Cygnus X-1
Cygnus X-1 is about 6000 light years from earth. Optical star HDE 226868 orbits around the X-ray source of X-1, with a calculated orbital radius of 14 million kilometers. Calculations carried out in the Cygnus X-1 system utlizing the observed orbit of the star have determined that the mass of the unobserved object is approximately six solar masses. Applying Chandrasekhar limit to this it is apparent that the unobserved object cannot be a white dwarf. It also has too large a mass to be a neutron star. Observations have been made in systems of two stars orbiting each other, being attracted by their respective gravitional forces. Where this type of observation hasb been made, where a star appears to orbit an unseen partner along with the presence of a X-ray source , A plausible explaination for this is that matter is attracted from the surface of the visible star spiralling towards the black hole. In doing so a large amount of heat is generated emitting X-rays. These observations and results have lead to a high degree of speculation on the presence of a Black Hole.
The arrow on the photograph below shows the location of Cygnus X-1. It is thought to be a normal star and a Black Hole orbiting around each other.
Click here to return to Space Observatory Computer