Formation of Unipolar Outflow and Protostellar Rocket Effect in Magnetized Turbulent Molecular Cloud Cores

Daisuke Takaishi  (Kagoshima University)

Observed molecular outflows exhibit various asymmetrical features, including unipolar and bending outflows. Revealing the formation and early evolution of such asymmetrical outflows, especially the unipolar outflows, is essential for a better understanding of the star and planet formation because they can dramatically change the mass accretion and angular momentum transport to the protostars and protoplanetary disks. Here, we conduct the three-dimensional non-ideal magnetohydrodynamics simulations to investigate the formation and early evolution of the asymmetrical outflows in magnetized turbulent isolated molecular cloud cores. The unipolar outflow forms even in the single low-mass protostellar system. The results show that the unipolar outflow is driven in the cloud cores with the initial Alfvén Mach number of MA>1. Furthermore, we find the protostellar rocket effect of the unipolar outflow, which is similar to the launch and propulsion of a rocket; the unipolar outflow ejects the protostellar system from the central dense region to the outer region of the parent cloud core and the resulting ram pressure suppresses the additional new outflow driving. In contrast, the bending bipolar outflow is driven in the cloud cores with MA≲1. The results indicate that the ratio of the turbulent to magnetic energies of the parent cloud core plays a key role in the formation of asymmetrical protostellar outflows.