Evolution of selected orbital parameters in the five-planet model. Left: evolution of the planetary semimajor axes, eccentricities, and the period ratio of adjacent-planet pairs. The results for planets e, d, c, b, and x are depicted with the same color-coding as in Figure 2, plus violet for Planet x. The gray region indicates the outer chaotic zone for Planet b, defined as 3 Hill radii. Right: resonant angles for each adjacent pair, trio, and quartet of planets.