Impact of Decay-Chain Feeding by Long-Lived Heavy Nuclei on Nuclear Cosmochronology
Abstract
Nuclear cosmochronology provides an independent method for determining the ages of astrophysical objects without relying on Galactic chemical evolution models. Long-lived radioactive actinides synthesized via the rapid neutron-capture process (r-process) particularly thorium and uranium serve as ideal chronometric nuclei. However, predicting the initial abundances of these nuclei and their subsequent long-term evolution remains a major source of uncertainty in nuclear cosmochronology. In this work, we investigate the impact of decay-chain feeding from long-lived progenitor nuclei on nuclear cosmochronology and estimate the corresponding age corrections. We develop a self-consistent radioactive decay network that includes all relevant decay pathways and couple it to r-process nucleosynthesis calculations. By tracking the long-term evolution of r-process nucleosynthesis based on neutron star merger trajectories, the dominant long-lived nuclei shaping the evolution of the chronometric elements Th and U are identified as 232Th, 235U, 236U, 238U, and 244Pu. It is found that delayed feeding substantially modifies the long-term evolution of actinides particularly for 232Th, which receives significant late-time contributions from heavier progenitor nuclei such as 244Pu and 236U. As a consequence, the U/Th and Th/X chronometers exhibit significant sensitivity to delayed feeding from the progenitor nuclei 244Pu and 236U, with age corrections reaching ∼5~Gyr. These results suggest that decay-chain feeding from long-lived progenitor nuclei plays a crucial role in nuclear cosmochronology and should be properly accounted for in age determinations based on actinide chronometers.
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BibTeX
@misc{chen2026impact,
title = {{Impact of Decay-Chain Feeding by Long-Lived Heavy Nuclei on Nuclear Cosmochronology}},
author = {Qiu-Hong Chen and Meng-Hua Chen and Xianlin Yang and En-Wei Liang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.14526},
eprint = {2610.14526},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.14526},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Impact of Decay-Chain Feeding by Long-Lived Heavy Nuclei on Nuclear Cosmochronology
AU - Qiu-Hong Chen
AU - Meng-Hua Chen
AU - Xianlin Yang
AU - En-Wei Liang
PY - 2026
DA - 2026/10/10
PB - arXiv
DO - 10.48550/arxiv.2610.14526
UR - https://arxiv.org/abs/2610.14526
AB - Nuclear cosmochronology provides an independent method for determining the ages of astrophysical objects without relying on Galactic chemical evolution models. Long-lived radioactive actinides synthesized via the rapid neutron-capture process (r-process) particularly thorium and uranium serve as ideal chronometric nuclei. However, predicting the initial abundances of these nuclei and their subsequent long-term evolution remains a major source of uncertainty in nuclear cosmochronology. In this work, we investigate the impact of decay-chain feeding from long-lived progenitor nuclei on nuclear cosmochronology and estimate the corresponding age corrections. We develop a self-consistent radioactive decay network that includes all relevant decay pathways and couple it to r-process nucleosynthesis calculations. By tracking the long-term evolution of r-process nucleosynthesis based on neutron star merger trajectories, the dominant long-lived nuclei shaping the evolution of the chronometric elements Th and U are identified as ^232Th, ^235U, ^236U, ^238U, and ^244Pu. It is found that delayed feeding substantially modifies the long-term evolution of actinides particularly for ^232Th, which receives significant late-time contributions from heavier progenitor nuclei such as ^244Pu and ^236U. As a consequence, the U/Th and Th/X chronometers exhibit significant sensitivity to delayed feeding from the progenitor nuclei ^244Pu and ^236U, with age corrections reaching ∼5~Gyr. These results suggest that decay-chain feeding from long-lived progenitor nuclei plays a crucial role in nuclear cosmochronology and should be properly accounted for in age determinations based on actinide chronometers.
ER -