Activity of symbiotic star CI Cyg between 2008 and 2012

The activity of the classical symbiotic star CI Cyg from 2006 to 2012 was studied based on the photometric and spectrophotometric data. The flux of the strongest spectral lines were calculated. It has been shown that the fluxes of H${\alpha}$, He I $\lambda$5876 lines with a low ionization potential were increased in the outburst. At the same time, the flux of lines with a high ionization potential of [Ne V] $\lambda$3426, [Fe VII] $\lambda$6087 lines were decreased or disappeared completely. In addition, during outbursts the molecular bands belonging to the cold component weakened and the ultraviolet excess behind the Balmer jump decreased or disappeared. At the maximum and close to it, only the emission lines H I, He I and Fe II were observed in the spectra. A comparison was made with the previous period of activity in 1971–1975. It is noted that both periods of activity have similar properties. In particular, a series of outbursts were observed, with each of the subsequent outburst being weaker than the previous one. In addition, the curve of eclipsing in the first outburst of the series was wider than the subsequent ones in both periods of activity. Besides, the brightness of the star weakened before the first flashes of the series.