20th April 2013 NASA's Kepler discovers its smallest 'habitable zone' planets to date NASA's Kepler mission has discovered two new planetary systems that include three super-Earth-sized planets in the 'habitable zone' – the range of distance from a star which might be suitable for liquid water.
The Kepler-62 system has five planets — 62b, 62c, 62d, 62e and 62f. The Kepler-69 system has two — 69b and 69c. Kepler-62e, 62f and 69c (all pictured above) are the super-Earth-sized planets. Kepler-22b, furthest on the left, was the previous smallest, and we reported on its discovery in December 2011. Two of the newly discovered planets orbit a star smaller and cooler than the Sun. 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. It is likely to have a rocky composition. Kepler-62e orbits on the inner edge of the habitable zone and is 60 percent larger than Earth. The third planet, Kepler-69c, is 70 percent larger than the size of Earth, and lies in the habitable zone of a G-type star remarkably similar to our Sun. Astronomers are uncertain about its composition, but the orbital period of 242 days around a Sun-like star resembles that of our neighbouring planet Venus. The Kepler-62 parent star is 1,200 light years from Earth in the constellation Lyra. Kepler-69 is 2,700 light-years away in the constellation Cygnus. For comparison, Kepler-22, the earlier discovery, is around 620 light years away. Scientists do not know whether life could exist on the newfound planets, but their discovery is another step closer to finding a world similar to Earth around a star like our Sun.
"The Kepler spacecraft has turned out to be a rock star of science," said John Grunsfeld, associate administrator of the Science Mission Directorate at NASA Headquarters. "The discovery of these rocky planets in the habitable zone brings us closer to finding a place like home. It 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." 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. "The detection and confirmation of planets is an enormously collaborative effort of talent and resources, and requires expertise from across the scientific community to produce these tremendous results," said William Borucki, Kepler science principal investigator at NASA's Ames Research Center. "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." Various other new telescopes are planned for the next decade — not just by NASA but other agencies too. The number of exoplanet discoveries has been growing exponentially and could surpass 10 million by the 2050s, if trends continue. However, this would be only 0.01 percent of the 100 billion planets thought to exist in our galaxy... not to mention the billions of other galaxies throughout the universe.
Comments »
|
