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The First Stars and Galaxies: Challenges for the Next Decade Participants
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Talk
Title: Magnetohydrodynamics of Population III Star Formation Author(s): Masahiro Machida Abstract: We study jet and fragmentation processes in a collapsing primordial cloud using three-dimensional MHD simulations. Starting from a rotating magnetized spherical cloud, we follow the evolution of the cloud until the protostar formation epoch. The evolution of collapsing primordial clouds is characterized by the ratio of the initial rotational energy to the magnetic energy, \beta_0 / \gamma_0. When the cloud rotates rapidly with \beta_0 > \gamma_0, fragmentation occurs before protostar formation, but no jet appears after protostar formation. On the other hand, when the initial cloud has the magnetic field of B_0 >10^-9G and \gamma_0 > \beta_0, a strong jet appears after protostar formation without fragmentation. Our results indicate that Population III protostars frequently show fragmentation and protostellar jets. Population III stars are therefore born as binary or multiple stellar systems; as in present-day star formation, they can drive strong jets that disturb the interstellar medium significantly, and thus they may induce the formation of next generation stars.
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