A study of the continuum flux of line structure in the IUE spectrum of Beta Lyrae

Abstract

A study of the available archival IUE images of Beta Lyrae has led the following results: a) for 1250 < λ < 1500 Å, the eclipse depth at the second conjunction is slightly larger than the eclipse depth at primary conjunction; they are equal to 1670 Å; b) the profiles of the resonance lines of Si IV (and the same seems to be true for N V and C IV) can be described as composite, formed by the superposition of a stationary P Cygni profile that suggests a velocity of approach of ∼170 km/s, and a broad, less strong, emission that seems to yield a velocity distribution in antiphase with the velocity curve of the BB II component of the system, suggesting that may be linked with the opaque disk that surrounds the undetected companion; c) the emission lines of the intercombination double of N II at about 2140 Å suggest a velocity of about -130 km/s. The interpretation of the composite profile under b), appears similar to the one suggested by Sahade (1966) to describe Hα and He I 5876 and He I 6678, and by Batten and Sahade (1973) to describe Hα.