Eclipsing millisecond pulsar - Excitation of the companion wind

Abstract

The 1957 + 20 system is a millisecond pulsar in an eclipsing binary. Even if the companion filled its Roche lobe, it could not explain the observed eclipse duration. It has been proposed that the pulsar evaporates a plasma wind from the companion to cause the eclipse and that the companion will eventually be destroyed. This paper presents a model for pulsar evaporation of a wind from a close binary companion. The wind solution is specified by the critical point behavior at the sonic point transition. The lifetime of the 1957 + 20 companion against evaporation is typically less than 3 x 10 to the 8th yr. The incident pulsar radiation that drives the wind is constrained to have penetration depths about 0.008-1 g/sq cm. Observable changes in orbital parameters are expected and may result mainly from mass loss of the companion.