The Binary Frequency of r-Process-Element Enhanced Metal-Poor Stars and its Implications: Chemical Tagging in the Primitive Halo of the Milky Way

Terese Hansen, Johannes Andersen, Birgitta Nordström +2

A few rare halo giants in the range [Fe/H] $\simeq -2.9\pm 0.3$ exhibit {\it r}-process element abundances that vary as a group by factors up to [$r$/Fe] $\sim 80$, relative to those…