Introduction . Wüstite (Fe 1- xO) has long been recognized for its prominent role in controlling the properties and evolution of Earth and other rocky planetary bodies1 , 2 , 3 , 4. In particular, FeO represents an end-member component in Earth’s major mineralogical systems, with its melting point being an essential parameter for constructing planetary interior models. In the FeO-MgO-SiO 2 system of the mantle, the melting curve of FeO controls crystallization sequence...