Webb clearly recorded all rings and 27 moons of Uranus

0
194
Webb clearly recorded all rings and 27 moons of Uranus
This image of Uranus from NIRCam (Near-Infrared Camera) on the NASA/ESA/CSA James Webb Space Telescope shows the planet and its rings in new clarity. The Webb image exquisitely captures Uranus’s seasonal north polar cap, including the bright, white, inner cap and the dark lane in the bottom of the polar cap. Uranus’ dim inner and outer rings are also visible in this image, including the elusive Zeta ring—the extremely faint and diffuse ring closest to the planet. This Webb image also shows 9 of the planet’s 27 moons. They are the blue dots that surround the planet’s rings. Clockwise starting at 2 o’clock, they are: Rosalind, Puck, Belinda, Desdemona, Cressida, Bianca, Portia, Juliet, and Perdita. The orbits of these moons share the 98-degree tilt of their parent planet relative to the plane of the solar system. One day on Uranus is about 17 hours, so the planet’s rotation is relatively quick. This makes it supremely difficult for observatories with a sharp eye like Webb to capture one simple image of the entire planet – storms and other atmospheric features, and the planet’s moons, move visibly within minutes. This image combines several longer and shorter exposures of this dynamic system to correct for those slight changes throughout the observing time

The James Webb Space Telescope recently has set its sights on the unusual and mysterious Uranus, an icy giant that spins on its side. Webb captured rings, moons, storms, and other atmospheric features of the distant planet, including a seasonal polar cap.

Mysterious Uranus

Thanks to his unique sensitivity, Webb captured Uranus’ faint inner and outer rings, including the elusive Zeta ring, the extremely faint and diffuse ring closest to the planet. He also captured images of many of the planet’s 27 known moons, even seeing some small satellites in the rings.

In the visible wavelength range, Uranus looked like a calm, solid blue ball. In the infrared, Webb reveals a strange and dynamic icy world filled with fascinating atmospheric features.

The polar caps of the planet

One of the most striking of these is the planet’s seasonal north polar cap. Compared to the image from earlier this year, the new images make it easier to see some of the details of the cap. These include the bright white inner cap and a dark band at the bottom of the polar cap towards lower latitudes.

Several bright storms can also be seen near and below the southern boundary of the polar cap. The number of these storms, as well as how often and where they appear in Uranus’ atmosphere, may be due to a combination of seasonal and meteorological effects.

The polar cap becomes visible when a planet’s pole begins to point toward the Sun as it approaches the solstice and receives more sunlight.

Uranus reaches its next solstice in 2028, and astronomers are looking forward to any possible changes in the structure of these elements. Webb will help to disentangle the seasonal and meteorological effects that influence Uranus’ storms, which is crucial to helping astronomers understand the planet’s complex atmosphere.

Because Uranus rotates on its side at an angle of about 98 degrees, it has the most extreme seasons in the solar system. For almost a quarter of every Uranian year, the Sun shines over one pole, plunging the other half of the planet into a dark winter that lasts 21 years.

зображення Урана, отримане камерою NIRCam (камера ближнього інфрачервоного діапазону) космічного телескопа NASA/ESA/CSA Джеймса Вебба
This image of Uranus, taken by the NIRCam (Near Infrared Camera) on the James Webb Space Telescope, shows the planet and its rings with new clarity. Image credit: NASA, ESA, CSA, STScI

Uranus’ rings and moons

NIRCam’s image of Uranus reveals the planet and its rings with new clarity. The planet’s seasonal northern polar cap gleams bright white, and Webb’s exquisite sensitivity distinguishes between Uranus’ faint inner and outer rings, including the Zeta ring, the extremely faint and diffuse ring closest to the planet.

Webb’s image shows 14 of the planet’s 27 moons: Oberon, Titania, Umbriel, Juliet, Perdita, Rosalind, Puck, Belinda, Desdemona, Cressida, Ariel, Miranda, Bianca, and Portia.

By the way, Uranus’ moons were named after characters from the works of William Shakespeare and Alexander Pope. The first two moons: Titan and Oberon were discovered by William Herschel in 1787. Two more large moons (Ariel and Umbriel) were discovered in 1851 by William Lascelles. In 1948, Gerard Kuiper discovered Miranda. All other moons are much smaller and were discovered after 1985 during the Voyager 2 mission or with the help of advanced ground-based telescopes.

The moons of Uranus are divided into three groups:

  • 5 large ones,
  • 13 internal moons,
  • 9 irregular moons.

One day on Uranus lasts about 17 hours, so the planet rotates relatively quickly. This makes it extremely difficult for observatories with a sharp eye like Webb to capture one simple image of the entire planet – storms and other atmospheric features, as well as the planet’s moons, move visibly in a matter of minutes. This image combines several longer and shorter exposures of this dynamic system to correct for these minor changes throughout the observation.

The Webb’s extraordinary sensitivity also picks up a small number of background galaxies – most of them appear as orange spots, and there are two larger fuzzy white galaxies to the right of the planet in this field of view.

An example for exoplanet research

Thanks to Webb‘s unparalleled infrared resolution and sensitivity, astronomers can now see Uranus and its unique features with groundbreaking clarity. These details, especially of the nearby ring of Zeta, will be invaluable for planning any future missions to Uranus.

Uranus can also serve as a model for studying the many distant exoplanets of the same size that have been discovered over the past few decades. This “exoplanet in our backyard” could help astronomers understand how planets of this size exist, what their meteorology is like, and how they formed. This, in turn, can help us understand our solar system as a whole by placing it in a broader context.

LEAVE A REPLY

Please enter your comment!
Please enter your name here