In the following image, we can see the central star that gave birth to the nebula. In not all cases do planetaries appear as elliptical or circular disks. It all depends on how the material was disbursed as the star exploded and how the glowing gases are oriented from our perspective here on Earth. M27 photographed by Kevin Bonges Images of planetaries taken in the red-light emission of hydrogen atoms show an amazing amount of structure. The complexity of the images presents a challenge to astronomers trying to explain why they look the way they do.
Planetary nebulae evolve from gas and dusty clouds surrounding red giant stars.
Analysis strongly suggests outflow patterns that change direction could be shaping these nebulae. Some researchers theorize that the slowly expanding cloud of gas surrounding each dying star begins with a roughly circular shape. Then, jet-like outflows carve away at the inner part of the shell. Hot stellar winds continually push on the shell, eventually producing the delicate shapes we see in planetary nebulae. It's also possible that a binary companion to a dying star stirs up the glowing gases, further changing the shape of the nebula.