The ultraviolet spectrum and interstellar environment of HD 50896.

Abstract

By combining the results from 52 IUE spectra of the WN5 star HD 50896 the authors have constructed a photometrically precise, flux-calibrated, mean high-resolution (R ≈ 10⁴) data set covering the wavelength range 1150 - 3274 Å. They give measurements of fluxes and widths for all detected emission lines and P Cygni profiles; approximately 25 per cent of the flux emitted in the IUE spectral region comes from line emission. Examination of the interstellar lines shows at least five components contributing to the line-of-sight: H I and H II systems at low velocity, a feature at ≡-30 km s^-1 (measured with respect to the low-velocity blend), and absorptions at about -75 and -130 km s^-1. The authors use a profile-fitting analysis to estimate column densities for all available ions in each velocity system.