If it just lost momentum, it would fall onto the sun, but it would take about 29 years to fall, meaning it most likely fell into another planet possibly derailing it, too, and so on. And this doesn't consider that its gravitation would likely start affecting orbits long before it actually hits anything
My first thought was. If a planet the size and location of neptune just vanished.
What effects would that have on the rest of the solar system. Given Pluto was found due to its effect on neptune I think. And this is a relatively small mass on a larger one.
I'd be very interested to hear opinions on what the sudden disappearance of a planet would do.
Just to put everyone's mind at rest. I am not an evil scientist working on quantum teleportation.
That said. Feel free to consider other planets. ... such as jupiter. ;)
Your forget that the sun isnt stationary. Our whole solar system would slowly move away from anything truly stationary while we continue our orbit of the milky way. It would take a good while but after a few years neptune would be pretty far from the sun. If it got stopped while in the path of the sun tho, it might just get run over by the sun and we would all die.