Inner solar system dynamical analogs for plutinos

Abstract

By studying orbits of near-Earth asteroids potentially in 2:3 mean motion resonance with Earth, Venus, and Mars, we have found plutino analogs. We identify 23 objects in the inner solar system dynamically protected from encounter through this resonance. Plutinos in the Kuiper belt share similar remarkable 2:3 mean motion resonant properties of Pluto with respect to Neptune. These objects orbit the Sun twice for every three Neptune orbits, in such a way that close approaches to Neptune are impossible. Inner solar system “plutinos” avoid their respective associated planet in much the same way. As many as 15% of Kuiper Belt objects share the 2:3 resonance, but are poorly observed. Since the resonant condition does not allow the secondary body to have ever been near the primary, a resonance sweeping mechanism is preferred to explain the origin of Pluto and plutinos. This mechanism likely did not operate in the inner solar system, but scattering by the next outer planet is a potential entry to 3:2 resonance with Venus and Earth. Mars plutinos, on the other hand, may be primordial objects as they are not planet crossing. The analogue resonant systems apparently arise from a different mechanism than the resonance sweeping and scattering thought to apply in the Kuiper Belt.