A. Kunder Abstract

The RR Lyrae Instability Strip in the Split Horizontal Branch Globular Cluster NGC 6569

A. Kunder (NOAO/CTIO), P. Stetson, M. Catelan, A. Walker, S. Cassisi, C. Johnson, and M. Soto

Of the three globular clusters with double HBs, only NGC 6569 hosts a sizable population of RR Lyrae variables, stars relatively straightforward to identify based on their colors and variability, therefore enabling the selection of samples with little contamination. Further, because of their relatively uniform absolute magnitude, they are powerful tools to determine distances and their pulsation properties are sensitive to the Helium abundance of their host system.  It is therefore of interest to use these stars to unravel the nature of the newly found HB complexities in NGC 6569.