Evolution in time of the S2 simulation for γ = 1.5. The light-blue shaded area represents the HZ and the curves with q = 0.8 AU and Q = 1.5 AU represent curves of constant perihelion and aphelion, respectively. Planetary embryos are plotted as colored circles, planetesimals with black dots. The color scale represents the fraction of water of the embryos with respect to their total masses. In this case there are two planets in the HZ with masses of 1.19 M_⊕ and 1.65 M_⊕. They present 4.51% and 39.48% of the water content by mass, which represents 192 and 2326 Earth oceans. The color figure is only available in the electronic version.