LIVE SCIENCE - The contentious exoplanet, called K2-18b, is a warm, watery world with a hydrogen-based atmosphere. Located about 120 light-years from Earth, it sits in the habitable zone around its home star, where liquid water (and, therefore, potentially life) is possible.
The distant world made headlines last year after observations with JWST's Near Infrared Spectrograph (NIRSpec) instrument revealed possible traces of a biologically produced gas called dimethyl sulfide (DMS) in the planet's atmosphere. On Earth, this chemical is known to originate only from microscopic marine creatures, such as phytoplankton — giving researchers hope that perhaps the oceans of K2-18b are swimming with life as well.
The detection came with caveats, however, mostly based on the faintness of the chemical signals when seen at such extreme distances from Earth.
"The DMS signal from the Webb telescope was not very strong and only showed up in certain ways when analyzing the data," study lead author Shang-Min Tsai, a project scientist at the University of California, Riverside, said in a statement. "We wanted to know if we could be sure."