Nebulae come in all shapes and sizes. There are spherical, there are annular in the form of butterflies, some create huge molecular star-forming clouds. But this nebula is completely different from all the others.
Captured by the Hubble Space Telescope, this planetary nebula was photographed in amazing detail. Located in the Giraffe constellation, NGC 1501 (Oyster Nebula) was formed when a massive star, seen in this photograph as a bright object in the center of the cloud, threw its outer layers into space. Although this is not something unusual in space (massive red giant stars always throw a huge amount of hot plasma into space by the end of life), the star in the center is rather strange. Pulsing in glare every 30 minutes, it represents a variable star. To detect a variable star of this scale in the center of a planetary nebula is rather strange, which made the Oyster Nebula a target for many astronomical studies.
But why does this hot expanding cloud look like a coma? At present, the answer is not known, but this is most likely due to the fact that the star violently blows off its outer shell of the plasma.
