  The origin of very low-mass stars (VLMS) and brown dwarfs (BDs) is still an
unresolved topic of star formation. We here present numerical simulations of
the formation of VLMS, BDs, and planet mass objects (planemos) resulting from
the gravitational collapse and fragmentation of solar mass molecular cores with
varying rotation rates and initial density perturbations. Our simulations yield
various types of binary systems including the combinations VLMS-VLMS, BD-BD,
planemo-planemo, VLMS-BD, VLMS-planemos, BD-planemo. Our scheme successfully
addresses the formation of wide VLMS and BD binaries with semi-major axis up to
441 AU and produces a spectrum of mass ratios closer to the observed mass ratio
distribution (q > 0.5). Molecular cores with moderate values of the ratio of
kinetic to gravitational potential energy (0.16 <= beta <= 0.21) produce
planemos. Solar mass cores with rotational parameters beta outside of this
range yield either VLMS/BDs or a combination of both. With regard to the mass
ratios we find that for both types of binary systems the mass ratio
distribution varies in the range 0.31 <= q <= 0.74. We note that in the
presence of radiative feedback, the length scale of fragmentation would
increase by approximately two orders of magnitude, implying that the formation
of binaries may be efficient for wide orbits, while being suppressed for
short-orbit systems.
