Cassiopeia A Supernova (B) (2023)

Using NASA’s James Webb Space Telescope, astronomers uncovered a mysterious feature within the remnant, nicknamed the “Green Monster,” alongside a puzzling network of ejecta filaments forming a web of oxygen-rich material. When combined with X-rays from Chandra, the data helped astronomers shed light on the origin of the Green Monster and revealed new insights into the explosion that created Cassiopeia A about 340 years ago, from Earth’s perspective.

Data Credits: Orlando, S. et al., 2021,A&A, 645, A66; DOI:10.1051/0004-6361/20203933