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Stars form in dense cores of molecular clouds that are observed to besignificantly magnetized. In the simplest case of a laminar (non-turbulent)core with the magnetic field aligned with the rotation axis, both analyticconsiderations and numerical simulations have shown that the formation of alarge, $10^2\au$-scale, rotationally supported protostellar disk is suppressedby magnetic braking in the ideal MHD limit for a realistic level of coremagnetization. This theoretical difficulty in forming protostellar disks istermed "magnetic braking catastrophe". A possible resolution to this problem,proposed by \citeauthor{HennebelleCiardi2009} and \citeauthor{Joos+2012}, isthat misalignment between the magnetic field and rotation axis may weaken themagnetic braking enough to enable disk formation. We evaluate this possibilityquantitatively through numerical simulations. We confirm the basic result of\citeauthor{Joos+2012} that the misalignment is indeed conducive to diskformation. In relatively weakly magnetized cores with dimensionlessmass-to-flux ratio $\gtrsim 5$, it enabled the formation of rotationallysupported disks that would otherwise be suppressed if the magnetic field androtation axis are aligned. For more strongly magnetized cores, disk formationremains suppressed, however, even for the maximum tilt angle of $90\degree$. Ifdense cores are as strongly magnetized as indicated by OH Zeeman observations(with a mean dimensionless mass-to-flux ratio $\sim 2$), it would be difficultfor the misalignment alone to enable disk formation in the majority of them. Weconclude that, while beneficial to disk formation, especially for therelatively weak field case, the misalignment does not completely solve theproblem of catastrophic magnetic braking in general.

Does Magnetic Field-Rotation Misalignment Solve the Magnetic Braking Catastrophe in Protostellar Disk Formation?