Thursday, November 26, 2009 - 2:00pm
Stefanie Walch (Cardiff):
"The Formation & Early Evolution of Protostellar Disks around Low-Mass Stars"
Abstract. Pre- and protostellar cores are highly obscured. As a result the collapse phase of protostellar cores as well as the early embedded stages of forming stars are only poorly understood. The missing pieces in the puzzle of low-mass star and disk formation can only be replaced by ambitious numerical studies. We present and compare high-resolution, 3D SPH simulations of isolated molecular cloud core collapse conducted with VINE. We model the initial cores as slightly supercritical Bonnor-Ebert spheres. The observed amount of core angular momentum may be explained by regular rotation or by sub-/transonic turbulence. Depending on each specific case one or the other model is in better agreement with observed velocity gradient maps. Within this framework, the density and temperature evolution of the forming star+disk system are in the center of this study. We address the questions: 1) Are disks, which were formed from turbulent cores comparable to disks from rigidly rotating cores concerning size and mass? 2) Is a disk's temperature evolution strongly influenced by the distribution of the infalling gas? This would lead to a modified temperature structure in an early evolutionary state of turbulent disk formation. 3) Are the fragmentation properties of subsonically turbulent cores essentially different from the properties of cores in rigid rotation