I looked at your file.
It is hard to work with small other planets especially when you want to use their atmo-clouds.
It can be done but it is sometimes tricky. I use this method in my animation for a scene now for example
In your case i would use a little different method. It depends on what you want to do and if you want to animate or not too of course.
With kind of tricky scenes like this the best way is to plan ahead and use the center point (0,0,0 is what i mean not the real center of the planet) of the main planet so much you can do.
Put the cloud and your object there at the "0,0,0" point.
Then use the clouds high (change it for how much you want) and-or the objects position.
After you have the high of the cloud how you want it disable the main planet surface rendering option and
change the camera angle like in the position that you want, like in the first image.
Think
relative.You don't have to change the objects position or angle at all.
Then put the other things like the planet in the far side etc.
For a still image i would render a separate scene with only the burning cloud and comp it in post.
This would be much easier especially if you haven't planed the scene before accordingly.
But i think you can change your scene very fast if you only have to change the place of that planet further away.
