The Webb telescope captures a "green monster" inside a young supernova

() — The James Webb Space Telescope captured never-before-seen colorful detail in one of the best-observed remnants of an exploded star.

The glowing gas and dust of Cassiopeia A is all that remains of a star that exploded in a supernova and whose light first reached Earth 340 years ago. It is the youngest known supernova remnant in our galaxy, which is why the celestial object has been studied by a multitude of terrestrial and space telescopes.

Cassiopeia A lies 11,000 light-years away, in the constellation Cassiopeia, and the remnant extends for 10 light-years.

Observing Cas A, as it is also known, allows scientists to better understand how stellar explosions occur.

The astronomers pointed the Webb telescope and its instruments in the direction of Cas A to see if the observatory’s infrared capabilities could pick up something other telescopes might have missed. Infrared light is invisible to the human eye, allowing the Webb to observe aspects of the universe that would otherwise be invisible.

“Cas A represents our best chance to look at the debris field of an exploded star and perform a kind of stellar autopsy to understand what kind of star was there before and how it exploded,” said Danny Milisavljevic, an assistant professor at Purdue University and principal investigator for the Webb program that captured the new observations, in a statement.

“Compared to previous infrared images, we see incredible detail that we haven’t been able to access before,” co-investigator Tea Temim, a research astronomer at Princeton University, said in a statement.

The new infrared image of Cas A obtained by Webb was translated into visible light so that the human eye can see the colors of the remnant. The red and orange light on the outside of the remnant indicates hot dust, where material ejected from the star before it exploded is colliding with the gas and dust around it.

Inside the remnant’s bubble-like structure, a glowing pink light can be seen, along with features resembling clumps and knots. This material comes from the exploded star and includes bright heavy elements such as argon, neon, and oxygen.

A bright green loop along the right side of the bubble has also caught the interest of researchers.

“We named it the Green Monster after Fenway Park in Boston. If you look closely, you can see that it’s dotted with what look like mini bubbles,” Milisavljevic explains. “His shape and complexity of him are unexpected and difficult to understand.”

The team is still trying to understand the sources of the different colors in the image.

Studying supernova remnants like Cas A can help scientists understand cosmic dust, a building block of stars and planets, and how exploding stars release crucial elements for life.

“By understanding the process of exploding stars, we are reading our own origin story,” says Milisavljevic. “I’m going to spend the rest of my career trying to understand what’s in this data set.”