Author(s): , , ,
Institution(s): 1. Harvard-Smithsonian Center for Astrophysics, 2. Lick Observatory, 3. Michigan State University
A prediction is tested that a second generation of stars in globular clusters contains an enhanced abundance of helium. We report a near-infrared study of helium in red giants of the globular cluster Omega Centauri. In this cluster, the presence of helium is found to be associated with increased abundances of [Na/Fe] and [Al/Fe]. A realistic quantitative calculation of the helium line profile formed in the chromosphere of the red giants indicates that the element helium is enhanced by ≧0.17 dex in Omega Cen, signaling that high temperature H-burning has occurred in a previous generation of stars. The Helium transition at 1.08μ also offers a sensitive probe of the presence of stellar winds.