Observation of an accretion wake and pre-eclipse dips in Centaurus X-3.

Report on the results of seven Copernicus observations of Centaurus X-3 in the energy range 2.5-7.5 keV, between 1973 April and 1974 June. An abrupt absorption event was observed at phase 0.5 which is interpreted as an accretion wake sweeping through the line of sight. The wake appears to be associated with an increase in the gas density prior to an extended low state. The data support a stellar wind model for the mass transfer in the Cen X-3 system. A series of pre-eclipse dips which are due to absorption by column densities of 1 to 4 x 10 to the 23rd hydrogen atoms per sq cm were also detected.