Exoplanet Interior

Layered terrestrial planet under the constant-density approximation: an iron core, a silicate mantle, an optional water/ice layer, an optional H/He envelope, each at its characteristic density. Mass conservation fixes the interface radii, hydrostatic equilibrium gives a closed-form central pressure, and the mass-radius curve falls on the standard families (pure iron is the densest, an H/He envelope inflates the planet). The 3D cutaway shows the layered structure as the planet rotates; the side panels track the mass-radius position and the pressure profile from centre to surface.