STAR-FORMATION AND THE SINGULAR ISOTHERMAL SPHERE

We caution against approximating the initial conditions for protostell ar collapse with a singular isothermal sphere. First, it is very unlik ely that nature can assemble anything like a singular isothermal spher e. Secondly, collapse of a singular isothermal sphere would seem to be severely prejudiced against binary formation either by fragmentation during collapse, or by disc instability following collapse. It is ther efore appropriate to explore star formation paradigms which (a) involv e initial conditions which are far less focused than the singular isot hermal sphere, and (b) take into account impulsive dynamical and therm odynamic processes - reflecting the rapidly varying environments in wh ich stars are formed. Even in relatively quiescent regions like Taurus , such processes must be reckoned with; they cannot realistically be r elegated to the status of small perturbations on an essentially quasis tatic theme.