Second Generation Stars in Globular Clusters from Rapid Radiative
  Cooling of Pre-Supernova Massive Star Winds
  Following work by W\"unsch and collaborators, we investigate a
self-enrichment scenario for second generation star formation in globular
clusters wherein wind material from first generation massive stars rapidly
radiatively cools. Radiative energy loss allows retention of fast winds within
the central regions of clusters, where it fuels star formation. Secondary star
formation occurs in $\sim3-5$ Myr, before supernovae, producing uniform iron
abundances in both populations. We derive the critical criteria for radiative
cooling of massive star winds and the second generation mass as a function of
cluster mass, radius, and metallicity. We derive a critical condition on $M/R$,
above which second generation star formation can occur. We speculate that above
this threshold the strong decrease in the cluster wind energy and momentum
allows ambient gas to remain from the cluster formation process. We reproduce
large observed second generation fractions of $\sim30-80\%$ if wind material
mixes with ambient gas. Importantly, the mass of ambient gas required is only
of order the first generation's stellar mass. Second generation helium
enrichment $\Delta Y$ is inversely proportional to mass fraction in the second
generation; a large second generation can form with $\Delta Y\sim0.001-0.02$,
while a small second generation can reach $\Delta Y\sim0.16$. Like other
self-enrichment models for the second generation, we are not able to
simultaneously account for both the full range of the Na-O anticorrelation and
the second generation fraction.
