Stability of Polar Solar Orbits: Can a Planet Change its Host Star?

[Noisy Rhysling]

I need a planet to be orbiting it's sun in a polar orbit. Is this a stable configuration?

 

[rootone]

It's unlikely that this could easily arise since a star and it's associated planets all form out of the same collapsing dust\gas cloud.
So the larger bodies which form tend to all inherit similar angular momentum.
I don't think there is anything which absolutely rules out that a planet might end up in a polar orbit of it's parent star.
In stellar systems having more than two large stars gravitationaly bound, it sounds plausible.
Then again, that setup might lead to chaotic planet orbits, although a planet might be in a polar orbit of one star for a while.

 

[Noisy Rhysling]

Okay, "natural" is out, what about a captured planet? Would a planet who wanders into a system have a chance of achieving a stable polar solar orbit? This would be the only planet in the system, with very low junk around the star before the wanderer arrived.

 

[Bandersnatch]

If it's the only planet, then how do you decide whether the orbit is polar or planar?

Rogue planet capture needs a third body to interact with, otherwise it'll just continue on a hyperbolic trajectory away from the system.

 

[Noisy Rhysling]

If it's the only planet, then how do you decide whether the orbit is polar or planar?

Rogue planet capture needs a third body to interact with, otherwise it'll just continue on a hyperbolic trajectory away from the system.

Doesn't our sun rotate?

 

[Noisy Rhysling]

Rogue planet capture needs a third body to interact with, otherwise it'll just continue on a hyperbolic trajectory away from the system.

Unless it doesn't have the relative velocity to escape the gravity well of the star, right?

 

[Bandersnatch]

Doesn't our sun rotate?

All right, if that's how you define planar, then polar orbits around a star are stable for most practical purposes. If there were any other massive bodies orbiting in the plane or solar rotation, then these would destabilise the polar orbit.

Unless it doesn't have the relative velocity to escape the gravity well of the star, right?

Consider that the planet comes from far away, from outside of gravitational influence of the star. As it falls into the gravity well it'll gain just as much velocity as it'll lose on the way out. I.e., if it was not bound to the star in the first place, then it won't become bound at all. Not without interaction with some third body.

 

[Noisy Rhysling]

All right, if that's how you define planar, then polar orbits around a star are stable for most practical purposes. If there were any other massive bodies orbiting in the plane or solar rotation, then these would destabilise the polar orbit.

I don't know another way to define it. What have I missed/

Consider that the planet comes from far away, from outside of gravitational influence of the star. As it falls into the gravity well it'll gain just as much velocity as it'll lose on the way out. I.e., if it was not bound to the star in the first place, then it won't become bound at all. Not without interaction with some third body.

I'm picturing the wanderer spiraling into the system, not a dive in/dash out incident.

 

[Bandersnatch]

I don't know another way to define it. What have I missed/

No, it's all fine.

I don't know another way to define it. What have I missed/I'm picturing the wanderer spiraling into the system, not a dive in/dash out incident.

It can't just spiral in without a way to lose energy. If you've got a free-floating planet that encounters a lone star, then it MUST fall towards it on a hyperbolic trajectory, swing around, and leave with the same velocity relative to the star as it had at the beginning.

What you could do, is have the star begin with some planets, one or two, have the planet fall in, make a number of close encounters with the original planetary system, and as a result end up with the original planet(s) ejected and the rogue one captured.

 

[Noisy Rhysling]

That would work. So it would be possible under certain circumstances... Interesting. Now to get Our Hero to figure out what's strange about the system. Thanks.

 

[snorkack]

It tends to be unstable due to Kozai resonances.

 

[Bandersnatch]

It tends to be unstable due to Kozai resonances.

There's no third body in this setup.

 

[Noisy Rhysling]

Yeah, I'm thinking the system is "strangely barren" with the exception of our oddly orbiting planet.

 

[Noisy Rhysling]

Next thing, is a star with almost no "junk" around it uncommon, unlikely, no big deal, or "never going to happen"?

 

[hsdrop]

Next thing, is a star with almost no "junk" around it uncommon, unlikely, no big deal, or "never going to happen"?

well you could have a neighboring star blow up and blow most to all the junk out from around it ( just a thought)

 

[Noisy Rhysling]

With so many double star sysem...

 

[Lren Zvsm]

It's unlikely that this could easily arise since a star and it's associated planets all form out of the same collapsing dust\gas cloud.
So the larger bodies which form tend to all inherit similar angular momentum.
I don't think there is anything which absolutely rules out that a planet might end up in a polar orbit of it's parent star.
In stellar systems having more than two large stars gravitationaly bound, it sounds plausible.
Then again, that setup might lead to chaotic planet orbits, although a planet might be in a polar orbit of one star for a while.

What if our polar orbit planet originated from outside the solar system? Rogue planets could come to our system by accident. Sufficiently advanced intelligent life might decide that planets made the best interstellar vehicles.

Even granted these possibilities, what if the orbit of our polar orbit planet intersected with the-plane-of-the-elliptic when it was nearby? Could the polar orbit visitor change the orbits of planets on the plane of the elliptic?

 

[snorkack]

Most hot Jupiters actually orbit at large inclinations to the star rotation, where that can be ascertained, and many are retrograde. So nothing unusual about it, merely inexplicable.
As for a "rogue" planet, look at Hale-Bopp comet. Inclination quoted as 89,4 degrees, so practically polar.
The one passage changed the aphelion distance from 525 AU to 370 AU.
Well, an equivalent passage of Solar System for a comet incoming on a parabolic orbit, first ever passage, could have captured it to a bound orbit, maybe 1250 AU aphelion distance!
And since the encounter was said to be with Jupiter, Jupiter would have had much the same effect if Hale-Bopp comet had had mass equal to that of Earth.
What would have happened if Hale-Bopp comet had had mass comparable to that of Saturn? Then it would have had a nonnegligible effect on orbit of Jupiter on its turn...

 

[stefan r]

The planet could have orbited some other star. During a close encounter between the stars the planet could switch. The planet's orbit around its new host would be random with respect to the host's rotation.