James Webb Telescope reveals never-before-seen exoplanet atmospheres

New observations of WASP-39 b reveal a molecule never seen before in the atmosphere of a sulfur dioxide planet, among other details.

New observations of WASP-39 b reveal a molecule never seen before in the atmosphere of a sulfur dioxide planet, among other details.

The telescope’s highly sensitive instrument array has been trained in the atmosphere of a “hot Saturn” — a planet about the same mass as Saturn orbiting a star about 700 years away. light — called WASP-39 b. While JWST and other space telescopes, including Hubble and Spitzer, have previously revealed distinct components of the hot planet’s atmosphere, the new readings provide a list of full of atoms, molecules and even signs of active clouds and chemistry.

Mercedes Lopez-Morales, astronomer at the Center for Astrophysics | Harvard & Smithsonian and one of the scientists who contributed to the new results.

Lopez-Morales adds: “We expected that we would see many such signals, but when I first saw the data, I was in awe.

The latest data also offer a hint for a close-up view of these clouds in exoplanets: split rather than a single uniform blanket over the planet.

These findings herald JWST’s ability to conduct a series of investigations into exoplanets — planets around other stars — that scientists hope. That includes probing the atmospheres of smaller, rocky planets like those in the TRAPPIST-1 system.

Natalie Batalha, astronomer at the University of California, Santa Cruz, who contributed to and said: “We observed the exoplanet using multiple instruments that together provide a wide and panoramic infrared spectrum. chemical traces were inaccessible until JWST”. helped coordinate new research. “Data like this is a game changer.”

The discovery set is detailed in a set of five newly submitted scientific papers, available on the arXiv preprint website. Among the unprecedented discoveries was the discovery of sulfur dioxide in an exoplanet’s atmosphere for the first time, a molecule created from chemical reactions triggered by high-energy light from the star. mother of the planet. On Earth, the protective ozone layer in the upper atmosphere is created in a similar way.

Diana Powell, a member of NASA’s Hubble, an astronomer at the Center for Astrophysics and a core member of the team that made the sulfur dioxide discovery, said: “Surprising discovery of the last sulfur dioxide finally confirmed that photochemistry shapes the climate of ‘hot Saturn’”. “Earth’s climate is also shaped by photochemistry, so our planet has more in common with ‘hot Saturn’ than we previously knew!”

Jea Adams, a graduate student at Harvard and a researcher at the Center for Astrophysics, analyzed data that confirmed the sulfur dioxide signal.

“As a first-time researcher in the field of exoplanet atmospheres, it’s exciting to be involved in a discovery like this,” Adams said. “The process of analyzing this data was magical. We saw hints of this feature in the original data, but this higher-precision instrument clearly revealed the signatures of SO2 and help us solve the puzzle.”

At an estimated temperature of 1,600 degrees Fahrenheit and a mostly hydrogen atmosphere, WASP-39 b is not thought to be habitable. The exoplanet has been compared with both Saturn and Jupiter, with a mass similar to Saturn, but the overall size of Jupiter. But the new work shows how to look for evidence of potential life on a habitable planet.

The planet’s distance from its host star – which is almost eight times more than Mercury is from our Sun – also makes it a laboratory for studying the effects of radiation from its host stars. exoplanets. Better knowledge of the planet-star connection will yield a deeper understanding of how these processes produce the diversity of planets observed in the galaxy.

Other atmospheric components detected by JWST include sodium, potassium and water vapor, confirming previous ground- and space-based telescope observations and finding additional water features, at wavelengths longer, never seen before.

JWST also saw carbon dioxide at a higher resolution, providing twice the data reported from previous observations. Meanwhile, carbon monoxide was detected, but obvious signs of neither methane nor hydrogen sulfide were present in the data. If so, these molecules are present at very low levels, an important finding for scientists who are inventorying exoplanet chemistry to better understand the formation and evolution of distant worlds. this sticky rice.

Such capture of WASP-39 b’s broad spectrum of atmospheres is a scientific achievement, as an international team numbered hundreds of independently analyzed data from four of the instrument modes tested. precision tuning of JWST. They then made detailed comparisons between their findings, yielding results that were more nuanced than science.

JWST observes the universe in infrared light, at the red end of the light spectrum beyond what the human eye can see; that allows the telescope to collect chemical fingerprints undetectable in visible light.

Each of the three devices even has some “IR” version of infrared in its name: NIRSpec, NIRCam, and NIRISS.

To see the light from WASP-39 b, JWST 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 analyzing exoplanet atmospheres with such precision, the JWST instruments have performed well beyond scientists’ expectations — and promise a new phase of discovery among so many exoplanets. in the galaxy.

“I’m looking forward to seeing what we find in the atmospheres of small terrestrial planets,” said Lopez-Morales.

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