The Effect of Misalignment between the Rotation Axis and Magnetic Field on the Circumstellar Disk

Abstract

Abstract The formation of circumstellar disks is investigated using three-dimensional resistive magnetohydrodynamic simulations in which the initial prestellar cloud has a misaligned rotation axis with respect to the magnetic field. We examine the effects of (i) the initial angle difference between the global magnetic field and the cloud rotation axis (θ 0) and (ii) the ratio of the thermal to gravitational energy (α 0). We study 16 models in total and calculate the cloud evolution until ∼5000 yr after protostar formation. Our simulation results indicate that an initial nonzero θ 0 (>0) promotes disk formation but tends to suppress outflow driving for models that are moderately gravitationally unstable, α 0 ≲ 1. In these models, a large-sized rotationally supported disk forms and a weak outflow appears, in contrast to a smaller disk and strong outflow in the aligned case (θ 0 = 0). Furthermore, we find that when the initial cloud is highly unstable with small α 0, the initial angle difference θ 0 does not significantly affect the disk formation and outflow driving.