Long-term light curves of 4 young variable stars

The photometric variability is a common property in the early phases of star formation. During the time of formation the young stellar objects pass through periods of a gravitational instability and a chromospheric activity. Both classes of pre-main sequence stars – T Tauri and Herbig Ae/Be stars – show various types of photometric variability. The study of different kinds of variability is very important for understanding stellar evolution. Collecting data from long-time photometry we can investigate the processes of star formation and the stellar environment around young stars. To construct the historical light curves of variable stars new data from CCD observations are complemented with data from photographic plate archives.