200 new planet candidates spotted

*Ten are in habitable zone, could support life, NASA reveals

The Kepler spacecraft has detected 219 new exoplanet candidates – and ten could be habitable. In a press briefing Monday at United States National Aeronautic Space Agency’s (NASA’s) Ames Research Center, scientists revealed the ‘most reliable’ catalog yet of potential planets in our galaxy, bringing the total to 4,034.

According to the scientists, over 2,300 planets spotted during the Kepler missions have been confirmed so far, including over 30 terrestrial-sized planets that lie in the ‘Goldilocks Zone’ of their star.

Of the 219 new planet candidates, 10 are near-Earth sized and orbit within the habitable zone of their host star, the Kepler scientists revealed during the briefing.
The habitable zone represents a range in which a planet could be the right temperature to host liquid water at the surface.

With the new analysis, the number of terrestrial-sized candidates in habitable zones has now climbed to about 50, with over 30 confirmed as exoplanets. The closest candidate to Earth is an object known as K77-11, the researchers say.

It receives just about the same amount of energy as we do from our sun, and is only slightly larger than Earth, at 1.3 Earth-radii, explained Susan Thompson, Kepler research scientist at the SETI Institute in Mountain View, California. The latest catalog represents Kepler’s final survey from the Cygnus constellation, and spans the spacecraft’s first four years of data.

Of the 4,034 candidates identified so far, 2,335 have now been verified. Researchers say the findings could ultimately help guide the search for alien life, offering “the most complete and reliable accounting of distant worlds to date.”

“This new result presented today has implications for understanding the frequency of different types of planets and galaxies, and helping us to advance our knowledge on how planets are formed,” said Mario Perez, Kepler program scientist in the Astrophysics Division of NASA’s Science Mission Directorate in Washington, during the conference.

In addition to the new exoplanet candidates, the researchers also identified a notable distinction between groupings of small planets, which could help guide the search for alien life.

With the Kepler observations and the W. M. Keck Observatory in Hawaii, the researchers found groups of small planets could be divided among two categories: rocky, Earth-sized planets, and gaseous planets smaller than Neptune.

The finding suggests that – for reasons not yet understood – the universe tends to create rocky planets up to about 75 percent bigger than Earth. And, roughly half of these planets take on small amounts of hydrogen and helium, causing them to dramatically increase in size. As a result, they ‘jump the gap,’ to become one of the Neptune-sized worlds.

The Kepler mission has spotted thousands of confirmed exoplanets over the years, with at least 30 planets not much larger than Earth now known to exist in the habitable zone.