2004A&A...427..995D

We present the very first analysis of the spectroscopic variability of the three rapidly rotating Oef stars HD 192281 (O5(ef)), HD 14442 (O5.5ef) and HD 14434 (O6.5(ef)). Radial velocities of the HeII λ 4541 line reveal no evidence of binarity on time scales of a few days, or from one year to the next, for any of the targets. The HeII λ 4686 double-peaked emission and, to some extent, the Hβ absorption line display significant profile variability in the spectra of all three stars. Data gathered during different observing runs spread over six years reveal a rather stable time scale for HD 192281 and HD 14442, whereas the variability pattern changes significantly from one year to the other. The case of HD 14434 is less clear as no obvious time scale emerges from our analysis. In a tentative way to interpret this variability, stellar rotation remains a possible clock for HD 192281 and HD 14442. However, currently available models addressing stellar rotation fail to explain some crucial aspects of the observed variability behaviour, which appear to be even more complex in the case of HD 14434.