Top: precession model. Component C7 is ejected from the core C0: the function χ²(i_o). The curve χ²(i_o) is convex and it does not have a minimum, i.e., there is no stable solution. Middle: BBH model (C0+C9)–C3 characterized by R_G − C3 = 0.37 mas and the mass ratio M_C3/(M_C0 + M_C9) = 0.01. Component C7 is ejected from the component C3: the function χ²(i_o). The curve χ²(i_o) has a minimum, at i_o ≈ 6.9°. Bottom: BBH model (C0+C9)–C3 characterized by R_G − C3 = 0.37 mas and the mass ratio M_C3/(M_C0 + M_C9) = 0.05. Component C7 is ejected from the stationary component C3: the function χ²(i_o). The curve χ²(i_o) does not have a minimum, i.e., there is no stable solution.