Astronomers have found eight new planets in the 'Goldilocks zone' of their stars, orbiting at a distance where liquid water can exist on the planet's surface, including two that are the most similar to Earth of any known exoplanets to date.
Lead author Guillermo Torres of the Harvard-Smithsonian Center for Astrophysics (CfA) said, "Most of these planets have a good chance of being rocky, like Earth."
Kepler-438b and Kepler-442b are the two most Earth-like planets of the group. Both these planets orbit red dwarf stars that are smaller and cooler than our Sun. Kepler-438b completes one orbit every 35 days, while Kepler-442b circles its star every 112 days. The teams calculations show that Kepler-438b has a diameter just 12 percent bigger than Earth, and has a 70-percent chance of being rocky, while Kepler-442b is about one-third larger than Earth, but still has a 60-percent chance of being rocky.
Kepler-438b receives about 40 percent more light than Earth, due to which the team calculates it has a 70 percent likelihood of being in the habitable zone of its star. Kepler-442b gets about two-thirds as much light as Earth and the scientists give it a 97 percent chance of being in the habitable zone.
Kepler-438b is located 470 light-years from Earth, while Kepler-442b is 1,100 light-years away from the Earth.