STUDY OF B AND Be STARS BY GAIA

摘要

All the Gaia instruments will provide fundamental information about the yet unexplained Be phenomenon. We hope that Gaia itself will provide a clear detection of Be stars among B stars with the help the photometric and spectroscopic instruments. Hipparcos definitely established that Be stars are brighter that B stars of the same spectral type. Parallaxes and extinction provided by Gaia could allow the determination of individual absolute magnitudes of B and Be stars to within a few hun-dredths of a magnitude, up to several kiloparsecs, and to study absolute magnitudes of Be stars versus fundamental parameters: temperature, emission strength, υ sin i .... and age for Be stars in open clusters. Spectroscopic information from Gaia will also be used to characterize Be stars with strong emission: we have already shown how the presence of emission in the lines in the wavelength range of the Gaia RVS, i.e., Paschen lines as well as CaII triplet, is a powerful index of the strength of emission in Be stars, and is correlated to a larger rotational velocity and to an infrared excess.