Water Ice Clouds Detected on Brown Dwarf 7.3 Light Years Away

Artists Conception : Credit Rob Gizis, CUNY BMCC

An astronomer at Penn State University appears to discovered the first ever direct evidence of water ice clouds on another world.  That world is WISE J0855-0714, an enigmatic brown dwarf of “failed star” located only 7.3 light years from Earth.

The discovery was made using images from NASA’s WISE infrared space telescope, and matches observations by a ground based telescope in Chile.

From the article in ScienceMag.org

“Kevin Luhman, an astronomer at Pennsylvania State University, University Park, recently discovered the nearby object by using images from NASA’s WISE infrared space telescope, which scanned the sky from 2010 to 2011. A brown dwarf is a failed star and has so little mass that it can’t sustain nuclear reactions, so after its birth it fades and cools. This brown dwarf, named WISE J0855-0714, is the coldest known. Its temperature is slightly below the freezing point of water, so it’s colder than Earth’s mean temperature but warmer than Jupiter’s.

“I’ve been obsessed with this object since its discovery,” says astronomer Jacqueline Faherty of the Carnegie Institution for Science in Washington, D.C. The new neighbor resembles a giant planet—it’s as large as Jupiter and three to 10 times as massive—but is solitary, which means it has no sun whose glare interferes with our view of it. Moreover, it’s nearby: the fourth closest system to the sun, after Alpha Centauri, Barnard’s star, and Luhman 16.

Still, because the object is small and cold, it’s so dim that no ground-based observatory had seen it. “I went to battle at the telescope to try and get this detection,” Faherty says. “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.”

For 3 nights in May, Faherty used the 6.5-meter Magellan Baade telescope in Chile to acquire 151 near-infrared images that she later combined to yield a detection. “I’m absolutely elated,” she says. Moreover, as her team will report in The Astrophysical Journal Letters, the observed colors match models of a brown dwarf with clouds of water ice and clouds of sodium sulfide.”

The costs have been outrageous, but with each new discovery by existing instruments along the lines of that announced here, anticipation builds for the advent of the James Webb Space Telescope. One can hardly imagine the food fight between eager astronomers and space scientists to get viewing time.

 

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