Kholtygin A.F., Burlakova T.E., Fabrika S.N.,
Valyavin G.G., Yushkin M.V.
Microvariability of Line Profiles in
the Spectra of OB Stars: delta Ori A
Astronomy Reports, 50, 887-901
(2006)
Original Russian Text published in Astronomicheskii Zhurnal, 83,
No. 11, pp. 990-1005 (2006)
We have studied variability of the spectral lines of the OB star delta Ori A
-the brightest component of the delta Ori triple system. Forty spectra
with signal-to-noise ratios nearly 500-800 and a time resolution of four
minutes were obtained. We detected variability in the
HeII4686, HeI4713
and Hbeta absorption and the
CIII5696 emission profiles. The amplitude of
the variability is about of (0.5-1)% of the continuum intensity.
The dynamical wavelet spectrum of the profile variations reveals large-scale
components in the interval 25-50 km/s that move within the Vsini
to Vsini band for the primary star of the system, Aa1,
with a band crossing time of 4h-5h. However, some of
the variable features go outside the band, presumably due to either
imhomogeneities in the stellar wind from .Ori Aa1 or non-radial pulsations
of the weaker
components of the system, Aa2 or Ab. The detected variability
may by cyclic with a period about of 4h. We suggest that it is
associated with non-radial pulsations of the primary in the sector
mode (l,m) = (2,-2).