Scientists have discovered 15 new planets - including one 'super-Earth' that could harbour liquid water - orbiting small, cool stars near our These stars, known as red dwarfs, are of enormous interest for studies of planetary formation and evolution. But while the researchers’ simulations further hinted at the exoplanet having an “Earth-like” atmosphere and other features, the study’s lead author, Teruyuki Hirano of the Tokyo Institute of Technology, stressed that it isn’t 100 percent certain that K2-155d is indeed a habitable super-Earth with at least some of the necessary ingredients for life. But the two new studies still yielded substantial takeaways, including the observation that planets orbiting red dwarfs might be similar to those that orbit stars with similar characteristics to the sun, though they may be smaller in number than those that orbit “solar-type stars.”

“Red dwarf systems, especially coolest red dwarfs, are just beginning to be investigated, so they are very exciting targets for future exoplanet research,” said Hirano. One of the brightest red dwarfs -- K2-155 that is around 200 light years away from Earth -- has three transiting "super-Earths", which are slightly bigger than our own planet. Of those three ‘super-Earths’, the outermost planet, K2-155d, with a radius 1.6 times that of Earth, could be within the host star’s habitable zone, the researchers noted in the study appeared in The Astronomical Journal. As noted by Phys.org, climate modeling simulations suggested that there is a chance that K2-155d, which has a radius about 1.6 times greater than our planet’s, might have liquid water on its surface. In two studies recently published in the Astronomical Journal, researchers detailed their observations on data from the Kepler space telescope’s K2 mission, which were combined with findings made using ground-based telescopes, such as Spain’s Nordic Optical Telescope and Hawaii’s Subaru Telescope. Hirano expresses both excitement and restraint, as he says: “In our simulations, the atmosphere and the composition of the planet were assumed to be Earth-like, and there’s no guarantee that this is the case.”

A more precise estimate of the radius and temperature of the K2-155 star would be needed to conclude definitively whether K2-155d is habitable. The few planets with a radius about three times that of Earth were found orbiting the most metal-rich red dwarfs.”

The studies were conducted as part of the KESPRINT collaboration, a group formed by the merger of KEST (Kepler Exoplanet Science Team) and ESPRINT (Equipo de Seguimiento de Planetas Rocosos Intepretando sus Transitos) in 2016. Researchers like Hirano have been relying largely on data from Kepler to find exoplanet candidates, but we'll soon enter a new era of planet discovery with the planned launch of NASA's Transiting Exoplanet Survey Satellite (TESS) in April.
K2-155d, a Super-Earth exoplanet, is discovered and could produce life.