What fate awaits the bright ring structure as the supernova remnant ages beyond its initial interaction phase?

Answer

It will fade as the shockwave moves into the much less dense general interstellar medium.

Once the shockwave passes completely through the dense torus region, the specific feature causing the bright ring will fade, and the remnant will evolve into a larger, more diffuse structure governed by large-scale galactic dynamics.

What fate awaits the bright ring structure as the supernova remnant ages beyond its initial interaction phase?
starsexpansionastrophysicssupernova remnantsshock waves