Inside 10 years, new space telescopes may most likely decide if K2-18b's environment contains gases that could be produced by living creatures. "While not a true Earth-analogue due to its size, this bodes well for our exploration of small planets", Josh Lothringer, who studies exoplanet atmospheres at Johns Hopkins University in the United States, said on Twitter.
The tenable zone is the locale around a star where temperatures are adequately considerate for water to exist in fluid-structure on the outside of a planet.
The exoplanet is orbiting within the habitable zone of dwarf star that is smaller, cooler and more active than the Sun.
University College London scientists used data from NASA's Hubble Space Telescope to analyse starlight filtered through the atmosphere of exoplanet K2-18b, which is around 110 light years away from Earth.
"This planet is about the same temperature as Earth, but 2.7 times larger". Pictured: A hand out image made available by the European Southern Observatory on August 24 2016, shows an artist's impression of the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to the Solar System.
According to the researchers, K2-18b lies within a habitable zone, which means it is not too close or too far from its host star.
"For instance, we have found also that there is still a lot of hydrogen in the atmosphere, and hydrogen is not necessarily something that we'll be comfortable with as a human being", Tinetti said.
WION: What do we know of this exoplanet, is it gaseous in nature or does it have a surface?
In contrast, the proportion of water vapor in the planet's atmosphere varies between 0.2 percent over the rods and around four percent at the tropics. Researchers believe that other molecules including nitrogen and methane may be present but, with current observations they remain undetectable.
"It is significantly heavier, and it has a different atmospheric composition", he said.
Further research will be able to determine the extent of cloud coverage and the percentage of water in the atmosphere.
Using data from the Hubble Space Telescope's Wide Field Camera 3, astronomers at the Center for Space Exochemistry Data at UCL in the United Kingdom made the discovery. It is suggested that K2-18b is the first-ever exoplanet with water found on it.