The stars in our galaxy are serenading us with songs, that is, if we take the time to translate them.
According to a new paper published in Nature, constant “starquakes” cause some stars to fluctuate in brightness — a result that seems mostly unrelated to music. But by translating these fluctuations in brightness into fluctuations in acoustic frequencies, scientists can tune in to a star’s sound, learning important information about its age and its other traits.
Studying 27 separate stars in our galaxy’s Open Cluster M67, the authors of the paper found that a star’s acoustic frequencies stop fluctuating at a specific point in its lifespan, allowing scientists to identify the age of a star with a stagnating sound.
“This research helps us better understand how stars evolve and provides a new tool to estimate their age,” said Claudia Reyes, a paper author and an asteroseismologist at Australian National University, according to a press release. “Which is crucial for studying the evolution of our galaxy.”
Read More: Stars Are Born and Die Every Day — Here’s How They Evolve in Space
The Sounds of a Starquakes
Though they seem quiet in the sky, the stars in our galaxy are always making music. That’s because starquakes, or vibrations in a star’s interior, can cause continual changes in its brightness that translate into continual changes in its auditory frequencies.
“Starquakes occur in certain stars, leading to a continuous cycle of brightening and dimming,” Reyes said in the press release. “By carefully observing these tiny fluctuations in brightness, we can listen to a star’s musical rhythm.”
With its own musical melody, a star’s song can tell scientists about its age as well as its mass.
“These fluctuations are like musical notes, similar to the vibrations of a string,” Reyes added in the press release. “Each frequency tells us more about the star’s size, chemical composition[,] and internal structure.”
Setting out to study these songs, the authors of the new paper turned to Open Cluster M67, an area of our galaxy that contains several subgiant and red giant stars. There, the team found that the fluctuations in a star’s acoustic frequencies pause at a particular point in the star’s life. At that point — “the plateau,” according to the press release — the star sends out a single auditory signal, “repeating itself like a broken record.”
“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,” Reyes said in the press release. “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.”
Read More: Getting to Know Our Galactic Home: The Milky Way
M67 Stars in Song
The 27 stars that the team studied weren’t selected for their specific musical stylings. Instead, they were chosen because their sounds made sense to compare. Similar in age, these stars all come from the same molecular cloud from around the same time, and they all show a similar chemical composition, a lot “like siblings,” according to the release.
The Open Cluster M67 stars also offered an opportunity to listen in on star evolution. “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,” Reyes said in the press release.
Taken as a whole, the team’s work shows that there’s always something to learn when we listen, even when it takes a bit of stellar translation.
Read More: 10 Facts You May Not Know About the Milky Way
Article Sources
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Sam Walters is a journalist covering archaeology, paleontology, ecology, and evolution for Discover, along with an assortment of other topics. Before joining the Discover team as an assistant editor in 2022, Sam studied journalism at Northwestern University in Evanston, Illinois.
