Brown Dwarfs Racked by Massive Storms
Brown dwarfs, also known as failed stars, may play host to one or more planet-size storms like Jupiter's "Great Red Spot," a new study found.
Presented at the 223rd annual meeting of the American Astronomical Society in Washington, the report suggests that the cloudy regions on brown dwarfs are massive storms, complete with strong winds and, possibly, lightening more violent than any found on our solar system's planets.
The researchers used the Spitzer Space Telescope's infrared capacities to monitor 44 brown dwarfs as they rotated for up to 20 hours.
"As the brown dwarfs spin on their axis, the alternation of what we think are cloud-free and cloudy regions produces a periodic brightness variation that we can observe," said Stanimir Metchev of the University of Western Ontario, Canada. "These are signs of patchiness in the cloud cover."
Given that previous results indicated that some brown dwarfs may be home to bad weather, the researchers anticipated uncovering a small number that varied in brightness over time. Instead, they found that half experienced a variation in brightness, and given that about half are believed to be oriented so that their storms are either hidden or always in view and unchanging, the researchers concluded that most - if not all - are ravaged by storms.
Although brown dwarfs form like stars, they lack the mass to produce the fusion needed to go on to become a fully fledged star - hence their nickname. In the past, astronomers believed brown dwarfs developed fast rotations when they formed and contracted and that they were able to maintain these quick paces even as they aged. The new study suggests otherwise, finding that some brown dwarfs rotate much more slowly than previously measured
"We don't yet know why these particular brown dwarfs spin so slowly, but several interesting possibilities exist," said Aren Heinze, a researcher from Stony Brook University and a co-author of the study. "A brown dwarf that rotates slowly may have formed in an unusual way - or it may even have been slowed down by the gravity of a yet-undiscovered planet in a close orbit around it."