Astronomers have discovered that a red dwarf along with its brown dwarf companion past within a light year from our sun 70000 years ago. The red dwarf moved through the outer limits of the Oort Cloud which surrounds our Solar System.
The star was designated as WISE J072003.20-084651.2, or Scholz’s star and is 20 light years away from us in the constellation Monoceros. According Astrophysical Journal Letters the red dwarf passed about 5 trillion miles from us. No other star has been known to have passed so close by.