I am trying to create a field of stars using the particles system.
The issue is that I once they are generated I don’t want them to disappear or generate at other places.
To solve that I simply give them a very long life time and then the same particles stay at the same place for a very long time.
The issue is that now I cannot practically use the “color over lifetime” to make the stars shimmer.
Is there a way to solve this with the particle system?
The only idea I can think of for this is to use a custom shader, which uses the current time to make them shimmer (plus a random animation offset per particle, so they don’t all shimmer at the same time).
This requires knowing how to write your own shaders, or having access to someone who does… 
What shader are you using currently?
And Unity version?
Unity 5.5
I know how to write shaders in OpenGL and DirectX(I come from native development) but I need to learn the tutorial on how to edit shaders on unity first.
Well thanks for the idea.
Ah, great!
Then I recommend taking a shader from this page and modifying it: Unity - Manual: Particle System vertex streams and Standard Shader support
If you add the random number stream, you’ll get 3 per particle random number to work with. Maybe try something like sin(_Time.x + random.x) * sin(_Time.y + random.y) to give you something cool to multiply the particle alpha with
Good luck!