Asteroid collisional evolution. I - Angular momentum splash - Despinning asteroids through catastrophic collisions

It is demonstrated that there exists an angular momentum loss following catastrophic breakup due to asymmetric escape of fragments. This so-called angular momentum splash mechanism in catastrophic collisions is shown to cause a spindown relative to the postimpact spin rate computed without this effect. For asteroids about 100 km in diameter, there is a net spindown relative to the preimpact spin rate. The relevance of this effect to the spin evolution of asteroids of different sizes is examined.