Sustained outward migration in the Grand Tack under realistic gas accretion

Establish whether sustained long-range outward migration of Jupiter and Saturn in a shared gap, as required by the Grand Tack scenario, can be maintained under realistic concurrent gas accretion during the protoplanetary disk phase.

Background

In the Grand Tack scenario, Jupiter first migrates inward and later, after Saturn catches up and the pair share a common gap, both migrate outward, effectively ‘tacking’ and reshaping the inner Solar System. This mechanism can deplete Mars’ feeding zone and restructure the asteroid belt to help reproduce the terrestrial planets.

Outward joint migration depends on specific disk conditions and the evolving Jupiter–Saturn mass ratio. The key uncertainty highlighted is whether such long-range outward migration can persist when realistic gas accretion onto both planets is included.