Similar to Fig. 2, this figure shows the orbital parameters of the four giant planets evolving in a colder disc, so lower aspect ratio, simulation C4². Additionally, the background of the figure shows the azimuthaly averaged surface density profile of the disc as a function of time throughout the simulation. For the sake of clarity, the left half of the plot shows all the planets’ orbital parameters in white. In the second half of the plot, from about 350 kyr, the phase of the gas disc’s dispersal is initiated. The vertical dashed and dotted lines mark the start t₀ and end t_f of this phase (see section Sec. 2.4 for more details). The system is stable in the resonance chain (2:1, 3:2, 5:4).