Chandra :: Photo Album :: Cygnus X-1 :: November 17, 2011
Cygnus X-1 is a black hole about 15 times the mass of the Sun in orbit with a massive blue companion star. Data have revealed the spin, mass, and distance of this black hole. On the left, an optical image from the Digitized Sky Survey shows Cygnus X-1, outlined in a red box. Cygnus X-1 is located near large active regions of star formation in the Milky Way, as seen in this image that spans some 700 light years across. The illustration depicts what astronomers think is happening within.