Was the propeller mechanism active during the periastron passage of PSR 1259--63?

Timing analisys of PSR 1259-63 during its recent periastron passage suggested that the pulsar was spinning-down due to the propeller mechanism (Manchester et al. 1995). This requires that the radio pulsar mechanism is temporarily quenched. On the basis of the Be equatorial disk model derived from the dispersion and rotation measures analysis (Melatos et al. 1995), we show that the mass inflow is sufficiently high to yield accretion down to the magnetospheric radius. In this case the X-ray spectrum might result from the propeller shock emission.