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Oh my five suns. ;) >The pair of stars orbit around a mutual centre of gravity, but are separated by more than the distance of Pluto's orbit around the Sun. But what could they be orbiting around?
> But what could they be orbiting around? >> a mutual centre of gravity The math of gravity is fascinating. Objects can orbit each other, with nothing in the middle.
Ok, so objects orbit not other objects but rather centres of gravity. This means that the system in question could have planets with small orbits (like the earth's for example) orbiting that system's centre of mass despite the stars being many AUs away from it. It may be unlikely but it's certainly possible, right? Am I missing something that'd make this impossible? Because that would be incredibly cool! edit: I'm as…
There could be stable point's in the middle, I don't know about that. Most certainly it can't be described by this approximation.
One more and a planet to go ( https://en.wikipedia.org/wiki/Nightfall_(Asimov_short_story_... , https://www.uni.edu/morgans/astro/course/nightfall.pdf )
Ok, so objects orbit not other objects but rather centres of gravity. This means that the system in question could have planets with small orbits (like the earth's for example) orbiting that system's centre of mass despite the stars being many AUs away from it. It may be unlikely but it's certainly possible, right? Am I missing something that'd make this impossible? Because that would be incredibly cool! edit: I'm as…
Orbiting around the center of gravity only can be applied for two body systems. For many body systems it can be applied too as a careful approximation (like in the article). The movement of a small planet in the middle couldn't be described by this however, since it's an approximate three body system now (the two pairs and the planet)- There could be stable point's in the middle, I don't know about that. Most certain…
Oh my five suns. ;) >The pair of stars orbit around a mutual centre of gravity, but are separated by more than the distance of Pluto's orbit around the Sun. But what could they be orbiting around?
Their center of gravity, say about here: o O---------------o ^ Pluto and Charon do it as well, even Earth and Moon to a small degree.
Ok, so objects orbit not other objects but rather centres of gravity. This means that the system in question could have planets with small orbits (like the earth's for example) orbiting that system's centre of mass despite the stars being many AUs away from it. It may be unlikely but it's certainly possible, right? Am I missing something that'd make this impossible? Because that would be incredibly cool! edit: I'm as…
A example for a triple star system would be Alpha Centauri and Proxima Centauri, the closest star system to the Solar System. Alpha Centauri is a double star and Proxima Centauri orbits it at a huge distance, such that the seperation between the components of Alpha Centauri is no longer important for the orbit.
So it is certainly possible to find stable orbits, even in a very unusual star system like this one. But they are ( except in very rare cases), just elliptical orbits at huge distances.
Ok, so objects orbit not other objects but rather centres of gravity. This means that the system in question could have planets with small orbits (like the earth's for example) orbiting that system's centre of mass despite the stars being many AUs away from it. It may be unlikely but it's certainly possible, right? Am I missing something that'd make this impossible? Because that would be incredibly cool! edit: I'm as…
No, this does not mean that at all! An orbit asks for a centripetal force. In heliocentric systems this force is the gravity of the star (considering the gravity of the orbiting body to be negligible). Here, pairs of stars are kept into orbits and for each star the force that keeps it around is not only the force of gravity of the other star, but also that of its own (since it's not negligible any more). A third body can not have a stable motion around the "centre of mass" between those stars because there does not exist any force to keep it there. Any body between the orbiting stars will be under forces that will pull it towards the stars. It may at most stay "stable" in the middle, where the gravity forces of the around-orbiting stars cancel each other.
One more and a planet to go ( https://en.wikipedia.org/wiki/Nightfall_(Asimov_short_story_... , https://www.uni.edu/morgans/astro/course/nightfall.pdf )