SIMBAD references

Spectrophotometry of the chromospherically active system σ₂ Coronae Borealis was obtained in the Hα region, during two observing campaigns at Catania Observatory. During the first campaign, 1988 June 22 - 29, 135 spectra were collected, while 12 spectra were obtained during the second campaign which spanned from June 2nd to June 12th 1989. We have recorded the spectra of the two stars composing the visual binary (σ₁ and σ₂ CrB) on the same frame by placing the spectrograph slit along the line connecting the two stars. This enabled us to obtain a light curve in the red band (λ6410-6590Å), using σ₁ CrB as comparison star. The light curve exhibits changes in the amplitude and in the phase of minimum light between the two observing seasons. The equivalent width of the Hα emission core has been evaluated using the spectrum synthesis method. Hα emission from both components of the inner system is detected in the spectra near quadrature, but it is stronger in the cooler G0 V star. The Hα equivalent width shows low-amplitude modulation in both years which seems to be anti-correlated with the simultaneous light curve. Comparing our results of the 1988 campaign with the contemporaneous X-ray, UV, and Radio measurements reported by Stern et al. (1992ApJ...391..760S) we show that the MgII flux of the cooler component is anti-correlated with our light curve, and a similar behaviour is displayed by the Ly-α flux reported by Hannikainen et al. (1990, ESA SP-310: Evolution in Astrophysics: IUE Astronomy in the Era of New space Missions, p. 387).