When a new star is born, it is surrounded by a disc of material. From this matter are created small planetesimals and later planets and other bodies like moons, comets and asteroids. According to a new study it is possible that more than a half of this material could end up in space between stars, as orphan planets or interstellar asteroids.
New simulations show, that there could be much more interstellar comets or asteroids in the Solar system than initially expected. To this day humanity recognized only 2 obejct coming from outside the Solar system: Oumuamua in 2017 and Borisov in 2019. However the theoretical Oort cloud around our Solar system could be full of them.