The NASA/ESA/CSA James Webb Space Telescope has identified the atmosphere composition of the hot gas giant exoplanet WASP-39 b. This image displays four transmission spectra from three instruments used by Webb in four different instrument settings. They are all shown on the same scale, which ranges from 0.5 to 5.5 microns.
The starlight that is filtered by a planet's atmosphere as it passes in front of the star is compared to the unfiltered starlight that is observed when the planet is next to the star to create a transmission spectrum. The amount of a particular wavelength of light that is absorbed by the planet's atmosphere and represented by each data point (white circle) on these graphs is blocked by the planet. Peaks can be seen in the transmission spectrum when the atmosphere preferentially absorbs certain wavelengths.
The blue line is the best-fit model that accounts for the data, known features of WASP-39 b and its star (such as size, mass, and temperature), and hypothesized atmospheric qualities. To improve the fit and gain a deeper understanding of the environment, scientists can alter the parameters in the model by altering unknown properties like cloud height in the atmosphere and abundance of different gases.
NIRISS data depicts the fingerprints of potassium (K), water (H2O), and carbon monoxide in the upper left corner (CO). Data from NIRCam reveals a distinct water signal in the upper right. NIRSpec data at lower left shows water, carbon dioxide, carbon monoxide, sulfur dioxide, and carbon dioxide (CO). Additional NIRSpec data at lower right shows each of these compounds as well as sodium (Na).
Credits: NASA, ESA, CSA, J. Olmsted (STScI)
November 22, 2022
In yet another significant milestone achieved by NASA's James Webb Space Telescope: a molecular and chemical profile of a faraway world's skies has been revealed by this engineering masterpiece. The latest readings from Webb show a comprehensive menu of atoms, molecules, and even hints of active chemistry and clouds, in contrast to earlier findings from Webb and other space observatories, such as NASA's Hubble and Spitzer. The most recent data also provides an indication as to how these clouds would seem up close: fragmented rather than covering the planet in a single, uniform layer. The atmosphere of WASP-39 b, a "hot Saturn" (a planet roughly as large as Saturn but in an orbit tighter than Mercury), orbiting a star some 700 light-years away, was the focus of the telescope's array of highly sensitive instruments.
The results are encouraging for Webb's equipment' potential to carry out the wide range of examinations of all forms of exoplanets, or planets around other stars, that the scientific community has hoped for. The atmospheres of smaller, stony planets like those in the TRAPPIST-1 system can be probed as part of this.
Five new scientific papers—three of which are under review and one of which is in press—cover the discoveries in depth. One of the ground-breaking discoveries is the discovery of sulfur dioxide (SO2) for the first time in an exoplanet's atmosphere. This molecule is the result of chemical processes started by high-energy light from the planet's parent star. Similar processes are used on Earth to produce the protective ozone layer in the upper atmosphere.
Eight times closer to its home star than Mercury is to our Sun, the planet serves as a testing ground for the effects of radiation from host stars on exoplanets. Improved comprehension of the star-planet relationship should lead to a greater comprehension of how these processes impact the variety of planets seen in the galaxy. Webb followed WASP-39 b when it crossed in front of its star, allowing part of the star's light to get through the planet's atmosphere and allowing for the detection of light from the object. Astronomers can identify the molecules by looking at the colors that aren't present because different kinds of compounds in the atmosphere absorb different colors of the starlight spectrum.
Webb can identify chemical fingerprints in the universe that are invisible to the human eye by observing it in infrared light. Other atmospheric components identified by the Webb telescope include sodium (Na), potassium (K), and water vapor (H2O). These results were confirmed by earlier space and ground-based telescope investigations, and new fingerprints of water were discovered at these longer wavelengths. Additionally, Webb saw carbon dioxide (CO2) with twice the resolution of its prior observations, yielding more information. In the meantime, carbon monoxide (CO) was found, but the Webb data lacked any detectable methane (CH4) or hydrogen sulfide (H2S) signs.
An exoplanet's atmosphere contains such a comprehensive list of chemical constituents that it also provides scientists with information on the abundance of certain elements in relation to one another, such as carbon-to-oxygen or potassium-to-oxygen ratios. This in turn sheds light on how this planet—and possibly others—formed from the ring of gas and dust that surrounded the parent star when it was still a young star. The chemical makeup of WASP-39 b points to a history of collisions and mergers between planetesimals, or smaller worlds, to form a final goliath of a planet.
The Webb telescope's equipment performed much above scientists' expectations in precisely parsing an extraterrestrial atmosphere, and they signal a new phase of study amid the wide variety of exoplanets in the galaxy.
The James Webb Telescope is one of the most important observatories for space science in the world. Webb will investigate the mystifying architecture and origins of our cosmos and our part in it while also looking beyond our solar system to faraway planets surrounding other stars. The European Space Agency and the Canadian Space Agency are partners in the international Webb program, which is run by NASA.