For a long time scientists have been searching for ways to estimate the age of a star.
Most properties of a star like the Sun – its size, mass, brightness and temperature – stay about the same throughout most of its life, and do not provide any indication of its age. The idea of measuring the spin of a star to calculate its age was first proposed in the 1970s and was named "gyrochronology" in 2003, but scientists lacked data to support their formulas.
"A cool star spins very fast when it's young, but just like a top on a table it gets slower and slower as the star grows older," BBC quotes senior author Dr Soren Meibom from the Harvard-Smithsonian Center for Astrophysics as saying.
Now a team of US scientists has measured the speed of the spin of 30 stars in a specific cluster known to be 2.5 billion years old.
Having used images from the very sensitive Kepler space telescope, which has been following Earth around the Sun since 2009, they say they can now estimate a star's age to within 10%.
"We can get age as accurately as about 10% from this method," said Dr Soren Meibom
The results of their work were presented in Seattle at a meeting of the American Astronomical Society and also in the journal Nature.
"More evidence has been slowly accumulating that lots of stars do seem to follow this pattern, but how reliably stars fall onto this relation is a bit of an unknown," BBC quotes Ruth Angus, a PhD student researching gyrochronology at the University of Oxford as saying, adding that the results were "a really big deal" for the field.
"This cluster will certainly help with our understanding of how good gyrochronology is as a method, and how valid it is”, she said. “It shows that these stars are doing what they're expected to do, and everything's peachy."
This method applies to "cool stars" — suns about the size of our own, or smaller. These are the most common stars in our galaxy which also have a long life-span.
