But what is the fastest known UNBOUND star that does NOT orbit a black hole? As of November 2019, it was S5-HVS1. Its speed is over 1,700 km/s or 1,056 mi/s. Th

But what is the fastest known UNBOUND star that does NOT orbit a black hole? As of November 2019, it was S5-HVS1. Its speed is over 1,700 km/s or 1,056 mi/s. That's about 0.57% of light speed. S5-HVS1 will be flicked out of the Milky Way. The previous record-holder was US708, a white dwarf travelling at 1,200 km/s or 746 mi/s.