Kepler Discovers Smallest 'Habitable Zone' Planets   
       
   April 18, 2013: NASA's Kepler mission has discovered two new planetary systems   
   that include three super-Earth-size planets in the "habitable zone," the range   
   of distance from a star where the surface temperature of an orbiting planet   
   might be suitable for liquid water.   
       
   The two planetary systems are Kepler-62 and Kepler-69.  The Kepler-62 system   
   has five planets; 62b, 62c, 62d, 62e and 62f. The Kepler-69 system has two   
   planets; 69b and 69c. Kepler-62e, 62f and 69c are the habitable-zone "super   
   Earths."   
       
   "The discovery of these rocky planets in the habitable zone brings us a bit   
   closer to finding a place like home," said John Grunsfeld, associate is only a   
   matter of time before we know if the galaxy is home to a multitude of planets   
   like Earth, or if we are a rarity."   
       
   http://tinyurl.com/dxghoqf   
       
   The diagram compares the planets of the inner solar system to Kepler-62, a   
   five-planet system about 1,200 light-years from Earth. The  planets of the   
   Kepler-62 system orbit a star classified as a K2 dwarf, measuring just   
   two-thirds the size of the sun and only one-fifth as bright. At seven billion   
   years old, the star is somewhat older than the sun. It is about 1,200   
   light-years from Earth in the constellation Lyra.   
       
   Kepler-62f is only 40 percent larger than Earth, making it the exoplanet   
   closest to the size of our planet known in the habitable zone of another star.   
   Kepler-62f is likely to have a rocky composition. Kepler-62e, orbits on the   
   inner edge of the habitable zone and is roughly 60 percent larger than Earth.   
       
   The planets of the Kepler-69 orbit a star in the same class as our sun, called   
   G-type. It is 93 percent the size of the sun and 80 percent as luminous and is   
   located approximately 2,700 light-years from Earth in the constellation Cygnus.   
       
   Kepler-69c is 70 percent larger than the size of Earth. Astronomers are   
   uncertain about the composition of Kepler-69c, but its orbit of 242 days   
   around a sun-like star resembles that of our neighboring planet Venus.   
       
   "We only know of one star that hosts a planet with life, the sun. Finding a   
   planet in the habitable zone around a star like our sun is a significant   
   milestone toward finding truly Earth-like planets," said Thomas Barclay,   
   Kepler scientist at the Bay Area Environmental Research Institute, and lead   
   author of the Kepler-69 system discovery published in the Astrophysical   
   Journal.   
       
   http://tinyurl.com/cxsvnnq   
       
   The diagram compares the planets of the inner solar system to Kepler-69, a   
   two-planet system about 2,700 light-years from Earth. "Kepler has brought a   
   resurgence of astronomical discoveries and we are making excellent progress   
   toward determining if planets like ours are the exception or the rule," added   
   William Borucki, Kepler science principal investigator at NASA's Ames and lead   
   author of the Kepler-62 system paper in Science.   
       
   Scientists do not know whether life could exist on the newfound planets, but   
   their discovery signals we are another step closer to finding a world similar   
   to Earth around a star like our sun.   
       
   Says Grunsfeld, "the Kepler spacecraft has certainly turned out to be a rock   
   star of science."   
       
   For more information about the Kepler mission and to view the digital press   
   kit, visit http://www.nasa.gov/kepler   
       
   Credits:   
       
   Production editor: Dr. Tony Phillips | Credit: Science@NASA   
       
   More information:   
       
   The Kepler space telescope, which simultaneously and continuously measures the   
   brightness of more than 150,000 stars, is NASA's first mission capable of   
   detecting Earth-size planets around stars like our sun.  When a planet   
   candidate transits, or passes in front of the star from the spacecraft's   
   vantage point, a percentage of light from the star is blocked. The resulting   
   dip in the brightness of the starlight reveals the transiting planet's size   
   relative to its star. Using the transit method, Kepler has detected 2,740   
   candidates. Using various analysis techniques, ground telescopes and other   
   space assets, 122 planets have been confirmed.   
       
   Early in the mission, the Kepler telescope primarily found large, gaseous   
   giants in very close orbits of their stars. Known as "hot Jupiters," these are   
   easier to detect due to their size and very short orbital periods. Earth would   
   take three years to accomplish the three transits required to be accepted as a   
   planet candidate. As Kepler continues to observe, transit signals of habitable   
   zone planets the size of Earth orbiting stars like the sun will begin to   
   emerge.   
       
   Ames is responsible for Kepler's ground system development, mission   
   operations, and science data analysis. NASA's Jet Propulsion Laboratory in   
   Pasadena, Calif., managed Kepler mission development.   
       
   Ball Aerospace & Technologies Corp. in Boulder, Colo., developed the Kepler   
   flight system and supports mission operations with the Laboratory for   
   Atmospheric and Space Physics at the University of Colorado in Boulder.   
       
   The Space Telescope Science Institute in Baltimore archives, hosts and   
   distributes Kepler science data. Kepler is NASA's 10th Discovery Mission and   
   was funded by the agency's Science Mission Directorate.   
       
       
   Regards,   
       
   Roger   
      
   --- D'Bridge 3.91   
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