DETECTION OF MOVING BUMPS FOR THE BE STAR ETA-CENTAURI

We present a series of high resolution spectra of the He I lambda667.8 nm line of eta Cen obtained in 1990 and 1992. Features < 1 % of the co ntinuum were detected moving from blue to red through the line profile s. These variations are examined in terms of nonradial oscillations. T he acceleration and average spacing of the features are consistent wit h an l = Absolute value of m = 14 +/- 4 sectorial mode or with an l al most-equal-to 7, m almost-equal-to 6 tesseral mode. The azimuthal degr ee did not change during the time span of the observations which sets a lower limit of about two years for the stability of stellar surface pattern.