Spin Rates Could Reveal the Age of Stars

Astronomers say that a new method of determining the age of stars will soon be made available to experts around the world. A group of them says that analyzing stellar spin rates could provide useful data for establishing the true age of a given star.

In numerous points in the long lives, stars similar to our Sun look pretty much alike, so the issue currently facing specialists is how to determine if one is a billion years older than the other, or not.

Separating these objects into age groups is turning out to be an extremely complex task, and most of the evidences that astronomers can collect today are circumstantial. But experts from the Harvard-Smithsonian Center for Astrophysics (CfA) may have the solution.

“A star’s rotation slows down steadily with time, like a top spinning on a table and can be used as a clock to determine its age.” explained CfA astronomer Soren Meibom yesterday, May 23, at the 218th meeting of the American Astronomical Society (AAS 2011).

“Ultimately, we need to know the ages of the stars and their planets to assess whether alien life might have evolved on these distant worlds,” the investigator told colleagues in attendance.

“The older the planet, the more time life has had to get started. Since stars and planets form together at the same time, if we know a star’s age, we know the age of its planets too,” he went on to say.

There are some stars that are particularly difficult to analyze, astronomers add. While some are found in clusters, and are known to have formed around the same time, many exist independently.

This makes establishing their age with any degree of certainty nearly impossible. The CfA method is pretty simple – find the correlation between age and spin in star clusters, and then apply it to lonely ones, Universe Today reports.

“This work is a leap in our understanding of how stars like our Sun work. It also may have an important impact on our understanding of planets found outside our solar system,” Meibom told colleagues at the conference.

He argued that determining stellar spin in cluster-based stars can be done by analyzing their sunspots and their rotation. This can lead astronomers to all the data they need to apply the new method.