Particle Systems!

Hello community . I am currently trying to design a galaxy. I watched a few tutorials related to Particle Systems, and I've read the manuals, but I still need a better understanding of how exactly Particle System Works. I'm also aware of the fact that in order to simulate a galaxy, I can't use the basic Shuriken Particle System. I need an Ellipsoid Particle Emitter, a Particle Renderer, and a Particle Animator. I played around a bit with it. I can make the System spin, particles at the edge change color(so the center is bright, and the edges are different collors), I can change the speed, etc., but all in all what I need exactly is indications to how to simulate a galaxy. I mean, I can't really figure out how to create the arms of the galaxy, coming out of it's center. I am not asking for someone to create the System for me, I just need a few indications. Thanks in advance.

 

Not sure about that,but an idea would be to get a texture of a real galaxy,remove the black space background to transparency-turn it into a sprite in Unity-attach it as a child of a cube primitive with all black texture so the cube is transparent and unseen-animate the cube to rotate-add your particles over top to give it some depth.