DPS Meeting, Madison, October 1998
Session 21. Planetary Formation and Dynamics
Contributed Oal Parallel Session, Tuesday, October 13, 1998, 2:00-3:40pm, Madison Ballroom D.

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[21.10] Radial Migration of Planets Embedded in a Massive Planetesimal Disk

J.M. Hahn, R. Malhotra (LPI)

Prior investigations have shown that the orbits of the giant planets can migrate while they are still embedded in a remnant disk of planetesimal debris (Fernandez and Ip 1984). This hypothesis is further motivated by the highly eccentric and inclined orbits of Pluto and its cohort of Kuiper Belt objects that lie at Neptune's mean-motion resonances. One natural explanation for the origin of these peculiar orbits is that these bodies were captured by Neptune's sweeping resonances as the planet's orbit expanded radially outwards (Malhotra 1993, 1995).

We have investigated the planet-migration phenomenon via direct numerical integration of a system of giant planets embedded in a massive planetesimal debris disk. We find that the rate and radial extent \Delta a of planet-migration varies with the disk mass Md. Although most of the debris disk is ultimately ejected by the giant planets, a small fraction of the disk gets emplaced in the Oort Cloud. These models also indicate that once the giant planets have stirred up the planetesimal disk, the terrestrial zone of the solar system suffers a period of considerable bombardment. Estimates of how all these phenomena (e.g., planet-migration \Delta a, the development of the Oort cloud, and impacts in the terrestrial zone) scale with the disk mass Md shall be presented at conference time. Comparison of model results to observations of the present Kuiper Belt promise to yield an estimation for the disk mass Md during the epoch of planet-migration.

The author(s) of this abstract have provided an email address for comments about the abstract: hahn@lpi.jsc.nasa.gov

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