An atlas of OB spectra from 1000 to 1200 angstrom

Copernicus low-resolution (0.2 Angstrom) observations of 16 O stars, 10 B stars (mostly supergiants), and one WN-A star with the highest data quality between 1000 and 1200 Angstrom are presented in the form of a classical spectral atlas. The purpose is to survey the systematic spectral-type/luminosity-class dependence of the line features, including those from the stellar winds, in this relatively less-studied wavelength range. Perhaps the most important new contribution is the demonstration of the pronounced luminosity effect in the S IV lambda lambda 1063, 1073 wind profiles, identical to those previously recognized in Si IV lambda lambda 1394, 1403 and C III lambda 1176, which share essentially the same ionization potential. The stellar-wind effects in O VI lambda lambda 1032, 1038; P V lambda lambda 1118, 1128; Si IV lambda lambda 1122, 1128; and C III lambda 1176 are also described. Attention is redrawn to the unidentified feature at 1099 Angstrom, which is one of the strongest absorption lines in this range of mid-O through early-B spectra. The atlas will facilitate interpretations of recent Hopkins Ultraviolet Telescope and future Far Ultraviolet Spectroscopic Explorer observations in this wavelength range, as well as sharpen the stellar-wind phenomenology for astrophysical analysis.