New krypton-88 measurement helps explain how stars produce strontium

By the Everything Space news desk · 17 Sep 2026 · written from the sources below

Image: Phys.org

Refined neutron-capture data narrow a nuclear physics gap that had left star models unable to account for observed strontium levels.

Researchers have made the first experimental measurement of a nuclear reaction that appears central to explaining how strontium forms inside certain stars. The work focused on how the isotope krypton-88 captures neutrons, a process that had been a major source of uncertainty in models of heavy-element formation.

Using indirect experimental methods, the team cut the uncertainty in this neutron-capture rate from roughly a factor of eight down to about a factor of three. They found that the actual rate is consistently lower than theoretical predictions had assumed.

When the team fed this more accurate rate into models of the intermediate neutron-capture process, a mechanism thought to operate in certain aging stars, the predicted strontium output increased and aligned more closely with what astronomers actually observe in old stars. This is significant because strontium abundances have long been difficult to reproduce using established stellar nucleosynthesis theories.

To obtain the data, scientists used a specialized detector at a Department of Energy accelerator facility, generating krypton-89 by adding a neutron to krypton-88 and analyzing the resulting gamma-ray emissions to infer the capture rate indirectly, since such reactions are difficult to observe directly due to short-lived isotopes and rare reaction occurrences.

Strontium is relevant both in practical applications, such as dating and origin analysis of archaeological materials, and in astrophysics, where its abundance patterns in ancient stars offer clues about the earliest element-forming processes in the universe.

With this nuclear physics uncertainty largely resolved, the researchers say the next step is refining the astrophysical side of the models, particularly factors like neutron density and the timing of nuclear burning inside stars, to further close the gap between simulations and observations of old stars.

Written in Everything Space’s own words by our news-desk model from the sources above, and checked against them in code: every number in this report appears in its sources, and no sentence is copied from them.