From top to bottom: binding energy parameter, primary ZAMS mass, WD mass and orbital period as a function of the Roche-lobe radius of the primary, as given in Eggleton (1983). The case B, case C and TPAGB case CE episodes are represented using green, blue and red dots, respectively. The two sides show the results for two models in which α_CE = 0.3 and n(q) = 1 but without and with a fraction of the internal energy contributing to expel the envelope: α_int = 0.0 (left panels) and α_int = 0.2 (right panels). (Color version online.)