Nuclear physicists at RIKEN have successfully created the extremely neutron-rich isotope sodium-39 (39Na), a discovery that challenges previous atomic nuclei models which suggested it should not exist. This breakthrough is crucial for advancing our understanding of nuclear structure and the astrophysical processes responsible for forming heavier elements on Earth. Sodium-39 contains 11 protons and 28 neutrons, more than double the neutrons found in the most stable sodium isotope, and its existence provides a key reference point for refining theoretical models of neutron-rich nuclei.
The creation of sodium-39 improves insights into nucleosynthesis—specifically the production of heavy metals from energetic astrophysical events, such as neutron star mergers. The existence of this isotope helps validate nuclear mass models and theories addressing the limits of nuclear stability. Following the creation of nine nuclei of 39Na during a two-day experiment at RIKEN’s Radioactive Isotope Beam Factory, physicist Toshiyuki Kubo emphasized the importance of this finding for nuclear theories and future research, as the team aims to investigate the neutron drip line for sodium and the structural characteristics of sodium-39.
