Researchers at the Department of Energy's (DOE) Oak Ridge National Laboratory (ORNL) and Michigan State University (MSU) have successfully replicated a reaction that occurs when a neutron star accumulates mass from a nearby star. Neutron stars, known for their extreme density and strong gravitational pull, can siphon hydrogen and helium from companion stars, leading to surface explosions that generate new chemical elements.

This collaborative effort includes contributions from nine institutions across three countries and utilizes the Facility for Rare Isotope Beams, a DOE Office of Science user facility managed by MSU. The research team recreated the nuclear reaction using the world's highest-density helium jet in a controlled laboratory environment. By directing a beam of the unstable isotope argon-34 at a helium-4 nuclei target, they simulated the conditions found in space. High-resolution detectors measured the energies and angles of the resulting particles, allowing the scientists to deduce the reaction dynamics through energy and momentum conservation.

The findings detailed the frequency of these nuclear reactions and identified the energy state of the newly formed potassium element. These results corresponded with existing theoretical models. The next phase of research will determine if the statistical model applies to other stellar reactions beyond those recreated on Earth.

"Our result has shown that the statistical model is valid for this particular reaction, and that removes a tremendous uncertainty from our understanding of neutron stars," said Kelly Chipps, who is leading the effort at ORNL. "It means that we now have a better grasp of how those nuclear reactions are proceeding."

The research received support from DOE's Office of Science, the National Science Foundation, and ORNL's Laboratory Directed Research and Development program.

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