s- and r-Process Element Abundances in the CMD of 47 Tucanæ Using the Robert Stobie Spectrograph on SALT*

A recent study by Wylie et al. (2006) has revealed that s-process element abundances are enhanced relative to iron in both red giant branch and asymptotic giant branch stars of 47 Tuc. A more detailed investigation into s-process element abundances throughout the colour-magnitude diagram of 47 Tuc is vital in order to determine whether the observed enhancements are intrinsic to the cluster. This paper explores this possibility through observational and theoretical means. The visibility of s- and r-process element lines in synthetic spectra of giant and dwarf stars throughout the colour magnitude diagram of 47 Tuc has been explored. It was determined that a resolving power of 10 000 was sufficient to observe s-process element abundance variations in globular cluster giant-branch stars. These synthetic results were compared with the spectra of eleven 47 Tuc giant branch stars observed during the performance verification of the Robert Stobie Spectrograph on the Southern African Large Telescope. Three s-process elements (Zr, Ba and Nd) and one r-process element (Eu) were investigated. No abundance variations were found such that [X/Fe] = 0.0 +/- 0.5 dex. It was concluded that this resolving power, R ~ 5000, was not sufficient to obtain exact abundances but upper limits on the s-process element abundances could be determined.