On the formation of brown dwarfs

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 postformation 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 circumbinary disks. Through postformation dynamical interaction with their host binary stars, young brown dwarfs are either scattered to large distances or removed, with modest speed, from their cradles.