DPS Meeting, Madison, October 1998
Session 12. Asteroid Dynamics II
Contributed Oral Parallel Session, Monday, October 12, 1998, 3:50-5:10pm, Madison Ballroom C

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[12.02] Asteroid formation in the presence of giant planets

G.W. Wetherill, S.J. Kortenkamp (DTM, Carnegie Institution of Washington)

As shown by meteoritic data, asteroids contain a record of events in the very early history of the Solar System. Full use of this data requires understanding the processes by which the asteroids were formed, and the nature of the counterparts of the present asteroids in the early Solar System. The long range goal of this research is to provide a quantitative taxonomy of the possible modes of asteroid formation. One conceivable mode is asteroid formation (and terrestrial planet embryo formation) after the formation of Jupiter and Saturn, a suggestion recently revived by A. Boss.

The principal question addressed here is whether or not the strong gravitational perturbations of the giant planets may preclude the growth of the asteroids, either by collisional destruction or by causing their growth period to be prolonged until the epoch in which the presently observed much higher asteroidal relative velocities became established. Calculation of the expected relative velocities are discussed in an accompanying abstract by the authors. In the present work "gas dynamic" modeling indicates that formation of the asteroid assemblage at 2.6 AU is precluded unless the semimajor axis of Jupiter is beyond about 8 AU at that time, and migrated to its present position subsequent to asteroid formation. In contrast, formation of planetary embryos within 1 AU of the Sun does not seem to be seriously hindered by prior formation of giant planets.

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