On the nature of eclipses in binary pulsar J0737-3039

We consider the magnetohydrodynamical interaction between the relativistic wind outflowing from pulsar A and the static magnetosphere of pulsar B in the binary pulsar system PSR J0737–3039. We construct a semi‐analytical model describing the form of the interface separating the two pulsars. The assumption of vacuum dipole spin‐down for pulsar B leads to a duration of the eclipse 10 times longer than observed. We discuss a possible torque modification for pulsar B and magnetic field estimates due to the interaction with the wind from pulsar A. Unless the orbital inclination is ≤ 86°, the duration of eclipses is typically shorter than that implied by the size of the eclipsing region. We propose that eclipses occur as a result of synchrotron absorption by mildly relativistic particles in the shocked wind from pulsar A. The corresponding optical depth may be high enough if the wind density from pulsar A is at the upper allowed limit. We derive jump conditions at oblique, relativistic, magnetohydrodynamical shocks and discuss the structure of the shocked wind from pulsar A. Finally, we speculate on a possible mechanism of orbital modulation of the radio emission from pulsar B.