SPOCK dynamical stability map for the three-planet validated system, computed over 10⁹ orbits, in the plane of TOI-789 d mass vs. the common orbital eccentricity of all planets, with the masses of b and c held fixed at their nominal mass–radius values (J. Chen & D. Kipping 2017); d is varied because it is the most massive, dynamically dominant body. Color encodes the stability probability P(stable) and the black contour marks P(stable) = 0.5. The shaded vertical band indicates the mass of d expected from its measured radius (1.40 R_⊕). The map shows that stability requires low eccentricity (e ≲ 0.05 at the expected mass), eccentricity rather than mass being the limiting factor.