NASA’s James Webb Space Telescope continues to capture extraordinary worlds in the universe whose existence humanity was unaware barely months ago. The latest to join that growing list is a planet now called “hot Saturn” only 700 light years away.
Although 700 light years make it about an unfathomably large 4200 trillion miles, in cosmic terms it is close by since it has taken light and therefore its visual data only 700 years to reach us.
What is extraordinary about the discovery of hot Saturn is that the space telescope is revealing the atmosphere of an exoplanet as never seen before.
According to NASA the telescope has revisited gas giant WASP-39 b, also known as Bocaprins, to produce the first molecular and chemical profile of an exoplanet’s atmosphere, revealing the presence of water, sulfur dioxide, carbon monoxide, sodium and potassium, as well as signs of clouds.
This builds on Webb’s initial examination of the planet in August, which showed the first clear evidence of carbon dioxide in a planet outside our solar system.
What makes this success particularly significant is that Webb can now investigate all types of exoplanets across our galaxy.
“We learn about exoplanet atmospheres by breaking their light into components and creating spectra. Think of a spectrum as a barcode. Elements and molecules have characteristic signatures in that “barcode” we can read,” NASA said.
“Hot Saturn” is about as massive as our Saturn but eight times closer in orbit around its star than Mercury is around the Sun. It sizzles at 1,600 degrees Fahrenheit or 871 degrees Celsius.
According to NASA. the data shown here is taken from 3 of Webb’s science instruments. “Together, they mark a series of firsts in science, including the first detection of sulfur dioxide in an exoplanet atmosphere. This, in turn, is the first concrete evidence of photochemistry — chemical reactions initiated by high-energy light, which are fundamental to life on Earth — on an exoplanet,” it said.
“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],” Natalie Batalha, an astronomer at the University of California, Santa Cruz, who contributed to and helped coordinate the new research, was quoted as saying. “Data like these are a game changer,” she said.
“Among the unprecedented revelations is the first detection in an exoplanet atmosphere of sulfur dioxide (SO2), a molecule produced 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,” NASA said.
“This is the first time we see concrete evidence of photochemistry – chemical reactions initiated by energetic stellar light – on exoplanets,” said Shang-Min Tsai, a researcher at the 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].”
“Planets are sculpted and transformed by orbiting within the radiation bath of the host star,” Batalha said. “On Earth, those transformations allow life to thrive.”
The fact that “hot Saturn” is so close to its host star also “makes it a laboratory for studying the effects of radiation from host stars on exoplanets. Better knowledge of the star-planet connection should bring a deeper understanding of how these processes affect the diversity of planets observed in the galaxy.”
NASA explained that to see 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 colors that are missing tell astronomers which molecules are present. By viewing the universe in infrared light, Webb can pick up chemical fingerprints that can’t be detected in visible light,” it said.
[Photo credit: Credits: NASA, ESA, CSA, J. Olmsted (STScI)]