The ultraviolet spectrum of CH CYG during the outburst started in 1977.

Abstract

The ultraviolet spectrum of the symbiotic star CH Cygni during the outburst phase that started in 1977 and continues to the present is described, with a discussion of the spectroscopic mechanisms able to explain the emission lines. A mechanism that can explain both the presence of the intersystem line lambda 1641.3 O I and the anomalous intensity ratio of the lambda 1303 O I triplet is proposed. Tables are included giving the fluxes at the earth of the strongest emission lines and the equivalent widths of the absorption lines.