Dynamical behaviour of the primitive asteroid belt

BRUNINI, A.

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 1997 vol. 293 p. 405 - 410

0035-8711

We consider the dynamical evolution and orbital stability of objects in the asteroid belt. A simple physical model, including full gravitational perturbations from both giant planets, is used to compute the dynamical evolution of 1000 test particles simulating the primitive asteroids. The criterion of planet crossing (or close approach in the case of resonant objects) is used to reject particles from the simulation. A total of 44 percent of the particles survived for the whole time-span covered by the numerical integration (about 10 exp 9 yr). The 4:1, 3:1, and, to a lesser extent, the 2:1 Kirkwood gaps are formed in about 10 exp 7 yr of evolution, representing direct numerical evidence about their gravitational origin. We found that the rms eccentricity and inclination of the sample experience a fast increase during the first 10 exp 6 yr. The final rms eccentricity is 0.11, about 60 percent smaller than the present rms eccentricity (0.17). Nevertheless, the gravitational action of the giant planets suffices to prevent the formation of large objects, allowing catastrophic collisions and the subsequent depletion of material from this zone of the solar system.