Some advance questions about pointlight

I am working on a dynamically generated star simulator. I am currently using a single point-light as the center of a star.

So made the attenuation radius of the star really high 5000000 then I noticed at a point around 130000 away from the star, the light of the star completely vanishes. I decided to increase the attenuation radius of the light to 15000000 then the light covered the rest of the parts but it still faded away this time around 140000 and I increased the radius of the light further to 150000000 and it lit up a long range but still vanished at a point not that far away.

I am using a movable light and not using square and I had to increase the light fall off exponent to 6000 to get the effect so that the light is fading towards the end of the borders(at 5000000 radius). However if I increase the radius, I need to increase the falloff to get a good effect.