© arXiv:1807.02960 [astro-ph.GA]Effect of a prograde, parabolic fly-by of a star with a) M=0.5 M, b) M2= 1, M and c) M2= 5 M that is inclined by 60 degree and has a angle of periastron equal zero. The perihelion distance is always chosen in such a way as to lead to a 30-35 AU disc. The top row indicates the eccentricity distribution of the matter with a central area of most particles on circular orbits and more eccentric orbits at larger distances form the Sun. The eccentricities are indicated by the different colours given in the bar. The origin of the different eccentricity populations in the original disc can be seen in bottom row, where matter indicated in grey becomes unbound from the Sun. Note that in c) the path of the perturber is not visible because it is outside the shown frame.
In recent years, space scientists have begun to suspect that something out of the ordinary happened to our solar system during its early years. Many have begun to wonder why there is not as much material in the outer solar system as logic would suggest. Also, why is Neptune so much more massive than Uranus, which is closer to the sun? And why do so many of the smaller objects in the outer solar system have such oddly shaped orbits? In addressing such questions, many space scientists have begun to wonder if a star might have wandered by during the early years of the solar system-coming just close enough to pull some of the objects in the outer parts of the solar system from their prior positions.
The idea of a rogue star has been debated for some time, but the theory has not been embraced because of the timing-if a star had wandered by, it would have been approximately 10 million years after the birth of our galaxy. But objects in the outer solar system would have still just been forming, making it unlikely that they would have been impacted by a rogue star.
Comment: Further reading: