The scientists discovered that the comparatively “dry” Trappist-1 exoplanets, located close to the host star were found to contain less than 15 percent water by mass. The discovery of Trappist-1, which is slightly bigger than Jupiter and is located in the Aquarius constellation, around 40 light years away from our sun, excited researchers, especially after seven exoplanets were spotted orbiting the star. The outermost planet of the system was a particularly interesting finding, as it had a radius about 1.6 times that of Earth and may be within this star's habitable zone, the researchers said. While all the planets are similar in size to Earth (no gas giants have been detected), only three of the planets (TRAPPIST-1e, f, and g) are orbiting at a distance that would allow them to have liquid water. The observations can be used to calculate how large the planet is and how far from a star it is — which reveals whether or not there could be liquid water, making a world habitable. "Red dwarf systems, especially coolest red dwarfs, are just beginning to be investigated, so they are very exciting targets for future exoplanet research," said Teruyuki Hirano, a researcher at the Tokyo Institute of Technology and lead author of the new work. In April 2018, the NASA mission Transiting Exoplanet Survey Satellite (TESS)is scheduled to launch; that spacecraft may provide greater precision for researchers in search of distant planets with conditions that could support life.
Fifteen new exoplanets are discovered. Three of them, larger than Earth, are also discovered around the dwarf star K2-155. Furthermore, a 3D climate simulation was created to find out if K2-155d has water.