This is the second in a series of five posts I have planned to celebrate the recent images from the James Webb Space Telescope. The image I’m covering today is entitled the Southern Ring Nebula, NGC 3132. Strictly from an aesthetic standpoint, this is my favorite image from Webb so far. It is stunning! The colors, textures, and details are amazing. And there is so much dimensionality. It’s like you’re looking at a massive tunnel lined with plush blue fleece.
But what exactly are we looking at here? Well, this object is known as a planetary nebula, which is a terrible name because it has nothing to do with a planet. That’s just a name early astronomers used to erroneously describe these objects. These nebulae are actually associated stars. Specifically, these nebulae are formed when stars of a certain mass exhaust the supply of fuel that makes them burn so brightly. Planetary nebulae form when a star dies. But unlike more massive stars that explode suddenly in a supernova, planetary nebulae stars don’t die all at once. Instead, they die in stages through the periodic ejection of huge amounts of material into space. As you can imagine, star death is violent even when the star doesn’t supernova. In a planetary nebula, the ejected material speeds away in all directions from the dying star at more than 30,000 mph. Eventually, the star ejects so much material that it has nothing left to give and forms a white dwarf, which is considered the final stage in the evolution of a star. Game over for the star. But take heart. Although small, a white dwarf is still quite bright. The light from the white dwarf is absorbed by the expanding material, which in turn emits specific colors to create the colorful circular structure we see in the Webb image. Pretty cool, right?
You may know that the Webb cameras measure infrared light, which is not visible to our human eyes. But the sensors in the JWST cameras are very sensitive to infrared. By the way, this is also why the mirrors on the JWST are coated with a thin layer of gold. Gold is really good at reflecting infrared light. To make the images useful to us humans, the light is transformed during image processing into colors we can see. It’s very similar to the process used by amateur astronomers like me. I have to admit that it’s pretty cool to know someone is on a computer out there processing Webb images in PixInsight and Photoshop just like I do with the images from my driveway! OK, I admit, they probably process images better than I do. : )
The Southern Ring Nebula is about 2000 light years away in the constellation Vela, which is not visible to us in the northern hemisphere. Sad face. Time to go back to Chile! The gases in the nebula are very diffuse. Even though it is created from immense amounts of ejected material, the nebula is spread across a very large area, so we’re essentially looking at empty space. Crazy.
OK, enough talk, let’s just look at this beautiful image. It sure doesn’t look like empty space to me. I get lost in all the details. The high-resolution image is spectacular. You can download a copy for free along with all the other Webb images so far. Just Google NASA/STSci and you’ll find the website.