O VI in stellar winds

Abstract

The region of the O VI resonance doublet around 1030 Å has been observed in 9 stars with the high resolution (0.051 Å FWHM) detector on the Copernicus satellite spectrometer. Although the spectra are confused with interstellar Lyman β and H2 absorption, P Cygni profiles or shifted absorption lines indicating mass flow were found in ζ Pup (O4If), 15 Mon (O7V), HD 151804 (O81af), 10 Lac (09.4V), υ Ori (BOV) and τ Sco (BOV). However, no O VI could be seen in ρ Leo (BlIab) or γ Ara (BlIb). The O VI profiles display a considerable variety that is not correlated with spectral type. Zeta Pup has a broad emission and deep absorption ranging over all velocities to about −2800 km s−1 while HD 151804 has only narrow absorption from −1060 to −1660 km s−1, and 15 Mon has a narrower feature from −1700 to −2100 km s−1. Both 10 Lac and τ Sco have broad relatively shallow absorptions extending from positive velocities to −1380 and −1000 km s−1 respectively. In contrast, the absorptions are narrower with steeper wings in ζ Oph and υ Ori. The latter star also has emission, while in ζ Oph the absorption is split into two components from about −1550 to −1280 and −1280 to −980 km s−1.