Webb detects carbon dioxide in atmosphere of a planet outside our solar system

NASA's most powerful space observatory, the James Webb Space Telescope, has captured the first clear evidence for carbon dioxide in the atmosphere of an exoplanet, a planet outside our solar system.

The gas giant planet, WASP-39 b, orbits a Sun-like star 700 light-years away and has a mass roughly one-quarter that of Jupiter (about the same as Saturn) and diameter 1.3 times greater than Jupiter.

While previous observations from other telescopes have revealed the presence of water vapour, sodium, and potassium in the planet's atmosphere, Webb's unmatched infrared sensitivity has now confirmed the presence of carbon dioxide on this planet as well.

Catch your breath — Webb has captured the first clear evidence of carbon dioxide (CO2) in the atmosphere of a planet outside of our solar system! WASP-39 B is a gas giant closely orbiting a Sun-like star 700 light years away: https://t.co/FenLqV6HSo pic.twitter.com/abJvqxfLdG

— NASA Webb Telescope (@NASAWebb) August 25, 2022

Researchers used Webb's Near-Infrared Spectrograph (NIRSpec) for observing WASP-39b. In the resulting spectrum of the exoplanet's atmosphere, a small hill between 4.1 and 4.6 microns presents the first clear, detailed evidence for carbon dioxide ever detected in a planet outside the solar system.

"As soon as the data appeared on my screen, the whopping carbon dioxide feature grabbed me. It was a special moment, crossing an important threshold in exoplanet sciences," said Zafar Rustamkulov, a graduate student at Johns Hopkins University and member of the JWST Transiting Exoplanet Community Early Release Science team, which undertook this investigation.

This is the first detailed exoplanet transmission spectrum ever captured that covers wavelengths between 3 and 5.5 microns. This observation of WASP-39 b is just one part of a larger investigation that includes observations of the planet using multiple Webb instruments, as well as observations of two other transiting planets, NASA said.

"Detecting such a clear signal of carbon dioxide on WASP-39 b bodes well for the detection of atmospheres on smaller, terrestrial-sized planets," said Natalie Batalha of the University of California at Santa Cruz, who leads the team.