  Geochemical and astronomical evidence demonstrate that planet formation
occurred in two spatially and temporally separated reservoirs. The origin of
this dichotomy is unknown. We use numerical models to investigate how the
evolution of the solar protoplanetary disk influenced the timing of protoplanet
formation and their internal evolution. Migration of the water snow line can
generate two distinct bursts of planetesimal formation that sample different
source regions. These reservoirs evolve in divergent geophysical modes and
develop distinct volatile contents, consistent with constraints from accretion
chronology, thermo-chemistry, and the mass divergence of inner and outer Solar
System. Our simulations suggest that the compositional fractionation and
isotopic dichotomy of the Solar System was initiated by the interplay between
disk dynamics, heterogeneous accretion, and internal evolution of forming
protoplanets.
