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Horizontal Branch stars belong to an advanced stage in the evolution of theoldest stellar galactic population, occurring either as field halo stars orgrouped in globular clusters. The discovery of multiple populations in theseclusters, that were previously believed to have single populations gave rise tothe currently accepted theory that the hottest horizontal branch members (theblue hook stars, which had late helium-core flash ignition, followed by deepmixing) are the progeny of a helium-rich "second generation" of stars. It isnot known why such a supposedly rare event (a late flash followed by mixing) isso common that the blue hook of {\omega} Cen contains \sim 30% of horizontalbranch stars 10 , or why the blue hook luminosity range in this massive clustercannot be reproduced by models. Here we report that the presence of helium coremasses up to \sim 0.04 solar masses larger than the core mass resulting fromevolution is required to solve the luminosity range problem. We model this bytaking into account the dispersion in rotation rates achieved by theprogenitors, whose premain sequence accretion disc suffered an early disruptionin the dense environment of the cluster's central regions wheresecond-generation stars form. Rotation may also account for frequentlate-flash-mixing events in massive globular clusters.

Rapidly rotating second-generation progenitors for the blue hook stars of {\omega} Cen