4 hours ago
Bubbles in the Sky: The Ring Nebula -
One of the most popular targets for summer outreach programs, this gorgeous planetary nebula is situated right between two bright stars in the constellation Lyra, and so it’s very easy to find and a treat in any medium-power eyepiece. The star creating this beauty is experiencing the end of its nuclear fusion phase. It lacks the radiative energy to resist gravity’s pull on its matter, so it’s contracting. As it shrinks, its temperature rises to incredible levels, enough to pretty much literally boil away some of its outer layers. As these layers expand away from the star, they create incredibly rich and complex shapes, glowing in the signature colors of the elements in the gasses. The star itself provides the energy to cause the gasses to fluoresce. As it heats up, it begins to emit enormous amounts of energy at ultraviolet wavelengths. This radiation is perfectly suited for making rarified gasses glow.
If you pay attention, you notice there are several shells in this nebula. The process that creates these nebulae is episodic. When active, it creates a shell that expands away from the star, and when inactive, so little is going on that sometimes the nearest gasses can begin to fall back onto the star. Perhaps this contributes to the periodic nature of these nebulae.
But what’s that to the side of the Ring Nebula? It’s galaxy IC1296, a lovely spiral galaxy far in the distant background. In fact, it’s 220 million light years away, a stark contrast to M57’s 2,200 light years distance. It’s coincidence that the galaxy is 100,000 times as distant. With that vast distance between them, the size of IC1296 becomes apparent. To be as close to the size of something 100,000x closer, it must be gigantic!
The last tidbit to point out in this image is the bright knot in the lower arm of IC1296. That is supernova sn2013ev. I happened to photograph M57 as that supernova was visible. I got so excited thinking that I’d discovered a supernova! A quick online search showed I’d missed it by a couple of weeks. Ah well.
#astronomy #astrophotography #scicomm #stars #nebula #lyra #m57 #ringnebula #timstoneastronomy #beautyallaround