For the first time astronomers have combined data from NASA’s Chandra X-ray Observatory and James Webb Space Telescope to study the well-known supernova remnant Cassiopeia A (Cas A).
Cas A is located about 11,000 light-years from Earth and spans approximately 10 light-years.
The research has helped explain an unusual structure in the debris from the destroyed star called the “Green Monster”, first discovered in Webb data in April 2023.
The research has also uncovered new details about the explosion that created Cas A about 340 years ago, from Earth’s perspective.
The Chandra data reveals hot gas, mostly from supernova debris from the destroyed star, including elements like silicon and iron.
The debris from the explosion is seen by Chandra because it is heated to tens of millions of degrees by shock waves, akin to sonic booms from a supersonic plane.
Webb can see some material that has not been affected by shock waves, what can be called “pristine” debris.
The authors conclude that the Green Monster was created by a blast wave from the exploded star slamming into material surrounding it, supporting earlier suggestions from the Webb data alone.
Ilse De Looze from Ghent University in Belgium, who is a co-investigator of the Webb study, says: “We concluded that the Green Monster is also part of the blast wave and is photobombing the central part of Cas A rather than being part of it.
“We then digitally removed the Green Monster from the rest of the image to learn more about what is behind it.
“It’s like we were handed a completed, 3D jigsaw puzzle, and we were able to take parts out to see what’s on the inside.”
These results were presented by Dan Milisavljevic from Purdue University on Monday (8 Jan) at the 243rd meeting of the American Astronomical Society in New Orleans.
