2025ApJ...995..190D

Direct imaging has revealed exoplanet systems hosting multiple wide-orbit Super-Jupiters, where planet-planet interactions can shape their long-term dynamical evolution. These strong perturbations may lead to orbital instability, raising questions about the long-term survival of such systems. Shortly after formation, planet-disk interactions can shepherd planets into mean-motion resonances, which may promote long-term stability, as seen in HR 8799. However, early-stage processes such as photoevaporation and disk viscosity can influence these outcomes. The ∼5 Myr old PDS 70 system offers a unique laboratory to investigate these processes: its two massive (>4 M_Jup), wide-orbit (>20 au) giants are still embedded in their natal disk. We perform 2D hydrodynamic simulations of the system, allowing the disk to disperse via photoevaporation. Once the disk dissipates, we continue to track the planets' orbital evolution over gigayear timescales using N-body simulations. We find that the system is likely to remain stable for >1 Gyr. To assess the importance of disk-driven evolution, we compare these results with disk-free N-body simulations using orbital parameters constrained by orbit fits that include recent relative astrometry and radial velocities from the literature. In this case, we find that only ≲4% of posterior is stable for 100 Myr, highlighting the importance of considering disk-driven evolution for long-term dynamics stability of exoplanetary systems. We also simulate two three-planet configurations including the proposed inner candidate “PDS 70 d,” finding that a higher photoevaporation leads the system to become unstable in <10 Myr.