NASA’s James Webb Space Telescope (JWST) has snapped a picture of Cassiopeia A (CasA), a dramatic structure left behind by the death throes of a star that exploded from Earth’s perspective about 340 years ago.
Using its powerful near-infrared camera (NIRCam), JWST peered through Cas A’s cosmic dust to reveal never-before-seen structures of the expanding shell of material hitting the gas shed by the star.
Studying these structures could help us understand how stardust spreads through the universe and how it helps, ultimately, create life.
“With NIRCam’s resolution, we can now see how the dying star absolutely shattered when it exploded, leaving filaments akin to tiny shards of glass behind,” research lead Danny Milisavljevic of Purdue University said in a statement.
“It’s really unbelievable after all these years studying Cas A to now resolve those details, which are providing us with transformational insight into how this star exploded.”
Studying a supernova remnant is like looking at a stellar “autopsy” Milisavljevic said in a previous statement.
Scientists study these images closely to reconstruct what a star might have looked like and what happened when it bursts.
JWST revealed delicate structures like “shards” of glass in Cas A, Milisavljevic explained. These could be the remnants from the star, glowing pink and gold when the sulfur, oxygen and neon of the dead star interacts with dust.
JWST also uncovered cosmic “bullet holes” behind a green cloud of cosmic gas that previously hid scientist’s view, NASA said in an accompanying video. It is believed that ionized gases punch through the gas left by the star to create these holes.
Another structure appeared, which the researcher nicknamed Baby Cas A.
Scientists are excited about this structure, because it is thought to have caught an “echo” of the explosion, seen as light from the supernova that is interacting with cosmic dust. Though it looks a lot smaller than Cas A, “Baby Cas A” is about 170 light-years behind the supernova remnant.
Cas A is particularly useful in stellar forensics. It is relatively close to us, about 11,000 light-years away in the constellation Cassiopeia.
It is also the newest known remnant from a massive stellar object in our galaxy. Scientists are witnessing the beginning of this event.
Understanding the last moments of nearby stars is important because they hold some of the building blocks of life. They spread calcium and iron through the cosmos, without which we wouldn’t have bones or blood.
” By understanding the explosion of stars, we are reading our origin story,” Milisavljevic said.