University of Rochester astronomer Eric Mamajek along with his collaborators, have published a paper in The Astrophysical Journal Letters (http://iopscience.iop.org/2041-8205/800/1/L17?fromSearchPage=true) that analyzed the trajectory and velocity of low mass star systems. They discovered that a dim star, given the name “Scholz’s Star”, probably passed through a vast cloud of comets on the outer edge of our solar system. Known as the Oort Cloud, this vast reservoir of trillions of comets lays far beyond the orbit of Pluto.
Scholtz’s Star was originally brought to the attention of public figures on Facebook who had already expressed interests in the astronomers discussions when it was determined that the star had a very slow motion across the sky even though it was only 20 light years distant. This meant it was moving directly away from the Solar System. Using an extrapolation technique, they calculated it moved directly by us at a distance of only 0.8 light years away, 70 millennia ago. For reference, the closest star today is Proxima Centauri, five times as distant.
Because the star was active magnetically, it probably underwent periods of “flaring”, or bright periods of intensity. This made it possible for our ancestors to perhaps have witnessed these flaring events in the sky with the naked eye.