Chemical composition as a function of mass coordinate m (panel a) and envelope binding energy as a function of radius r (panel b) of the RSG primary star. In both panels, the grey shaded area indicates the convective envelope and the vertical dot-dashed black line is the location at which the hydrogen mass fraction X = 0.1. In panel b, the released orbital energy of inspiralling companions of 1.4 and 5.0 M_⊙ are also shown (Eq. (2)) as well as the envelope binding energies as computed from the relaxed AREPO model (thick transparent lines at r ≥ 20 R_⊙; the maximum deviation with respect to the MESA model is < 5%).