Planet Kepler-421b Is The Planet With The Longest Known Year At 704 Days

The planet takes nearly two Earth years to circle its star.
By Monica Lowe
  • In brief
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    Source: David A. Aguilar

  • IB Times has the story…

    The following is an excerpt from Kepler-421b Has Longest Year of Any Exoplanet and Lies on the ‘Snow Line’

    Astronomers have discovered a planet with the longest known orbit of any planet outside our solar system.

    Kepler-421b orbits its star once every 704 days, travelling a distance of 110 million miles. Its star, Kepler-421, is located 1,000 light years from Earth towards the constellation Lyra.

    Most of the exoplanets that have been discovered so far are much closer to their stars, and thus have far shorter orbital periods.

    Lead author David Kipping, from the Harvard-Smithsonian Centre for Astrophysics (CfA), said Kepler-421’s discovery was a “stroke of luck” because the further away a planet is from its star, “the less likely it is to transit the star from Earth’s point of view”. In this case, he said, the planet had to “line up just right”.

  • NASA has more…

    The following is an excerpt from NASA’s Kepler Discovers First Earth-Size Planet In The ‘Habitable Zone’ of Another Star

    Using NASA’s Kepler Space Telescope, astronomers have discovered the first Earth-size planet orbiting a star in the “habitable zone” — the range of distance from a star where liquid water might pool on the surface of an orbiting planet. The discovery of Kepler-186f confirms that planets the size of Earth exist in the habitable zone of stars other than our sun.

    While planets have previously been found in the habitable zone, they are all at least 40 percent larger in size than Earth and understanding their makeup is challenging. Kepler-186f is more reminiscent of Earth.

    “The discovery of Kepler-186f is a significant step toward finding worlds like our planet Earth,” said Paul Hertz, NASA’s Astrophysics Division director at the agency’s headquarters in Washington.