Supernova remnant Cassiopeia A (Cas A) shines in a new image taken by NASA’s James Webb Space Telescope on December 10, 2023. The Webb Near Infrared Camera (NIRCam) displays this stellar explosion at a resolution not previously available at these wavelengths, revealing intricate details of the expanding envelope of material seeping into the gas ejected by the star before the explosion.

Cas A is one of the best-studied supernova remnants in the entire universe. Over the years, ground- and space-based observatories, including NASA’s Chandra X-ray Observatory, the Hubble Space Telescope, and the retired Spitzer Space Telescope, have collected multiwavelength images of the object’s remnants.

However, astronomers have now entered a new era in Cas A research. In April 2023, the Webb Mid-Infrared Instrument (MIRI) began this chapter by revealing new and unexpected features in the inner shell of the supernova remnant. Many of these features do not appear in the new NIRCam image, and astronomers are trying to find out why. Source