The James Webb Space Telescope is approaching its first anniversary of operation, and it has already viewed the universe’s earliest eras. It has also concentrated on nearby celestial objects, such as the supernova remnant Cassiopeia A. (Cas A). Webb has transmitted a new image of Cas A that reveals never-before-seen details that may aid astronomers in understanding our origins.
Cassiopeia A is notable because it is the earliest known supernova remnant in our galaxy. It is only 11,000 light-years away, and the supernova’s light has been reaching Earth for 340 years. The Cas A progenitor star, like all massive stars, ran out of fuel and erupted in a supernova, leaving behind a steadily expanding cloud of debris. Similar structures are much farther away or much older, but Cas A allows scientists to examine the elements and molecules ejected by the deceased star.
Webb’s images of Cassiopeia A, our galaxy’s youngest supernova remnant, are unmatched.
Webb was built specifically for this type of observation. The Mid-Infrared Instrument (MIRI) of the telescope can see through the dust and atmosphere encircling Cas A, revealing previously unseen features. The Webb image’s colors have been shifted to the visible spectrum.
The orange and crimson sections that spiral around the top of the image represent warm dust, indicating where the material ejected by the dying star has begun colliding with interstellar gas. The pink spirals on the exterior of the shell originate from heavy-element-rich material within the star, such as oxygen, argon, and neon. In these regions, scientists are still attempting to categorize all the emissions.
If you look closely, you’ll see small bubbles.
The large verdant swath that arcs around the right side of the stellar cavity is perhaps the most notable aspect of the new Cas A photograph. “In homage of Fenway Park in Boston, we’ve christened it the Green Monster. According to Purdue University’s Danny Milisavljevic, a Webb scientist, “if you look carefully, you’ll observe that it’s covered in what appear to be tiny bubbles.”
Scientists anticipate that Cas A will aid in determining the origin of all of the cosmic material observable in the universe. We believe that supernovae like Cas A, which disperse heavy elements throughout space, are essential to life as we know it. When Carl Sagan famously remarked that we are all “stellar material,” he was referring to this concept. Cas A is only a few hundred years into this process from our perspective, and Webb is uniquely positioned to observe its progression.