Cyberpunk girl on a planet with everlasting sun

The everlasting sun was a phenomenon that happened 50 years ago on a planet far away from our galaxy, this led the people that lives there to used a kind of armor that allows them to feel at a temperature that is easier to live, this phenomenon happened by experiments with nuclear energy that almost killed all the life on the planet and those who could survive devised this technology to be able to live better, the radiation is so much that they have to wear a helmet that transforms the air around into oxygen and what they call "the new sun" is actually a ball of fire that will not go out for many hundreds of years and that little by little burns the little that remains of the breathable atmosphere.