'Ultrasound of stellar embryos' determines age of stars

You can find out how old a baby star is simply by listening to it, say researchers at Europe's KU Leuven.

Scientists listened in on stars in the Christmas Tree Cluster nebula to determine their age. T.A. Rector (NRAO/AUI/NSF and NOAO/AURA/NSF) and B.A. Wolpa (NOAO/AURA/NSF)

Just like for young humans, adolescence is a turbulent time for stars. It's a time when dust and gases begin to smash together under the force of gravity, causing a steady buildup in core temperatures. Eventually the temperature gets high enough to spark thermonuclear fusion, which marks the star's entry into a more stable state, and its "adulthood" begins. This process takes about 10 million years for a star that's the same size as our own sun.

Until now, researchers haven't had a precise way to measure the exact age of a young star. But research conducted at Belgium's Katholieke Universiteit Leuven (KU Leuven) might be set to change that.

Working with a team of researchers, Konstanze Zwintz, a postdoctoral researcher at KU Leuven's Institute for Astronomy, listened to the vibrations from 34 stars using the Canadian MOST space telescope, the European CoRoT satellite, and data from ground-based facilities such as the European Southern Observatory (ESO) in Chile.

Each star the team studied studied was in the Christmas Tree Cluster and was between one and four times the size of our own sun. The stars were also less than 10 million years old. (For comparison, our sun is about 4.5 billion years old.)

"Our data shows that the youngest stars vibrate slower while the stars nearer to adulthood vibrate faster. A star's mass has a major impact on its development: stars with a smaller mass evolve slower. Heavy stars grow faster and age more quickly," Zwintz said in a statement.

"Think of it as ultrasound of stellar embryos," added University of British Colombia professor Jaymie Matthews, a co-author of the study, which appeared recently in the journal Science. "Stars can vibrate due to sound waves bouncing inside. We detect the sound vibrations across the vacuum of space by the subtle changes in stellar brightness. Then we translate the frequencies of those vibrations into models of the structures of those stars' hidden interiors."

According to the statement about the research released by KU Leuven, this is the first time concrete evidence has been obtained that proves what theoretical physicists have posited: that young stars vibrate differently than older ones.

I'm guessing that's something parents might also say about their adolescent kids.