This new image of Saturn, taken with the Near-Infrared Camera (NIRCam) onboard the NASA/ESA/CSA James Webb Space Telescope on June 25, 2023, serves as context for an observing program that will test the telescope’s capacity to detect faint moons around the giant planet and its bright rings. Any newly discovered moons could help planetary scientists put together a more complete picture of the current system of Saturn, as well as its past.
This image from Webb’s NIRCam instrument shows Saturn, its rings and some of its moons. Image credit: NASA / ESA / CSA / STScI / M. Tiscareno, SETI Institute / M. Hedman, University of Idaho / M. El Moutamid, Cornell University / M. Showalter, SETI Institute / L. Fletcher, University of Leicester / H. Hammel, AURA / J. DePasquale, STScI.
Saturn itself appears extremely dark at this picture’s specific infrared wavelength (3.23 microns), as methane gas absorbs almost all of the sunlight falling on the atmosphere.
However, the icy rings stay relatively bright, leading to the unusual appearance of Saturn.
The image also reveals intricate details within the ring system, showcasing several of the planet’s moons like Dione, Enceladus, and Tethys.
“We are very pleased to see Webb produce this beautiful image, which is confirmation that our deeper scientific data also turned out well,” said Dr. Matthew Tiscareno, a researcher at the SETI Institute.
“We look forward to digging into the deep exposures to see what discoveries may await.”
Over the past few decades, missions like NASA’s Pioneer 11, Voyagers 1 and 2, Cassini spacecraft and the NASA/ESA Hubble Space Telescope have observed Saturn’s atmosphere and rings.
The new Webb image is just a taste of what this observatory will uncover about Saturn in the coming years as scientists.
The image is part of a suite of deeply exposed images where astronomers hope to identify new ring structures and perhaps even new moons of Saturn.
“Moving from the inner to the outer features of Saturn’s rings, we can observe the dark C ring, the bright B ring, the narrow and dark Cassini Division, and the medium-bright A ring with the dark Encke Gap near its outer edge,” the researchers said.
“Additionally, off the outer edge of the A ring, we can see the narrow strand known as the F ring.”
“The rings cast a shadow on the planet and vice versa, creating intriguing visual effects.”
“In-depth exposures not shown in this image will allow us to investigate Saturn’s fainter rings, including the thin G ring and diffuse E ring, which are not visible here.”
Saturn’s rings consist of an assortment of rocky and icy fragments, ranging in size from smaller than a grain of sand to as large as mountains on Earth.
Using Webb, astronomers recently explored Enceladus and discovered a substantial plume emanating from the moon’s southern pole.
This plume contains particles and copious amounts of water vapor, contributing to Saturn’s E ring.
“Comparing the northern and southern poles of Saturn in this image, we can observe typical seasonal changes,” the scientists said.
“It’s currently summertime in Saturn’s northern hemisphere, while the southern hemisphere emerges from winter darkness.”
“However, the northern pole appears unusually dark, potentially due to an unknown seasonal process affecting polar aerosols.”
“A faint brightening at the edge of Saturn’s disk might be attributed to high-altitude methane fluorescence or emission from the ionosphere’s trihydrogen ion (H3+).”
“Spectroscopy from Webb could help confirm these possibilities.”
