"Nightfall" is a chilling story, but it is physically impossible. There is no way to keep 5 stars (I think it was) in stable orbits close enough to each other to serve as suns for a planet wandering among them. I gather that the recent discovery was of a planet circling a binary at a long distance compared to the stars' separation; so see from the planet they would always be in the same part of the sky. I don't know if it's possible for a planet to orbit *one* star of a binary, close in; if so, it would see a lot of daylight.