Through images by James Webb, Science reviews what is known so far about the explosion of a star

As a New Year’s Eve gift, it is very appropriate to “place” on our imaginary Christmas tree, a Round shiny object Through the world’s most advanced telescope.

This is the residue Supernova Cassiopeia A (Cass A) shines in a new form The James Webb Space Telescope From NASA.

Using powerful The NIRCam instrument (near-infrared camera) on the web, Gauss A shows this starburst at a previously unattainable resolution at these wavelengths. According to the experts who operated it, this high-resolution image reveals intricate details of the expanding layer of material that collided with the gas released by the star before it exploded.

Located 11,000 light-years away from the Solar System, Cassiopeia A It is one of the most well-known and studied objects in the galaxy. Records from the late 17th century indicate that it was discovered by several astronomers, but the supernova remnant was not officially recorded until some time later. In 1948.

However, it has fascinated astronomers ever since, providing a rare opportunity to study the evolution of the remnants of an exploded star as it expands into space. Supersonic speed. Gauss A is one of the best-studied supernova remnants in the entire universe. Over the years, including ground-based and space-based laboratories Chandra X-ray Lab From NASA, Hubble Space Telescope Y Spitzer Space Telescope Removed, they compiled a multi-wavelength image of the remnants of the object.

However, astronomers have now entered a new era in the study of Gauss A. In April 2023, Webb’s MIRI (Mid-Infrared Instrument) This chapter begins, revealing new and unexpected features within the inner layer of the supernova remnant. Many of those features are invisible in the new NIRCam image and astronomers are investigating why.

The new infrared image appears more transient than previous observations at other wavelengths, but it helps scientists Study Mechanics The rest. And there is an amazing new feature. In the lower right corner of the image is a scratch spot, which scientists call Baby Caus A because it looks like Caus A’s baby.

It may seem close supernova remnant, But it’s actually about 170 light-years away. And it’s not a supernova: it’s light from Gauss A that travels through space and hits now-distant dust, lighting it up. This phenomenon is called light echo, and some of it has been captured in new film.

straw bright pink-orange slender curls; That’s the explosion’s inner layer: clumps of gas and dust containing elements like sulfur, oxygen, argon, and neon that will one day coalesce into newly formed stars.

“With NIRCam’s resolution, we can now see how the dying star completely disintegrated as it exploded, leaving filaments like tiny glass particles.” Astronomer Dani Milisavljevic says from Purdue University. “It is truly incredible that these details can now be resolved after studying Case A for so many years. Changing perspective How this star exploded.”

The smoky outer layer of the remnant is the expanding region of interstellar space. It is bright at mid-infrared wavelengths, but too cool to glow in the near-infrared. The white light in the image is produced by synchrotron radiation, when electrons are accelerated into a spiral around magnetic field lines.

The reason A point of light that glows bright green in infrared Right in the middle of the bubble that baffled scientists. In the new NIRCam image, the region is dotted with what appear to be holes surrounded by white and purple, representing ionized gas.

Astronomers now think that the mixing of light is caused by supernova ejecta reaching and piercing the material ejected by the star before it explodes.

Infrared light is invisible to our eyes, so image processors and scientists translate these wavelengths of light into visible colors. In the most recent image of Cas A, different NIRCam filters are assigned colors, and each of those colors represents a different activity occurring within the object.

At first glance, A NIRCam image may appear less colorful than a MIRI image. However, this simply comes down to the wavelengths at which the material emits its light.

The most striking colors in Webb’s most recent image are the bright oranges and pale pinks that make up the inner layer of the supernova remnant. Webb’s keen eye can detect small Gas knots, mixtures of sulfur, oxygen, argon and neon from the star. Embedded in this gas is a mixture of dust and molecules that eventually become the components of new stars and planetary systems. Some debris filaments are too small for the web to resolve, meaning they have diameters comparable to or smaller than 10 billion miles (about 100 astronomical units). Compared to The entirety of Cas A is 10 light-years in diameter, or 60 trillion miles.

“With NIRCam’s resolution, we can now see how the dying star completely disintegrated when it exploded, leaving filaments that resemble tiny shards of glass,” said Purdue University’s Danny Milisavaljevic, who leads the research team. “It’s really incredible, after all these years of studying Cas A, to now be able to resolve those details, which gives us a transformative view of how this star exploded.”

Comparing the infrared view of Webb’s new Gauss A to the mid-infrared, its inner cavity and outer shell are curiously colorless.

A suburb of the main inner layer, this MIRI appeared in bright orange and red in the image, Now they look like smoke from a fire. This marks the point where the supernova shock wave collides with the surrounding atmospheric material. Dust from the atmosphere is too cool to be directly detected at near-infrared wavelengths, but glows in the mid-infrared.

say the researchers White color is light from synchrotron radiation, It emits across the entire electromagnetic spectrum, including the near-infrared. It is made up of charged particles traveling at very high speeds and rotating around magnetic field lines. Synchrotron radiation is also visible in the bubble-like layers in the lower half of the inner cavity.

The near-infrared view does not show a ring of green light in the central cavity of Gauss A, which glows in the mid-infrared, the nickname Green Monster By the research team. The researchers described the feature as “difficult to understand” at the time of its first appearance.

Although the Green Monster’s “greenness” is not visible in NIRCam, the infrared remnants in the area may provide insight into this mysterious feature. Circular holes visible in the MIRI image are faintly outlined in white and violet emission in the NIRCam image; It stands for ionized gas. Researchers believe this happens because supernova debris pushes away the gas left behind before the star exploded.