Solutions of core–envelope models for planet TOI-5398 b. (Left) Core radius vs. theoretical planetary radius for total mass fixed at the measured value and a rock-ice core (locus of purple points) or a rock-iron core (green points). The vertical line indicates the measured planetary radius. The two black points mark two different configurations selected for exploring the photoevaporation history of the planet. (Right) Similar to the previous plot but for the atmospheric mass fraction.