Growth tracks of Jupiter and Saturn. The gas giants start with an initial mass of 10⁻² M_⊕ and grow to their current mass. Jupiter migrates from 18 au to its current orbit at 5.2 au and Saturn migrates from 21 au to 9.5 au. The migration starts at ~2.2 Myr and stops when the gas dissipates at 3 Myr. The green solid line corresponds to the core accretion phase, the orange solid line corresponds to the gas accretion phase, and the cyan solid line corresponds to the runaway gas accretion phase.