Dynamical constraints on the unseen companion. Top: companion mass M₂ versus orbital inclination i, derived from the mass function (red curve). Bottom: primary-companion separation at periastron versus i (green curve). The intersection of the primary’s radius R₁ (gray curve) and primary-companion separation (green curve) sets the stringent upper limit i ≲ 10﹩\mathop{.}\limits^{\unicode{x000b0}}﹩1 (dark green dot), corresponding to the lower mass limit M₂ ≳ 2.5M_⊙ (dark red dot). The gray hatched region denotes parameter space excluded.