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Every two body orbit involves a barycenter that is not exactly in the center of either body (i.e. every planet/sun combo "orbit around one another"). The uniqu
by klank 3y ago
Every two body orbit involves a barycenter that is not exactly in the center of either body (i.e. every planet/sun combo "orbit around one another").
The unique aspect of Jupiter is that the Jupiter/Sun barycenter is outside of the surface of the Sun. This requires an incredible amount of mass in Jupiter.
- kibwen 3y agoFor the same reason that we demoted Pluto to dwarf-planet status, I'm fully prepared to elevate Jupiter to super-planet status for this fact alone.
- undersuit 3y agoWhat if we demote the sun? It is in a class of stars that is too small to have a internal barycenter for all it's planets, there are larger stars that do because planets like Jupiter have a limit before they start being classed as Brown Dwarfs.
- digging 3y agoThe sun is a pretty ordinary star. It's not nearly so small that it should be demoted or we would be rewriting our entire stellar classification system.
- pfdietz 3y agoThe sun is actually fairly unusual for a star. Most stars are smaller than the sun.
- anticensor 3y agoAnd more variable than the Sun.
- digging 3y agoSure, greater-than-dwarf-sized stars are actually the minority. But among greater-than-dwarf-sized stars the sun is fairly typical.
- malfist 3y ago74% (don't quote me here, this is from memory) of stars are less massive red dwarfs. Only about 4% (again don't quote) stars fall into our weight class.
- digging 3y agoYes but I mean our sun is not at the low end of that spectrum. As you say, most stars are smaller than the sun. So rewriting the system would mean that the majority of stars are no longer stars.
- undersuit 3y agoWe're not just rewriting the system for the sun though. There have to be many stars that aren't large enough to have internal barycenters for all their planets. Maybe we do want to define the stars that have this trait and not the planets in their solar systems.
- dragonwriter 3y ago> What if we demote the sun? You mean, make it a “dwarf star”? It... already is.
- kbutler 3y agoWould the category of "mid-size star with a large planet" be useful? Maybe if it is predictive of having earth-like planets in the habitable zone...
- goatlover 3y agoWould a small enough celestial object orbiting the sun have a barycenter that is effectively the center of the sun? How small would it need to be?
- tremon 3y agoHow close is "effectively"?
- kuchenbecker 3y agoWithin the radius of the smaller body within the larger body.
- goatlover 3y agoI'll go with that answer.
- throwbadubadu 3y agoSure, just depends on your definition of "effectively" if that's a pea or a moon?
- deleted 3y ago[deleted]