  PSR B1259-63 is a gamma-ray binary system with a radio pulsar orbiting an
O9.5Ve star, LS 2883, with a period of ~3.4 yr. Close to the periastron the
system is detected at all wavelengths, from radio to the TeV energies. The
emission in this time period is believed to originate from the interaction of
LS 2883 and pulsar's outflows. The observations of 4 periastra passages taken
in 2010-2021 show strong correlation of the radio and X-ray lightcurves with
two peaks just before and after the periastron. The observations of the latest
2021 periastron passage reveal the presence of the 3rd X-ray peak and
subsequent disappearance of radio/X-ray flux correlation. In this paper we
present the results of our optical, radio and X-ray observational campaigns on
PSR B1259-63 performed in 2021 accompanied with the analysis of the publicly
available GeV FERMI/LAT data. We compare the properties of different periastron
passages, discuss the obtained results and show that they can be explained in
terms of the 2-zone emission cone model proposed by us previously.
