Abstract
The dynamical structure of the Kuiper Belt beyond 50 au is not well understood. Here we report results of a numerical model with long-range, slow, and grainy migration of Neptune.
The model implies that bodies scattered outward by Neptune to semimajor axes a > 50 au often evolve into resonances which subsequently act to raise the perihelion distances of orbits to q > 40 au. The implication of the model is that the orbits with 50 40 au should cluster near (but not in) the resonances with Neptune (3:1 at a = 62.6 au, 4:1 at a = 75.9 au, 5:1 at a = 88.0 au, etc.).
The recent detection of several distant Kuiper Belt Objects (KBOs) near resonances is consistent with this prediction, but it is not yet clear whether the orbits are really non-resonant as our model predicts. We estimate from the model that there should presently be similar to 1600-2400 bodies at the 3:1 resonance and similar to 1000-1400 bodies at the 4:1 resonance (for q > 40 au and diameters D > 100 km).
These results favorably compare with the population census of distant KBOs inferred from existing observations.