A dwarf planet coming within 11 AU of the sun over the next 10 years

I suppose that makes sense... if something is in an orbit that's flattened down until it's only slightly off from being a straight line in and out, then any very slight perturbations could really affect how close it comes to the sun on the next pass.

The sun moves too a little bit, due to the pull of the planets. Maybe it's enough to make a difference?

Landing a telescope on it would only make sense if orbits around it are highly unstable (like our moon) and if the dwarf planet was geothermally active so energy on the surface would be "easy" to extract (which comes with it's own set of headaches). Orbiting it with a "big for space probes" camera would most likely give us more interesting data.

Using the plant as a Coronagraph if orbiting far out is another interesting idea, but using a near earth astroid would be a better idea as the telescope could be powered by solar panels they.

I don't think we should be shaming asteroids in this way - how about "gravitationally challenged"?

Just for fun, I did some ballpark calculations. Let's consider the simpler problem of just putting 2014 UN271 into a circular orbit around the sun at its periapsis of 11 AU.

Calculating the exact path of an orbiting body under thrust is difficult. But the object will be within 1% of the desired orbital radius for roughly a 22-degree arc of its orbit centered on the periapsis, during which time its path will be closely approximated by a circular arc 648 million km long.

Let's say that over the course of this arc, we want to slow it from its initial speed of 12.7 km/s to the required circular orbital speed of 9.0 km/s. That means we need a continuous deceleration of roughly 0.00006 m/s^2 over a period of 2 years.

Assume that we'll produce this thrust by launching material from the object into space using mass drivers. By the Tsiolkovsky rocket equation, the smaller the fraction of the object that we want to use as reaction mass, the larger our "exhaust" velocity has to be. If we want to only lose 10% of the total starting mass, we need our exhaust velocity to be about 10x the total desired delta-V -- that is, 37 km/s, or roughly 0.01% the speed of light. This is a tall order, but let's say we can somehow solve the engineering problems and build a linear accelerator that can get rocks moving that fast.

Assume the object is 160 km in diameter and made entirely of ice, giving it a total mass of about 2.0e18 kg. The total required momentum change is therefore about 7.5e21 kg m/s, and the required energy input is 1.4e26 J. If we assume constant thrust for two years, this means we would have to launch about 3.2 million tons of material per second, averaging out to 2.2 exawatts of power required.

To put this number in perspective, it's several million times higher than the average electricity generation of the entire planet Earth. To generate this much power using 100%-efficient solar panels, at a distance of 11 AU from the sun, you would need a solar array approximately half the diameter of the sun itself.

So a direct propulsion approach, at least, doesn't really seem like it's within the realm of feasibility.

You get it into an orbit that will have several close encounters with Mars or other planets with atmosphere and you do a bit of aerobraking/thrusting on each pass.