The Effect of Yarkovsky Thermal Forces on the Dynamical Evolution of Asteroids and Meteoroids

Abstract

The Yarkovsky effect is a thermal radiation force that causes objects to undergo semimajor axis drift and spinup/spindown as a function of their spin, orbit, and material properties. This mechanism can be used to (1) deliver asteroids (and meteoroids) with diameter D < 20 km from their parent bodies in the main belt to chaotic resonance zones capable of transporting this material to Earth-crossing orbits, (2) disperse asteroid families, with drifting bodies jumping or becoming trapped in mean-motion and secular resonances within the main belt, and (3) modify the rotation rates of asteroids a few kilometers in diameter or smaller enough to possibly explain the excessive number of very fast and very slow rotators among the small asteroids. Accordingly, we suggest that nongravitational forces, which produce small but meaningful effects on asteroid orbits and rotation rates over long timescales, should now be considered as important as collisions and gravitational perturbations to our overall understanding of asteroid evolution.