PSR 0943 + 10: A bare strange star?

Abstract

Recent work by Rankin & Deshpande strongly suggests that there exist strong "microstorms" rotating around the magnetic axis of the 1.1 s pulsar PSR 0943+10. Such a feature hints that most probably the large-voltage vacuum gap proposed by Ruderman & Sutherland (RS) does exist in the pulsar polar cap. However, there are severe arguments against the formation of the RS-type gap in pulsars, since the binding energies of both the ⁵⁶Fe ions and the electrons in a neutron star's surface layer are too small to prevent thermionic ejection of the particles from the surface. Here we propose that PSR 0943+10 (and probably also all of the other "drifting" pulsars) might be bare strange stars rather than normal neutron stars, in which the "binding energy" at the surface is merely infinity for the case of either a "pulsar" or an "antipulsar." It is further proposed that identifying a drifting pulsar as an antipulsar is the key criterion for distinguishing strange stars from neutron stars.