FUNA Lunch Talk:

David Nataf

Ohio State University

Probing the Age and Helium Abundance of the Galactic Bulge Stellar Population

February 3

12:10PM, Room 230, NRAO, Edgemont Road


I discuss ongoing measurements of the red giant branch bump (RGBB) in globular clusters and the Galactic bulge, as well as comparisons with models, and how these measurements can be combined to yield a unique probe of the age-helium-metallicity relationship in the bulge. Using the OGLE-III bulge photometric survey, we find that the bulge RGBB may indicate a much higher level of helium enrichment than that observed in globular clusters, closer to Y~0.32 than Y~0.27 for stars at solar metallicity. In addition, I discuss how a helium-enhancement can be used to reconcile the age discrepancy of spectroscopic and photometric studies of the bulge, and how these questions can be better tackled in the future.