C/O mass ratio in planets of the planet population synthesis of A13 for the model with irradiation (left) and without irradiation (right) in a mass-semimajor axis diagram. Different contribution to the C/O ratio in planets are shown. a)–e) the C/O ratio in solids (ices and minerals); b)–f) the total C/O ratio (in solids and in gas phase); c)–g) the C/O ratio in atmospheres if ices are assumed to fully desorb into the gas phase; and d)–h) the C/O ratio obtained with the gas phase of the protoplanetary disc alone. The plot is shown for CO/H₂O = 0.2.