Mass–radius exponent ζ_R (grey), stellar radius R (blue), and radii where the gas pressure contributes only 15% (R₁₅) and 30% (R₃₀) to the total pressure (see text), as function of the remaining stellar mass for the three models with different values of the mixing length parameter α_ML shown in Fig. 6 (the lines for ζ_R are identical). All radii are measured in units of the initial stellar radii R₀, which can be read off Fig. 5.