Element abundance patterns in stars indicate fission of nuclei heavier than uranium.
basic_science · Level V
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- Record sourced from PubMed, PMID 38060658.
- Also identified by DOI 10.1126/science.adf1341.
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Abstract
The heaviest chemical elements are naturally produced by the rapid neutron-capture process (<i>r</i>-process) during neutron star mergers or supernovae. The <i>r</i>-process production of elements heavier than uranium (transuranic nuclei) is poorly understood and inaccessible to experiments so must be extrapolated by using nucleosynthesis models. We examined element abundances in a sample of stars that are enhanced in <i>r</i>-process elements. The abundances of elements ruthenium, rhodium, palladium, and silver (atomic numbers <i>Z</i> = 44 to 47; mass numbers <i>A</i> = 99 to 110) correlate with those of heavier elements (63 ≤ <i>Z</i> ≤ 78, <i>A</i> > 150). There is no correlation for neighboring elements (34 ≤ <i>Z</i> ≤ 42 and 48 ≤ <i>Z</i> ≤ 62). We interpret this as evidence that fission fragments of transuranic nuclei contribute to the abundances. Our results indicate that neutron-rich nuclei with mass numbers >260 are produced in <i>r</i>-process events.