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E. K. Holmes, S. F. Dermott, B. A. S. Gustafson (University of Florida)
There is a possible connection between structure in circumstellar disks and the presence of planets, our own zodiacal cloud being a proven example. Asymmetries in such a disk could be diagnostic of planets which would be otherwise undetectable. At least three different types of asymmetries can serve to indicate bodies orbiting a star in a disk: (1) a warp in the plane of symmetry of the disk, (2) an offset in the center of symmetry of the disk with respect to the central star, and (3) density anomalies in the plane of the disk due to resonant trapping of dust particles. In the asteroid belt, collisions between asteroids supply dust particles to the zodiacal cloud. By comparison, it has been postulated that collisions between Kuiper Belt Objects (KBOs) could initiate a collisional cascade which would produce a Kuiper dust disk. A Kuiper Disk would most likely have a resonant structure, with two concentrations in brightness along the ecliptic longitude. This large scale structure arises because many of the KBOs, the Plutinos, are in the 2:3 mean motion resonance with Neptune. By running numerical integrations of particles in Pluto-like orbits, the resonant structure of the Kuiper belt can be studied by determining the percentage of particles trapped in the resonance as a function of their initial velocity and beta, where \beta = Frad/Fgrav. The dynamical evolution of the particles is followed from source to sink with Poynting Robertson light drag, solar wind drag, radiation pressure, the Lorentz force, neutral interstellar gas drag, and the effects of planetary gravitational perturbations included. The integrations are run with and without the Lorentz force to determine what effect the Lorentz force has on particles in the Kuiper Belt as a function of particle size.
This research was funded in part by a NASA GSRP grant.