Type II migration strikes back -- An old paradigm for planet migration in discs

Understand

In this paper we analyse giant gap-opening planet migration in protoplanetary discs, focusing on the type II migration regime.

• According to standard type II theory, planets migrate at the same rate as the gas in the disc, as they are coupled to the disc viscous evolution; however, recent studies questioned this paradigm, suggesting that planets migrate faster than the disc material.
• We study the problem through 2D long-time simulations of systems consistent with type II regime, using the hydrodynamical grid code FARGO3D.
• Even though our simulations confirm the presence of an initial phase characterised by fast migration, they also reveal that the migration velocity slows down and eventually reaches the theoretical prediction if we allow the system to evolve for enough time.