Dim, cool dwarf star is unusually powerful, stormy

BOSTON, Nov. 20 (UPI) -- For such a small, cool star, TVLM 513-46546 -- the official name of the M9 dwarf -- can be rather tempestuous. The broody little star sends out storms many times more powerful than our sun's.

Astronomers with the Harvard-Smithsonian Center for Astrophysics studied the star using Atacama Large Millimeter/submillimeter Array, or ALMA, a radio telescope in the Chilean desert.

The red dwarf emits solar flares at unusually high frequencies for its size. Its electromagnetic emissions are ten times brighter than our sun's.

Its stormy disposition is just one of several differences between TVLM 513-46546 and our sun. The red dwarf is so dim and cool, its very close to being a brown dwarf, a star incapable of fusion. Despite its outsized temper, it weighs very little -- just a one-tenth the mass of the sun.

And yet, it spins with a ferocity that matches its solar output, making a rotation in just two hours. Our sun takes a month to make a full revolution. The red dwarf also boasts a magnetic field several hundred times stronger than our sun's, which may explain the violent storms.

Still, astronomers didn't think such a small star could host such a significant magnetic field. They remain befuddled.

TVLM 513-46546 made for a relatively easy research project. It lies just 35 light-years away. The astronomers observations were shared in a new paper, published this week in The Astrophysical Journal.

What's interesting about the red dwarf is that it has many brothers and sisters. Red dwarfs are the most common star type in the Milky Way.

If others are similarly disagreeable, it could spell bad news for the chances of finding alien life. In order for planets orbiting such cool, dim stars to be warm enough to host liquid water, they'd have to hug a rather intimate path around their host star.

"If we lived around a star like this one, we wouldn't have any satellite communications," lead author Peter Williams said in a press release. "In fact, it might be extremely difficult for life to evolve at all in such a stormy environment."

"It's like living in Tornado Alley in the U.S. Your location puts you at greater risk of severe storms," he added. "A planet in the habitable zone of a star like this would be buffeted by storms much stronger than those generated by the Sun."