Main Question or Discussion Point
Are there any stars in the solar neighborhood that orbit the galactic center in the opposite direction?
These are 'wandering stars', which in greek is asteria planetes, from which the English word 'planets' derives.What about stars with retrograde rotation (like Venus and Uranus)?
No, people answered you question: Are there any nearby stars in retrograde orbit?Sorry for the confusion. I understand the difference between retrograde orbit and retrograde rotation. After my original question was answered that there are no known stars in the Milky Way with a retrograde orbit, I then asked if any stars have a retrograde rotation.
Interesting! From Wikipedia's article Retrograde and prograde motion:There are however billions of stars in retrograde galactic orbits in the milky way, most of them are in the halo, in-falling star streams from dwarf galaxies being absorbed or in the galactic bulge. They are mostly tens or hundreds of thousand light years away from Earth but at just 12 ly one star that is hard to exclude is the M1 sub-dwarf Halo star known as Kapteyn's Star (A&A paper).
Stars with a retrograde orbit are more likely to be found in the galactic halo than in the galactic disk. The Milky Way's outer halo has many globular clusters with a retrograde orbit and with a retrograde or zero rotation.
I'm merely speculating here, but I guess a galactic collision between a big galaxy like ours and a much smaller galaxy (so that the big galaxy does not lose it's individuality) could produce retrograde motions of stars.Are there any stars in the solar neighborhood that orbit the galactic center in the opposite direction?
While technically correct, it hides the causal order. The Milky Way started with gas clouds with a random total angular momentum, which then assembled to a disk over time based on collisions between gas clouds. Those clouds then formed the stars in the disk with prograde motion. Stars with retrograde motion were captured from outside or got their motion from violent events in binary systems (e. g. their partner star exploded in a supernova) or similar events.Stars with a retrograde orbit are more likely to be found in the galactic halo than in the galactic disk.