Regulus 350 times Brighter


An Old Friend
Dec 6, 2004
Gulf Coast
'Bullet Star' Shines 350 Times Brighter Than the Sun
ATLANTA -- For decades, scientists have observed that Regulus, the brightest star in the constellation Leo, spins much faster than the sun. But thanks to a powerful new telescopic array, astronomers now know with unprecedented clarity what that means to this massive celestial body.
Most stars rotate sedately about their spin axes, McAlister says. The sun, for example, completes a full rotation in about 24 days, which means its equatorial spin speed is roughly 4,500 miles per hour. Regulus' equatorial spin speed is nearly 700,000 miles per hour and its diameter is about five times greater than the sun's. Regulus also bulges conspicuously at its equator, a stellar rarity
In fact, if Regulus were rotating about 10 percent faster, its outward centrifugal force would exceed the inward pull of gravity and the star would fly apart,
"We're looking at the star essentially equator-on, and the spin axis is tilted about 86 degrees from the north direction in the sky," he says. "But, curiously enough, the star is moving through space in the same direction its pole is pointing. Regulus is moving like an enormous spinning bullet through space. We have no idea why this is the case."
Space is so Kool!
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