A Lifetime of Influence: Abstracts, Talks, and Posters
 

The Role of Massive Stars in the Oxygen-Sodium Anti-correlation in Globular Clusters

George Wallerstein
University of Washington

Observations as long as 30 years ago showed that the ratio of Na/Fe varied from star-to-star within several globular clusters. In the same clusters the ratio of O/Fe also varies and there is an anti-correlation so that stars with high sodium show low oxygen. No such phenomenon is seen in halo stars of any metallicty. It is genarally agreed that at temperatures above about 30 million degrees O may be depleted by proton capture and Na may be enhanced by proton capture by the neon isotopes. There are 3 posible locations where conditions may be favorable for these nuclear reactions: 1-Within the observed stars themselves. 2-In a prior generation of relatively massive assymptotic giant branch stars. 3-In very massive rotating main sequence stars very early in the history of the globulars themselves. The last of these are closely related to the stellar types studied by Peter Conti during much of his scientific career.