Ionization-regulated star formation in magnetized molecular clouds

The present theory for the early evolution of contracting, magnetized flattened clouds in molecular clouds undergoing magnetic braking and field slip reasons that, if angular momentum is removed from disks by magnetic torques, then accretion rates and protostellar masses depend on the efficiency of braking with respect to field line slip; it can accordingly be highly dependent on ionization conditions. Accretion rates are shown to be sensitive to the ratio of magnetic to gravitational energies in the core and the ratio of field slip to disk free-fall times. Cores that accrete out of very weakly ionized packages may have their masses increased by a factor of 5-10 through a decade-increase of the material's ionization rate. 52 references.