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)