The ultraviolet spectrum of upsilon Sagittarii.

Abstract

IUE high resolution spectra of Upsilon Sgr are analyzed. The interstellar lines of metal and ionized elements and the phase-dependent variations of the stellar and circumstellar lines are studied. The characteristics (absorption strength and terminal velocities) of stellar wind features at all the orbital phases are described. The data reveal that Upsilon Sgr is formed from a B8-A2 star and the hot secondary star is three times more massive than the primary.