Population III Star Formation in Magnetized Primordial Clouds

Abstract

The evolution of primordial collapsing clouds and formation of proto-Population III stars are investigated using three-dimensional ideal MHD simulation. We calculated the evolution of magnetized primordial clouds from the prestellar stage until the epoch after the proto-Population III star formation, spatially resolving both parsec-scale clouds and sub-AU scale protostars. The formation process of proto-population III star is characterized by the ratio of rotational to magnetic energy of the parent cloud. When the rotational energy is larger than the magnetic energy, fragmentation occurs in the collapsing primordial cloud before the proto-Population III star formation and binary or multiple system appears. Instead, when the magnetic energy is larger than the rotational energy, strong jet with >100km s^-1 is driven by circumstellar disk around the proto-population III star without fragmentation. Thus, even in the early universe, the magnetic field plays an important role in the star formation process.