WASHINGTON (CBS DC) — Astronomers say they’ve discovered water ice clouds on a “brown dwarf” just 7.3 light-years from Earth – the first candidate outside our own solar system to have direct evidence of water clouds.
The water ice clouds were discovered by Kevin Luhman, an astronomer at Penn State University, using NASA’s WISE infrared space telescope, Science Mag reports. The water ice clouds, if confirmed, would be less than twice the distance of Alpha Centauri, the nearest star system to our sun.
The water ice clouds are shrouding a Jupiter-sized “brown dwarf,” which is a failed star that has too little mass to sustain nuclear reactions and thus cools and fades in orbit. Ground-based observatory has been unable to view the dim object, but the brown dwarf could provide astronomers with more information on cool giant planets orbiting suns outside our solar system.
“I’ve been obsessed with this object since its discovery,” astronomer Jacqueline Faherty of the Carnegie Institution for Science in Washington, D.C., told Science Mag.
The newly-discovered object is estimated to be as large as Jupiter and three-to-ten times as massive and is relatively close being the fourth closest system to our sun after Alpha Centauri, Barnard’s star and Luhman 16.
However, the dim object has no sun that glares in the direction Earth.
“I went to battle at the telescope to try and get this detection,” Faherty told Science Mag. “I wanted to put war paint under my eyes and wear a bandanna, because I knew this was not going to be an easy thing to do. At the telescope, I’ve never been so nervous. I’ve never wanted clear conditions so badly.”
The upcoming report in The Astrophysical Journal Letters said the infrared images detected colors that match models of brown dwarf objects shrouded by clouds of water ice and clouds of sodium sulfide.
“It’s incredibly interesting,” Jonathan Fortney of the University of California, Santa Cruz, an astronomer who helped develop those models but was not involved in the discovery, told Science Mag. “It’s tentative,” he says, but “it’s the first evidence for water clouds” outside our solar system.
Faherty says that water vapor has been detected in areas outside of our solar system, but that water clouds are an entirely new discovery.
“One of the things we don’t really know is how common partly cloudiness is,” he says. Venus, whose clouds consist of sulfuric acid, is totally cloudy, but Earth is partly cloudy. Faherty said that the brown dwarf is an example of partly cloudy with about half of it obscured by clouds.