“People have thought fission was happening in the cosmos, but to date, no one has been able to prove it.” - Matthew Mumpower, theoretical physicist at Los Alamos National Laboratory
Fission yields occur in splitting heavy atoms into lighter ones - the same process also met in nuclear weapons and reactors. It was long believed that heavy elements, beyond iron, were a product of stellar explosions, called supernovae, or when two neutron stars merged. However, we might rethink that now.
The analysis on Stellar abundances and nucleosynthesis led by Ian Roederer - an Astronomy Scientist, based on the observation of 42 stars would debate these assumptions and state that precisely the predicted correlation between the abundant presence of heavy elements and the stellar explosions was found.
At Los Alamos, besides the nuclear weapon research, some nuclear mission models were developed. The models work well when compared to measured data and thus give credence to their extrapolations where there are no measurements.