Tuning into the Stars

Researchers at UNSW have interrogated the 'sounds' of a cluster of stars within the Milky Way, uncovering a technique for astrophysicists to probe the universe and learn more about its evolution

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Most galaxies are estimated to be between 10 billion and 13.6 billion years old, with some potentially being as old as the universe itself, which is around 13.8 billion years old. Now, a study led by researchers at the University of New South Wales (UNSW), Sydney, Australia, into a cluster of stars 2,700 light years away reveals their stages of evolution through the 'sounds' they make. This discovery will allow scientists to map the history of the Milky Way and other galaxies, accelerating knowledge in astrophysics.

Dr. Claudia Reyes is the lead author of the study published in Nature. While undertaking her PhD at the UNSW School of Physics, she studied 27 stars in a cluster of stars called M67 (Messier 67), all born from the same cloud of gas 4 billion years ago.

She says these stars have similar chemical compositions, but different masses which made them ideal for studying evolution in real-time. "When we study stars in a cluster, we can see their whole sequence of individual evolution," Dr. Reyes says, adding that while these stars are the same age, it's their mass that gives away how quickly they have evolved. And, she adds that M67 is a very special cluster as it includes a broad range of 'giants', from the smaller, less-evolved subgiants to red giants—the latter being the most-evolved stars.