Exoplanet K2-18 b – NIRISS

This illustration shows what exoplanet K2-18 b could look like based on science data.

K2-18 b is located 120 light-years away from Earth and orbits a cool dwarf star called K2-18 within what's known as the habitable zone. 

Working in tandem with Near-Infrared Spectrograph (NIRSpec), another instrument on the James Webb Space Telescope, the Near-Infrared Imager and Slitless Spectrograph (NIRISS), a Canadian instrument, has collected data that offers a captivating glimpse into the atmosphere of exoplanet K2-18 b, revealing the presence of methane and carbon dioxide, and possibly detecting a molecule called dimethyl sulfide.

These findings support the hypothesis that there may be a water ocean underneath a hydrogen-rich atmosphere in K2-18 b, which is 8.6 times more massive than Earth. (Credits: NASA, ESA, CSA, Joseph Olmsted (STScI))