2002A&A...394..603S

We present time series of high-resolution spectra of the βCephei star ν Cen, showing multi-periodic variations in the SiIII λ4552 and λ4567 line profiles. After correction for the binary motion, we analyse the time series of spectra by Fourier transforms for each position in the line profile. For selected frequencies we perform a direct fit of multiple sinusoids. Four frequencies are needed to describe the pattern of moving bumps in the line profiles. We present the distributions of variational amplitude and phase across the line profile and use these diagnostics to show that most of the variability can be explained by multiple non-radial pulsations. From the phase distributions across the line profiles we derive estimates for the degree l of the individual pulsation modes in ν Cen. We find l values ranging from 6 to 10. We find no trace of a previously reported low-degree l≲2 pulsation with a period of 0.17day. We briefly discuss these observations, and those of the other close-binary β Cephei stars α Vir and ψ² Ori, in terms of tidal effects on pulsation-mode stability.