NASA’s Webb Rings in Holidays With Ringed Planet Uranus

NASA’s James Webb Space Telescope recently trained its sights on unusual and enigmatic Uranus, an ice giant that spins on its side. Webb captured this dynamic world with rings, moons, storms, and other atmospheric features – including a seasonal polar cap. The image expands upon a two-color version released earlier this year, adding additional wavelength coverage for a more detailed look.

With its exquisite sensitivity, Webb captured Uranus’ dim inner and outer rings, including the elusive Zeta ring – the extremely faint and diffuse ring closest to the planet. It also imaged many of the planet’s 27 known moons, even seeing some small moons within the rings.

Image: Uranus and its rings

The planet Uranus on a black background. The planet appears blue with a large, white patch taking up the right half. The patch is whitest at the center, then fades into blue at it expands from right to left. A thin outline of Uranus is also white. Around the planet is a system of nested rings. The outermost ring is the brightest while the innermost ring is the faintest. Unlike Saturn’s horizontal rings, the rings of Uranus are vertical and so they appear to surround the planet in an oval shape. There are 9 blueish white dots scattered around the rings.

This image of Uranus from NIRCam (Near-Infrared Camera) on NASA’s James Webb Space Telescope exquisitely captures Uranus’s seasonal north polar cap and dim inner and outer rings. This Webb image also shows 9 of the planet’s 27 moons – clockwise starting at 2 o’clock, they are: Rosalind, Puck, Belinda, Desdemona, Cressida, Bianca, Portia, Juliet, and Perdita.

NASA, ESA, CSA, STScI

In visible wavelengths as seen by Voyager 2 in the 1980s, Uranus appeared as a placid, solid blue ball. In infrared wavelengths, Webb is revealing a strange and dynamic ice world filled with exciting atmospheric features.

One of the most striking of these is the planet’s seasonal north polar cloud cap. Compared to the Webb image from earlier this year, some details of the cap are easier to see in these newer images. These include the bright, white, inner cap and the dark lane in the bottom of the polar cap, toward the lower latitudes.

Several bright storms can also be seen near and below the southern border of the polar cap. The number of these storms, and how frequently and where they appear in Uranus’s atmosphere, might be due to a combination of seasonal and meteorological effects.

The polar cap appears to become more prominent when the planet’s pole begins to point toward the Sun, as it approaches solstice and receives more sunlight. Uranus reaches its next solstice in 2028, and astronomers are eager to watch any possible changes in the structure of these features. Webb will help disentangle the seasonal and meteorological effects that influence Uranus’s storms, which is critical to help astronomers understand the planet’s complex atmosphere.

Image: Uranus Wide-Field

alt="An image with a black background. The planet Uranus is a glowing orb near the center surrounded by rings. The planet appears blue with a large, white patch taking up the right half. The patch is whitest at the center, then fades into blue at it expands from right to left. A thin outline of Uranus is also white. Around the planet is a system of nested rings. There are faint orange and off-white smudges, some oval, some circular, that are background galaxies scattered throughout the image. Several bright blue point sources closer to Uranus are the planet’s moons. There is also a bright star at the left of the field, with 8 diffraction spikes."

This wide-field image of Uranus from NIRCam (Near-Infrared Camera) on NASA’s James Webb Space Telescope shows the planet amid a smattering of distant background galaxies. This image also includes 14 of the planet’s 27 moons: Oberon, Titania, Umbriel, Juliet, Perdita, Rosalind, Puck, Belinda, Desdemona, Cressida, Ariel, Miranda, Bianca, and Portia.

NASA, ESA, CSA, STScI

Because Uranus spins on its side at a tilt of about 98 degrees, it has the most extreme seasons in the solar system. For nearly a quarter of each Uranian year, the Sun shines over one pole, plunging the other half of the planet into a dark, 21-year-long winter.

With Webb’s unparalleled infrared resolution and sensitivity, astronomers now see Uranus and its unique features with groundbreaking new clarity. These details, especially of the close-in Zeta ring, will be invaluable to planning any future missions to Uranus.

Uranus can also serve as a proxy for studying the nearly 2,000 similarly sized exoplanets that have been discovered in the last few decades. This “exoplanet in our backyard” can help astronomers understand how planets of this size work, what their meteorology is like, and how they formed. This can in turn help us understand our own solar system as a whole by placing it in a larger context.

Image: Uranus' Moons Labelled

An image titled James Webb Space Telescope, Uranus, September 4, 2023. An image with a black background, a glowing orb near the center surrounded by rings. There are smudges that are background galaxies scattered throughout the image and several bright blue point sources that are the planet’s moons. At the bottom left are compass arrows indicating the orientation of the image on the sky. The north arrow points in the 12 o’clock direction. The east arrow points toward 6 o’clock. Below the image is a color key showing which filters were used to create the image and which visible-light color is assigned to each infrared-light filter. From left to right, Webb NIRCam filters are F140M (blue), F210M (cyan), F300M (yellow), and F460M (orange). A scale bar at the lower right of the image is about one-seventh the total width of the image, and text below it reads 16 arcseconds.

Annotated wide-field compass image of Uranus with some of its 27 moons and a few prominent stars (with characteristic diffraction spikes) labelled.

NASA, ESA, CSA, STScI

The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and the Canadian Space Agency.