It happens due to magnetic activity.
Sun spots.
sun spots are cooler parts of the sun
the sun spots like black little spots on the sun that explode every 11 years
Saturn may or may not have Saturn spots. Only the sun has sun spots.
sun spots
Sun spots are not permanent, therefore it depends.
We call them sunspots, but dark and cool are relative terms. A sunspot is dark only relative to the surrounding solar surface, but still intensely bright compared to your common household light bulb. It's cooler than the surrounding solar material, but still hot enough to vaporize a spaceship and anyone inside it in a fraction of a second.
Sun spots are colder than adjacent parts of the sun.
Sun spots
it is just fire
The circular discoloration spots on your back are most likely sun spots. These are caused from over exposure to the sun.
Huge streams of hot, magnetically charged gases. The sun spots are cooler parts of the surface.