Episodic accretion onto a protostar

Abstract

AbstractWe introduce hydrodynamic simulations in which a protostar captures a cloudlet with a relatively small angular momentum. The cloudlet accretes onto the protostar and perturbs the gas disk rotating around the protostar. This cloudlet capture can reproduce some features observed in the molecular emission lines from TMC-1A. First, the cloudlet can reproduce the blue asymmetry observed in the CS emission. Second, the cloudlet can explain the slow infall observed in the C18O emission. Third, the impact of the cloudlet can explain the offset of the SO emission from the disk center. We also argue that a warm gas should confine the cloudlet through pressure. A protostar may obtain substantial mass by capturing cloudlets.