Instabilities in the envelope of the Be star HD 37202 zeta Tauri.

The profiles of the underlying star were determined in order to estimate the contribution in emission and absorption of the envelope of HD 37202. These have been compared 1) to the theoretical profiles of Milialas and 2) to the observed profiles of B stars of the same spectral type and of similar class of luminosity. We have compared the value of the radial velocity of the star obtained from our measurements with the ones found in the literature. The study of the radial velocities of the absorption lines shows that the motions of the envelope have considerably increased since 1958. The strong oscfflation (amplitude 60 km/s) we discovered between 1960 and 1967 is a pseudo-periodic phenomenon connected with active phases of the inner layers. Key words: Tauri - unstable shell star - radial velocities - pseudo-period