Kengo Tomida, Kohji Tomisaka, Tomoaki Matsumoto, Yasunori Hori, Satoshi Okuzumi, Masahiro N. Machida, Kazuya Saigo
We report the first three dimensional radiation magnetohydrodynamic (RMHD) simulations of protostellar collapse with and without the Ohmic dissipation. We take many physical processes required to study star formation processes including a realistic equation of state into account and we follow the evolution from molecular cloud cores until protostellar cores are formed with sufficiently high resolutions without introducing a sink particle. The physical processes involved in the simulations and adopted numerical methods are described in detail. We can calculate only about one year after the formation of the protostellar cores with our direct 3D RMHD simulations because of the extremely short timescale in the deep interior of the formed protostellar cores, but successfully reveal the early phase of star formation processes. The thermal evolution and the structure of the first and second (protostellar) cores are consistent with previous one dimensional simulations using full radiation transfer, and considerably differ from preceding multi-dimensional studies with the barotropic approximation. The protostellar cores evolve virtually spherically symmetric in the ideal MHD models due to efficient angular momentum transport by magnetic fields, but the Ohmic dissipation enables the formation of the circumstellar disks in the vicinity of the protostellar cores as in previous MHD studies with the barotropic approximation. We also confirm that two different types of outflows are naturally launched by magnetic fields from the first cores and protostellar cores in the resistive models.
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http://arxiv.org/abs/1206.3567
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