HE I 5876 LINE STRUCTURE IN THE SPECTRA OF STARS IL CEP A
N.Z.Ismailov, O.V. Khalilov, G.R. Bahaddinova
Shamakhi Astrophysical Observatory of the Azerbaijan National Academy of Sciences
ismailovn@yahoo.com
We are presents the results of researches of the He l λ5876 Å line in the spectrum of Herbig
Be type star IL Cep A. Spectral observations were performed at the 2 m telescope of ShAO for
2006-2014. This line represents the absorption structure which has a width at the level of the
continuum about 15-18 Å, and a FWHM about 6-8 Å. It is shown that the line Hel λ5876 Å has a
complex, multi-component structure. It has been allocated a total of 7 line components that
confidence observed in all spectrograms. Radial velocities were measured for each of the
selected components and the line center at half of the total intensity. The radial velocity of the
individual components shows smooth time variability. The range of variation radial velocities of
the individual components is from 20 to 70 km/s. The average value of the radial velocities
showed smooth variability, and the maximum value Vr achieved in 2009-2010.
Equivalent width of the line also shows significant changes from year to year, and during the
one observation season. The total average value of this parameter remains constant for all
observations. For all of the data, a mean value of the equivalent width of the absorption is equal
0.56 ± 0.025 Å, and the standard deviation from the mean ± 0.16 Å. The observed features in the
line indicates that the field of education this line has a complex structure and physical conditions.
The observed variability in the line indicates that possible the star is a spectroscopic binary
system.