Scientists at the Harvard-Smithsonian Center for Astrophysics have developed a new method to determine the age of stars by measuring the speed of their spin.
The new method that calculates the age of stars based on their masses and rotations is called gyrochronology. The researchers tested it in 30 cool solar-type stars in the 2.5 billion-year-old cluster NGC 6819 and compared the ages to existing calculations. They were surprised that their calculations were almost the same.
"The relationship between mass, rotation rate and age of the observed stars is now defined well enough that by measuring the first two parameters, the third, the star's age, can be determined with only 10 percent uncertainty," Sydney Barnes, AIP scientist and co-author of the study, said in a press release.
It is long-known that as the star becomes older, its rotation becomes slower; heavy stars also rotate faster than the smaller stars. Based on this belief, the researchers led by Soeren Meibom of the Harvard-Smithsonian Center for Astrophysics developed the new method to calculate the age of the stars accurately. They used NASA's Kepler space telescope to observe the brightness of the stars that tell how fast they rotate.
"These new data show, with real observations, that this is on solid ground," Meibom told BBC News.
"We can get age as accurately as about 10 percent from this method."
The new star age determination method will help scientists better understand the evolution of our galaxy and can be used for future explorations outside our solar system.
"This cluster will certainly help with our understanding of how good gyrochronology is as a method, and how valid it is," Ruth Angus, a Ph.D. student researching gyrochronology at the University of Oxford, told BBC News. She is not part of the study.
"It shows that these stars are doing what they're expected to do, and everything's peachy."
This study was published in the Jan. 5 issue of Nature.
