|Right Ascension|| 19:11:49.48 (h:m:s)
|Declination|| +04:58:57.8 (deg:m:s)
|Distance|| 18000 (ly)
|Visual brightness|| 14.2 (mag; var)
|Spectral type|| cont
SS 433 is a peculiar neutron star, component in a binary system with a hot "normal" star as companion. Material from the normal star has flown to the neutron star to form, and finally overload, an accretion disk. The excess material has been ejected from the accretion disk in two polar jets, with relativistic velocities (more than a quarter of the speed of light). This object can be found just west of Delta Aquilae at normally about 14th visual and 16th photographic magnitude; note it is an eclipsing variable (14.0 to 14.6 visually with 166d period). At least 60 percent of the light comes from the accretion disk. It is a strong X-ray source.
SS 433 is surrounded by nebulous material, possibly its supernova remnant, and mixed up with the material from the polar jets. This nebula was cataloged as W50 or G39.7-2.0.
This object was cataloged in various compilations, but became known from its entry as object No. 433 in the list of H-Alpha emissoion objects by Stephenson and Sanduleak (published 1977 in ApJS). This identification was, in particular, given in the discovery announce of highly variable radio emission, by Seaquist, Gregory and P.C. Crane (1978), which made the object famous. Other catalog identifications include 4C 04.66 (radio), CC 493 (Clark and Crawford catalog of radio sources, 1974), A1909+04 (Seward's catalog of Ariel V X-ray discoveries), or W50-X as central X-ray source in nebula W50. This discovery was followed by numerous investigations which are well summarized, e.g., in the reference listed below.
Hartmut Frommert [contact]