K2-18b, also known as EPIC 201912552 b, is an exoplanet orbiting the red dwarf star K2-18, located 124 light-years (38 pc) away from Earth. The planet, initially discovered through the Kepler Space Observatory, is about eight times the mass of Earth, thus is classified as a super Earth. It has a 33-day orbit within the star’s habitable zone, but it is unlikely to be habitable.
In 2019, two independent research studies, combining data from the Kepler space telescope, the Spitzer Space Telescope, and the Hubble Space Telescope, concluded that there are significant amounts of water vapour in its atmosphere, a first for a planet in the habitable zone.
So, first exoplanet in a habitable zone with water vapor in the atmosphere! Neat! But it’s around a red dwarf star, and tidally locked. So it’s not likely to be actually habitable by humans. Red dwarfs are small stars that last much longer than our sun. They tend to have too much radiation to let life as we know it evolve. Being tidally locked means the same side of the planet always faces the star, so one side is hot and the other is cold. Life as we know it could probably only live on the circular edge where the star is near the horizon.