Some stars in our galaxy pulse like musical instruments, and scientists have found a way to listen in. These rhythmic starquakes, like vibrations in a string or drum, reveal vital clues about a star’s age, composition, and life cycle.
By studying these “melodies” in a star cluster called M67—whose stars are like solar siblings—researchers uncovered a strange pause in stellar evolution called the “plateau.” This discovery helps pinpoint stellar ages with remarkable precision, bringing us closer to understanding how stars, and ultimately our galaxy, have evolved.
Celestial Music: Listening to Starquakes
They say music is the universal language, and it turns out some stars may be playing their own cosmic tunes. Certain stars in our galaxy show rhythmic changes in brightness, clues that are helping scientists better understand how these stars, and our galaxy as a whole, have evolved over time.
An international team of researchers, including scientists from The Australian National University (ANU) and UNSW Sydney, found that these brightness fluctuations are caused by ongoing “starquakes,” vibrations that ripple through the stars’ interiors.
These vibrations can be measured as frequencies, which in turn reveal key information about a star’s age, mass, and internal structure.
Stars as Instruments of Cosmic Insight
Lead author Dr. Claudia Reyes from ANU describes stars as musical instruments, each producing its own unique melody.
“Starquakes occur in certain stars, leading to a continuous cycle of brightening and dimming. By carefully observing these tiny fluctuations in brightness, we can listen to a star’s musical rhythm,” Dr. Reyes, who completed most of this work during her time at UNSW Sydney, said.
“These fluctuations are like musical notes, similar to the vibrations of a string or the hum of a drum, that can be translated into frequencies. Each frequency tells us more about the star’s size, chemical composition and internal structure.”
Nuclear Furnaces and the Birth of Elements
Dr. Reyes said that each of the stars they studied has a “shell of energy around its core” that helps keep them alive. This region of the star is like a furnace where nuclear reactions take place and elements are formed. These reactions produce very large amounts of energy, and elements produced during these reactions are emitted into the universe.
As a star ages and its mass and internal structure changes – such as when a star evolves into a subgiant or red giant – these so-called furnace regions near their core can become bigger or smaller.
When this happens, a star emits different frequencies, an important discovery that brings scientists a step closer to piecing together the history of our galaxy.
Stellar Siblings: Probing the M67 Cluster
The researchers studied frequencies emitted by stars in a region of our galaxy known as the ‘open cluster M67’. Dr. Reyes said the research team was interested in these specific stars because they are like siblings – they were born from the same molecular cloud at the same time and therefore share the same age and chemical composition.
Stars in the M67 cluster also share similar qualities to stars close to Earth, such as our Sun.
“We studied frequencies emitted by stars in this cluster as they evolved into subgiants and red giants – something that had never been fully explored before,” Dr. Reyes said.
The Plateau: A Celestial Pause in Time
The scientists discovered that stars in this cluster reach a point in their life where the signature of the frequency they emit temporarily halts once it reaches a certain point, as if the signal were caught in a loop, repeating itself like a broken record, before resuming its progression. Dr. Reyes calls this moment the “plateau”.
“Stars have multiple layers, similar to an onion. We discovered that the plateau occurs due to events in a specific layer of the star and at specific frequencies that are influenced by a star’s mass and metallicity,” Dr. Reyes said.
“This means we can predict when and at what frequency the plateau will occur during a star’s life cycle, enabling extremely precise age estimates for stars currently in their plateau phase.
A New Tool to Map Galactic History
“This research helps us better understand how stars evolve and provides a new tool to estimate their age, which is crucial for studying the evolution of our galaxy.”
The research is published in Nature.
Reference: “Acoustic modes in M67 cluster stars trace deepening convective envelopes” by Claudia Reyes, Dennis Stello, Joel Ong, Christopher Lindsay, Marc Hon and Timothy R. Bedding, 2 April 2025, Nature.
DOI: 10.1038/s41586-025-08760-2
This work involved scientists from ANU, UNSW Sydney, the University of Sydney, Yale University, the University of Hawaii, and the Massachusetts Institute of Technology.
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