The impact of the Hall effect during cloud core collapse: Implications for circumstellar disk evolution

We perform three-dimensional radiation non-ideal magnetohydrodynamics simulations and investigate the impact of the Hall effect on the angular momentum evolution in collapsing cloud cores in which the magnetic field B and angular momentum J_ang are misaligned with each other. We find that the Hall effect noticeably changes the magnetic torques in the pseudo-disk, and strengthens and weakens the magnetic braking in cores with acute and obtuse relative angles between B and J_ang, respectively. This suggests that the bimodal evolution of the disk size may occur in the early disk evolutionary phase even if B and J_ang are randomly distributed. We show that a counter-rotating envelope forms in the upper envelope of the pseudo-disk in cloud coreswith obtuse relative angles. We also find that a counter-rotating region forms at the midplane of the pseudo-disk in cloud cores with acute relative angles. The former and latter types of counter-rotating envelopes may be associated with young stellar objects with large (r ~ 100 au) and small (r ≤ 10 au) disks, respectively.