HRDs of collision between an M₁ = 0.61 M_⊙ star and a M₂ = 0.51 M_⊙ star. Left panel: Evolutionary tracks of parent stars (dashed black lines), with the position of the parent stars at the moment of the collision (cyan for the primary, red for the secondary). Right panel: Evolutionary tracks of BSS (orange; dotted lines = relaxation, solid lines = MS) and of the equivalent-mass SSE star (black dashed line). The triangle marks where the relaxation phase starts.