PROFILES VARIATIONS OF THE H-ALPHA EMISSION-LINE IN THE HERBIG-B3E STAR HD-200775

Fifty-two high-resolution CCD spectra (1986-1990) centered on Halpha o f the Herbig B3 ve star HD 200775 are presented and analyzed. A consid erable variability of the Halpha double-peak emission profile is found on timescales from days to months. The general picture of these profi le variations is rather complicated, but two primary types can be dist inguished, namely (i) variations of the emission line strength and (ii ) positional displacements of the central absorption which range from -10 to +70 km s-1. Secondary variations occur in the intensity and sha pe of the emission wings, the relative intensity of the red and blue e mission peaks, and the position variations of the line centroid. Signi ficant correlations between the variations of any of these profile par ameters have not been found. A particular sequence of events was obser ved in 1986 when a slow growth of the sharp blue emission peak and a s ubsequent decrease of the depth of the absorption component in May-Jun e were in July followed by the apparition of a complex structure of di screte line components in the velocity interval between -50 km s-1 and +40 km s-1. This fine structure underwent considerable night-to-night variations. A qualitative interpretation of this development of the H alpha profile is suggested in terms of a stellar wind which interacts with an external shell where it leads to a fragmentation of the matter into smaller clumps which are then accreted by the central star.