case western reserve university



Binary Asteroids

Derek Richardson (University of Maryland)

Since the first discovery in 1993 of an asteroid with its own moon, many dozens of companions have been found orbiting near-Earth asteroids (NEAs), main-belt asteroids (MBAs), and Kuiper-belt objects (KBOs). Surprisingly, it seems a different mechanism is required to explain the origin of satellites in each population. I will review current observations and theoretical understanding of these small-body binaries in our Solar System, with a special emphasis on the formation of near-Earth asteroid binaries bt tidal disruption. I will present results from numerical simulations of over 100,000 different encounter scenarios between an asteroid and the Earth, where it is assumed the asteroid has little-to-no tensile strength (evidence supporting this assumption will be presented briefly). We find that our simulations produce binaries with properties consistent with the observed population, taking into account simple tidal evolution. I will also present our results in the context of Asteroid 2004 MN4, which is predicted to pass within 5 Earth radii of our planet on April 13, 2029.