Aluminum Abundances on the Red Giant Branch: Testing Helium Mixing as a Second Parameter

Abstract

We present new data and discuss the relationship between the Al abundances on the red giant branches (RGBs) and the horizontal-branch (HB) morphologies of the second-parameter pair of globular clusters M3 and M13. Since Al is produced during RGB evolution inside the H-burning shell where He is synthesized, its overabundance in stellar atmospheres can indicate He mixing, which has been shown to be a viable second parameter in explaining HB morpohogies.

2 pages, 2 figures, to appear in Galaxies: Connecting the Distant Universe with the Local Fossil Record

References in corpus (2)

• Multimodal Distributions along the Horizontal Branch
• Proton-Capture Nucleosynthesis in Globular Cluster Red Giant Stars