Like never before: A NASA website reveals an exoplanet unlike any in our solar system

“data-gt-translate-attributes=”[{” attribute=””>Saturn-sized behemoth that orbits its star closer than Mercury is to our Sun. When

This illustration shows what exoplanet WASP-39 b could look like, based on the current understanding of the planet. WASP-39 b is a hot, puffy gas giant with a mass 0.28 times Jupiter (0.94 times Saturn) and a diameter 1.3 times greater than Jupiter, orbiting just 0.0486 astronomical units (4,500,000 miles) from its star. The star, WASP-39, is fractionally smaller and less massive than the Sun. Because it is so close to its star, WASP-39 b is very hot and is likely to be tidally locked, with one side facing the star at all times. Credit: NASA, ESA, CSA, Joseph Olmsted (STScI)

NASA’s Webb Space Telescope Reveals an Exoplanet Atmosphere as Never Seen Before

Another first was just scored by NASA’s James Webb Space Telescope: a molecular and chemical profile of a distant world’s skies.

While Webb and other space telescopes, including NASA’s Hubble and Spitzer, previously have revealed isolated ingredients of this broiling planet’s atmosphere, the new readings from Webb provide a full menu of atoms, molecules, and even signs of active chemistry and clouds.

A hint of how these clouds might look up close is also provided by the latest data: they are likely broken up rather than a single, uniform blanket over the planet.

The telescope’s array of highly sensitive instruments was trained on the atmosphere of WASP-39 b, a “hot Saturn” (a planet about as massive as Saturn but in an orbit tighter than Mercury) orbiting a star some 700 light-years away.

The findings bode well for the capability of Webb’s instruments to conduct the broad range of investigations of all types of exoplanets – planets around other stars – hoped for by the science community. That includes probing the atmospheres of smaller, rocky planets like those in the TRAPPIST-1 system.

“We observed the exoplanet with multiple instruments that, together, provide a broad swath of the infrared spectrum and a panoply of chemical fingerprints inaccessible until [this mission]said Natalie Batalha. “Data like this is a game-changer.” Batalha, an astronomer at the University of California, Santa Cruz, contributed to the new research and helped coordinate it.

The composition of the atmosphere of hot gas giant exoplanet WASP-39 b has been revealed by NASA’s James Webb Space Telescope. This graphic shows four transmission spectra from three Webb instruments operating in four instrument modes. The transmission spectrum is made by comparing starlight that is filtered through a planet’s atmosphere as it moves in front of the star, to unfiltered starlight that is detected when the planet is next to the star. Each of the data points (white circles) on these graphs represents the specific wavelength amount of light that the planet blocks and is absorbed by its atmosphere. At top left, data from NIRISS show fingerprints of potassium (K), water (H2O) and carbon monoxide (CO). At top right, data from NIRCam show a prominent hydrophilic signature. At bottom left, data from NIRSpec indicate water, sulfur dioxide (SO2), carbon dioxide (CO2), and carbon monoxide (CO). At lower right, additional NIRSpec data reveal all of these molecules in addition to sodium (Na). Credit: NASA, ESA, CSA, Joseph Olmsted (STScI)

The collection of discoveries has been detailed in a set of five new scientific papers, three of which are pending publication and two of which are under review. Among the unprecedented discoveries is the first detection in the atmosphere of an exoplanet of sulfur dioxide (SO).₂), a molecule that results from chemical reactions triggered by high-energy light from the planet’s parent star. On Earth, the protective ozone layer in the upper atmosphere is created in a similar way.

said Shang Min Cai, researcher at

“data-gt-translate-attributes=”[{” attribute=””>University of Oxford in the United Kingdom and lead author of the paper explaining the origin of sulfur dioxide in WASP-39 b’s atmosphere. “I see this as a really promising outlook for advancing our understanding of exoplanet atmospheres with [this mission]. “

This led to the first one: scientists applying computer models of photochemistry to data that would require a full explanation of such physics. The resulting improvements in modeling will help build technological knowledge to interpret potential signs of habitability in the future.

“Planets are being sculpted and transformed by spinning inside the host star’s radiation bath,” said Batalha. “On Earth, these transitions allow life to flourish.”

The planet’s proximity to its host star — eight times closer than Mercury is to our sun — also makes it a laboratory for studying the effects of radiation from host stars on exoplanets. Better knowledge of the star-planet connection should lead to a deeper understanding of how these processes affect the diversity of planets observed in the galaxy.

To see the light from WASP-39 b, Webb tracked the planet as it passed in front of its star, allowing some of the star’s light to filter through the planet’s atmosphere. Different types of chemicals in the atmosphere absorb different colors of the starlight spectrum, so the missing colors tell astronomers which molecules are present. By viewing the universe in infrared light, Webb can pick up chemical signatures that are undetectable in visible light.

Other components of the atmosphere detected by the Webb telescope include sodium (Na), potassium (K), and water vapor (H₂O), confirming previous space and ground-based telescope observations as well as finding additional fingerprints of water, at these longer wavelengths, which have not been seen before.

Webb also saw carbon dioxide (CO₂) at a higher resolution, providing twice the reported data from its previous observations. Meanwhile, carbon monoxide (CO) was detected, but clear signs of both methane (CH₄) and hydrogen sulfide (H₂S) was absent from Webb’s data. If present, these molecules occur at very low levels.

To capture this broad spectrum of WASP-39 b’s atmosphere, an international team of hundreds independently analyzed data from four modes of precisely calibrated Webb telescope instruments.

“We expected what [the telescope] said Hannah Wakeford, an astrophysicist at

“data-gt-translate-attributes=”[{” attribute=””>University of Bristol in the United Kingdom who investigates exoplanet atmospheres.

Having such a complete roster of chemical ingredients in an exoplanet atmosphere also gives scientists a glimpse of the abundance of different elements in relation to each other, such as carbon-to-oxygen or potassium-to-oxygen ratios. That, in turn, provides insight into how this planet – and perhaps others – formed out of the disk of gas and dust surrounding the parent star in its younger years.

WASP-39 b’s chemical inventory suggests a history of smashups and mergers of smaller bodies called planetesimals to create an eventual goliath of a planet.

“The abundance of sulfur [relative to] Hydrogen indicates that the planet has presumably experienced a large buildup of young planets that could be born [these ingredients] said Kazumasa Ono, an exoplanet researcher at the University of California, Santa Cruz who worked on Webb’s data. The data also indicates that oxygen is more abundant than carbon in the atmosphere. This likely indicates that WASP-39 b originally formed far from the central star.”

In accurately analyzing an exoplanet’s atmosphere, the Webb telescope’s instruments have performed beyond scientists’ expectations — and promise a new phase of exploration among the galaxy’s wide range of exoplanets.

“We will be able to see the big picture of the outer atmospheres of the exoplanets,” said Laura Flagg, a researcher at Cornell University and a member of the international team. “It is very exciting to know that everything will be rewritten. That is one of the best aspects of being a scientist.”

The James Webb Space Telescope is the most powerful space telescope ever built and the world’s most prominent space science observatory. He will solve mysteries in our solar system, look beyond to distant worlds around other stars, and explore the mysterious structures and origins of our universe. Webb is an international program led by NASA with its partners ESA (European Space Agency) and CSA (Canadian Space Agency).