Helioseismologists have investigated how the Sun absorbs energy.

Just as geophysicists "scan" the Earth, helioseismologists "listen" to the Sun by analyzing the vibrations generated within its core, which cause oscillations on the surface of the star. These "acoustic waves" are recorded using space observatories and ground-based telescopes: decoding the frequencies and amplitudes allows scientists to effectively "see through" the star, calculating its temperature and density. You can hear what the Sun "sounds" like on NASA's website.

Using their own helioseismic methodology, an international research team led by Gaël Buldgen from the University of Liège (Belgium) reproduced the conditions inside the star through computer modeling—density, pressure, chemical element distribution, and temperature. The results of this scientific work were published in the journal Nature Communications.

This research addresses a very important property of matter—the opacity of solar plasma, which refers to its interaction with radiation in the star's core. This process affects the transfer of energy from the core to the surface of the star: the higher the opacity, the slower the heat "makes its way" to the outside. Accurate knowledge of this parameter allows for calculations of the age of stars, their evolution, and internal structure, while any inaccuracies directly influence existing models of stellar formation.

Previously, in addition to theoretical calculations, researchers attempted to recreate extreme solar conditions in laboratories, particularly at the Z Machine facility in Sandia National Laboratories (USA), but the results significantly diverged from theoretical predictions. Since helioseismology provides a broader picture, covering a wide range of temperatures and pressures within the star, the authors of the new study discovered exactly where those

The results indicated that in the region transitioning to the convective zone—the area where matter begins to actively "boil" and mix—the opacity of solar plasma is approximately 10% higher than most models predicted. Furthermore, some theoretical values were overestimated by nearly 30-35%.

This means that the processes observed in solar plasma are much more complex than previously thought, and existing theoretical models of stellar evolution require revision and "refinement." It is important to note that this new discovery is not just a detail in the portrait of the Sun, but a fundamental step towards a better understanding of similar luminous inhabitants of the Universe.