Population of Be Stars in Young Open Clusters

Both high and medium resolution spectroscopy of Be stars and binary stellar systems in young open clusters (e.g., NGC 869 & 884, NGC 6913, NGC 6871, NGC 7160 and NGC 7419) were carried out. The high resolution spectroscopy of 100 stars in Hα region and medium resolution one of 42 stars in 4400 4960 A range were obtained. From them 52 B stars and 48 Be stars spectra were studied. Teff , log g and V sin i were determined from the medium resolution spectra. One new Be star was found. One another star showed a complex variability of Hα. It characterizes the star as a close binary system. Some of stars demonstrate a long term V/R variability of the emission peaks that can be easy described by one arm oscillations in theirs envelopes. Our clusters survey approved that classical Be stars mostly appear at age of 10 Myr, and their concentration reaches the maximum at the age of 12-20 Myr.