Relationship between the orbital inclination and the mass of the donor star (M₂), with the mass of the compact object (M₁) represented by colour, for orbital periods of 2.25 (left) and 4.50 h (right). The solid cyan line and cyan shaded area correspond to a mass ratio of 0.032 and its uncertainty, respectively. The light grey dashed line marks M₁ = 3 M_⊙, and the dark grey triangular areas correspond to M₁ < 1.5 M_⊙.