Astronomers this week announced that they have produced a "weather map" for a brown dwarf that shows planet-sized clouds driven by wind.
Brown dwarfs are objects at the edge of becoming a star. They lack the mass to begin hydrogen fusion, and in some ways are similar to gas giant planets. The new study, published in The Astrophysical Journal Letters, will provide researchers with a better understanding of brown dwarfs and the atmospheres of the billions of planets outside our solar system.
"With Hubble and Spitzer, we were able to look at different atmospheric layers of a brown dwarf, similar to the way doctors use medical imaging techniques to study the different tissues in your body," said Daniel Apai, principal investigator on the research at the University of Arizona.
Apai refers to the Hubble and Spitzer space telescopes, which were used simultaneously to observe a brown dwarf named 2MASSJ22282889-431026. He and his colleauges found that its light varied every 90 minutes as the object rotated, depending in what wavelength of infrared light it was observed. These variations were discovered to be the different layers of the brown dwarf's clouds, which swirl around the its atmosphere.
"Unlike the water clouds of Earth or the ammonia clouds of Jupiter, clouds on brown dwarfs are composed of hot grains of sand, liquid drops of iron, and other exotic compounds," said Mark Marley, co-author of the study and a research scientist at NASA's Ames Research Center. "So this large atmospheric disturbance found by Spitzer and Hubble gives a new meaning to the concept of extreme weather."
This was the first time astronomers were able to study the variability of a brown dwarf's atmosphere at different altitudes at the same time. Researchers are planning to do the same with other nearby brown dwarfs.
"What we see here is evidence for massive, organized cloud systems, perhaps akin to giant versions of the Great Red Spot on Jupiter," said Adam Showman, a theorist at the University of Arizona. "These out-of-sync light variations provide a fingerprint of how the brown dwarf's weather systems stack up vertically. The data suggest regions on the brown dwarf where the weather is cloudy and rich in silicate vapor deep in the atmosphere coincide with balmier, drier conditions at higher altitudes - and vice versa."