Jupiter's asteroid BZ is an interstellar visitor orbiting near the planet since 4.5 billion years.
BZ’s orbit is retrograde, unlike most of the bodies in our solar system. It is not orbiting Jupiter as a moon would, but only crossing Jupiter’s orbit while orbiting the sun. Bz’s orbit also has the same duration as that of Jupiter (one year of Jupiter). THis is this , that is, 4.5 billion years ago.