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Thursday 01 Jul 2010: Formation, Evolution and Observability of low-mass First cores
Kengo Tomida - NAOJ, Japan
Physics, 4th Floor interaction area 15:30-16:30
The first core is a hydrostatic object formed in the early phase of low mass star formation process. Although it is a transient object, the first core plays a crucial role in the star formation process. The typical angular momentum and magnetic flux of the initial cloud core are too large compared to those of the resulting main sequence star, and redistribution of the angular momentum and magnetic flux is sometimes considered to happen during the first core phase. MHD simulations show the bipolar molecular outflow is also driven just outside the first core by the magnetic Lorentz force. The first core will continuously evolve into circumstellar or protoplanetary discs. Therefore the first core is critically important because it will give us direct evidence to constrain and understand the star formation process if we could observe it. We study the early-phase of low mass star formation process, focusing on the properties of first cores. Using our nested-grid self-gravitational RMHD simulation code, we investigated the formation and evolution of the first core without assuming artificial thermal evoltuion track. Since RMHD simulation gives us realistic temperature distribution, our RMHD results can be directly compared with the observation via the post-processing radiation transfer calculation or observational visualization. We show the characteristics of the first core in the RMHD simulation and discuss its observational possibilities.