Figure 3.

Conceptual dependence of the supply of water to a terrestrial planet in the habitable zone for a system with a Jupiter-mass giant planet. The curve is drawn under the assumption that the solar system's configuration, with Jupiter near 5 AU, is close to the peak efficiency of delivery of water from hydrated (“wet”) embryos in a primordial asteroid belt. The snowline is drawn in between 4 and 5 AU, but this is approximate. For a Jupiter with orbital semimajor axis of 3 AU or smaller around a solar-mass star, terrestrial planets in the habitable zone may not be stable,§ so water accreted is set to zero inward of that point. For a Jupiter at large semimajor axes, large numbers of icy planetesimals might get perturbed inward to collide with terrestrial planets (question mark on figure).