The Stars in M15 Were Born with the r-process

  title={The Stars in M15 Were Born with the r-process},
  author={Evan N. Kirby and Gina E. Duggan and Enrico Ramirez-Ruiz and Phillip Macias},
  journal={The Astrophysical Journal Letters},
High-resolution spectroscopy of stars on the red giant branch (RGB) of the globular cluster M15 has revealed a large (∼1 dex) dispersion in the abundances of r-process elements such as Ba and Eu. Neutron star mergers (NSMs) have been proposed as a major source of the r-process. However, most NSM models predict a delay time longer than the timescale for cluster formation. One possibility is that a NSM polluted the surfaces of stars in M15 long after the cluster finished forming. In this case… 
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