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A comment on 'Mathematically perfect' star system being investigated for potential alien tech. Parent comment

Re:'Mathematically perfect' star system being investigated f... by marcosdumay on Wednesday February 28, 2024 @10:27AM (#39539161)
Well, perfectly spaced is the only way 3 planets can share the same orbit.

And if we go for a gas giant and two small planets, there are probably many of those out there. We almost got one such trio.

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Re:'Mathematically perfect' star system being investigated f... by pavel_lishin on Wednesday February 28, 2024 @11:05AM (#39539764)
Tell that to Janus & Epimetheus: https://en.wikipedia.org/wiki/Janus_(moon)
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Re:'Mathematically perfect' star system being investigated f... by hinkley on Wednesday February 28, 2024 @10:46AM (#39539467)
Perfectly spaced is not a stable orbit.

https://en.wikipedia.org/wiki/Lagrange_point

You want L4 and L5 for that.

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Re:'Mathematically perfect' star system being investigated f... by Retric on Wednesday February 28, 2024 @11:08AM (#39539826)
L4 and L5 are unstable unless there is an extreme, as in many orders of magnitude, difference in the masses involved.

At equal mass the separation increases until they are all equidistant from each other assuming a completely circular orbit.

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Re:'Mathematically perfect' star system being investigated f... by zeroonetwothree on Wednesday February 28, 2024 @11:06AM (#39539775)
That applies to a small body with two large ones, not three similarly sized planets.
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Re:'Mathematically perfect' star system being investigated f... by hinkley on Wednesday February 28, 2024 @10:32PM (#39546149)
Ah, you are correct.

Is there any statically stable shared orbit for planets though? The first wobble and they start accelerating toward each other don't they?

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