Protostars and Planets VI, Heidelberg, July 15-20, 2013
Poster 1K026
MHD Modelling of Protostellar Disk Winds and Jets
Nolan, Christopher (Research School of Astronomy and Astrophysics, The Australian National University)
Sutherland, Ralph (Research School of Astronomy and Astrophysics, The Australian National University)
Salmeron, Raquel (Research School of Astronomy and Astrophysics, The Australian National University)
Bicknell, Geoff (Research School of Astronomy and Astrophysics, The Australian National University)
Abstract:
One of the outstanding challenges in star formation is the angular momentum problem. Angular momentum transport is required to allow a cloud core to collapse to form a star. Angular momentum in the initial collapsing cloud prevents the majority of material falling directly onto the protostar, instead settling into a circumstellar disk around it. It is from this point that the angular momentum must be redistributed to allow material to accrete.
Radial transport of angular momentum is accomplished via the magnetorotational instability (MRI). Vertical angular momentum transport has generally been attributed to centrifugally driven winds (CDWs) from the disk surface. Both modes of transport depend on the strength of the local magnetic field, parametrised by the ratio of the vertical Alfven speed to the isothermal sound speed, a0. MRI is expected to dominate in the presence of weak fields (a0 ≪ 1), whereas CDWs require a strong field (a0 ≲ 1).
Here we present calculations of the structure of minimum-mass solar nebula protostellar disks in strong fields (a0 = 1) around a solar mass star, focusing on the regions of these disks that may launch a CDW from their surface. These results have implications for disk-driven models of protostellar jet launching including the connection between disk properties and large scale features of jets.
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