Stability analysis of the circular six-planet solution (S1). The panels show the influence of changing the initial eccentricity (left) and initial mean anomaly (right) on the stability of the complete planetary system. “Red” corresponds to highly unstable orbits while “black” denotes regular motion. Each of the 100 initial conditions per planet were integrated numerically for 1 kyr, for which we then computed the stability criterion D (Eq. (2)).