Mass to Line Strength Relations from IUE Spectra of Early-Type Stars

An extensive survey of the 1200 - 1900 Å region in OB type stellar spectra obtained from the IUE archives has been used to establish line-strength versus spectral-type relationships. One hundred and sixty-three low-resolution IUE spectra of 124 well-classified O3 to B5 stars were examined. The authors confirm earlier results that the equivalent width of Si IV (λ 1400) and C IV (λ 1550) features are well correlated with optical spectral type. The equivalent width/spectral type/luminosity class relations for these features are then established.