Jeremy Leconte.
Guillaume Bonnaud/Southwest
Jeremy Leconte work in Purdue Astrophysical LaboratoryMixed unit CNRSPurdue University. It is part of a global consortium of 300 exoplanet specialists, selected to obtain the first JWST observations under the Early Launch Science (ERS) program. Why this honor? “We don’t ‘see’ the exoplanet itself: only that the light of its star diminishes as it passes in front of it,” explains the 37-year-old researcher. And when it passes in front of it, its atmosphere, depending on the particles it contains, blocks this or that wavelength of light emitted by the star. »
Signature”
to carbon dioxide (CO2), we find this “signature” in the infrared. “Compared to Hubble, it is precisely these spectral ranges that promise JWST ahead. Therefore, our request made it possible to verify that the telescope is licensed to do what it was designed to do. And from first observation, we saw a huge signal on WASP-39b, in the constellation Virgo, where we expected Find them.The results fell on July 12. The Union of Scientists has been working to “reduce” this data one by one and quickly Found consistent results. who was the subjectPublished in the journal “Nature” on September 2.
“We’ve focused our communication on having a CO2which we expected. But paradoxically, we were more excited about the presence of another molecule that wasn’t necessarily expected: sulfur dioxide (SO).2). But we’re not about to go to WASP-39b: there are several thousand degrees. On the other hand, this discovery allows us to see in action, for the first time, photochemical phenomena: SO2 WASP-39b forms the Earth’s equivalent of the ozone layer, as photons scatter oxygen molecules (O2) of our atmosphere, which combines into the ozone layer (O3). Like on earth…
Exoplanets are known to the general public because they would likely host life, if it existed elsewhere. “But that’s not what motivates me, cut Jeremy LeConte. If you try too hard to find life, you risk seeing bacteria everywhere.”
Joëlle Mascetti, a researcher using images from the James Webb Telescope in her laboratory at ISM – UMR 5255 CNRS – Purdue University.
Claude Petit/Southwest
We also find the beginnings of life far beyond planets. This is part of Joëlle Mascetti, which also benefits from the ERS program. You can meet her on the chemistry side of campus, atInstitute of Molecular Sciences, another joint UB-CNRS unit. “You don’t have to imagine it’s like organic chemistry, with benches and balloons and things that explode,” warns the sixty-year-old. Replete with cables and tubes, the Molecular Spectroscopy Group’s laboratory looks like a mad inventor’s lair. “Here, we’re trying to reproduce the conditions that prevail in interstellar space: a very high vacuum and 10 degrees Kelvin (-263.15 degrees Celsius).”
The spatial “void” is not completely empty. When stars die and explode, they throw out all the atoms they produced through a nuclear reaction. Astrochemistry studies how they recombine “at low energy” in dust clouds that are nebulae.
Images of the Orion Nebula taken by JWST have been seen all over the world. They also revealed the presence of so-called polycyclic aromatic hydrocarbon molecules, the “building blocks of life.”
NASA, ESA, CSA, PDRs4All ERS Team
In her laboratory, Joëlle Mascetti simulates these reactions and analyzes them with infrared spectroscopy: “In the interstellar ice, we can observe the formation of complex molecules that are the first building blocks of life,” the researcher continues. “Among these, I am interested in polycyclic aromatic hydrocarbons, whose first observations from JWST highlighted their presence in the Orion Nebula thanks to their infrared signature.”
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