Press release of February 26, 2026

HEARTS takes aim at helium burning

Junior research group for nuclear astrophysics launches at HZDR

In the cores of massive stars, the balance between carbon and oxygen is largely determined, providing the chemical foundation for life. Yet this crucial stage of stellar evolution, known as helium burning, remains insufficiently understood. To measure key nuclear reaction rates more precisely, the new junior research group HEARTS begins its work at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) on March 1, 2026. The Helmholtz Association is funding the project with 1,75 million euros over five years.

With HEARTS (Helium Burning Experiments for Astrophysics), HZDR is expanding its research in nuclear astrophysics. The team, which includes the group leader Dr. Eliana Masha, a postdoc, and three doctoral students at the Felsenkeller underground laboratory, investigates the helium-burning phase of stellar evolution, in which helium nuclei fuse to produce mainly carbon and oxygen. The ratio of these elements influences how a star ages and ends its life and also affects the chemical evolution of entire galaxies.

Despite decades of research, significant uncertainties remain in the reaction rates governing helium burning. In particular, the carbon-to-oxygen ratio cannot yet be predicted with sufficient accuracy. These uncertainties make precise modeling of star evolution, supernova explosions, and the formation of chemical elements in the universe more difficult.

Measuring rare nuclear reactions underground

A key role in HEARTS is played by a reaction that is considered by experts to be the “Holy Grail of nuclear astrophysics.” In this reaction, a helium nucleus fuses with a carbon nucleus to form oxygen, emitting a high-energy gamma photon. The frequency of this reaction under stellar conditions largely determines the cosmic carbon-to-oxygen ratio.

To study such processes, the researchers recreate the conditions found in stellar cores. A particle accelerator produces a beam of carbon or other light nuclei, which is directed onto a helium target. When a reaction occurs, gamma rays – or in other reactions, free neutrons or other particles – are emitted and detected by highly sensitive instruments. The number and energy of these events allows the team to determine the reaction probability.

Because the relevant reactions are extremely rare at stellar energies, the measurements are carried out deep underground, shielded from cosmic radiation. The Felsenkeller, Germany’s only underground facility for nuclear astrophysics operated by HZDR and TU Dresden, lies beneath 45 meters of rock, providing an exceptional platform for high-precision measurements. HEARTS will begin experiments at Italy’s Gran Sasso underground laboratory, followed by campaigns at the Felsenkeller and the CRYRING storage ring of the GSI Helmholtz Centre for Heavy Ion Research.

Beyond the carbon-oxygen reaction, the team is measuring other helium-burning processes that produce elements such as neon and magnesium. In addition, the researchers will investigate nuclear reactions that release neutrons – key ingredients in the formation of elements heavier than iron – and explore the still uncertain astrophysical origin of fluorine. By systematically studying these different reactions, HEARTS aims to clarify open questions and integrate the results into astrophysical models.

“Connecting the biggest picture with the smallest particles”

HEARTS is led by physicist Dr. Eliana Masha. For the 34-year-old, leading the junior research group represents the next logical step in her scientific career. “I have always been fascinated by stars and other cosmic phenomena,” she says. “What excites me about nuclear astrophysics is that it connects the biggest picture – our universe – with the smallest particles. Insights into what happens inside stars on a nuclear level primarily serve fundamental research, but they could also play an important role in the search for exoplanets and potentially habitable worlds.”

Masha grew up in Albania and studied physics in Italy. She first came to Dresden in 2016 during her master's studies and took part in the HZDR Summer Student Program – a decisive moment in her career. She then completed her doctorate at the University of Milan, received a scholarship from the German Academic Exchange Service (DAAD), and, from 2023 to 2025, has worked at HZDR as an Alexander-von-Humboldt Fellow. “I feel at home at the Felsenkeller and have grown here as a researcher over the past few years,” Masha explains. “Now I want to contribute with my own team to a better understanding of how stars chemically shape the universe.”

Further information:

Dr. Eliana Masha
HEARTS Junior Research Group at HZDR | Head
Phone: +49 351 260 3915 | Email: e.masha@hzdr.de

Media contact:

Simon Schmitt | Head
Communications and Media Relations at HZDR
Phone: +49 351 260 3400 | Mobile: +49 175 874 2865 | Email: s.schmitt@hzdr.de