How to implement the illumination of the planets by the Sun when simulating a model of the solar system?

Question

Graphic arts

My task is to create a solar system simulator.
You can see an example of what I want to do here: spaceengine.org
Most lighting modeling algorithms assume that the light source is a point, but in my problem the Sun is not a point at all.
Googled that light sources are point, directional and spotlights, but all the algorithms that I see are for point sources.
It seems that a directional IS fits the description, but the description says that all its rays are considered parallel, but this is not true for the Sun ...
Please help me decide what type of source it is and how to implement this.

Answer 1

Point source + ideally scattering sphere ("frosted glass") coinciding with the surface of the Sun. By overlaying the desired texture on the sphere in the alpha channel, you can even simulate granulation and sunspots .
Prominences and the solar corona will already be more difficult tasks.