IUE Archival Spectra of 31 Cygni

Abstract

UV light curve of 31 Cygni has been made from the IUE high dispersion spectra. The depth of primary minimum of the light curve is 5.2 magnitudes because the B4 star's steep spectral gradient. The light curve has been analyzed by the method of Wilson and Devinney Differential Correction(WD). The radial velocities have been measured using the Mg ¥± h lines. The spectroscopic elements have been determined by the method of WD. The change of the Mg ¥± resonance doublet has been investigated based on the eight representative spectra taken at well distributed orbital phases.