The statistics of extrasolar planetary systems indicate that the default mode
of planet formation generates planets with orbital periods shorter than 100
days, and masses substantially exceeding that of the Earth. When viewed in this
context, the Solar System is unusual. Here, we present simulations which show
that a popular formation scenario for Jupiter and Saturn, in which Jupiter
migrates inward from a > 5 AU to a ~ 1.5 AU before reversing direction, can
explain the low overall mass of the Solar System's terrestrial planets, as well
as the absence of planets with a < 0.4 AU. Jupiter's inward migration entrained
s ~ 10-100 km planetesimals into low-order mean-motion resonances, shepherding
and exciting their orbits. The resulting collisional cascade generated a
planetesimal disk that, evolving under gas drag, would have driven any
pre-existing short-period planets into the Sun. In this scenario, the Solar
System's terrestrial planets formed from gas-starved mass-depleted debris that
remained after the primary period of dynamical evolution.Comment: Main text: 5 pages, 3 figures; Supplementary Information: 5 pages, 3
figures; accepted to PNA
