The month-old James Webb Space Telescope has added another major scientific discovery to its growing list: discovering for the first time signs of carbon dioxide in the atmosphere of a planet outside our solar system.
Although an exoplanet may never support life as we know it, the successful detection of CO2 gives researchers hope that similar observations can be made on rocky objects that are friendlier to life.
“My first thought: wow, we really have a chance to see the atmospheres of terrestrial-sized planets,” tweeted Natalie Batalha, a professor at the University of California at Santa Cruz and one of hundreds who worked on the project of Webb.
Their study of the exoplanet WASP-39, a hot gas giant closely orbiting a star 700 light years away, will soon be published in the journal Nature.
“For me, this opens the door for future research on super-Earths (planets larger than Earth but smaller than Neptune), or even Earth-sized planets,” Pierre -Olivier Lagage, an astrophysicist at France’s Atomic Energy Commission (CEA), told AFP.
The detection of CO2 will also help scientists learn more about how WASP-39 formed, NASA said in a press release. The exoplanet, which orbits its star once every four Earth days, has a quarter of Jupiter’s mass but a diameter 1.3 times larger.
Its orbit frequency and large atmosphere made WASP-39 an ideal candidate for an early test of Webb’s innovative infrared sensor, known as NIRSpec.
Whenever an exoplanet crosses in front of its star, it blocks an almost imperceptible amount of light.
But around the edges of the planet, a small amount of light passes through the atmosphere.
Webb’s highly sensitive NIRSpec can detect tiny changes the atmosphere has in light, allowing scientists to determine its gas composition.
The Hubble and Spitzer telescopes have already detected water vapor, sodium and potassium in WASP-39’s atmosphere, but carbon dioxide can now be added to that list thanks to Webb and its NIRSpec instrument.
“This is a special moment, crossing an important threshold in exoplanet sciences,” said Zafar Rustamkulov, a researcher at Johns Hopkins University, in the NASA press release.