First water clouds detected outside the solar system

SANTA CRUZ, Calif., July 8 (UPI) -- A team of astronomers have for the first time observed clouds of water outside of our solar system. The clouds were discovered around WISE 0855, an object 7.2 light-years from Earth.

Though WISE 0855 resembles gas giants like Jupiter or Saturn, it is in fact a failed star -- a brown dwarf. It began life the way most stars do, as a cloud of gas and dust collapsed by gravity. But WISE 0855 never gained the critical mass to generate stellar fusion.

Instead, WISE 0855 became a swirling ball of frigid gas and dust. It is the coldest known object outside our solar system. The object is minus 10 degrees Fahrenheit, nearly as cold as Jupiter.

Recent analysis of the object by the Gemini North telescope in Hawaii yielded the first details of its chemical composition, including evidence that it hosts clouds of water or ice.

"We would expect an object that cold to have water clouds, and this is the best evidence that it does," Andrew Skemer, assistant professor of astronomy and astrophysics at the University of California, Santa Cruz, said in a news release.

Because WISE 0855 is so faint, it's impossible to study using traditional spectroscopic techniques. Astronomers were able to observe a spectral signature by targeting a narrow band of thermal emissions from the deep atmosphere using the Gemini Near Infrared Spectrograph.

"It's five times fainter than any other object detected with ground-based spectroscopy at this wavelength," Skemer said. "Now that we have a spectrum, we can really start thinking about what's going on in this object. Our spectrum shows that WISE 0855 is dominated by water vapor and clouds, with an overall appearance that is strikingly similar to Jupiter."

Researchers developed a model to interpret the spectrograph data, using simulations to entertain different scenarios, including cloudy and cloud-free atmospheric conditions. Simulations suggest a cloudy atmosphere rich in water vapor best matched the observational data.

"The spectrum allows us to investigate dynamical and chemical properties that have long been studied in Jupiter's atmosphere, but this time on an extrasolar world," Skemer concluded.

The new research was published this week in the Astrophysical Journal Letters.