We demonstrate that magnetically-collimated protostellar winds will sweep ambient material into thin, radiative, momentum-conserving shells whose features reproduce those commonly observed in bipolar molecular outflows. We find the typical position-velocity and mass-velocity relations to occur in outflows in a wide variety of ambient density distributions, regardless of the time histories of their driving winds.
@article{arxiv.astro-ph/9909479,
title = {Bipolar molecular outflows driven by hydromagnetic protostellar winds},
author = {Christopher D. Matzner and Christopher F. McKee},
journal= {arXiv preprint arXiv:astro-ph/9909479},
year = {2009}
}