JWST Finds CO2 in Exoplanet Atmosphere

Using JWST’s spectrograph, researchers have measured a distant exoplanet’s atmospheric composition and found carbon dioxide for the first time.

IMAGE: A transmission spectrum of the hot gas giant exoplanet WASP-39 b captured by Webb’s Near-Infrared Spectrograph (NIRSpec) on July 10 reveals the first definitive evidence for carbon dioxide in a planet outside the solar system. This is the first detailed transmission spectrum ever captured that covers wavelengths between 3 and 5.5 microns. CREDIT: NASA, ESA, CSA, Leah Hustak (STScI), Joseph Olmsted (STScI)

JWST can do more than just take pretty — and sometimes blobby — images. Using its spectrograph, researchers can measure the composition of distant objects. In a first-of-its-kind measurement, JWST revealed carbon dioxide in the atmosphere of the exoplanet WASP-39 b.

The results will appear in a forthcoming paper in Nature led by Eva Maria Ahrer.

The planet in question is WASP-39 b, a gas giant discovered back in 2011 orbiting a star similar to our own Sun. The planet’s mass is similar to that of Saturn, but it’s orbiting very close in to the star every four days, which means the atmosphere is extremely hot at 1,400 degrees Celsius. And don’t get too excited about where this star system is, either, because it’s 700 light years away. This is not a “let’s find life here” kind of place.

And to avoid confusion, this is not the same planet NASA earlier released spectrographic results for during the press conference in July. That was WASP-96b, and its atmosphere was found to have lots of water.

But the methods are the same. WASP-39 b appears to pass directly in front of that star during what is called a planetary transit. JWST observed the…