New Highly r-Process-Enhanced Halo Stars

There are roughly 25 very metal-poor (VMP; [Fe/H] < -2.0), highly r-process-enhanced (`r-II' [Eu/Fe] > + 1.0) stars currently known, discovered over the past 20+ years. These stars provide nearly pure signatures of r-process events early in the Galactic history. We are conducting a high-resolution follow-up survey of RAVE and other bright targets to identify a total of > 100 r-II stars. Our pilot runs on the du Pont 2.5-m at Las Campanas Observatory and the ARC 3.5-m at Apache Point Observatory have already identified up to fourteen new r-II stars. We are continuing our high-resolution follow-up efforts to constrain the astrophysical site(s) and nature of the r-process.