The accretion picture of Cen X-3 as inferred from one month of continuous X-ray observations.

COS-B X-ray observations of Cen X-3 in December 1975 include a turn-on of the source and a high state extending over the rest of the observation period, during which a clear transition in intensity occurs. These data are used to show that the accretion picture of Cen X-3 is reconcilable with a stellar wind only by taking the most extreme assumptions on the mass loss of the primary and the velocity of the wind. It is argued that the observed high X-ray luminosity, together with the intensity behavior of the source, demonstrates the presence of an accretion disk, for which a radial flow time of about 15 days is derived.