Detailed look at the evolution of a M_ZAMS = 47.5 M_⊙ model at Z = 0.1 Z_⊙ metallicity. Panel a shows the Kippenhahn diagram with stellar radius over-plotted in red. We note that the purple color shows regions of semiconvective mixing. Panel b shows the time evolution of the binding energy E_bind and its components: E_grav and E_int = U_th + E_rec (see Eq. (3)) together with the convective envelope mass fraction f_conv. Panels c–e show several internal profiles of the model, the position of which are marked in panels a and b with dashed vertical lines in corresponding colors. The outer convective zone is marked in bold in panel c. Solid vertical lines in panels c–e mark the core-envelope boundary for the CE evolution (i.e., the bifurcation point at X_H = 0.1).