NASA's James Webb Space Telescope (JWST) has spotted carbon dioxide in the atmosphere of a planet 700 light years away called WASP-39b, the Guardian reported.
The finding, accepted for publication in Nature, is the first indisputable evidence of carbon dioxide in the atmosphere of a planet orbiting a distant star.
Webb's Near-Infrared Spectrograph analyzed starlight passing through the atmosphere of the giant gas planet WASP-39b, which is a massive warm fuzzy of a world. The planet has a mass about a quarter that of Jupiter but a diameter 1.3 times larger, making it quite a puffy planet.
The analysis revealed an unequivocal detection of CO2, which is well known for being associated with life here on Earth. While it seems unlikely that there is life as we know it on WASP 39b where temperatures are consistently about 1,600 degrees Fahrenheit (900 degrees Celsius), scientists are excited by the display of Webb's capabilities.
"We want to know how unique we are and what the chance is of life elsewhere in the universe," said Dr. Vivien Parmentier, associate professor in physics at Oxford University and a member of the collaboration behind the work.
A central aim of James Webb is to analyze the atmospheres of distant planets and search for biosignature gases that could indicate the presence of life on the planet below.
Wasp-39b was discovered in 2011 after astronomers spotted subtle, periodic dimming of light from its host star, caused by the planet passing in front. The latest work goes further by measuring starlight that is being filtered through the planet's atmosphere. Because different gases absorb different wavelengths of light, analyzing the rainbow of starlight can indicate exactly which gases are present.
Previous results from the Hubble and Spitzer telescopes had given hints of the presence of carbon dioxide, but the latest observations, due to be published in the journal Nature, give the first conclusive evidence.
Wasp-39b's vast size and cloudless atmosphere made it an ideal first target. Astronomers now plan to apply the same techniques to analyze the atmospheres of smaller, rocky planets that are viewed as potentially habitable, such as those in the Trappist-1 star system. They will be looking for Earth-like atmospheres, dominated by nitrogen, carbon dioxide and water vapor and an overall balance of gases that hints at a contribution from biological processes.
"We're looking for a combination of gases that we can't easily explain with our understanding of chemistry could indicate that something is producing it," said Dr Jo Barstow, an astronomer at The Open University and a member of the JWST collaboration behind the paper.