Discovered how elements are formed in stars

The Luna collaboration has measured the speed of this process. The results concern a particular process that leads to the production of neutrons from a carbon 13 nucleus and a helium nucleus.

The Luna experiment (Laboratory for Underground Nuclear Astrophysics) science collaboration has measured, for the first time, the speed of the neutron production process with very high precision at stellar temperatures. The results provide valuable information for building models that reproduce the evolution of a star. The Luna experiment was carried out at the National Laboratories of Gran Sasso of Infn and the study has been published in the scientific journal "Physical Review Letters".

How elements are formed in stars

The results of the experiment are the result of an experimental campaign lasted about four years and concern a particular process that leads to the production of neutrons from a carbon 13 nucleus and a helium nucleus. Neutrons are crucial for the production of heavy elements, because they can be easily "captured" by the nuclei present in stars.

This allows the synthesis of elements heavier than iron such as Cadmium, Tungsten or Lead. "Until now, our knowledge of this process was based on extrapolations from measurements at higher energies, compared to those of stars, and from indirect experiments," said Gianluca Imbriani, spokesman for the Luna collaboration, as reported by Agi. "This led to large uncertainties in determining the rate of neutron production in stars.

The Luna experiment

"Luna is the only experiment that to date has succeeded in directly measuring this neutron production process in the energy window of astrophysical interest, drastically reducing the uncertainties of other experimental results," explained Alba Formicola and Andreas Best, who coordinated the work for this measurement.

The scientific activity of the Luna experiment is not over, however. Over the next decade, the Luna-Mv project, which is currently underway, will attempt to reproduce the processes that take place in the hearts of massive stars in laboratories.

A team of international researchers collaborating on Luna includes about 50 researchers from Italy, Germany, Scotland and Hungary, including the National Institute of Nuclear Physics for Italy, the Helmholtz-Zentrum Dresden-Rossendorf for Germany, Mta-Atomki for Hungary, and the School of Physics and Astronomy, University of Edinburgh for the United Kingdom.

Recently, instead, a research published on the Royal Astronomical Society has discovered the birth of the first stars being able to identify when the cosmic dawn dates back. In the meantime, in October there are several appointments in which it is worth observing the sky to see swarms of stars or planets.

Stefania Bernardini