The past, present, and future of r-process enhanced stars.

Terese Hansen

Texas A&M University

A small fraction of old, metal-poor stars exhibits large enhancements in elements produced in the rapid neutron capture (r-)process. Their chemical composition, mapped through detailed abundance analysis, is a direct fingerprint of the elements produced in the stellar generation before them. This makes them excellent laboratories for studying the r-process. The first r-process enhanced star was discovered over 30 years ago. Since then, about 30 highly r-process enhances stars have been found in the Milky Way halo. However, in 2016 the R-Process Alliance (RPA) initiated a successful new search to uncover bright metal-poor halo stars with r-process element enhancements. To date, the RPA has collected spectra of ~2000 stars and discovered over 70 new highly r-process enhanced. I will report on RPA efforts over the past four years and plans for the future. I will also review recent detections of r-process enhanced stars in Milky Way satellites where r-process enhanced stars have been detected in a number of systems providing a birth environment for these stars.