Seven earth-sized habitable-zone exoplanets discovered orbiting single star

NASA’s Spitzer Space Telescope has revealed a set of seven planets that could have liquid water orbiting a single star. Three of those planets are firmly within the system’s habitable zone. Because they are outside of our own solar system, the planets are scientifically known as exoplanets.

According to NASA, the discovery sets a new record for the greatest number of habitable-zone planets found around a single star.

NASA said under the right atmospheric conditions all seven planets could have liquid water, but the chances are highest with the three planets in the habitable zone.

This illustration shows the possible surface of TRAPPIST-1f, one of the newly discovered planets in the TRAPPIST-1 system. Scientists using the Spitzer Space Telescope and ground-based telescopes have discovered that there are seven Earth-size planets in the system.
Credits: NASA/JPL-Caltech

“This discovery could be a significant piece in the puzzle of finding habitable environments, places that are conducive to life,” said Thomas Zurbuchen, associate administrator of the agency’s Science Mission Directorate in Washington. “Answering the question ‘are we alone’ is a top science priority and finding so many planets like these for the first time in the habitable zone is a remarkable step forward toward that goal.”

The expoplanet system, called TRAPPIST-1, is 40 light years from Earth — in the constellation Aquarius.

Based on measured densities and observations, all TRAPPIST-1 planets are likely to be rocky, according to NASA. Further study is required to determine whether they are rich in water.

The TRAPPIST-1 planets all share a very close orbit to their star, closer than Mercury is to our sun. The possibility of water exists because unlike our sun, the TRAPPIST-1 star is an ultra-cool dwarf.

NASA wrote, “If a person was standing on one of the planet’s surface, they could gaze up and potentially see geological features or clouds of neighboring worlds, which would sometimes appear larger than the moon in Earth’s sky.”

Follow-up studies of the system are planned, including using NASA’s upcoming James Webb Space Telescope, which is slated for launch in 2018. Scientists said Webb will be able to detect water, methane, oxygen and other components of a planet’s atmosphere.

For more information on the TRAPPIST-1 system, visit: https://exoplanets.nasa.gov/trappist1