Published online by Cambridge University Press: 12 April 2016
We present preliminary results of observations of the Hα, HeI 5876 and NaI D lines profiles in spectra of PU Vul. The variability of profiles is confronted with the photometric behaviour. The observations were carried out with a CCD camera, installed in the coudé spectrograph of the 2.6 m Shajn telescope. 68 spectra of the Hα line and 25 spectra in the region of the HeI and NaI lines were obtained.
Fig. 1 (left panel) presents the evolution of the Hα line from 1985 to 1994, displaying selected typical profiles in different years. The profiles are shown in a heliocentric wavelength scale and in logarithms of intensity. Variations of line intensity, line width, as well as radial velocity of the centre of weight of the total emission and absorption components are observed.
Stronger and more complex variability is observed in the region of the HeI and NaI D lines. The strong P Cyg type absorption in the NaI D lines during 1985-1987 disappeared in later spectra as a result of total ionization of NaI (Fig. 1., right panel). Contrary to that behaviour, HeI 5876 shows variations from a pure absorption profile to a very strong and wide emission profile.
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