Yet more on the circumbinary disk of SS 433

TL;DR

This paper analyzes the emission lines of SS 433, supporting the hypothesis that they originate from a circumbinary ring, and explains differences between hydrogen and helium lines based on ionization potentials, implying a system mass of about 40 solar masses.

Contribution

It provides a physical explanation for emission line features in SS 433, confirming their origin in a circumbinary ring and estimating the system's mass.

Findings

Emission lines originate from a circumbinary ring.

Differences between H and He lines explained by ionization potentials.

System mass estimated at approximately 40 solar masses.

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.