A long resonant chain shaping the disk around HD 163296

ALMA observations of the protoplanetary disk around HD 163296 have revealed prominent gaps and rings in both the gas and the dust continuum and a distinctive crescent in the dust. These features along with detected departures of the disk’s Keplerian flow show clear evidence of multiple planets embedded in the disk.

Using multi-species hydrodynamic simulations (Fargo-3D) we show that the crescent likely arises as dust accumulated in the Lagrange point L5 of a Saturn-mass planet at ∼50 au. We show that this proposed planet completes a long resonance chain with outer planets lying in density gaps whose presence has been claimed using velocity perturbations. Furthermore, we show that for the observed disk parameters the planet may be undergoing convergent orbital migration, stably locking in the long resonance chain, while their resonance three-body angles can constrain their angular positions.