A solar system comprises a star (or combination of gravity bound
stars) and their orbiting planets.
We think the majority of stars are solar systems an we have
detected p…lanets orbiting stars other than the Sun.
However in the process of forming a solar system we believe that
planets my be permanently ejected from orbiting their stars and
flung off into interstellar space. These planets would therefore
indeed be outside any solar system. (MORE)