|
|||||
|
|
Collapse of weakly ionized rotating turbulent Cloud Cores |
|
| Authors: | A Hujeirat P Myers M Camenzind A Burkert |
| Institution: | a LSW-Konigstuhl, 69117 Heidelberg, Germany b CfA, 60 Garden Street, Cambridge, MA 02138, USA c MPIA, Konigstuhl, 69117 Heidelberg, Germany |
| Abstract: | In view of the Turbulent Cooling Flows scenario we carry out several 3D axisymmetric calculations to follow the evolution of magnetically subcritical weakly ionized and rotating turbulent cloud cores. Turbulent Cooling Flows appear to pronounce the effects of ambipolar diffusion considerably, inducing thereby a runaway collapse of the core already on a diluted free-fall time scale. Ambipolar diffusion significantly weakens the efficiency of magnetic braking. This implies that most of the rotational energy is trapped into the dynamically collapsing core and that initiation of outflows is prevented at least in the early isothermal phases. The trapped rotational energy is found to enhance the formation of rings that may afterwards fragment. It is shown that the central region of a strongly ionized magnetically subcritical core is principally overdense, with central density up to one order of magnitude larger than the surroundings. These results confirm that large scale magnetic fields threading a cloud core relax the supersonic random motions on an Alfvén wave crossing time. Moreover, ambipolar diffusion enhances dissipation of supersonic turbulence even more. |
| Keywords: | ISM: clouds Stars: formation Diffusion MHD (magnetohydrodynamics) Ambipolar diffusion |
| 本文献已被 ScienceDirect 等数据库收录！ | |