What Supernova Remnants Reveal About Stellar Explosions

Supernovae are among the most energetic events in the universe and play a key role in shaping the energy balance, structure, and chemical content of galaxies. They are responsible for the formation and distribution of heavy elements and dust grains that enrich the interstellar media in which they evolve, and they leave behind compact objects whose high densities and magnetic field strengths represent matter under some of the most extreme conditions known. Despite their great importance in astrophysics, the details of how the explosions occur – from how the final stages of progenitor evolution proceed to which massive stars produce which subtypes of supernovae – are still not entirely understood. Supernova remnants, the nearby remains of supernova explosions, allow us to spatially resolve and study the expelled material and the circumstellar environment in detail. I will describe how multi-wavelength studies of supernova remnants can inform us about their stellar progenitors and supernova explosion properties. I will also discuss the highlights from new JWST observations that have revealed never-before-seen details in the structure of young supernova remnants.