Are the outflows in FU Orionis systems driven by the stellar magnetic field?

FU Orionis (FUOR) outbursts are major optical brightening episodes in low-mass protostars that evidently correspond to rapid mass-accretion events in the innermost region of a protostellar disc. The outbursts are accompanied by strong outflows, with the inferred mass outflow rates reaching ∼ 10 % of the mass inflow rates. Shu et al. proposed that the outflows represent accreted disc material that is driven centrifu-gally from the spun-up surface layers of the protostar by the stellar magnetic field. This model was critiqued by Calvet et al., who argued that it cannot reproduce the photospheric absorption-line shifts observed in the prototype object FU Ori. Calvet et al. proposed that the wind is launched, instead, from the surface of the disc on scales of a few stellar radii by a non-stellar magnetic field. In this paper we present re-sults from numerical simulations of disc accretion on to a slowly rotating star with an aligned magnetic dipole moment that gives rise to a kilogauss-strength surface field. We demonstrate that, for parameters appropriate to FU Ori, such a system can develop a strong, collimated disc outflow of the type previously identified by Romanova et al