K2-18 b’s atmosphere: methane, carbon dioxide detected

Detailed look at the potentially habitable exoplanet through NASA’s James Webb Space Telescope

The cosmos remains a frontier of countless mysteries, but recent discoveries are adding nuance to our understanding of what distant worlds might hold.

One such compelling case is that of exoplanet K2-18 b. Located 120 light-years away in the constellation Leo, this intriguing celestial body has given scientists new perspectives on habitable environments beyond our solar system. A recent study employing NASA’s James Webb Space Telescope has deepened this understanding by identifying the presence of methane and carbon dioxide in the planet’s atmosphere.

“Our findings underscore the importance of considering diverse habitable environments in the search for life elsewhere,”

Nikku Madhusudhan, an astronomer at the University of Cambridge and lead author of the study.

The role of NASA’s telescopes in our understanding of K2-18 b

The journey to understanding K2-18 b’s atmosphere began with observations from NASA’s Hubble Space Telescope. These initial insights have propelled further research, primarily using the James Webb Space Telescope, resulting in a broader comprehension of the planet’s atmospheric conditions.

The Webb Telescope’s data significantly adds to recent studies, suggesting that K2-18 b could be a ‘Hycean’ exoplanet—a type potentially boasting a hydrogen-rich atmosphere and water-covered surface.

Spectra of K2 18 b obtained with Webbs NIRISS Near Infrared Imager and Slitless Spectrograph and NIRSpec Near Infrared Spectrograph Credits Illustration NASA CSA ESA R Crawford STScI J Olmsted STScI Science N Madhusudhan Cambridge University

Unique features of K2-18 b

K2-18 b is unlike anything in our solar system. It’s categorized as a ‘sub-Neptune,’ an exoplanet type with sizes falling between Earth and Neptune.

This particular category remains poorly understood due to the absence of similar planets within our own system. The Webb Telescope’s revelations could play a pivotal role in expanding our understanding of these celestial outliers.

K2-18 b’s atmosphere

Methane and carbon dioxide were identified in K2-18 b’s atmosphere, with a noticeable absence of ammonia.

This data supports the possibility that beneath its hydrogen-rich exterior lies a water ocean. Additional observations also indicated the potential presence of dimethyl sulfide (DMS), a molecule primarily produced by life on Earth, making the planet a fascinating subject for future investigations.

Technical hurdles: overcoming the glare

Studying the atmospheres of exoplanets like K2-18 b presents a significant challenge. These celestial bodies are often overshadowed by the glare from their much larger parent stars. To overcome this obstacle, researchers employed a technique involving the analysis of starlight as it passed through K2-18 b’s atmosphere.

This approach has allowed scientists to conduct the most detailed spectrum of a habitable-zone sub-Neptune to date.

Plans for further exploration: MIRI spectrograph in the spotlight

The scientific community eagerly awaits further data on K2-18 b, and the team has plans to deliver. Their results were accepted for publication in The Astrophysical Journal Letters, adding credibility to their ground-breaking work. They are now gearing up for follow-up research using Webb’s MIRI (Mid-Infrared Instrument) spectrograph. The aim is not just to corroborate existing data but to unearth new details about K2-18 b’s environmental conditions.

  • Exoplanet mass: 8.6 times as massive as Earth
  • Distance: 120 light-years from Earth
  • Located: In the constellation Leo
  • Orbits: The cool dwarf star K2-18
  • Atmosphere: Abundance of methane and carbon dioxide, shortage of ammonia
  • Potential Molecule: Dimethyl sulfide (DMS)

What Webb’s eye in the sky suggests for the future

As humanity continues to peer into the cosmic abyss, planets like K2-18 b not only expand our scientific understanding but also prompt contemplation about life’s possibilities in the distant universe.The James Webb Space Telescope will undoubtedly play a crucial role in these explorations, offering glimpses into environments that could one day redefine what we consider ‘habitable.’


More Aerospace


More Agriculture


More Automotive


More Energy


More Technology


More Environmental