Presentation #322.08 in the session “Abundances & Dynamics of Galactic Star Clusters”.
The globular cluster (GC) M15 is known to host a spread in the elements that form the rapid (r-)neutron capture process, which produces heavy elements such as Europium (Eu) and Barium (Ba). High resolution spectra of RGB and AGB stars in M15 were obtained with the Michigan/Magellan Fiber System (M2FS) on the 6.5 m Clay Telescope at Las Campanas Observatory. The spectra have resolution (R ~ 30,000), signal-to-noise ratios (S/N) >25 per resolution element, and a wavelength range of 4425–4625 Å. In this poster, I report the chemical abundances of 56 RGB and 7 AGB stars in M15, a GC in the Milky Way, particularly their r-process enhancement. I will discuss the determination of atmospheric parameters, which are used to generate model atmospheres needed to fit synthetic spectra to observed spectra via the MOOG line analysis code (Sneden 1973; 2014 version). The spectrum syntheses yield derived measurements for the chemical abundances of heavy elements such as Sr, Ba, La, Ce, Nd, Sm, Eu, and Dy. These chemical abundances give us insight into the site(s) of r-process nucleosynthesis and into the structure and evolution of the Milky Way.