Constraints on the Abundances of Carbon and Silicon in Mercury's Core From Experiments in the Fe‐Si‐C System

The composition of a planet’s core has important implications for the thermal and magmatic evolution of that planet. Here, we conducted carbon (C)solubility experiments on iron-silicon (Fe-Si)metal mixtures (up to 35 wt%(~52 atom%)Si) at 1 GPa and 800–1800°C to determine the carbon concentration at graphite saturation (CCGS) in metallic melt and crystalline metal with varying proportions of Fe and Si to constrain the C content of Mercury’s core. Our results, combined with those in the literature, show that composition is the major controlling factor for carbon solubility in Fe-rich metal with minimal effects from temperature and pressure. Moreover, there is a strong anti-correlation between the abundances of carbon and silicon in iron-rich metallic systems. Based on the previous estimates of