I'm using a volume scatter shader to render an atmosphere for a planet. To save on time I used a spherical gradient and ran it through a color ramp to get white only on the rims of the sphere. This was then fed into the density value of the volume scatter. When rendered it is behaving as if there are more, smaller spheres of volume inside of it. I'll attach images of my nodes and the results. Note: The atmosphere and planet are on separate render layers so I can apply a blur to the atmosphere without affecting the planet.
Solution found: Including my directional light in my atmosphere render layer fixed the issue, although I still don't know why. Does anyone know why having them separate would result in that artifact?