An older Vega: New insights about the star all others are measured by

December 11, 2012
Credit: John Monnier

Vega, a star astronomers have used as a touchstone to measure other stars' brightness for thousands of years, may be more than 200 million years older than previously thought. That's according to new findings from the University of Michigan.

The researchers estimated Vega's age by precisely measuring its spin speed with a tool called the Michigan Infrared Combiner, developed by John Monnier, associate professor of astronomy in U-M's College of Literature, Science, and the Arts.

MIRC collects the light gathered by six telescopes to make it appear to be coming through one that's 100 times larger than the . It's installed at the Georgia State Center for High Angular Resolution Astronomy Array located on Mt. Wilson, California.

The tool boosts resolution so astronomers can zoom in, relatively speaking, to observe the shape and surface characteristics of stars that would otherwise look like mere points even through the most powerful telescopes. By tracking stars' surface characteristics, scientists can calculate how fast they rotate and deduce their inner workings.

Vega is a summer star in the , just visible toward the west at sunset. It's the in the constellation Lyra. At 25 away, Vega is close on cosmic scales. A light year is the distance light travels in one year.

About six years ago astronomers discovered that Vega is rotating so fast it's nearly flinging itself apart. They haven't been able to agree on many of the related details, however. One of the debates centers on Vega's exact , which is essential to gauge both its mass and age. Other controversies deal with Vega's tilt as viewed from Earth and the amount of turbulence in the system from roiling gases at the star's surface.

With MIRC's unprecedented resolution, Monnier and his colleagues have taken steps to rectify competing estimates of Vega's rotation rate and other properties The new findings indicate that the star rotates once every 17 hours, rather than once every 12. The sun's equator, for comparison, rotates much slower—once every 27 days, or 648 hours. In addition to finding that Vega is older than previously thought, the Michigan group confirmed its mass to be just over two times the sun's.

"Vega continues to challenge and surprise us," Monnier said. "We found out not too long ago that it has a disk of dusty debris, or a leftover solar system, around it. Then we found out it was a rapid rotator. It's a reference point for other stars, but it certainly isn't boring or normal."

The work will help astronomers build more accurate computer models of , so they can simulate those too far away to observe and gain a better understanding of their life cycles.

A paper on the findings is published in the current edition of Astrophysical Journal Letters. It's titled "Resolving Vega and the inclination controversy with CHARA/MIRC." The research is funded by the National Science Foundation and NASA.

Explore further: Vega: the star with comets?

More information: John Monnier:

Related Stories

Vega: the star with comets?

April 12, 2006

The observation of the immediate vicinity of a star other than the Sun has just been carried out for the first time. A debris disc made up of hot (1300 degrees) dust grains, residues of comet evaporation and collisions between ...

Gazing up at the man in the star?

May 31, 2007

[B]Researchers take picture of the face of Altair, a first for a star like our own[/B] Using a suite of four telescopes, astronomers have captured an image of Altair, one of the closest stars to our own and a fixture in ...

Magnetic field on bright star Vega

June 23, 2009

Astronomy & Astrophysics journal publishes the first detection of a magnetic field on the bright star Vega. Using the NARVAL spectropolarimeter of the Bernard-Lyot telescope on top of the Pic du Midi (France), astronomers ...

Europe's Vega rocket launch set for early 2012

December 8, 2011

Europe's new Vega rocket, which can place a 1.5-ton satellite into low-Earth orbit, is expected to see its first launch early next year, Arianespace chief Jean-Yves Le Gall said Thursday.

Recommended for you

What are white holes?

October 9, 2015

Black holes are created when stars die catastrophically in a supernova. So what in the universe is a white hole?

How to prepare for Mars? NASA consults Navy sub force

October 5, 2015

As NASA contemplates a manned voyage to Mars and the effects missions deeper into space could have on astronauts, it's tapping research from another outfit with experience sending people to the deep: the U.S. Navy submarine ...

A mission to a metal world—The Psyche mission

October 9, 2015

In their drive to set exploration goals for the future, NASA's Discovery Program put out the call for proposals for their thirteenth Discovery mission in February 2014. After reviewing the 27 initial proposals, a panel of ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Dec 12, 2012
If Vega is older than expected, it might be a bona fide member of the Ursa Major star association.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.