DDA 33rd Meeting, Mt. Hood, OR, April 2002
Session 4. Kuiper Belt
Monday, April 22, 2002, 4:10-4:50pm

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[4.01] Normal Modes of a Perturbed Particle Belt

Wm. R. Ward (Department of Space Studies, SwRI)

The orbital inclinations of a bounded, self-gravitating particle belt subject to secular perturbations from an inclined planet is studied. The particle belt is shown to have discrete modes and pattern speeds where the wave behavior is very pronounced compared to the non-wave behavior. The response is in the form of a standing wave produced by bending wave reflections at the secular resonance and at a finite outer edge of the disk. In the absence of dissipation, the standing wave pattern consists of inclined annuli with nodes alternately aligned and anti-aligned with the perturber's node. In this case, the net torque between disk and perturber vanishes, with equal angular momentum fluxes carried by the incoming and outgoing wave trains. We apply this resonant cavity theory to Neptune's perturbations of the primordial Kuiper belt. If the nodal regression rate of Neptune was close to one of the disk's normal mode frequencies, very high inclinations compared to that of the planet would result for this population. We assess whether the migration of Neptune and/or erosion of the belt could have tuned the system into such a resonant state.


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Bulletin of the American Astronomical Society, 34, #3
© 2002. The American Astronomical Society.