Jet velocity in SS 433: its anti-correlation with precession-cone angle and a dependence on orbital phase

We present a re-analysis of the optical spectroscopic data on SS 433 from the last quarter-century and demonstrate that these data alone contain systematic and identifiable deviations from the traditional kinematical model for the jets: variations in jet speed which agree with our analysis of recent radio data, in precession cone angle and in phase. We present a simple technique for separating out the jet speed from the angular properties of the jet axis, assuming only that the jets are symmetric. With this technique, the archival optical data additionally reveal that the variations in jet speed and in precession-cone angle are anticorrelated in the sense that when faster jet bolides are ejected the cone opening angle is smaller. We also find speed oscillations as a function of orbital phase. Subject headings: Stars: Binaries: Close, Radio Continuum: Stars, Stars: Individual: SS 433