Ultraviolet and Optical Observations of AG Draconis

Abstract

IUE satellite observations and ground-based spectroscopic observations of the yellow symbiotic star AG Dra obtained at irregular intervals from 1975 to 1984 are presented. No forbidden lnes are observed in the optical, indicating a high density. The hydrogen emission lines often show a second blueshifted component that is not as strong as the main component. The He I and He II lines do not show a blueshifted component. AG Dra shows photometric variability with a period of 554 days (particularly below 4000 A) and radial-velocity variations with an amplitude of about 7 km/s which are consistent with a period of about 550 days. The N V line in the IUE region shows a P Cygni profile, indicating at least one region of outflow in the system. There may be some density stratification in the emission-line region(s).