Transuranic Fission Fragments in Stars

Recent observations of the chemical compositions of metal-poor stars suggest that fission fragments of transuranic elements contributed to the abundance patterns of stars enhanced in products of rapid neutron-capture process (r-process) nucleosynthesis. The elements Ru, Rh, Pd, and Ag (atomic numbers 44 ≤ Z ≤ 47, mass numbers 99 ≤ A ≤ 110) and heavier elements (63 ≤ Z ≤ 78, A > 150) appear to be coproduced as the lighter and heavier fission fragment peaks from transuranic nuclei. If so, then nuclei with A > 260 may be regularly produced in r-process events. I will present the evidence for this discovery, and I will explore how this signature can be used to break the degeneracy between "yields" and "dilution" in star-forming environments, such as the low-mass dwarf galaxies where r-process-enhanced stars are likely born.