Pluto near the edge of chaos

Abstract: The dwarf planet, Pluto, has stirred the imagination of the public and of planetary scientists due to its many unusual properties. Amongst these properties is its Neptune-crossing orbit, but Pluto avoids collision with Neptune because of the protection afforded by an orbital resonance with that planet. Less well understood is the role of the other planets on the long term dynamics of Pluto. Numerical simulations teach us that the orbit of Pluto is chaotic under the perturbations from all four giant planets, and also teach that there is no dramatic manifestation of that chaos on the size and shape of the orbit of Pluto even on gigayear timescales. I will discuss some new insights about the orbital architecture of the giant planets that enable the long term stability of Pluto-like orbits. These may also yield new constraints on the orbital migration history of the giant planets.