(ORDO NEWS) — The James Webb Space Telescope, already famous for its mesmerizing images of space, has done it again: for the first time, it has recorded clear evidence of the presence of carbon dioxide in the atmosphere of a planet outside the solar system.
This discovery can not only tell a lot about how the exoplanet formed, but also serves as a harbinger of what lies ahead, because Webb is already studying more and more new worlds.
The details of the discovery were outlined in an article hosted on the arXiv server. In the next few days, they are expected to be published in the journal Nature.
This discovery is presented as a graphical representation of the data. It is completely devoid of the bewitching brilliance of the James Webb telescope images that have appeared on the net earlier, which show galaxies performing space steps surrounded by light-emitting clouds in star-forming regions.
But Jessie Christiansen, an astronomer at NASA‘s Exoplanet Science Institute at Caltech, Pasadena, called the graphics “luxurious.”
These graphical images, which are spectroscopic data, give us detailed information about the composition of the atmosphere of exoplanet WASP-39b.
Some scientists call it “hot Jupiter” because it has the same diameter as Jupiter, only it orbits much closer to its star than Mercury does to the Sun, causing it to heat up to extremely high temperatures.
This exoplanet, located about 700 light-years from Earth, was first discovered during observations from Earth, and later recorded by NASA’s Spitzer Space Telescope, which was active from 2003 to 2020. Data from Spitzer indicated that WASP-39b could have carbon dioxide in its atmosphere, but it was not accurate.
And then “James Webb” came into play. On July 10, this infrared telescope observed the exoplanet WASP-39b moving across the disk of its star for a little over eight hours.
All the while, the star’s light has passed through the planet’s atmosphere, where different molecules absorb specific portions of the color spectrum. The astronomers were wondering if they would see a trace of carbon dioxide in the spectrum.
“And we saw it – it appeared right on the computer screen,” said study co-author Natalie Batalha, an astronomer at the University of California, Santa Cruz, who leads the James Webb Transiting Exoplanet Early Release Science team.
Batalha was not alone. When Christiansen, who is not part of this team, saw the data, she caught her breath. “I thought, this is it!” she said. “We have seen hints of carbon dioxide before, but the first time the data was undeniable.”
Mysterious origin
This discovery strengthened the belief that James Webb would revolutionize the study of exoplanets. In the first year of its operation alone, the telescope will have to explore 76 exoplanets, and during the entire time of its travel, there will be several hundred such celestial bodies.
It will watch through the atmospheres of gas giants and tiny rocky planets that could be Earth-like. “My first thought when I saw this signal was ‘wow, this is working,'” Batalha said.
However, the detection of carbon dioxide is a very impressive discovery in itself. “Scientifically, it’s incredibly exciting,” said Jonathan Fortney, director of the Other Worlds Laboratory at UC Santa Cruz and co-author of the published paper.
It would be logical to assume that a planet similar to Jupiter, which formed from the same accumulation of matter as its star, would have approximately the same chemical composition as the star itself. But in our solar system, things are different.
And in the case of WASP-39b, everything is different too. A strong signal of the presence of carbon dioxide in the atmosphere of this exoplanet indicates that it contains heavier elements than the hydrogen and helium that stars are usually made of. The question is why?
“This is where the story gets even more interesting,” explains Batalha. Perhaps when WASP-39b was a young planet, comets and asteroids often crashed into it, which could deliver heavier elements such as carbon and oxygen there.
Interestingly, the planet WASP-39b seems to have about the same amount of heavy elements as Saturn, which, scientists believe, also had a “stormy” youth.
Or the planet WASP-39b could have formed from elements that were dispersed in space within its planetary system and then migrated towards the center.
At some point, it approached its host star, which forced some of the hydrogen out of the atmosphere, as a result of which the concentration of heavier elements in it increased, and there was more carbon dioxide than it was originally.
Fortney, Batalha and their colleagues are currently working on four scientific papers in which they will analyze the spectrum of the exoplanet and various hypotheses in much more detail.
Building material of life
The detection of carbon dioxide in an exoplanet’s atmosphere is an important step towards discovering life beyond Earth. Astronomers don’t expect WASP-39b to be suitable for life, because it’s too close to its star.
They don’t even expect the James Webb telescope to find clear signs of life on other planets. However, using the Webb to search for carbon dioxide could help lay the groundwork for future discoveries.
Astronomers believe that the mixture of carbon dioxide and methane in a planet’s atmosphere can serve as an indicator of life – this is called a biosignature.
According to Christiansen, the signal from the planet WASP-39b is “halfway to a good biosignature.” Bataglia’s team built a model that the planet’s atmosphere also contains water, carbon monoxide and hydrogen sulfite, but very little methane.
Ultimately, a much more advanced observatory than James Webb may be required to detect life. But, according to Batalha, “this is a really important stage that we need to go through to prepare for the appearance of such technologies in the future.”
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