CAMBRIDGE, Mass. — The James Webb Space Telescope (JWST) has captured another beauty in the cosmos. NASA recently released images showing the molecular and chemical portrait of a distant world’s skies. The pictures give scientists an in-depth look at the broken up blanket formed by the clouds and atmosphere above this planet.
The telescope was focusing on the atmosphere of a “hot Saturn” called WASP-39 b. This is a planet estimated to be the size of Saturn and orbiting a star 700 light years away. Past pictures taken by the Hubble and Spitzer space telescopes have shown a glimpse of the planet’s atmosphere, but this is the first time a full image depicts a complete view of its clouds and molecular composition.
“The clarity of the signals from a number of different molecules in the data is remarkable,” says Mercedes López-Morales, an astronomer at the Center for Astrophysics | Harvard & Smithsonian, in a media release. “We had predicted that we were going to see many of those signals, but still, when I first saw the data, I was in awe.”
James Webb ‘a game changer’ for space exploration
The findings are proof that JWST is an essential tool for studying exoplanets — planets outside of our solar system, including those that may have atmospheres and surfaces similar to Earth.
“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 JWST,” says Natalie Batalha, an astronomer at the University of California, Santa Cruz. “Data like these are a game changer.”
The photographs were analyzed by multiple science teams, with results published across five papers on the preprint server arXiv. One of the most important discoveries was that the exoplanet has an atmosphere of sulfur dioxide, molecules created from chemical reactions triggered by high-energy light from the planet’s parent star. Earth’s ozone layer in the upper atmosphere works in a similar fashion.
“The surprising detection of sulfur dioxide finally confirms that photochemistry shapes the climate of ‘hot Saturns,’” says Diana Powell, a NASA Hubble fellow and astronomer at the Center for Astrophysics, whose team made the sulfur dioxide discovery. “Earth’s climate is also shaped by photochemistry, so our planet has more in common with ‘hot Saturns’ than we previously knew!”
‘Hot Saturn’ is closer to its sun than Mercury
The sulfur dioxide atmosphere was estimated to be 1,600 degrees Fahrenheit. Along with being mostly made of hydrogen, the exoplanet is not believed to be habitable. The exoplanet is most comparable to Saturn and Jupiter as its mass resembles Saturn, but its size is on par with Jupiter. The new work, the science teams suggest, is but one of the many steps needed to potentially find life on other planets.
The planet’s close orbit to its host star — eight times closer than Mercury is to our Sun — makes it a great opportunity for studying how radiations emitted from host stars affect exoplanets. Having a better knowledge of the star-planet connection is expected to bring a greater understanding of how these processes create such diverse planets in the galaxy. Other atmospheric features seen through JWST are sodium, potassium, and water vapor, along with other features of water that have not been seen before.
The JWST also found traces of carbon dioxide at higher resolution, showing twice as much data as previous reports. Carbon monoxide was detected as well, but not methane and hydrogen sulfide. If they do exist, the scientists suggest they must be present at extremely low levels.
To look at the light coming from WASP-39 b, JWST tracked the planet’s orbit as it passed in front of the star. The starlight partially filtered through the planet’s atmosphere with different chemicals in the atmosphere absorbing different colors of the light spectrum. The missing colors tell astronomers which molecules are there.
“I am looking forward to seeing what we find in the atmospheres of small, terrestrial planets,” concludes López-Morales.