A High-Resolution Spectroscopic Survey of beta Cephei Pulsations in Bright Stars

Abstract

We present preliminary results of our high-resolution (R>=50000) spectroscopic survey of line-profile variations in stars with spectral types similar to beta Cephei stars. In this paper we focus on the observations obtained on La Palma with the William Herschel Telescope (WHT) and with the Nordic Optical Telescope (NOT), to complement both the Southern survey of tet*{schrijvers2002} and the survey results obtained at the NOT already reported in tet*{telting2003}. In August 2002 we obtained spectra of 34 main-sequence stars with the NOT. In several observing runs executed in service mode between 1997 and 2002 we obtained spectra of 96 main-sequence stars with the WHT. Altogether, we obtained more than 200 high-quality spectra centered on the SiIII 4552 and 4567 lines, with S/N typically better than 350. For 27% of the targets discussed in this paper we find clear evidence for the existence of pulsations, in the form of bump patterns in the line profiles or in the form of line width/depth variability. For another 17% we need more data to confirm suspected line-profile variability. This indicates that many early-B type stars may be pulsationally excited. We briefly discuss the implications of our findings for Be stars, and the possibility that pulsations contribute to the process of disk formation.