Fabrice Thomas & Alessandro Morbidelli (1996)
Shows Kozai resonance with Neptune can drive long‑period comet perihelia down to Uranus/Saturn distances, aiding inward injection.
Thomas and Morbidelli analyze how the Kozai resonance operates for highly eccentric, distant cometary orbits under the perturbations of the outer planets. They show that Kozai cycles can trade inclination for eccentricity in a way that substantially lowers perihelion distance, providing an efficient dynamical pathway for transferring long‑period comets from the trans‑Neptunian region into the Uranus–Saturn (and potentially Jupiter) planet‑crossing zone. The paper matters because it links a well-known secular resonance mechanism to a concrete supply channel for observable long‑period comets. It also clarifies when this mechanism is expected to be effective in the real outer solar system, where multiple planets and precession sources can disrupt idealized Kozai behavior.
Analytical secular dynamics (Kozai Hamiltonian/averaging) combined with numerical orbit integrations to map resonance behavior and perihelion evolution.
Celestial mechanics of secular perturbations and resonance dynamics (Kozai mechanism, perihelion/inclination coupling) in multi-planet systems.