The asteroid belt and Mars' small mass explained by large-scale gas-driven migration of Jupiter

Dynamical simulations of terrestrial planet accretion consistently fail to produce reasonable Mars analogs; planets at Mars' orbital distance are systematically too massive [1]. A recent model, dubbed the "Grand Tack", has found that the inward migration of Jupiter to 1.5 AU, and its subsequent outward migration, can explain the small mass of Mars [2, 3]. This migration, described below, must have occurred while the gas disk was still present, during the first 3-10 Myr of solar system evolution. The asteroid belt is a first-order constraint for this model, as its survival and structure must be accounted for after the migration of the giant planets. The work we present provides an explanation for the compositional and orbital structure of the asteroid belt as the result of Jupiter and Saturn scattering bodies from two different source populations onto stable orbits in the asteroid belt