  The observational properties of brown dwarfs pose challenges to the theory of
star formation. Because their mass is much smaller than the typical Jeans mass
of interstellar clouds, brown dwarfs are most likely formed through secondary
fragmentation processes, rather than through the direct collapse of a molecular
cloud core. In order to prevent substantial post-formation mass accretion,
young brown dwarfs must leave the high density formation regions in which they
form. We propose here that brown dwarfs are formed in the optically thin outer
regions of circumbinary disks. Through post-formation dynamical interaction
with their host binary stars, young brown dwarfs are either scattered to large
distance or removed, with modest speed, from their cradles.
