SS433 modelled as an aligned magnetic neutron star

Abstract

SS433 is a variable X-ray, optical and radio source lying centrally within the supernova remnant W50 (see review in ref. 1). The notoriety of SS433 rests on the unique, opposing pair of collimated gaseous jets of opening angle approx5° and velocity 0.27 c (ref. 2). It is a binary system of period 13 days (ref. 3). The jets describe a cone of half-angle 20° with period 164 days (refs 4, 5) which is usually interpreted as a precession. We propose here that SS433 is a neutron star whose rotational and magnetic axes are almost aligned. Alignment provides collimation of the jets which originate in supercritical accretion bursts. Precession of the neutron star is invoked to account for the observed 164-day periodicity. The corotating magnetosphere gives the star a quadrupole moment so that classical precession occurs in the gravitational field of the accretion disk.