Modeling of the self-consistent formation and evolution of disks as a result
of prestellar core collapse reveals an intense early phase of recurrent
gravitational instability and clump formation. These clumps generally migrate
inward due to gravitational interaction with trailing spiral arms, and can be
absorbed into the central object. However, in situations of multiple clump
formation, gravitational scattering of clumps can result in the ejection of a
low mass clump. These clumps can then give rise to free-floating low mass
stars, brown dwarfs, or even giant planets. Detailed modeling of this process
in the context of present-day star formation reveals that these clumps start
out essentially as Larson first cores and grow subsequently by accretion. In
the context of Pop III star formation, preliminary indications are that the
disk clumps may also be of low mass. This mechanism of clump formation and
possible ejection provides a channel for the formation of low mass objects in
the first generation of stars.Comment: 4 pages, 2 figures, to appear in proceedings of First Stars IV
meeting (Kyoto, Japan; 2012