Lab Measurements Solve Strontium Puzzle in Ancient Stars
A research team led by Caley M. Harris at Michigan State University has used laboratory measurements to address a long-standing mismatch in the chemical makeup of ancient stars. The work focuses on strontium production and the previously uncertain neutron-capture behavior of krypton-88. The new data help explain why observations of carbon-enhanced metal-poor stars showed more strontium than earlier models predicted.
The puzzle centers on old, metal-poor stars enriched in carbon. Their heavy-element ratios did not match the slow or rapid neutron-capture pathways, so scientists proposed an intermediate process. Yet models still underpredicted strontium compared with observations.
The missing input was how readily radioactive krypton-88 captures neutrons. With only a 2.8-hour half-life, it is hard to study directly. Instead, researchers at Argonne used bromine-89, which decays into krypton-89, and a SuN detector to infer the needed rate.
This result may sharpen astrophysical models of element creation in the early universe, affecting researchers who interpret ancient stellar spectra. It could also inform nuclear-physics experiments and teaching about where everyday elements originate. For the public, it may deepen appreciation of how laboratory work connects to cosmic history, though immediate practical applications are unlikely.