The main asteroid belt may have been restructured by the giant planets, Jupiter and Saturn, as they migrated to their present orbits around 4 billion years ago, a new study by scientists of the University of Arizona suggests. It is published in the most recent issue of the prestigious journal Nature (25 February 2009).
The belt lies between the orbits of Mars and Jupiter, but the region is not uniformly filled with asteroids. In distinct locations there are gaps (so-called Kirkwood gaps). Some of these gaps correspond to unstable zones, where the gravitational influence of the giant planets, Jupiter and Saturn, will eject them.
But some gaps are in zones that are currently stable, researchers David A. Minton and Renu Malhotra of the Lunar and Planetary Laboratory, University of Arizona report. These missing asteroids are likely to have been ejected during the migration of Jupiter and Saturn as the changing orbits of the planets caused different regions of the belt to be unstable.
The paper is titled 'A record of planet migration in the main asteroid belt.'