Time variability of NRP modes along orbital phase in Per

The B0.5 star Per shows a complex variability in line-profiles, complexity being due to an apparent multiperiodic behavior to which is superposed a binary motion, highly eccentric, with a 14-days orbital period. In addition, the star is a fast rotator. Using the Si III triplet at 4553 AA, 4568 AA, 4575 AA from previous high resolution and high signal-to-noise ratio spectroscopic observations (De Cat et al. 2000) that cover a whole orbital period, we did another data analysis applying a Fourier-Doppler Imaging (FDI) technique and CLEANEST time series deconvolution algorithm. In addition to the frequencies previously found in this data set, we detect new frequencies especially in the short period domain. Although co-rotating structure can also be invoked, we focus here on the Non Radial Pulsation (NRP) interpretation and we tentatively derive the degree of the main modes. We show that even on a so short observation range, the Fourier power spectrum changes during the 14 continuous observation nights. The data set is however too scarce to conclude that these variations along the orbital period can be related to any tidal interactions.

 
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