COMMISSION 27 OF THE I.A.U.
                 INFORMATION BULLETIN ON VARIABLE STARS
                             Number 3216

                                                        Konkoly Observatory
                                                        Budapest
                                                        15 July 1988

                                                        HU ISSN 0374 - 0676


              SHELL SPECTRUM VARIATIONS OF PLEIONE

We have been monitoring Pleione with the grating spectrograph attached
to the 60/90-cm Schmidt telescope of the Beijing Observatory since the
end of 1983. 27 spectrograms of the star at 50 A/mm were obtained to date.
They cover a wavelength range of lambdalambda 3500-6600 A.
   Figure 1 gives the microphotometer tracings of the selected spectra of
Pleione. On our plates the shell spectra of Pleione showed conspicuous
variations. The shell absorption lines are weakening while the emission
lines are strengthening with time. The rich metallic shell lines, in
particular CaIIK and NaID, were strong on the spectrogram taken on
1983 December 17. Then the lines gradually weakened. Most of the metallic

                                [FIGURE 1]

 Figure 1:  The microphotometer tracings of the selected spectra
            of Pleione (The zero points of ordinate are fog of 
            the plate).

                                [FIGURE 2]
                             [Fig. 1.(cont.)]

shell lines, including CaIIK and NaID, became almost invisible on 1987
December 8. The Balmer shell lines gradually became diffuse, and the higher
quantum number lines were the first to do so. The H_beta shell absorption was
very strong on the plate of 1983 December 17. It weakened considerably with
time because of the strengthening of H_beta emission. The two emission peaks at
H_beta were distinctly visible to the eye on the plate of 1987 December 8. The
emission at H_alpha also became appreciably stronger during the same time
interval.
   It appears that the shell phase of Pleione which began in 1972-1973 is
ending slowly. Pleione is changing from shell phase to Be phase. Continued
observation and analysis would be of great interest.


                        GUO YU-LIAN

               Beijing Astronomical Observatory
                       Academia Sinica
                       Beijing, China