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arXiv · 2601.17246

The r-Process: History, Required Conditions, Astrophysical Sites, and Observations

Friedrich-Karl Thielemann·John J. Cowan
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Abstract

This review of the rapid-neutron-capture (i.e. r-) process starts with determining the Solar System r-abundance pattern via first obtaining (and subtracting) the contribution from the slow-neutron capture (s-) process. We emphasize the extensive work in this area by our late colleague Roberto Gallino and continue in an overview, concentrating on attempts to reproduce the solar r-process pattern with historical site-independent approaches, based on nuclear physics far from stability. In a second step we address the existing proposals for astrophysical sites. Among stellar observations we start with available observations of individual events before analyzing low-metallicity stars, which witness r-process contributions in the early Galaxy. We conclude with a comparison of observations and model predictions, focusing on our present ability to identify the responsible individual astrophysical sites by their imprint in Galactic evolution.

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Friedrich-Karl Thielemann, John J. Cowan. 2026-01-24. The r-Process: History, Required Conditions, Astrophysical Sites, and Observations. https://arxiv.org/abs/2601.17246

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