The James Webb Space Telescope has for the first time detected the presence of carbon dioxide (COtwo) in the atmosphere of an exoplanet, a planet outside our solar system. The discovery demonstrates its immense capabilities and excites scientists.
The planet in question is a hot gas giant where life as we know it would be impossible, but the new finding indicates that these observations could also take place on rocky planets — with the ultimate goal of determining whether any of them have conditions conducive to life.
“For me, it’s a door that opens for future studies of super-Earths, including Earths,” astrophysicist Pierre-Olivier Lagage, from the Atomic Energy Commission (CEA), one of the three co-authors of these works published in the scientific journal Nature.
“My first thought was, wow, we really have the possibility to detect the atmospheres of Earth-sized planets,” astrophysics professor Natalie Batalha, from the University of California at Santa Cruz, commented on Twitter.
In addition, the identification of COtwo will allow us to learn more about the formation of this planet, called WASP-39b, discovered in 2011, explained NASA. Located 700 light-years away, the planet is about a quarter the mass of Jupiter and very close to its sun.
This planet was selected on the basis of several criteria that made its observation easier while scientists are still evaluating the capabilities of the telescope, which revealed its first images less than two months ago.
WASP-39b periodically passes in front of its sun, with a four-day orbit.
For his observations, James Webb uses the method of transits, that is, when the planet passes in front of its star, the telescope captures the tiny variation of the resulting luminosity.
It then analyzes the light “filtered” through the planet’s atmosphere. The different molecules present in the atmosphere leave specific marks that make it possible to determine their composition.
The Hubble and Spitzer telescopes had already detected water vapor, sodium and potassium in the atmosphere of this planet, but the James Webb can go further thanks to its enormous sensitivity to infrared light.
In the NASA statement, Zafar Rustamkulov, from Johns Hopkins University, comments on what he felt when the presence of COtwo was clearly stated: “It was a special moment, reaching a tipping point in exoplanet science.”
