SS 433

SS 433 is most likely a black hole. It lies within supernova remnant W50, which is though to be 10,000 years old. A companion star orbits it and provides material for an accretion disc.

The system lies 16,000 light years away, in the constellation of Aquila, and is both an X-ray and radio source. Coming from the compact object is a pair of jets that corkscrew through space, distorting W50 and producing both blue and red Doppler shifts in the observed visible spectrum. The star is 14th magnitude and the jets produce material travelling at 26% of the speed of light. The precession period of the jets is 164 days.

This star is considered one of the weirdest, considering that the spectrum of the star is shifted not just by Doppler shifts but also by relativity. The star's mass is between 11 and 27 solar masses. Its stellar wind travels at 2.16×10⁷ mph.