Primary astrophysical site(s) of the r-process nucleosynthesis

Determine the primary astrophysical site(s) responsible for rapid neutron-capture (r-process) nucleosynthesis that produces many elements heavier than zinc, in order to resolve its role in Galactic chemical enrichment and evolution.

Background

The paper surveys the status of r-process element observations in the Milky Way and beyond, noting that while r-process elements are widely detected, the actual stellar or explosive environments where the r-process occurs remain undetermined.

Identifying the dominant production site(s) is crucial for interpreting the chemical evolution of the Galaxy and for connecting abundance patterns in metal-poor stars to specific astrophysical events.

References

However, the primary astrophysical site(s) of $r$-process\ nucleosynthesis is still unresolved, contributing to a substantial gap in our understanding of Galactic chemical enrichment and evolution.

— The $R$-Process Alliance: Detailed Composition of an $R$-Process Enhanced Star with UV and Optical Spectroscopy  (2401.12311 - Shah et al., 2024) in Introduction, Section 1

What is, however, still an open debate are the astrophysical sites in which the r-process can occur.

— Investigating the influence of the full-kinematics treatment for charged-current processes in binary neutron star mergers  (2609.19922 - Jaeger et al., 17 Sep 2026) in Section 1, Introduction