The R-Process Alliance

Stellar spectroscopy of ancient stars to unravel the origin of the heaviest elements on the periodic table

Who we are

The R-Process Alliance is an interdisciplinary collaboration of astronomers and nuclear physicists, including observers, theorists, and experimentalists. We are all dedicated to exploring and answering the biggest questions related to heavy element nucleosynthesis, in particular the rapid (r-) neutron-capture process and its astrophysical site(s) and sources. Find out more about our members here.

Our goals

Split into five main "Phases," the RPA aims to provide a robust, homogeneously analyzed database of metal-poor stars and quantify their r-process enrichment. This data set will be used to motivate studies of yields from r-process sites, Galactic Chemical Evolution, and nuclear data.

See our progress, news, and recent publications here!


Phase I: Identify bright, very metal-poor targets

Phase II: Obtain "snapshot" high-resolution spectra

Phase III: Obtain "portrait" high-resolution spectra

Phase IV: Galactic chemical evolution and modeling

Phase V: Lab measurements and theory

Acknowledgments

Investigators in the R-Process Alliance acknowledge generous finanacial support from the US National Science Foundation (NSF):

  • PHY 14-30152 (Physics Frontier Center/JINA Center for the Evolution of the Elements)

  • OISE 1927130 (International Research Network for Nuclear Astrophysics/IReNA)

  • AST 1716251 (PI A. Frebel)

  • AST 1815403 (PI I. Roederer)

  • AST 2205847 (PI I. Roederer)


and from NASA:

  • ADAP 80NSSC21K0627 (PI I. Roederer)

  • HST GO-15657 (PI I. Roederer)

  • HST GO-15951 (PI T. Hansen)

  • HST GO-17166 (PI I. Roederer)


and from the US Department of Energy (DOE):

  • DE-FG02-95-ER40934 (PI R. Surman)


and from the Swedish Research Council

  • VR 2021-05556 (PI T. Hansen)


Contact Us

Email: rprocessalliance [at] gmail.com