Triton's long lost twin.

[Maria Sirona]

As we all should know, the generally accepted theory about Neptune's moon Triton is that it used to be the other half of a binary dwarf planet. This Triton-????? binary eventually ended up around Neptune, with one half of the pair being ejected and the other- Triton- getting stuck in orbit around Neptune.

But what about the other twin? What happened to it, and where did it end up? 

My (very quickly and haphazardly thought of) idea, is that the other twin is Pluto. I mean, its orbit is quite close to Neptune's, so it would make sense, right? 

Discuss.

[kerbiloid]

(Not about Triton, but about the whole idea).

Wait... The Moon... If Teia Proto-Moon was a twin dwarf planet. then it could be capturd without collision, and its counterpart was thrown away.

***

The Plutonian orbit strangely coincidents with the Titius-Bode predicted orbit of Neptune.

[Piscator]

At least today, Pluto doesn't come very close to Neptune due to different inclinations of their orbits. Also, Pluto would have had to acquire its current set of moons afterwards as the system wouldn't have survived the encounter.

 

It seems more likely that Tritons hypothetical binary partner met its fate during one of the subsequent encounters with Neptune and was either ejected out of the solar system or inwards where it either disintegrated or collided with another body.

[insert_name]

Considering Pluto already has a twin and several moons I doubt that it has lost a member of its system to Neptune

[darthgently]

31 minutes ago, insert_name said:

Considering Pluto already has a twin and several moons I doubt that it has lost a member of its system to Neptune

Not what OP or replies posited from what I can tell.  I think OP was positing that Pluto could be the lost twin maybe?

[Maria Sirona]

On 3/3/2023 at 6:58 PM, insert_name said:

Considering Pluto already has a twin and several moons I doubt that it has lost a member of its system to Neptune

 

On 3/3/2023 at 7:32 PM, darthgently said:

Not what OP or replies posited from what I can tell.  I think OP was positing that Pluto could be the lost twin maybe?

What i postulate is that Pluto is Triton's twin, and in the same encounter Pluto would have both lost Triton to Neptune, and captured Charon fro, Neptune.

Yeah, the Charon part might go a bit too far and be distracting

[JoeSchmuckatelli]

On 3/3/2023 at 11:32 AM, darthgently said:

Not what OP or replies posited from what I can tell.  I think OP was positing that Pluto could be the lost twin maybe?

Roight - bawt, 'ow does Pluto be the twin in the 'Leaving Triton at Neptune' scenario, bawt then get anover twin to become the Planet/NawtPlanet we awl know and luv? 

 

(Sorry - been watching too many British crime shows) 

[Piscator]

On 3/3/2023 at 6:32 PM, darthgently said:

Not what OP or replies posited from what I can tell.  I think OP was positing that Pluto could be the lost twin maybe?

Same thing, really. Whether Triton lost Pluto or Pluto lost Triton is merely a matter of perspective. The important question is whether an event strong enough to separate a hypothetical Pluto-Triton binary would leave Pluto's sub-moons untouched. Since the Plutonian system is apparently rather compact, this doesn't seem completely out of the question and as mentioned, there's always the possibility that Pluto acquired its moons in a later collision event. It doesn't make the whole idea more likely though, especially since there's little evidence pointing to Pluto in the first place. After all, there are more than a dozen objects that pretty much share Pluto's orbital characteristics and there are a whole lot more with perihelia inside Neptune's orbit which would be as likely candidates. And this doesn't even take the possibility into account that Tritons mysterious partner was simply lost or destroyed - either during the separation event itself or during a later encounter with Neptune - which seems far more likely.

[kerbiloid]

What if Neptune was happily orbiting its legal Titius-Bode orbit (now belongs to Pluto), and both Triton and Pluton were its moons.

Then something heavy threw away Neptune together with some moons, while Pluto stayed placeholding Neptune.

Say, a fast blackhole passed nearby. I did similar things in the Universe Sandbox.

Edited March 5, 2023 by kerbiloid

[lajoswinkler]

If there was one, Triton's twin might've been gobbled up by Neptune.

[Maria Sirona]

15 hours ago, lajoswinkler said:

If there was one, Triton's twin might've been gobbled up by Neptune

I don't think so, the theory states that Triton's twin gained speed while Triton lost it, so Neptune can't have pulled it in by gravity. This leaves the possibility of it simply having happened to go in the direction of Neptune... I don't think that's very likely.

17 hours ago, kerbiloid said:

Say, a fast blackhole passed nearby. I did similar things in the Universe Sandbox.

Unless the black hole travelled at a significant fraction of the speed of flight (which it probably didn't), it would still be nearby and noticeable. Nope, doesn't seem likely.

[kerbiloid]

2 hours ago, Maria Sirona said:

Unless the black hole travelled at a significant fraction of the speed of flight (which it probably didn't),

Oberth maneuver in Sgr A* close proximity.

[sevenperforce]

3 hours ago, Maria Sirona said:

I don't think so, the theory states that Triton's twin gained speed while Triton lost it, so Neptune can't have pulled it in by gravity. This leaves the possibility of it simply having happened to go in the direction of Neptune... I don't think that's very likely.

Agreed. I don't believe that there is any angle from which a binary can enter Neptune's SOI and end up with one member of the binary trapped in a retrogade Neptunian orbit where the trajectory of the other member of the binary intersects Neptune's surface.

[lajoswinkler]

On 3/6/2023 at 1:56 PM, Maria Sirona said:

I don't think so, the theory states that Triton's twin gained speed while Triton lost it, so Neptune can't have pulled it in by gravity. This leaves the possibility of it simply having happened to go in the direction of Neptune... I don't think that's very likely.

But not zero.

[darthgently]

18 minutes ago, lajoswinkler said:

But not zero.

"So you're saying there's a chance..." 

[sevenperforce]

1 hour ago, lajoswinkler said:

On 3/6/2023 at 7:56 AM, Maria Sirona said:

I don't think so, the theory states that Triton's twin gained speed while Triton lost it, so Neptune can't have pulled it in by gravity. This leaves the possibility of it simply having happened to go in the direction of Neptune... I don't think that's very likely.

But not zero.

It is zero, actually.

No matter what direction the Triton-containing binary was coming from in order to make its close approach to Neptune, it would have had to experience the momentum exchange at what would become the periapsis of the resulting (originally very eccentric) Triton orbit. The way this works, Triton was bent toward Neptune and slowed into an elliptical orbit, while Triton's twin (whether larger or smaller) was bent away from Neptune and accelerated. There's no twin trajectory that intersects Neptune's surface here.

[tomf]

Couldn't you have a scenario something like this?

Triton and it's partner are in a fairly right orbit whose barycentre passed just above Neptune. At pe the partner is orbiting with the direction of travel and Triton is orbiting in the opposite direction so Triton is in fact moving at less than escape velocity and the partner at more than escape. however the partners trajectory actually passes through Neptune and it is destroyed, leaving Triton in a very eccentric orbit.

 

[lajoswinkler]

38 minutes ago, sevenperforce said:

It is zero, actually.

No matter what direction the Triton-containing binary was coming from in order to make its close approach to Neptune, it would have had to experience the momentum exchange at what would become the periapsis of the resulting (originally very eccentric) Triton orbit. The way this works, Triton was bent toward Neptune and slowed into an elliptical orbit, while Triton's twin (whether larger or smaller) was bent away from Neptune and accelerated. There's no twin trajectory that intersects Neptune's surface here.

What if it was a case of two quite distant bodies (distance > Neptune's Roche limit), barely held together, coming close to Neptune so that Triton was further away and twin was inside Roche limit?

I can see few scenarios where twin is destroyed, maybe forming a temporary ring that later get eaten by Neptune, or just being crumbled and sprayed outwards.

[sevenperforce]

48 minutes ago, lajoswinkler said:

What if it was a case of two quite distant bodies (distance > Neptune's Roche limit), barely held together, coming close to Neptune so that Triton was further away and twin was inside Roche limit?

I can see few scenarios where twin is destroyed, maybe forming a temporary ring that later get eaten by Neptune, or just being crumbled and sprayed outwards.

You're not intuitively wrong about the latter scenario -- it's generally believed that Triton gobbled up the bulk of any moons Neptune had prior to the capture. A big moon in retrograde orbit will do that.

However, the scenario you're suggesting wouldn't work because if Triton's twin was ripped apart into a ring by Neptune's tidal forces, conservation of momentum would have given Triton more than enough extra umph to be yeeted well out of Neptune's sphere of influence. Remember that the binary would have been coming in on a hyperbolic trajectory to begin with, and so if one thing is captures, the other thing has to leave on an even-more-hyperbolic trajectory.  

Clarification: hyperbolic with respect to Neptune's SOI, not hyperbolic with respect to the sun.

[sevenperforce]

20 hours ago, tomf said:

Couldn't you have a scenario something like this?

Triton and it's partner are in a fairly right orbit whose barycentre passed just above Neptune. At pe the partner is orbiting with the direction of travel and Triton is orbiting in the opposite direction so Triton is in fact moving at less than escape velocity and the partner at more than escape. however the partners trajectory actually passes through Neptune and it is destroyed, leaving Triton in a very eccentric orbit.

Triton isn't terribly large, and so its co-orbital velocity in a binary system would be fairly low. Neptune, on the other hand, is quite large, and the binary system would be accelerated inward by Neptune's gravity with the greatest speed at periapsis. Even with perfect alignment, I don't see how the co-orbital velocity would be great enough that subtracting it from the increased periapsis speed would actually bring Triton into an orbit of Neptune.