Plot of the log P_i−q_i diagram for the binary grid of models from Jin et al. (in prep.), with M_{1, i} = 12.6 M_⊙. Each pixel represents one detailed binary evolution model. The color coding represents the mass of the primary star at core helium depletion. The solid lines cover the models where the radius of a single HeS of the same mass (see Fig. 2) matches their Roche lobe radius at core He depletion. White pixels are models that terminated before core-carbon ignition (see Sect. 2.4). The dotted patches correspond to the models which exhibited Case BC RLOF in the binary grid. The star marker in the top-left corner corresponds to the lowest-period model shown in Ercolino et al. (2024).