NASA’s Kepler spacecraft spotted more than 100 new exoplanets during its K2 mission, as confirmed by a team of astronomers led by the University of Arizona. All planets are between 20 and 50 percent bigger than Earth, four of which could be rocky and habitable.

Initially, the scientists counted up to197 potential planet candidates but only 104 were actual exoplanets. The planets are located in the Aquarius constellation 181 light years away, orbiting the M dwarf star K2-72. The planets revolve from five and half to 24 days around the star. Two can even have the same orbital period as Earth.

To determine the planets’ existence, the spacecraft observed a subtle dip in the star’s brightness. This phenomenon is caused when a planet passes in front of its star, which is also a  method used by other spacecrafts in search of planets outside the solar system.


An exoplanet and its moon. Credit: Wikimedia/IAU/L. Calçada

The findings are now published in the Astrophysical Journal Supplement Series. The study also involved follow-up observations conducted by researchers using the North Gemini telescope and the W. M. Keck Observatory in Hawaii, the Automated Planet Finder of the University of California Observatories and the Large Binocular Telescope by the University of Arizona.

The mission opens the way for the Transiting Exoplanet Survey Satellite and James Webb Space Telescope, NASA’s other exoplanet missions.

“This bountiful list of validated exoplanets from the K2 mission highlights the fact that the targeted examination of bright stars and nearby stars along the ecliptic is providing many interesting new planets,” points out Steve Howell, the project scientist for Kepler and K2 mission at the space agency’s Ames Research Center located in Moffett Field, California. “This allows the astronomical community ease of follow-up and characterization, and picks out a few gems for first study by the James Webb Space Telescope, which could perhaps provide information about their atmospheres.”