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A roughly circular cloud of gas and dust with complex structure. The inner shell is made of bright pink and orange filaments studded with clumps and knots that look like tiny pieces of shattered glass. Around the exterior of the inner shell, there are curtains of wispy gas that look like campfire smoke. Around and within the nebula, various stars are seen as points of blue and white light. Outside the nebula, there are also clumps of dust, colored yellow in the image Hi-Res Zoomable Image Source/Credit: NASA, ESA, CSA, STScI, D. Milisavljevic (Purdue University), T. Temim (Princeton University), I. De Looze (University of Gent) |
Like a shiny, round ornament ready to be placed in the perfect spot on the holiday tree, supernova remnant Cassiopeia A (Cas A) gleams in a new image from the NASA/ESA/CSA James Webb Space Telescope. However, this scene is no proverbial silent night — all is not calm.
Webb’s NIRCam (Near-Infrared Camera) view of Cas A displays a very violent explosion at a resolution previously unreachable at these wavelengths. This high-resolution look unveils intricate details of the expanding shell of material slamming into the gas shed by the star before it exploded.
Cas A is one of the best-studied supernova remnants in all the cosmos. Over the years, ground-based and space-based observatories, including the NASA/ESA Hubble Space Telescope, have collectively assembled a multiwavelength picture of the object’s tattered remains.
However, astronomers have now entered a new era in the study of Cas A. In April 2023, Webb’s MIRI (Mid-Infrared Instrument) started this story, revealing new and unexpected features within the inner shell of the supernova remnant. But many of those features are invisible in the new NIRCam image, and astronomers are investigating why that is.