Important donut question.

[rah]

I was wondering if a planet in a binary star system could "switch" stars. Seems it's possible, but not stable. I think such a scenario would make an interesting setting for a story.

Check out Bowl of Heaven.
Starting premise Earth start out as a binary system and Ancient Earthlings used the second sun to travel the universe. Yes, it takes a lot of believing.

[Lorizael]

The article in question.

The first challenge to overcome is forming a planet in the first place.

Yeah, a couple of things I read said circumbinary planets don't form that way but migrate into the situation.

[Lorizael]

I'm testing out the switcheroo in my gravity simulator now. During the first close approach, the planet survived and continued with its parent star but with a highly elliptical orbit. During the second close approach, its parent ate it.

[Lorizael]

Got it to switch on the first close approach. Got ejected on the second.

[DaShi]

Now I want to eat a planet.

[molly bloom]

Now I want to eat a planet.

Snack on Planet Hollywood.

[Dinner]

I have a question about circumbinary planets. So you have two stars orbiting each other, normally smaller stars who's individual orbits of each other (or rather their mutual center of gravity), and planets can (obviously) only form outside of the orbit of those two stars. Would such planets have strange orbits (I.E. a really elongated ellipse) or maybe even a slightly perturbed orbit depending upon where each star was at any given time? Like maybe the two stars were playing tug a war with it? Also is it even theoretically possible that such a planet could be rocky (rather than gaseous) and be in the habitable zone?

If it is possible then it might make a really cool fantasy world setting.

[Lorizael]

The answer is there's no simple solution to what a circumbinary planet's orbit is going to look like. If the planet is far enough away from its two parent stars, it treats them like a point mass and would have a fairly ordinary orbit, perhaps eccentric. The closer in the planet gets, the less stable its orbit becomes.

Configurations that aren't ellipsoid are in general not going to be very stable. That much can be said to be true just based on an anthropic principle. After four and a half billion years, we pretty much only see elliptical orbits in the solar system, yet there were probably pieces of matter doing some very strange things in the early periods. As far as why this is true (and why it isn't in the case of the exceptions that do exist), I don't have the math to know (except that I understand why Newton's gravity creates elliptical orbits). Perturbation theory holds the answers, I believe.

[Lorizael]

And yes, the planet could probably be rocky and in the habitable zone, but we're still not very good at detecting those types of planets, so it's hard to say what the frequency might be.

[Sava]

Sorry. Beer is proof that God exists and that he wishes us to be happy.

God made weed. Man made beer.

Who do you trust?

[molly bloom]

God made weed. Man made beer.

Who do you trust?

In some ancient civilizations, women made the beer.

[Sava]

You didn't help beer's case.

[molly bloom]

You didn't help beer's case.

Men saw it, drank it, and came back for refills.

M'Lud, defence rests.

[Sava]

General Ludd

[molly bloom]

General Ludd

Ned Ludd.

Noye's Fludd.

The Bludy Serk.

Erm, yeah...