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NASA’s Kepler Marks 1,000th Exoplanet Discovery, Uncovers More Small Worlds in Habitable Zones

NASA Kepler's Hall of Fame: Of the more than 1,000 verified planets found by NASA's Kepler Space Telescope, eight are less than twice Earth-size and in their stars' habitable zone. All eight orbit stars cooler and smaller than our sun. The search continues for Earth-size habitable zone worlds around sun-like stars.

Kepler's 8 small habitable zone planets


  • Monday, 2015 January 5 AAS Press Conference Webcast
    Exoplanets & Host Stars I
    • The Kepler Cluster Study: Toward the Ages of Stars & Their Planets
      Soren Meibom (Harvard-Smithsonian Center for Astrophysics)
    • Just Add Water? A Recipe for Earth-like Planets
      Courtney D. Dressing (Harvard-Smithsonian Center for Astrophysics)
    • The Persistence of Oceans on Earth-like Planets
      Laura Schaefer (Harvard-Smithsonian Center for Astrophysics)
    • Commentary: Exoplanets 20 Years After 51 Pegasi b
      Debra Fischer (Yale University)
  • Tuesday, 2015 January 6, 10:15 am PST
    Exoplanets & Host Stars II
    • The Kepler Q1-Q16 Planet Candidate Catalog
      Fergal Mullally (Kepler Science Office)
    • Validation of 12 Small Kepler Transiting Planets in the Habitable Zone
      Douglas A. Caldwell (SETI Institute)
    • The First 1,000,000 Classifications
      Marc Kuchner (NASA Goddard Space Flight Center)
    • First Semester Science Operations with the Gemini Planet Imager
      Marshall D. Perrin (Space Telescope Science Institute)
  • Complete NASA RELEASE 15-004.

Excerpts of NASA press release:

NASA’s Kepler Space Telescope ... to date has offered scientists an assortment of more than 4,000 candidate planets for further study -- the 1,000th of which was recently verified. [All verified planets are listed in the Kepler Discoveries Table.]

...The Kepler team also has added another 554 candidates to the roll of potential planets, six of which are near-Earth-size and orbit in the habitable zone of stars similar to our sun.

Three of the newly-validated planets are located in their distant suns’ habitable zone, the range of distances from the host star where liquid water might exist on the surface of an orbiting planet. Of the three, two are likely made of rock, like Earth.

"Each result from the planet-hunting Kepler mission's treasure trove of data takes us another step closer to answering the question of whether we are alone in the Universe," said John Grunsfeld, associate administrator of NASA’s Science Mission Directorate at the agency’s headquarters in Washington. “The Kepler team and its science community continue to produce impressive results with the data from this venerable explorer."

...Two of the newly validated planets, Kepler-438b and Kepler-442b, are less than 1.5 times the diameter of Earth. Kepler-438b, 475 light-years away, is 12 percent bigger than Earth and orbits its star once every 35.2 days. Kepler-442b, 1,100 light-years away, is 33 percent bigger than Earth and orbits its star once every 112 days.

Both Kepler-438b and Kepler-442b orbit stars smaller and cooler than our sun, making the habitable zone closer to their parent star, ....

"With each new discovery of these small, possibly rocky worlds, our confidence strengthens in the determination of the true frequency of planets like Earth," said co-author Doug Caldwell, SETI Institute Kepler scientist at NASA's Ames Research Center at Moffett Field, California. "The day is on the horizon when we’ll know how common temperate, rocky planets like Earth are.”

..."Kepler collected data for four years -- long enough that we can now tease out the Earth-size candidates in one Earth-year orbits", said Fergal Mullally, SETI Institute Kepler scientist at Ames who led the analysis of a new candidate catalog. "We’re closer than we’ve ever been to finding Earth twins around other sun-like stars. These are the planets we’re looking for"....

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