It is all done with magents...
There is one final part that needs clarifying with nebulae, the odd appearance of most planetary nebulae and some other exotic types that are associated with an odd type of star called Wolf-Rayet stars, and also supermassive stars that are just about to go supernova.
The one an only astro-physics lesson here. I promise!
Single stars like our Sun, are more of an exception than the norm. Most stars are actually in pairs (binary systems), trios (tertiary) and sometimes higher.
This means that several stars can be orbiting around each other. In some cases, some stars are so big that they have smaller stars orbiting around them just like planets!
The closest star to us (apart from the Sun), Alpha Centauri, is a tertiary system. The brightest star in the sky, Sirius, is a binary with a big parent and a wee companion (affectionately known as "The Pup", and being able to separate the pair is a good test of telescope optical quality).
When one of these stars starts to die (usually the larger one first - stars live the rock'n'roll lifestyle!), they throw off their outer layers of their structure, becoming what is called a planetary nebula (PN). However, ALL stars have very strong magnetic fields around them. This magnetic field influences the appearance of the PN - to a point. It is the complex magnetic, orbital and gravitational interplay between the various component stars that then gives rise to the really odd appearance of so many nebulae!
Here endth the lesson...
With the complex interplay between the various component and ACTIVE stars, the expanding shell/shells of glowing gas and material is then rearranged into some very curious and beautiful shapes and forms.
The Helix nebula has a massive spiral-like structure:
The Spiral Galaxy Nebula in the constellation Musca resembles a barred spiral galaxy:
Thor's Helmet surrounds one of these Wolf-Rayet stars:
The Homunculous Nebula is created by the interplay of the pre-supernova parent star shedding material and then formed with the interplay of the parent star's massive magnetic field and with the much smaller and invisible binary companion. It is invisible because it lies deep inside the nebula and orbits very close to the parent star:
NASA image
Alex.