⁶⁰Fe and²⁴⁴Pu deposited on Earth constrain the r-process yields of recent nearby supernovae

Natural plutonium from supernovae The rapid neutron capture process (r-process) produces many of the heavy chemical elements, but the astrophysical settings where it occurs remain unclear. Leading candidates are neutron star mergers and some types of supernovae. Wallner et al. analyzed the plutonium content of a deep-sea crust sample, identifying a few dozen atoms of the r-process isotope plutonium- 244 that were delivered to Earth within the...