ORFEUS-SPAS II EUV Spectroscopy of epsilon Canis Majoris (B2 II)

Abstract

We report on extreme-ultraviolet (EUV) spectroscopic observations of the B bright giant epsilon Canis Majoris made during the ORFEUS-SPAS II mission. We assess the performance of the instrument in the EUV and find that the effective area is roughly 3 times that of the Extreme-Ultraviolet Explorer (EUVE) long-wavelength spectrometer and that the spectral resolution is lambda/Delta(lambda) = 1250. We identify most of the features, qualitatively compare different models, and examine the wind-broadened O V and Si IV lines, which display blue edge velocities up to 800 km/s.

10 pages LaTeX, 5 figures, accepted by ApJ Letters, replacement includes just a few editorial changes