A Binary System: Be Star LS 2883/PSR B1259-63 and Spectrum Evolution of Pulsar: the Gigahertz-Peaked Spectra

The radio spectrum evolution of the pulsar B1259-63 in the binary system with Be star LS 2883 is presented. It appears that near periastron passage the spectrum shows a deficit of observed energy below 2 GHz, and we observe significant changes in flux density of the radio pulsed emission depending on the orbital phase of the pulsar. We suggest the cause is the influence of the Be star companion on the pulsar radio emission.