Illustration of the different phases of the planet and envelope during the growth process. In the beginning, the undifferentiated planet is surrounded by a H₂/He rich envelope (Phase 1). In Phase 2, the planet has differentiated into a metallic core and a magma ocean. Enough silicates sublimate in the atmosphere to inhibit convection in this phase. In Phase 3, the region close to the surface of the planet is dominated by SiO and becomes convective again. The planet becomes hot enough to form a supercritical magma ocean in Phase 4.