Superfast Stellar Pulsations from O to A Stars

New results of our studies of superfast variability on the minute and second scales of line profiles in the spectra of early type stars are presented. The spectra of program BA stars were obtained with the 1.25-meter telescope of the Crimean SAI station with exposures from 1.5 to 20 seconds and a total observation time of 2–3 hours. The variability of H β and H α line profiles in spectra of program stars is analyzed. The studied stars have regular line profile variations with periods from 5 to 90 minutes and amplitudes of 0.5–2% of the continuum level. For better understanding the superfast variability of BA stars the X-Ray spectra and X-Ray light curves of selected Be stars obtained on the XMM-Newton satellite are analyzed. The variability of X-ray fluxes for HD 110 432, the analogue of γ Cas stars, on minute time scales is detected. It is shown that a nonthermal contribution into X-rays of the γ Cas analogues can be significant.