Yet more on the circumbinary disk of SS 433

Abstract

The H and He emission lines of the microquasar SS 433 contain features that look very like emission from a circumbinary ring. Phenomenological models have been successful but contain certain ad hoc features. In this note the lines are treated as recombination lines from a highly ionized environment and differences between H and He, previously unexplained, are understood in terms of the different ionization potentials. It now seems inconceivable that these spectral features have origin other than in a circumbinary ring orbiting at approximately 250 km/s - in which case the system mass is approximately 40 solar masses.