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.
