APOD: 2025 January 17 - Supernova Remnant Cassiopeia A

Good Red Friday morning, Rallypoint, and welcome to the Astronomy Picture of the Day (APOD) for January 17, 2025.

The Near-Infrared Camera (NIRCam) aboard the Webb Telescope enables us to capture infrared light at wavelengths between 0.6 and 5 microns. As you can see with today's APOD, there's alot out there to look at. The clumps of bright orange and light pink that make up the inner shell of this supernova remnant are knots of gas, comprised of sulfur, oxygen, argon, and neon from the star itself. They provide a glimpse of how the dying star shattered like glass when it exploded.

The 'smoke' surrounding the main inner shell marks where ejected material from the exploded star is ramming into surrounding circumstellar material. The light 'echoes' visible in the bottom right corner indicate where light from the star’s long-ago explosion has warmed adjacent dust, causing it to glow as it cools down.

Fun stuff.