Stability plot of the possible location of a 7th planet in the stable S₆ solution (Table 5). We investigate the stability of an additional planet with 1.1 Earth masses around the location found by the Bayesian analysis. For these integrations, we varied the semi-major axis and eccentricity of the putative planet on a regular grid. The orbital angles ω and M₀ were set to the values of the statistically preferred solution, while the inclination was fixed to zero. The nominal positions of the planets as given in Table 6 are marked with white crosses.