tau draconis, latinized from τ draconis, is an astrometric binary star system in the northern circumpolar constellation of draco. the star is faintly visible to the naked eye, having an apparent visual magnitude of 4.45. based upon an annual parallax shift of 22.28 mas as measured from earth, it is located around 146 light years from the sun. its proper motion is propelling it across the sky at the rate of 0.176 arc seconds per year.