A Strange Star Model for Pulsars

Abstract

It is suggested in this paper that the `bare' strange star might be not bare, and there could be a magnetosphere around it. As a strange star might be an intensely magnetized rotator, the induced unipolar electric field would be large enough to construct a magnetosphere around the strange matter core. This kind of magnetosphere is very similar to that of the rotating magnetized neutron stars discussed by many authors. A magnetosphere will be established very soon through pair production by gamma-B or two photon processes after a strange star was born in a supernova explosion. It is emphasized that the fact that the strange star surface can not supply charged particles does not stop the formation of a space charge separated magnetosphere around the bare strange star. An accretion crust is quite difficult to come into being around an isolated strange star. Therefore the observed radio signals of an rotation-powered pulsar may come from a bare strange stars rather than a neutron stars or a strange star with an accretion crust. The idea, that the radio pulsars are the strange stars without crusts, is supported by some observations. The fact, that the iron emission lines have been observed in many X-ray pulsars but never been reported in X-ray emission of radio pulsars, is difficult to be understood if the radio pulsars are the neutron stars or strange star with crust where the surface binding energy of iron ions is too low to avoid a ion free-flow from the surface.