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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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ScienceShot: Older Vega Mature Enough to Nurture Life
3 December 2012 11:20 am
Shining just 25 light-years from Earth in the constellation Lyra, Vega (false-color infrared image shown) is the fifth brightest star in the night sky. In 1983, astronomers discovered dust orbiting the star, suggesting it had a solar system, and Carl Sagan (pictured) chose to make Vega the source of a SETI signal in his 1985 novel Contact, though the responsible aliens weren't native to the star: At the time, Vega was thought to be only about a couple hundred million years old, probably too young for any planets to have spawned life. Since then, however, estimates of Vega's age have increased, because astronomers learned that the star spins fast—once every 17 hours—which stirs up the star's interior and forces the surface composition to match the overall composition of the star. This discovery meant that scientists had been overestimating the star's abundance of heavy elements, which in turn meant they had been overestimating its mass—and thus underestimating its age, because less massive stars evolve more slowly. Now, scientists have studied Vega with the CHARA interferometer, an array of telescopes in California yielding crisp views of stars, and modeled the observations by using new computations of how fast-spinning stars age. As the researchers will report in The Astrophysical Journal Letters, Vega is 2.15 times as massive as the sun—agreeing with work from recent years—but considerably more mature than had been previously thought. The star is between 625 million and 850 million years old, so suitable planets have probably had sufficient time to develop primitive life.
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