly understood. Hydrogen is known to form alloys with metallic iron at high pressure. This program will conduct a systematic study of the phase relations of such alloys at the pressure and temperature conditions expected for the Martian core. This research will provide Arizona State University undergraduate students with comprehensive research experiences. Teaching modules motivated by this research will be implemented in coding and data analysis courses at ASU. The primary goal of this project is to advance the understanding of the dynamics and structure of the Martian core by conducting experiments to measure the melting behavior and sub-solidus phase relations in Fe-S-H systems at pressures of 25-40 Gigapascals (GPs) expected to exist at the Martian core. To achieve this goal a series of high-pressure, high temperature experiments will be conducted for: (1) possible miscibility (or solubility) gaps in Fe-S-H systems at high pressure and high temperature conditions relevant to the Martian core, (2) the effects of hydrogen on the melting temperature of sulfide alloys and (3) sub-solidus phase relations in Fe-S-H systems at high pressures and high temperatures.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.