Monster Storms Raging on Failed Stars

This illustration shows what the weather might look like on cool star-like bodies known as brown dwarfs. These giant balls of gas start out life like stars but lack the mass to sustain nuclear fusion at their cores, so they fade and cool with time. Credit: NASA/JPL-Caltech/University of Western Ontario/Stony Brook University

Hurricanes as large as planets may sweep across the face of brown dwarfs—failed stars bigger than planets but smaller than real stars.

A new study looks at 44 brown dwarfs using the infrared camera of NASA’s Spitzer space telescope. The astronomers report that they recorded periodic changes in brightness and saw the largest variations ever seen in these failed stars. That suggests the brown dwarfs see very turbulent weather. (Related: “Coldest Star Found—No Hotter Than Fresh Coffee.”)

New observations from the Spitzer space telescope suggest that most brown dwarfs are roiling with one or more planet-size storms akin to Jupiter’s Great Red Spot, says NASA.

“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,”  study co-author Stanimir Metchev, astronomer at the University of Western Ontario, Canada, said in a statement.

“These are signs of patchiness in the cloud cover.”

Brown dwarfs have masses ranging from 10 to 80 times that of Jupiter, not enough to spark the nuclear fusion that powers stars. Instead, their atmosphere becomes cool and cloudy over time, becoming similar to those of gas giant planets.

This artwork shows an oval shaped storm, larger than Jupiter's Great Red Spot raging on a failed star - known as a brown dwarf. New research could new shed light on the weather on exo-planets. Credit: Jon Lomberg, University of Toronto
This illustration shows an oval-shaped storm larger than Jupiter’s Great Red Spot raging on a failed star known as a brown dwarf. New research is shedding light on the weather on exoplanets. Credit: Jon Lomberg, University of Toronto

Metchev and his team believe these colossal storms, complete with high winds and lightning, are most likely much larger than any storms seen in our solar system, and could be even larger than the Great Red Spot on Jupiter. That oval, hurricane-like storm on the Jovian giant is so large that it could easily swallow three Earths. It has raged for at least three centuries.

On brown dwarfs, however, the storms would not swirl among clouds made of water or hydrogen, but of hot sand, molten iron, and perhaps salt.

What’s exciting to scientists is that the study’s failed stars appear to share many of the same characteristics as their little cousins, Jupiter-like gas giant planets. This discovery will help our understanding of atmosphere dynamics not just on brown dwarfs, but also on planets inside and outside our solar system.

Since brown dwarfs are common across the galaxy, they make for a convenient weather laboratory for planets, say the researchers, who hope to do further studies. (See also: “Surprisingly Close Star System Discovered.”)

These results were presented at a news conference this week at the 223rd annual meeting of the American Astronomical Society in Washington, D.C.

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Changing Planet

Meet the Author
Andrew Fazekas, aka The Night Sky Guy, is a science writer, broadcaster, and lecturer who loves to share his passion for the wonders of the universe through all media. He is a regular contributor to National Geographic News and is the national cosmic correspondent for Canada’s Weather Network TV channel, space columnist for CBC Radio network, and a consultant for the Canadian Space Agency. As a member of the Royal Astronomical Society of Canada, Andrew has been observing the heavens from Montreal for over a quarter century and has never met a clear night sky he didn’t like.