Images by Date
Images by Category
Solar System
White Dwarfs
Neutron Stars
Black Holes
Milky Way Galaxy
Normal Galaxies
Galaxy Clusters
Cosmology/Deep Field
Images by Interest
Space Scoop for Kids
Sky Map
Photo Blog
Top Rated Images
Image Handouts
Fits Files
Image Tutorials
Photo Album Tutorial
False Color
Cosmic Distance
Look-Back Time
Scale & Distance
Angular Measurement
Images & Processing
Image Use Policy
Web Shortcuts
Chandra Blog
RSS Feed
Email Newsletter
News & Noteworthy
Image Use Policy
Questions & Answers
Glossary of Terms
Download Guide
Get Adobe Reader
Videos: NASA Telescopes Chase Down "Green Monster" in Star's Debris
Tour: NASA Telescopes Chase Down "Green Monster" in Star's Debris
(Credit: NASA/CXC/A. Hobart)
[Runtime: 02:52]

With closed-captions (at YouTube)

The curious structure was first identified in Webb’s infrared data from April 2023. The origin of this feature, dubbed the “Green Monster” because of its resemblance to the wall in the left field of Fenway Park, was not clear.

However, by combining the Webb data with X-rays from Chandra, researchers think they have hunted down the source of the Green Monster.

While the astronomers already suspected the Green Monster was created by a blast wave from the exploded star slamming into material surrounding it, the Chandra data helped clinch the case. They showed that the properties of the X-rays from the Green Monster are similar to the X-rays from the blast wave rather than from the supernova debris.

When a massive star exploded to create Cas A about 340 years ago, from Earth’s perspective, it created a ball of matter and light that expanded outward. In the outer parts of Cas A the blast wave is striking surrounding gas that was ejected by the star between about 10,000 and 100,000 years before the explosion.

Chandra detects debris from the star 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. Much of this lies behind the Green Monster. This means the combination of Webb and Chandra data gives a fuller census of debris from the exploded star.

Astronomers will continue to use every tool available — including Chandra and Webb — to study this object that has fascinated them for years.

Quick Look: NASA Telescopes Chase Down "Green Monster" in Star's Debris
(Credit: NASA/CXC/A. Hobart)
[Runtime: 00:45]

With narration (video above with voiceover)

Two NASA telescopes — Chandra and Webb — looked at a supernova remnant.

Cassiopeia A is the aftermath of a star that exploded about 340 years ago.

Recently, a mysterious structure dubbed the “Green Monster” was found there.

The combined data show it comes from the explosion’s blast wave hitting material.

Return to: NASA Telescopes Chase Down "Green Monster" in Star's Debris (January 8, 2024)