Discovered: A Cold, Close Neighbor of the Sun   
       
   April 25, 2014: NASA's Wide-field Infrared Survey Explorer (WISE) and Spitzer   
   Space Telescope have discovered what appears to be the coldest "brown dwarf"   
   known -- a dim, star-like body that  surprisingly is as frosty as Earth's   
   North Pole. Named "WISE J085510.83-071442.5," the brown dwarf appears to be   
   7.2 light-years away, earning it the title for fourth closest system to our   
   sun.   
       
   "It's very exciting to discover a new neighbor of our solar system that is so   
   close," said Kevin Luhman, an astronomer at Pennsylvania State University's   
   Center for Exoplanets and Habitable Worlds, University Park.   
       
   http://www.nasa.gov/sites/default/files/pia18002-full-640.gif   
       
   This animation shows the brown dwarf WISE J085510.83-071442.5 moving across   
   the sky. It was first seen in two infrared images taken six months apart in   
   2010 by NASA's Wide-field Infrared Survey Explorer (WISE). Two additional   
   images of the object were taken with NASA's Spitzer Space Telescope in 2013   
   and 2014. All four images were used to measure the distance to the object --   
   7.2 light-years -- using the parallax effect.  Movie   
       
   Brown dwarfs start their lives like stars, as collapsing balls of gas, but   
   they lack the mass to burn nuclear fuel and radiate starlight. The newfound   
   coldest brown dwarf is named WISE J085510.83-071442.5. It has a chilly   
   temperature between minus 54 and 9 degrees Fahrenheit (minus 48 to minus 13   
   degrees Celsius). Previous record holders for coldest brown dwarfs, also found   
   by WISE and Spitzer, were about room temperature.   
       
   "It is remarkable that even after many decades of studying the sky, we still   
   do not have a complete inventory of the sun's nearest neighbors," added   
   Michael Werner, the project scientist for Spitzer at NASA's Jet Propulsion   
   Laboratory. "This exciting new result demonstrates the power of exploring the   
   universe using new tools, such as the infrared eyes of WISE and Spitzer."   
       
   WISE was able to spot the rare object because it surveyed the entire sky twice   
   in infrared light, observing some areas up to three times. Cool objects like   
   brown dwarfs can be invisible when viewed by visible-light telescopes, but   
   their thermal glow -- even if feeble -- stands out in infrared light. In   
   addition, the closer a body, the more it appears to move in images taken   
   months apart. Airplanes are a good example of this effect: a closer,   
   low-flying plane will appear to fly overhead more rapidly than a high-flying   
   one.   
       
   "This object appeared to move really fast in the WISE data," said Luhman.   
   "That told us it was something special."   
       
   After noticing the fast motion of WISE J085510.83-071442.5, Luhman spent time   
   analyzing additional images taken with Spitzer and the Gemini South telescope   
   on Cerro Pachon in Chile. Spitzer's infrared observations helped determine the   
   frosty temperature of the brown dwarf. Combined detections from WISE and   
   Spitzer, taken from different positions around the sun, revealed the object's   
   parallax, and thus its distance. The closest system to Earth, a trio of stars,   
   is Alpha Centauri, at about 4 light-years away. WISE J085510.83-071442.5 is   
   only a few light years farther than that.   
       
   http://www.nasa.gov/jpl/wise/spitzter/pia18003/#.U1qsLlfYGWc   
       
   This diagram pinpoints star systems closest to the sun. The year when the   
   distance to each system was determined is listed after the system's name. More   
       
   WISE J085510.83-071442.5 appears to be 3 to 10 times the mass of Jupiter. With   
   such a low mass, it could be a gas giant similar to Jupiter that was ejected   
   from its star system. But scientists estimate it is probably a brown dwarf   
   rather than a planet since brown dwarfs are known to be fairly common. If so,   
   it is one of the least massive brown dwarfs known.   
       
   In March of 2013, Luhman's analysis of the images from WISE uncovered a pair   
   of much warmer brown dwarfs at a distance of 6.5 light years, making that   
   system the third closest to the sun. His search for rapidly moving bodies also   
   demonstrated that the outer solar system probably does not contain a large,   
   undiscovered planet, which has been referred to as "Planet X" or "Nemesis."   
       
   Credits:   
   Production editor: Dr. Tony Phillips | Credit: Science@NASA   
       
   More information:   
       
   For more information on NASA's WISE mission, visit: http://www.nasa.gov/wise   
       
   For more information on NASA's Spitzer mission, visit: http://ww   
   .nasa.gov/spitzer   
       
   The California Institute of Technology in Pasadena manages JPL for NASA.   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.99   
    * Origin: NCS BBS - Houma, LoUiSiAna (1:3828/7)