How can i make a proper light inside a circle with objects so their surface is illuminated? I'm trying to do a Solar System representation with Cycles, i already have the planets in order, the orbits, and i'm basing my file on a picture, and i'm trying to achieve the same illumination, but it seems pretty hard, so maybe or i'm using the wrong options, or even position of lighting.
The thing is, i do not want to put the Sun on the image because later i'll add it in another software, but what i want to achieve is the same kind of lighting effect.
Here's my reference (plus, my image will not have any kind of background image)



And this is what happens if i add a Point light inside the circles, i think the lighting is too weak for the objects and also if i add more Strenght to it, probably the planets would end up being totally white (or the color of the light)


Also, i tried putting an Emission object (a simple sphere, on this case) and again, the lighting seems too weak compared to the reference, and if i add more Strenght..this happens: 



Please if someone have a method to add this kind of lighting, or maybe even a trick, please tell me, i'm really in trouble right now with this one..
The light sources can be invisible to the camera. Set Cycles Ray Visibility to FALSE

You mentioned trick.  Consider the point light external to the sphere.  Set Cycles Ray Visibility to FALSE.  Each planet has a sister light planet not visible to the camera.  They can both rotate relative to Sun. You may consider [Tracking] Constraint.
The Sun. Set Cycles Ray Visibility to FALSE.