What would happen to Superman, or any Kryptonian, on a planet in a binary system where there is one yellow (G Type main sequence) star and one Red star? If the planet circles both stars? Or if it does a kind of figure eight and goes between both stars? Or if its orbits only one of the stars? Or if one of the stars is putting out more energy than the other? The things that come into my mind at night to my mind at night.
This was covered in comics years ago. Superman came into spitting distance of a blue dwarf and got a completely new set of superpowers. Does Bizarro World circle a square Sun?
That's may be, but a red star stops his powers while a yellow star gives him his powers, what happens then?
Different coloured stars give him different powers, or no powers. https://www.cbr.com/superman-suns-orange-green-blue/
Yes, but in a binary system, there are two stars. I'm proposing a situation where he is in a binary system with a red star and a yellow star. How would that affect him? We know under a yellow star he has the powers we know, while under a red sun he has none. So on a planet in a binary system with one red star and one yellow star what happens to his powers and I gave different situations on the planet's orbit in the OP. So it's not a single star situation, it's a binary system (red star and yellow star) what happens?
Red star wins. He's been attacked with miniature, softball sized red suns during the silver age, and they flush out the yellow sunlight from his body very quickly. Starfire from the Titans is also solar powered. If she powered up from a red star, she should be a very effective anti-kryptonian weapon.
As I've always interpreted it, red sunlight doesn't actively weaken Kryptonians; it's just that it lacks the frequencies of yellow sunlight that supercharge their cells. After all, Kryptonians evolved under a red sun and lived perfectly normal lives there, so it's not like it has a toxic or subtractive effect, just a neutral one. So a positive effect (yellow sun) plus a neutral effect (red sun) is basically 1 + 0 = 1. Therefore, it should be no different from being in a yellow-star system. Now, granted, some versions show Superman only weakening gradually under red sunlight as his solar supercharge wears off (e.g. Superman: The Animated Series: "Solar Power"), while others show him or Supergirl losing their power instantly when exposed to red light (Supergirl does this). In those latter versions, we could suppose that the "natural" Kryptonian-style sunlight tricks their metabolism into reverting to normal mode or something, so their powers are immediately shut down. But that still wouldn't matter much in a binary system. Most red stars are dwarfs, not giants, and are far smaller and dimmer than most yellow stars. Certainly a red dwarf is far more likely in an inhabited system, since the swelling of a main-sequence star into a red giant would likely have rendered any habitable-zone planets unlivable or destroyed them. So if a yellow star had a red-dwarf companion, or a distant enough red giant companion that the planet was able to survive, then the red star's light would be pretty much swamped by the yellow star's light anyway. The only way it would be a concern is if it's a wide binary with the planet orbiting the red star, with the yellow star distant enough to be just a bright point source in the sky. That would be tantamount to being in a red-star system, with maybe a slight power boost while the yellow star was visible. Conversely, if the planet orbits the yellow star, then maybe if the red star is in the sky after the yellow star sets, and if it's close enough to be a significant illumination source and we're going with the "instant metabolic reset" theory, then it could leave Superman (or -girl) temporarily weakened while it was in the sky.
It‘s not like he isn’t exposed to the light of thousands of red suns all the time anyway. They are just so much weaker due to distance. Of course yellow suns and every other color just as much. The proximity to our yellow sun is what’s doing it, where it is the dominating radiation source. in a binary system it might depend on which star dominates the Sky. We could end up with a situation where he has his powers, but a weaker version of them. He could be a Superman who is merely able to leap tall buildings instead of outright flying, and just as fast as a speeding bullet and only strong enough to stop a train.
Which, again, would be the yellow star in most cases, since red stars are cooler and dimmer, and usually smaller as well. That's presumably the whole reason for the power difference -- yellow sunlight includes shorter, more energetic wavelengths and is generally more intense, and thus provides more power to Kryptonian cells. Which means that, logically, Kryptonians should be even more supercharged under a blue or white star (type O,B, A, or F). I think some relatively recent comics have shown that blue stars amp up Superman's powers even more, but in some really weird, silly way like giving him "Superman vision," the power to shoot eye beams that gave other people superpowers.