BUBBLY SUPERNOVA-Cassiopeia

 

A new three dimensional model of the Cassiopeia A supernova remnant provides insights into how these massive explosions occur....
The detailed model reveals a bubble-like interior of debris that connects with a bright shell of ejecta arranged in multiple circular structures.
Cassiopeia A was created 340 years ago when a massive star exploded to form a neutron star, making it a good subject for a cosmic post mortem.
In this type of explosion, known as a core-collapse supernova, the outer layers of the star drop in free fall, reaching speeds of 70,000 kilometers per second, a significant fraction of the speed of light.
Somehow, that material suddenly stops and ends up traveling the other way at up to 10,000 kilometers per second. Scientists call this sudden reversal a "bounce", but until now they've been unsure exactly how it happens.
"We know the core collapses down to form a neutron star, and the rest blows up somehow after that," said Fesen. "But most of our models have had problems blowing up stars because the outer layers of the star collapse into the core and smother the explosion!