For the first time, astronomers have found unambiguous evidence of carbon dioxide in the atmosphere of an exoplanet (a planet outside our solar system).

The team of astronomers discovered carbon dioxide using JWST to observe a exoplanet called WASP-39b which orbit very close to a sun-like star about 700 light-years from Earth.

Carbon dioxide is an important component of the atmosphere of planets in our solar system, found on rocky planets like Mars and Venus as well as gas giants like Jupiter and Saturn.

Stars and gas giant planets are made primarily of the lightest element, hydrogen and helium, but the abundance of heavier elements is a critical factor in planet formation.

Batalha's team observed WASP-39b as part of a JWST Early Release Science program to study transiting exoplanets.

Astronomers examine the sunlight that passes through a planet's atmosphere, where molecules like carbon dioxide absorb specific wavelengths of light.

Using the Near Infrared Spectrograph (NIRSpec) on JWST, the team obtained a high-resolution "transmission spectrum" showing the light transmitted through WASP-39b's atmosphere.

This detection will serve as a useful benchmark of what we can do to detect carbon dioxide on terrestrial planets.

Batalha said. "It's the most likely atmospheric gas we'll detect with JWST in terrestrial-size exoplanet atmospheres.

Reserchers noted that WASP-39b appears to have a similar composition to Saturn.

Saturn's metallicity is 10 times that of the sun, and WASP-39b also seems to be enriched in heavy elements by about 10 times relative to the sun.