SS433: a black hole candidate?

Stewart et al. recently derived limits on the masses and dimensions of the components of the SS433 binary system. In this paper we show how their limits can be improved by using a better Roche lobe geometry and by taking account of the fact that the accretion disc in this system (which is geometrically thick according to optical observations by Wagner) may occupy a considerable fraction of the Roche lobe of the compact object. Our results are based on the minimum amount of information from X-ray and optical observations. We find that the mass of the compact object is $$\approx 10 \enspace M_\odot$$ and that the length of the X-ray jet is $$L_\text j \approx 1.4 \times 10^{12} \text {cm}$$.