In the literature to non-radial oscillations of gamma Cassiopeia one finds besides reports to rapid variations in X-ray, linear polarisation, UV-lines and Balmer emission lines, predominantly investigations to sub-features moving through the line profiles of the major spectral lines Hgamma, HeI4388, HeI4471, HeI5876 and Si III4552.
As I could show for the gamma Cas related star zeta Oph (IBVS No. 6034), also the EW of certain photospheric absorption lines can be a suitable indicator for observing of non-radial oscillations.The attached picture shows the time behavior of the intensity of the photospheric absorption lines HeI4388 and HeI4471.The number of the left of each spectrum is the corresponding midexposure time in fractions of a day (2013-07-14). The plot at the right shows the rapid variation of the EW of both lines.
The time coverage for this time series has been approx. 4 hours only and it requires urgently a repetition (possibly at the coming OHP workshop). The observation has been performed with a LHIRES III at the SC-telescope C14 in the observatory of the Vereinigung der Sternfreunde Köln.
Ernst Pollmann
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Non-radial-pulsations of gamma Cas
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Ernst Pollmann
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Non-radial-pulsations of gamma Cas
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