Comparison of the internal helium abundance and mass-radius profiles between the standard model (solid lines) and numerical variations with increased resolution (other lines), plotted for the case with M_ZAMS = 47.5 M_⊙ and 0.4 Z_⊙ analyzed in Sect. 3.4. As in Fig. 8, different colors correspond to different internal profiles of a model selected based on the depth of the outer convective zone (increasing as the color changes from blue to red). Vertical lines show the location of the bifurcation point for CE evolution.