Posted on August 25, 2022 by Nathalie Ouellette
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Showing just how precise it can be, the James Webb Space Telescope detects the first definitive signature of carbon dioxide in an exoplanet atmosphere.
Illustration showing what the exoplanet WASP-39 b might look like, based on current understanding of the planet. (Credits: NASA/ESA/CSA/J. Olmsted)
In a remarkable display of its precision and accuracy, the James Webb Space Telescope (JWST), a collaboration between NASA, the European Space Agency and the Canadian Space Agency, has captured definitive evidence of carbon dioxide in the ‘atmosphere of a gas giant planet. orbiting a Sun-like star 700 light years away.
The result, which has been accepted for publication in Nature, provides important information about exoplanet composition and formation and is indicative of Webb’s ability to detect and measure carbon dioxide in the planets’ thinnest atmospheres smaller rocks. And beyond that, a better understanding of these exoplanets could lead to finding worlds that could harbor extraterrestrial life.
The team that made the discovery got time on the telescope through an Early Release Science program, which was chosen to collect some of the first data from Webb after science operations began in late June.
Led by Natalie Batalha of the University of California Santa Cruz, the team includes astronomers from around the world, including Björn Benneke of the University of Montreal, who is also a member of the Institute for Research on Exoplanets (iREx).
The target of the observing program, WASP-39 b, is a hot gas giant planet with a mass about one-fourth that of Jupiter (about the same as Saturn) and a diameter 1.3 times that of Jupiter . Its extreme swelling is partly related to its high temperature (about 900 °C). Unlike the cooler, more compact gas giants in our Solar System, WASP-39 b orbits very close to its star, only about one-eighth the distance between the Sun and Mercury, completing one orbit in just over four days terrestrial The discovery of the planet, reported in 2011, was based on ground-based detections of the subtle, periodic dimming of its host star’s light as the planet transits, or passes, in front of the star.
During a transit, some of the starlight is blocked by the planet entirely (causing overall dimming) and some passes through the planet’s atmosphere. Because different gases absorb different combinations of colors, researchers can analyze small differences in the brightness of light transmitted across a spectrum of wavelengths to determine exactly what an atmosphere is made of.
With its combination of a puffy atmosphere and frequent transits, WASP-39 b is an ideal target for transmission spectroscopy. The team used Webb (NIRSpec) to make this detection.
First clear detection of CO2
A transmission spectrum of the hot gas giant exoplanet WASP-39 b captured by Webb (NIRSpec) on July 10, 2022, reveals the first definitive evidence of carbon dioxide on a planet outside the Solar System. (Credits: NASA/ESA/CSA/L. Hustak/J. Olmsted/STScI)
What the discovery team saw was extremely impressive. A major signal, an absorption feature, was detected at wavelengths between 4.1 and 4.6 microns in the infrared. It is the first clear, detailed and indisputable evidence of carbon dioxide ever detected on a planet outside the Solar System.
“I was absolutely blown away,” said Benneke, professor of physics at UdeM and member of the Transiting Exoplanets team, who worked on the design of the observing program and the analysis of the NIRSpec data with the graduate students of the UdeM Louis-Philippe Coulombe, Caroline Piaulet. , Michael Radica and Pierre-Alexis Roy and postdoctoral researcher Jake Taylor.
“We analyzed the data here in Montreal and we saw this huge signature of carbon dioxide—26 times stronger than any noise in the data. Before JWST, we were often digging through the noise, but here we had a signature perfectly robust. It’s like seeing something clearly with your own eyes.”
University of Montreal and iREx professor Björn Benneke is a key member of the team that discovered the first definitive signature of carbon dioxide in an exoplanet atmosphere. (Credit: Amélie Philibert)
No observatory has ever measured such subtle differences in the brightness of so many individual infrared colors in the transmission spectrum of an exoplanet. Access to this part of the spectrum, from 3 to 5.5 microns, is crucial for measuring the abundance of gases such as water and methane, as well as carbon dioxide, which are believed to exist in many different types of exoplanets.
“Detecting such a clear signal of carbon dioxide in WASP-39 b bodes well for the detection of atmospheres on smaller, Earth-sized planets,” said Batalha, the program’s principal investigator.
“On Earth,” Benneke added, “carbon dioxide plays such an important role in our climate, and we’re used to seeing its spectroscopic signatures here. Now, we’re seeing that signature on a distant world. This really makes get the message across that these exoplanets are real worlds: as real as Earth and the planets in our Solar System.”
The James Webb Space Telescope is the world’s leading space science observatory. Webb will solve the mysteries of our solar system, look beyond distant worlds around other stars, and investigate the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.
About this study
“Identifying Carbon Dioxide in an Exoplanet Atmosphere,” by the JWST Transiting Exoplanet Community Early Launch Science Team, was published online on arXiv today and will be published on September 1 2022 in Nature.
For more information, NASA/STScI press release, preprint of the scientific article
Scientific contact Björn BennekeProfessorInstitute for Research on Exoplanets, University of Montreal Email: bjorn.benneke@umontreal.caTel: 514-578-2716
Media ContactNathalie Ouellette Webb Outreach ScientistInstitute for Research on Exoplanets, University of MontrealEmail: nathalie.ouellette.2@umontreal.caTel: 613-531-1762
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