SS 433
SS 433 is the astronomical name of an exotic binary star system in the constellation Aquila. It is the first known microquasar.
SS 433 was discovered in 1976 by the X-ray satellite Ariel V at a screening of the sky for strong X-ray sources along the galactic plane. He was one of ten unknown sources, and was first performed under the name of A1909 04. After this source in the optical range an object (the center of the 16,000 light years away bizarre supernova remnant W50 ) could be assigned, in 1977 found in studies of the star that its spectrum shows strong H- α emission lines. He was then taken up by the astronomer C. Bruce Stephenson and Nicholas Sanduleak as number 433 in a catalog of such stars and so came to its name (SS 433 ).
Further studies in the following years showed that the star not only X-rays, but also strong and rapidly changing emits radio waves. Also in the optical domain, it has some special features. To shift its emission lines with a period of 164 days considerably, which could be explained only by himself with a relativistic speed moving gas. This gas ( and hence also the emission lines ) is derived only indirectly from the visible star. It flows from this in a ( the invisible companion heavy surrounding ) accretion disk and is thrown out ( similar to a quasar ) by two opposite jets with 26% of the speed of light. The periodic shifts of the emission lines originate from the precession of the jets. The binary star system is therefore also called microquasar. The massive main star belongs to the spectral class A3 to A7 and fills his maximum possible volume ( Roche volume ) in full. His companion could only be a neutron star or a black hole due to its mass, which was not clear because of uncertainties in the determination of the mass start.
Recent studies of the spectrum of the star and its static and variable proportions by the European Southern Observatory showed that the binary star system is probably surrounded by a gas ring. Furthermore, it could be determined with 40 solar masses from these data, the total mass of the system, which itself is just a black hole as a companion of the star is due to the mass ratios with deduction of three solar masses for the accretion disk in question, which these orbits in 13 days. The total apparent brightness of the system is 14.2 mag.