Temporal evolution of semi-major axis as a function of the eccentricity in the “Set 2” N-body simulations, which illustrates the most likely planetary-formation scenario. The planetary embryos (and the resulting planets) are represented by circles, which show a colour code that indicates their fraction of water by mass. The solid blue lines illustrate curves of constant pericentric distance (q = 0.08 au) and apocentric distance (Q = 0.2 au), while the light blue shaded region represents the optimistic HZ of the system.