<sup>129</sup>I and <sup>247</sup>Cm in meteorites constrain the last astrophysical source of solar r-process elements.
basic_science · Level V
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- Record sourced from PubMed, PMID 33632846.
- Also identified by DOI 10.1126/science.aba1111.
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Abstract
The composition of the early Solar System can be inferred from meteorites. Many elements heavier than iron were formed by the rapid neutron capture process (r-process), but the astrophysical sources where this occurred remain poorly understood. We demonstrate that the near-identical half-lives [Formula: see text] of the radioactive r-process nuclei iodine-129 and curium-247 preserve their ratio, irrespective of the time between production and incorporation into the Solar System. We constrain the last r-process source by comparing the measured meteoritic ratio <sup>129</sup>I/<sup>247</sup>Cm = 438 ± 184 with nucleosynthesis calculations based on neutron star merger and magneto-rotational supernova simulations. Moderately neutron-rich conditions, often found in merger disk ejecta simulations, are most consistent with the meteoritic value. Uncertain nuclear physics data limit our confidence in this conclusion.