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SS 433 is a microquasar and eclipsing X-ray binary system, consisting of a compact object—most likely a stellar-mass black hole (though this is not yet fully confirmed)—that accretes matter from an A-type companion star. Using archival multi-epoch (39-epoch) VLBA observations of the jets launched by the compact object, we were able to trace their evolution: starting from a nearly fixed axis and later exhibiting clear precession.

This binary lies at the center of the W50 nebula, a supernova remnant in the constellation Aquila. The interaction between SS 433’s jets and the surrounding medium has dramatically shaped W50, making Aquila home to one of the best natural laboratories for studying jet phenomena in the Milky Way.

SS 433 serves as a key laboratory for investigating jet physics, accretion processes, and the coupling between relativistic outflows and the interstellar medium. Unlike distant quasars, SS 433 is close and small enough that the jets can be tracked on human timescales. High-resolution VLBA observations allow us to analyze the jets on milliarcsecond scales. By measuring their velocities and precession, we can construct models of jet formation mechanisms and explore the relationship between jet velocity, energy, and their impact on the surrounding nebula.