Fragmentation, stability, and chemistry towards high-mass
J. Kauffmann, F. Wyrowski, J. Hatchell, M.A. Thompson, A.G. Gibb
We present high-resolution studies (PdBI, SMA, VLA, CARMA; Pillai et al. 2011a, A&A) of pre-cluster regions just at the onset of massive star formation. These data provide exciting, and sometimes unexpected, insights to the physics of massive star formation. First, we demonstrate that non-thermal "turbulent" motions are often much lower than often assumed (<<1 km s−1). Indeed, many massive pre-cluster cores may be out of equilibrium sub-virial structures where turbulence is too weak too support them against collapse. Second, core-envelope relative motions and envelope densities indicate that massive stars can easily accrete mass that initially resides much beyond the core boundary (i.e., as in competitive accretion). Third, the cloud structure is consistent with turbulent Jeans fragmentation, but not with thermal fragmentation.