Just to clarify, what exactly do you mean by orbiting the center of the galaxy? Do you mean that in the same sense that earth orbits the center of the galaxy?
No, The earth orbits our sun. The sun is a star that orbits the galaxy center, a Black Hole. The rogue planet does not have a star. It orbits the galaxy center like stars do. The rogue planet has lost it's star.
Do you agree that a planet ejected from an orbit around Alpha Centauri A and heading in our direction would be called a rogue?
There is no evidence for this. Alpha Centauri A is the closest star system to our Sun 4.37 light years away. A planet headed our way would be attracted to gravitational pull of our sun, and not a rogue planet. It likely would have an elliptical orbit associated with our sun or the Alpha Centauri A. This is very very unlikely.
There was a large cigar shaped asteroid called Oumuamua that passed through our solar system recently that had a trajectory associated with another unknown star?, but not Alpha Centauri A. The gravity of our sun turned the asteroid into a different trajectory.
All stars, planets, meteors, galactic clouds, or other heavenly bodies in the our galaxy or any other galaxy are under the influence of gravity, ultimately the galactic black hole center, Planets and meteors, are orbiting stars, except for rogue planets, which have lost their star and orbit the galactic center.
Gravity rules!
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