By 2017, the Kepler spacecraft has detected 219 new exoplanet candidates, of which 10 are orbiting in the inhabitable zone of its parent star.
The habitable zone is an area where a planet is at the right temperature to have water on its surface.
"The new results presented today have implications for understanding the frequency of different planets and galaxies, and helping us to increase our knowledge of how planets are formed," said Kepler program scientist at NASA Science Mission Division Astrophysics Division Mario Perez.
In addition to exoplanet candidates, the researchers also identified striking differences between small planetary groups. It helps to drive alien searches.
With the observations of Kepler and W.M. Keck Observatory in Hawaii, the researchers found that small planetary groups could be divided into two categories, rocky and Earth-sized as well as smaller gas planets than Neptune.
The discovery found that in the universe formed more rocky planets measuring 75 percent larger than Earth. However, half the planet has only hydrogen and helium in small quantities so they can turn into a gas planet the size of Neptune.
