  PSR B1259-63/LS 2883 is a binary system where a 48 ms pulsar orbits a massive
Be star with a highly eccentric orbit (e=0.87) with a period of 3.4 years. The
system exhibits variable, non-thermal radiation visible from radio to very high
energies (VHE) around periastron passage. This radiation is thought to
originate from particles accelerated in the shock region between the pulsar
wind (PW) and stellar outflows. The consistency of the H.E.S.S. data with the
inverse Compton (IC) scenario is studied in the context of dominant orbital
phase dependent adiabatic losses. The dependence of the observed TeV flux with
the separation distance is analyzed. Model calculations based on IC scattering
of shock accelerated PW electrons and UV photons are performed. Different
non-radiative cooling profiles are suggested for the primary particle
population to account for the variable TeV flux. The TeV fluxes obtained with
H.E.S.S. in the years 2004 and 2007 seem to be only dependent on the binary
separation. The presented results hint at a peculiar non-radiative cooling
profile around periastron dominating the VHE emission in PSR B1259-63. The
location of the stellar disc derived from this non-radiative cooling profile is
in good agreement with that inferred from radio observations.
