Abundance anomalies observed in globular cluster stars indicate pollution
with material processed by hydrogen burning. Two main sources have been
suggested: asymptotic giant branch stars and massive stars rotating near the
break-up limit. We discuss the potential of massive binaries as an interesting
alternative source of processed material.
We discuss observational evidence for mass shedding from interacting
binaries. In contrast to the fast, radiatively driven winds of massive stars,
this material is typically ejected with low velocity. We expect that it remains
inside the potential well of a globular cluster and becomes available for the
formation or pollution of a second generation of stars. We estimate that the
amount of processed low-velocity material that can be ejected by massive
binaries is larger than the contribution of two previously suggested sources
combined.Comment: 6 pages, 2 figures, to appear in the proceedings of IAU Symposium
266, "Star Clusters - Basic Galactic Building Blocks throughout Time and
Space", 10-14 August 2009, at the general assembly in Rio de Janeiro, Brazi