SS 433

SS 433

Mica schist. Credit: U.S. National Parks Service.

SS 433 is an X-ray binary and the first discovered member of a group of very exclusive objects that have to be known as microquasars. SS443 lies about 18,000 light-years away in the constellation Aquila within a 40,000-year-old supernova remnant designated W50.


SS433 consists of a normal O or B star, with a mass of 10 to 20 solar masses, in a 13.1-day orbit around a compact object that is either a neutron star or a black hole. Material transfers from the normal star into an accretion disk surrounding the compact object blasting out two jets of ionized gas in opposite directions at about a quarter of the speed of light. In addition the jets precess (wobble like a top) with a period of about 164 days. Radio studies show that the jets extend to 0.16 light-year from the central "engine", while X-ray studies reveal emission from about 100 light-years on either side, where the jets interact with the surrounding supernova remnant.


SS433 gets its name because it is object number 433 in the Stephenson-Sanduleak catalogue of stars with strong emission lines compiled by two astronomers at Case Western Reserve University, Bruce Stephenson and Nicholas Sanduleak, in 1977.


visual magnitude 14.2
distance 18,000±700 light-years
(5,500±200 pc)
position R.A. 19h 11m 49.56s,
Dec. +04° 58' 57.6"
other designations V1343 Aql, 4C 04.66,
1RXS J191149.7+045857,
4U 1908+05