Maunakea telescope tunes into stellar symphony of nearby star

A team of astronomers led by Yaguang Li, a postdoctoral fellow at the University of Hawai‘i Institute for Astronomy, has used a Maunakea telescope to listen to the music of a nearby star, uncovering surprises that shake our understanding of how stars work.

The study used a new cutting-edge instrument at the W.M. Keck Observatory called the Keck Planet Finder—which detected oscillations rippling through star HD 219134. The team’s findings, published in the Astrophysical Journal, open a new window into the interiors of stars that were once thought too quiet to probe.

“The vibrations of a star are like its unique song,” said Li. “By listening to those oscillations, we can precisely determine how massive a star is, how large it is, and how old it is.”

A stellar symphony

Although we cannot directly hear them with our own ears, stars are not silent. Like musical instruments, stars resonate with natural frequencies that astronomers can “hear” with the right tools. This field of research, known as asteroseismology, allows scientists to use these frequencies to probe the interiors of stars. 

Stellar oscillations have mostly been detected in hotter stars using space telescopes such as Kepler and the Transiting Exoplanet Survey Satellite, however, HD 219134’s subtle “stellar song” couldn’t be captured this way due to its cooler, orange-hued nature.

Through four consecutive nights, the team used the Keck Planet Finder to collect more than 2,000 ultra-precise velocity measurements of the star—enabling them to catch the star’s vibrations in action.

10-billion-year-old time capsule

Using the oscillations detected in HD 219134, the team determined the star’s age to be 10.2 billion years, more than twice the age of our Sun. This makes it one of the oldest main-sequence stars with an age determined using asteroseismology.

This new measurement offers key insights into stellar aging. For stars like HD 219134, spin-down appears to stall later in life. The asteroseismic age helps refine models and improve age estimates for other stars.

“This is like finding a long-lost tuning fork for stellar clocks,” Li said. “It gives us a reference point to calibrate how stars spin down over billions of years.”

A puzzle

Surprisingly, the team also discovered that HD 219134 appears smaller than expected. While other measurements using multiple telescopes indicated that the star’s radius is about 4% larger, the asteroseismic measurement suggests it’s more compact. 

The findings challenge current models, especially for cooler stars like HD 219134, which hosts at least five planets—including two super-Earth-sized, rocky worlds with possible Earth-like compositions. 

“When we find life on another planet, we will want to know how old that life is,” said astronomer Daniel Huber, who was a co-author of the study.

Instruments like the Keck Planet Finder will enable age measurements for other stars which are slated to become the focus for searching for life on other planets using future NASA missions.