The new study published in the journal Nature, shows a close mathematical relationship between mass, spin, and age so that by measuring the first two, astronomers can calculate the third.
Sydney Barnes of the Leibniz Institute for Astrophysics in Germany, who is a co-author on the study, said:
We have found that the relationship between mass, rotation rate, and age is now defined well enough by observations that we can obtain the ages of individual stars to within 10 percent.
To measure a star’s spin, astronomers look for changes in its brightness caused by dark spots on its surface — the stellar equivalent of sunspots. But these are very difficult to spot because the stars are very small. A periodic dimming of the light on a regular basis is what is looked for.
For their report, the team used data from NASA’s Kepler spacecraft, giving precise and continuous measurements of stellar brightnesses.
The discovery allows astronomers to estimate the age of stars to within 10%, but the age of older stars are harder to detect as they are usually far dimmer to begin with.