OPTICAL SPECTROSCOPIC OBSERVATIONS OF Cyg X-1 = HDE 226868
OPTICAL SPECTROSCOPIC OBSERVATIONS OF Cyg X-1 = HDE 226868
We present the results of the spectroscopic observations of HDE 226868, the optical counterpart to the black hole X-ray binary Cyg X-1, from 2001 to 2006. We analyze the variabilities of the two components in the complex H$α$ line: one P-Cygni shaped component which follows the motion of the supergiant …