Scientists have found a way to study the inner workings of some of the brightest stars in the sky. Using data from NASA’s Kepler space telescope, an international team of researchers has found new evidence that red giants — stars that have reached the end of their life cycles and depleted their hydrogen reserves — often undergo significant structural changes or “failures.” deep in their inner core.

The star failures popularized in the media are all about the star’s return, but lead author Mathieu Vrard is working on a different type of flaw. Interruptions in this work can affect the oscillations of the star or the frequencies and paths that sound waves travel through the star.

Red cluster stars, objects burning in a helium core, are often used in astrophysical research as distance probes to measure properties such as the density of galaxies and to learn more about the physical processes behind the chemical evolution of stars. That’s why it’s vital for scientists to understand why these refractions occur, said Wrard, an astronomy research associate at Ohio State University.

“By analyzing these variations, we can use them not only to derive the overall parameters of the star, but also to obtain information about the exact structure of these objects,” he said.

A study recently published in the journal Nature CommunicationHe was the first to make detailed observations of the properties of the deepest layers of these red giants.

To determine whether these failures are becoming more common in certain star groups, the team selected a sample of 359 red giants below a certain stellar mass and measured the different characteristics and individual frequencies of each star.

The team found evidence that 24 of the surveyed red giants (about 7% of the sample) experienced periodic structural breaks at some point during their lifetime. While 7% might not seem like much, if it were applied to all known stars in our universe, the number of stars with these irregularities would be enormous.

There are two main theories that explain how these disorders work. The first scenario suggests that perturbations have been present throughout the evolution of the star, but these are typically very weak and below the threshold that astronomers would classify as a true rupture.

Second, it assumes that the irregularities are “corrected” by some unknown physical process, which then leads to changes in the structure of the star’s core. It seems that the first scenario is not supported by the model of this study, suggesting that the observed failures are actually common, but more accurate data is needed before scientists can confidently subscribe to the second.

“We think the second theory might hold up better because the first didn’t make sense in our observations,” Vrard said. Said.

As the research offers a better characterization of the physical processes that occur inside red giant stars, Vradr’s work could potentially have important implications for the field of asteroseismology – the branch of astronomy that studies the internal composition of stars using sound wave vibrations – and galactic archaeology. , is a field that uses detailed stellar fossils to decipher the history of the universe. And with Vradra’s current analysis out, he aims to improve the scientific community’s knowledge of red giant stars by working on more precise data. more sophisticated star models.