So two bodies can't have a gravitational interaction which throws one off of the plane of the ecliptic and just 'happens' to also have a circular orbit?
We've only got one body here to go on. If it was an entire accretion disk remnant (lots of co-planar bodies in circular orbits) off of the plane of the ecliptic, then we'd have a major theory malfunction.
It could happen -- but the sticking points are that for the orbit to be as circular as this, the perturbing body must:
1. have been about the same distance from the sun when the conjunction occurred (the new orbit has to include the point of close approach);
2. have a pretty circular orbit (else it would probably have been spotted by now);
3. has got to be fairly large.
So where is the perturbing body?
We've only got one body here to go on. If it was an entire accretion disk remnant (lots of co-planar bodies in circular orbits) off of the plane of the ecliptic, then we'd have a major theory malfunction.
True. It's an odd duck -- and there's no good answer to how it got the way it is. Now that they've found this guy outside of the ecliptic they might try to find others. If they do, then indeed there's a major theory malfunction. If not, then they've got to explain this guy's orbit.