Layered structure of Earth embryos considered in this work. Embryos are divided into a rocky interior and a surrounding gas envelope accreted from the primordial nebula of the solar system. We assume that the rocky interior is made of an innermost iron core and an outer silicate mantle, analogous to the Earth’s current internal structure. As argued in Section 2.1, the energy transport within the inner and outer atmospheric layers is set by convection and radiation, respectively, which follows from the Schwarzschild criterion. Note that the figure is not to scale. In reality, the envelope dominates the volume despite its small contribution to the total embryo mass.