Ejecta structure at the shock breakout

3D ModelNoAI

Observations by the James Webb Space Telescope have revealed a stunning network of unshocked ejecta filaments within the supernova remnant Cassiopeia A. To unravel the origins of this intricate filamentary structure, we carried out cutting-edge 3D simulations of a supernova explosion driven by neutrinos, tracing the evolution of the remnant, starting from the collapse of the star’s core to its appearance approximately 1,000 years after the explosion. The scene represents the ejecta distribution soon after the shock wave breaks through the stellar surface. At this stage, a nascent network of ejecta filaments is already visible, indicating that the complex dynamics of the supernova explosion itself play a key role in sculpting these structures. As the remnant evolves, the simulations reveal that these filaments grow thinner and denser over time, due to the “Ni-bubble effect”, a process fueled by the radioactive decay of nickel synthesized during the explosion.

Credit: Orlando et al. (A&A 696, id.A108)