a) Size of Roche-lobe radius of the donor as a function of its mass, M₂, for the orbital period of P = 22620.5 s. As IGR J17451−3022 is an accreting LMXB, R₂ is the actual radius of the donor. b) Relation between the system inclination and the donor mass obtained by using the measured orbital period and eclipse duration. The black solid (red dashed) curve represents the obtained relation in case of an NS accretor with M₁ = 1.26 M_⊙ (M₁ = 2 M_⊙). We also show the relation for a BH accretor of M₁ = 10 M_⊙ (blue dotted curve).