Prolate cores in filamentary molecular clouds

We present a new model of molecular cloud cores that originate from filamentary clouds that are threaded by helical magnetic fields. Only modest toroidal fields are required to produce elongated cores, with intrinsic axis ratios in the range 0.1 less than or similar to q less than or similar to 0.9 and mean projected axis ratios in the range 0.2 less than or similar to [p] less than or similar to 1. Thus many of our models are in good agreement with the observed shapes of cores, such as those of Myers et al. and Ryden, which find axis ratios distributed about the mean values [p] approximate to 0.5-0.6 and q approximate to 0.4-0.5. We find that the Bonnor-Ebert critical mass is reduced by about 20% by the helical field threading our models. We also find that models are generally most elongated when the mass is significantly less than the Bonnor-Ebert critical mass for unmagnetized cores.