Apr 16, 2023

Stunning New Snapshot of a Supernova

Just over three centuries ago, light from a massive exploding star reached Earth for the first time. The remnants of this outburst, called a supernova, became known as Cassiopeia A.

The supernova Cassiopeia A, as imaged by the James Webb Space Telescope's Mid-Infrared Instrument — Credit: NASA, ESA, CSA, Danny Milisavljevic (Purdue University), Tea Temim (Princeton University), Ilse De Looze (UGent)

Now, thanks to the James Webb Space Telescope, astronomers are delighted to have a new, highly detailed view of the supernova, which could help them work backward and unravel some of the mysteries surrounding the star before it exploded.

Scientists are particularly interested in this supernova - located about 11,000 light-years from Earth in the constellation Cassiopeia - because it’s the youngest-known leftover from an exploding star in the Milky Way Galaxy. As such, according to a statement from NASA, it gives scientists the “best opportunity to look at the debris field of an exploded star and run a kind of stellar autopsy to understand what type of star was there beforehand and how that star exploded.”

Webb captured Cassiopeia A with its Mid-Infrared Instrument (MIRI), which gives scientists a unique view of what’s happening in the supernova outside the realm of visible light. The image shows a colorful array of cloud-like shapes and patterns, including a bright green lasso-shaped structure that astronomers have named the “Green Monster”. Scientists are still trying to decipher the significance of that shape, which is “unexpected and challenging” to understand, says NASA.

In Webb’s new mid-infrared view, the supernova also appears to be surrounded by fiery reds and oranges. Astronomers say these hues represent material from the exploded star crashing into surrounding dust and gas. The bright pink sections of the image are full of dust and heavy elements from the star, including neon, argon and oxygen.

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