Uranus and a supernova – the spectacular new images from the James Webb telescope

The James Webb telescope was launched more than a year ago. It has been orbiting the sun ever since – unlike the Hubble telescope that orbits the Earth. James Webb, which takes high-precision images by detecting infrared radiation, regularly delivers extraordinary images from space.

Images of the planet Uranus recently reached Earth in this way. Moments later, the “James Webb” telescope sent images of the “debris field” of an exploded star, Cassiopeia A. Here are the images and their stories.

“Uranus has never looked so good. Really.” This is what NASA writes about the images of the planet on her James Webb Twitter account. The infrared image published by Esa and NASA shows the “ice planet” Uranus and eleven of the 13 known rings. Some of these rings are so bright with the James Webb telescope that when they are close together they appear to merge into one larger ring, NASA writes.

Uranus, the “seventh” planet in distance from the sun, is unique, according to NASA: Because it is tilted sideways at about a 90-degree angle — relative to its orbit around the sun — the planet experiences extreme seasons. The poles of the planet therefore experience many years of constant sunlight, followed by an equal number of years in complete darkness. In total, Uranus takes 84 (Earth) years to orbit the sun once. Visible in the image above is the north pole of the planet. It is currently late spring there – in 2028, the north pole of Uranus will experience its summer.

And something else is visible, as NASA writes: To the right of the planet, there is a brightening area at the solar-facing pole known as the polar cap. This polar cap near Uranus is unique: “It seems to appear when the pole gets direct sunlight in the summer and disappear again in the fall,” according to NASA. The data collected by the “James Webb” telescope would help scientists understand the currently puzzling mechanism.

The telescope also revealed another “surprising aspect” of the polar cap – and this is where you really need to look closely: a subtle, amplified brightening in the center of the polar cap. “The sensitivity and longer wavelengths of Webb’s camera may be why we’re seeing this enhanced polar feature of Uranus,” NASA said. Such details were previously unknown because the same resolution was not achieved with other powerful telescopes such as the “Hubble” telescope.

Also striking are the two white dots in the Uranus image. NASA speaks of clouds: “There is a bright cloud on the edge of the polar cap and a second, very bright cloud can be seen on the left edge of the planet.” Such clouds are typical of infrared images of Uranus and are likely associated with storm activity.

A second photo shows the “ice giant” from a slightly greater distance. The telescope also included some of the 27 known moons orbiting Uranus. However, according to NASA, most are too small and dim to be seen here. However, the six brightest moons can be seen in the wide-angle image. They have names like Umbriel, Ariel or Titania.

“The explosion of a star is a dramatic event, but the debris left behind by the star could be even more dramatic,” NASA writes of the “James Webb” image of a so-called supernova. It shows the supernova remnant Cassiopeia A (also called “Cas A”), which was formed 340 (Earth) years ago by a stellar explosion.

The glow created when a star dies is called a supernova. This causes an explosion and the star’s brightness briefly increases a million to billions of times.

“‘Cas A’ gives us the best opportunity to examine the debris field of an exploded star and perform a kind of autopsy on stars to understand what kind of star existed before and how this star exploded,” said Purdue’s Danny Milisavljevic. University in West Lafayette, Indiana, Principal Investigator, Webb Program. Compared to previous infrared images, it shows “incredible detail that we haven’t had access to before.”

It turns out that the newness of the images is initially a big puzzle for the researchers at NASA and Esa. “The striking colors of the new ‘Cas A’ image, which converts infrared light to wavelengths of visible light, contain a wealth of scientific information that the team is only just beginning to decipher,” writes NASA.

Then things get a bit more complicated: on the outside of the bubble, especially at the top and left, there are “curtains of dust” that appear orange and red due to the emission of hot dust. They mark the places where ejecta from the exploded star meets the gas and dust around the former star.

Inside this shell are “speckled threads” of light pink, studded with “lumps” and “knots”. According to NASA, this is material from the star itself, which glows from a mixture of various heavy elements such as oxygen, argon and neon, as well as dust emission. “We are still trying to decipher all these emission sources,” says Ilse De Looze of Ghent University in Belgium, who is also involved in the program.

Supernovas like the one that formed “Cas A” are also crucial to the formation of our planet. They spread elements such as the calcium we find in our bones and the iron in our blood into interstellar space, creating new generations of stars and planets.

“By understanding the process of the starburst, we read our own formation history,” says Milisavljevic of the Webb program. “I’ll spend the rest of my career trying to understand what’s in this dataset.”

The remains of “Cas A” span about ten light-years and are located 11,000 light-years away in the constellation Cassiopeia.

(lacquer)