ON THE BIMODAL MAGNETIC-FIELD DISTRIBUTION OF BINARY PULSARS

We combine the idea of movement of magnetic flux tubes in the stellar interiors with the analysis of crustal physics of accreting neutron st ars in low- and high-mass X-ray binaries to explain the bimodal magnet ic field distribution of binary pulsars. We propose that this distribu tion may result from different crustal properties of neutron stars wit h different accretion sates and amounts of accreted matter. In additio n, we may provide an explanation for why the magnetic field strengths of millisecond pulsars with low-mass companions saturate at similar to 3 x 10(8) G when accreted mass exceeds similar to 0.5 M..