Scientists have moved closer to understanding how chemical elements are born in stellar explosions and how those elements then spread through the cosmos. Two new studies, published in the July issue of Physical Review Letters, provide a more precise picture of the processes occurring during supernovae.

Titanium‑44 as an "Imprint" of the Explosion

Astronomers have long observed the bright flashes of massive stars, but the details of how the explosion actually develops remain only partially understood. One way to study supernovae is to track radioactive titanium‑44. This element forms at the moment of the explosion and continues to glow long after the flash itself has faded.

The researchers obtained experimental data on the amount of titanium‑44 produced in supernovae. It turned out that such explosions generate 35% more of this element than previously assumed. The new figures will allow for more accurate computer models and better comparisons with real astronomical observations.

"It is pleasing to see how far the field has advanced," said Christopher Cousins, a postdoctoral researcher at the University of Surrey. "A couple of decades ago, such a measurement was considered practically unattainable, and now it is giving us new insight into one of the major open questions in astrophysics."

What Happens During Flares on Neutron Stars

The second study focuses on a particular type of stellar explosion associated with neutron stars. The dense remnant of a star—with a mass of one to two Suns but a diameter of only about 20 kilometres—pulls matter from a companion star. When the stolen material falls onto the neutron star's surface, a thermonuclear explosion occurs. Such outbursts produce heavy elements and release enormous amounts of energy, including in the form of X‑ray bursts.

Scientists at the Facility for Rare Isotope Beams in Michigan studied in detail the nuclear reaction that triggers these X‑ray bursts. Particular attention was paid to the so‑called nickel‑copper cycle—a temporary "capture" of nuclear material. Previously, it was unclear whether such retention actually occurs during bursts. The new data showed that the cycle does indeed operate, but only in a small fraction of the material. This refines the picture of how such explosions develop.

Why This Matters

Despite decades of research, the nuclear reactions that power some of the most spectacular stellar catastrophes are not yet fully deciphered. The two new studies provide a clearer sequence of events, allowing models to be matched more closely with observations and offering a better understanding of how chemical elements are created in stars and scattered across the Universe—including those from which planets and living organisms ultimately form.

In Brief

Two scientific studies have refined our understanding of how chemical elements are born and spread in supernovae. Experiments showed that explosions produce 35% more radioactive titanium‑44 than previously thought—a finding that will help improve supernova models. The second study determined that, in thermonuclear bursts on neutron stars, the nickel‑copper cycle does temporarily capture some nuclear material, but only in small amounts. Together, the results bring scientists closer to understanding how stars create the matter that makes up our world.