On the propensity of the formation of massive clumps via fragmentation
  of driven shells
  Early type massive stars drive thin, dense shells whose edges often show
evidence of star-formation. The possibility of fragmentation of these shells,
leading to the formation of putative star-forming clumps is examined with the
aid of semi-analytic arguments. We also derive a mass-spectrum for clumps
condensing out of these shells by performing Monte-Carlo simulations of the
problem. By extending on results from our previous work on the stability of
thin, dense shells, we argue that clump-mass estimated by other authors in the
past, under a set of simplifying assumptions, are several orders of magnitude
smaller than those calculated here. Using the expression for the fastest
growing unstable mode in a shock-confined shell, we show that fragmentation of
a typical shell can produce clumps with a typical mass $\gtrsim 10^{3}$
M$_{\odot}$. It is likely that such clumps could spawn a second generation of
massive and/or intermediate-mass stars which could in turn, trigger the next
cycle of star-formation. We suggest that the ratio of shell thickness-to-radius
evolves only weakly with time. Calculations have been performed for stars of
seven spectral types, ranging from B1 to O5. We separately consider the
stability of supernova remnants.
