Wow I knew that stars have that radiation pressure but had no idea it caused mass to get so crazy far away from the ignited area of the star!

What’s particularly interesting to me is that for stars the size of our sun, regular old gas pressure dominates. The sun’s atmosphere is held up essentially just from the temperature (and therefore high kinetic energy) of the plasma.

Only once you get to 10+ solar masses does radiation (light) pressure begin to become significant, and at 50+ solar masses is when it dominates and the atmosphere is held up by the momentum of light.

In most star photospheres the role of radiation pressure is negligible. They are supported by the pressure gradients. The exception is very hot stars.