A team of researchers from KU Leuven's Institute of Astronomy in Belgium has been using acoustic vibrations, more commonly known as sound waves, to determine the age of stars.

Similar to how medical doctors use ultrasound to study a baby that is still within a mother's womb, the team of astronomers used the sound waves produced by the pressure of radiation within stars to estimate how old they are.

The research report, led by postdoctoral researcher Konstanze Zwintz, is the first to confirm the long-standing hypothesis that younger stars produce different vibrations and sound waves compared to older stars.

The study had the researchers monitor and analyze the vibrations of a total of 34 stars. The stars involved in the research are all younger than 10 million years old, which are considered young stars. Their sizes range from as big as our solar system's sun to four times its size.

"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. 

Zwintz adds that the team's research had led to the development of a model that features a higher precision in determining how old stars are. The more precise age measurements taken with the model also allows scientists to classify young stars according to the several phases in the life cycle of stars.

Stars, formed from the contraction of molecular clouds made up of dust particles and gas, are often born in groups called clusters. As the star grows older, the pull of gravity causes the star to become smaller and hotter, up to the point when its core reaches a high enough temperature to be able to burn hydrogen. When that star achieves this, it becomes stable and is considered an adult star.

Before a star reaches adulthood, they are shrouded in a gas cloud that makes it very difficult to determine their age. In addition, there are very few facilities that are dedicated to the examination and collection of data required for this purpose.

The 10-year-old Microvariability and Oscillations of Stars spacecraft, which the team used for the observations of half the stars involved in the study, will be ceasing operations in September.

Zwintz has submitted a proposal for an almost $3 million European research grant to continue the team's research, wherein 10 percent of the amount will be used to extend MOST operations for almost one year.

The study was published in the journal Science on July 3.