The star Vega, used as a "yardstick" to gage other stars' brightness for thousands of years, may be much older than previously thought, U.S. astronomers say.

Researchers at the University of Michigan have estimated Vega's age by precisely measuring its spin speed with a tool called the Michigan Infrared Combiner, a university release reported Monday.

Developed by astronomy Professor John Monnier, the combiner collects the light gathered by six telescopes for a resolution that would be found in a telescope 100 times larger than the Hubble Space Telescope.

Based on the spin of Vega, a Northern Hemisphere star that's the brightest in constellation Lyra, Monnier and his colleagues say it may be as much as 200 million years older than previously believed.

At 25 light-years away, Vega is comparatively close to the Earth on a cosmic scale.

About six years ago astronomers observed Vega is rotating so fast it's nearly flying apart, and it is the precise measurement of that spin that provided the new estimate of the star's age, researchers said.