Different Modes of Star Formation II: Gas Accretion Phase of Initially
  Subcritical Star-Forming Clouds
  The accretion phase of star formation is investigated in
magnetically-dominated clouds that have an initial subcritical mass-to-flux
ratio. We employ nonideal magnetohydrodynamic simulations that include
ambipolar diffusion and ohmic dissipation. During the early prestellar phase
the mass-to-flux ratio rises toward the critical value for collapse, and during
this time the angular momentum of the cloud core is reduced significantly by
magnetic braking. Once a protostar is formed in the core, the accretion phase
is characterized by the presence of a small amount of angular momentum but a
large amount of magnetic flux in the near-protostellar environment. The low
angular momentum leads to a very small (or even nonexistent) disk and weak
outflow, while the large magnetic flux can lead to an interchange instability
that rapidly removes flux from the central region. The effective magnetic
braking in the early collapse phase can even lead to a counter-rotating disk
and outflow, in which the rotation direction of the disk and outflow is
opposite to that of the infalling envelope. The solutions with a
counter-rotating disk, tiny disk, or nonexistent disk (direct collapse) are
unique outcomes that are realized in collapse from magnetically-dominated
clouds with an initial subcritical mass-to-flux ratio.
