Science matters. Wonder matters. You matter. Join our 2025 Donation Campaign today.<\/strong><\/p>\n You might have heard of the music of the spheres or musica universalis<\/em>. It was an ancient Greek philosophical concept that regarded proportions in the movements of celestial bodies as a form of music. Now, on May 6, 2025, an international team of astronomers using the W. M. Keck Observatory in Hawaii said it has listened to the \u201cmusic\u201d of a nearby star. The researchers said the subtle stellar vibrations revealed the star is smaller than previously thought, challenging scientists\u2019 understanding of stars\u2019 interiors and how they slow down as they age. <\/p>\n It also helped to better measure the sizes and densities of the star\u2019s five known planets.<\/p>\n Of course, stars don\u2019t actually play music, but they do emit sound waves \u2013 subtle vibrations or oscillations \u2013 that astronomers can study. Astronomers can \u201chear\u201d these natural frequencies using the right instruments. And that\u2019s what the team of astronomers did with the nearby star HD 219134, 21 light-years away. They used the Keck Planet Finder (KPF) at the W. M. Keck Observatory in Hawaii to listen to the star. Scientists call this technique of listening to stars\u2019 sound waves asteroseismology.<\/p>\n The vibrations can provide clues about the interiors of stars and other data. Lead author Yaguang Li at the University of Hawaii at Manoa said:<\/p>\n The vibrations of a star are like its unique song. By listening to those oscillations, we can precisely determine how massive a star is, how large it is, and how old it is.<\/p>\n<\/blockquote>\n The researchers published their peer-reviewed findings in The Astrophysical Journal<\/em> on May 6, 2025.<\/p>\n HD 219134 is an orange star, cooler than our sun. It\u2019s been easier to detect such stellar vibrations from hotter stars. With HD 219134, the stellar songs are much more subtle and harder to detect with most telescopes.<\/p>\n But the Keck Planet Finder is ideally suited for this task. It can precisely measure the motion of a star\u2019s surface toward and away from the observer. Overall, the astronomers listened to the star for four consecutive nights and collected over 2,000 velocity measurements. Those measurements were extremely precise. Li said:<\/p>\n KPF\u2019s fast readout mode makes it perfectly suited for detecting oscillations in cool stars, and it is the only spectrograph on Mauna Kea currently capable of making this type of discovery.<\/p>\n<\/blockquote>\n The oscillations inside stars can also provide clues about their ages and what happens as they get older. Young stars rotate rapidly, but then slow down as they age. The researchers determined that HD 219134 is more than twice the age of our sun, about 10.2 billion years old. The sun and solar system are about 4.6 billion years old. So its rotation is a lot slower now than when it was younger.<\/p>\n But the new analysis of HD 219134 can also help scientists understand another peculiarity. The slowing rotation, or spin-down, of stars similar to HD 219134 tends to eventually come to a halt. The asteroseismic data enables scientists to anchor stellar models at the oldest end of a star\u2019s lifetime. This, in turn, helps astronomers determine the ages of stars more precisely. As Li noted:<\/p>\n This is like finding a long-lost tuning fork for stellar clocks. It gives us a reference point to calibrate how stars spin down over billions of years.<\/p>\n<\/blockquote>\n The new asteroseismic measurements revealed another surprise, too. HD 219134 is slightly smaller than astronomers thought it was. It\u2019s about 4% smaller than previous studies had suggested. That doesn\u2019t sound like a lot, but it poses challenges for current stellar models, especially for stars like HD 219134.<\/p>\n Why the discrepancy? The researchers said it could be due atmospheric effects in Earth\u2019s atmosphere, magnetic fields or even issues with the stellar models themselves.<\/p>\n W. M. Keck Observatory: Astronomers Tune Into the Music of a Nearby Star Unlocking a Surprising Discovery keckobservatory.org\/hd-219134\/<\/p>\n \u2014 AAS Press Office (@press.aas.org) 2025-05-06T15:40:20.100Z<\/p>\n<\/blockquote>\n Like many \u2013 or even most \u2013 stars, HD 219134 has at least five known confirmed planets, and possibly more, including two super-Earths. Super-Earths are rocky and larger than Earth but smaller than Neptune. Being able to better refine the size of the star also helped the researchers measure the sizes and densities of its family of planets as well.<\/p>\n Keck Planet Finder and similar instruments will also be able to assist in the search for life on exoplanets. Knowing how old the stars and planets are more accurately will help astronomers estimate how old life is on a planet, if it is found. Co-author Daniel Huber said:<\/p>\n When we find life on another planet, we will want to know how old that life is. Listening to the sounds of its star will tell us the answer.<\/p>\n<\/blockquote>\n Bottom line: Astronomers have listened to a nearby star\u2019s music \u2013 subtle interior vibrations \u2013 to learn more about how stars\u2019 rotation speed slows down as they age.<\/p>\n Source: K Dwarf Radius Inflation and a 10 Gyr Spin-down Clock Unveiled through Asteroseismology of HD 219134 from the Keck Planet Finder<\/p>\n Via W. M. Keck Observatory<\/p>\n Read more: Cool! A Hubble photo translated to music<\/p>\n Read more: Listen to space with these new sonification videos<\/p>\n <\/div>\n\n
Listening to a nearby star\u2019s music<\/h3>\n
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Stellar songs from hot and cool stars<\/h3>\n
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![\"Nearby](\"https:\/\/earthsky.org\/upl\/2025\/05\/HD219134-star-Keck-Observatory-May-6-2025.png\")
Measuring the ages of stars<\/h3>\n
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Smaller than expected<\/h3>\n
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A family of planets and extraterrestrial life<\/h3>\n
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