Stability analysis of the outermost planet HD 141399e for the Keplerian fit (Table 4). For fixed initial conditions, the phase space of the system is explored by varying the semi-major axis a_e and the eccentricity e_e. As in Fig. 13, the color scale shows D values between −6 and 2. The red zone corresponds to highly unstable orbits, while the dark blue region can be assumed to be stable on a billion-years timescale. The contour curves indicate the 2, 3, 5, 10σ confidence intervals from Δχ². The best fit lies well inside a red chaotic region.