A detailed spectroscopic analysis of epsilon Per I. Determination of the orbital parameters and of the frequencies

We present the analysis of 445 high signal-to-noise spectra of the Si III t riplet at 4553 Angstrom, 4568 Angstrom, 4575 Angstrom of the line-profile v ariable star epsilon Persei. The data were gathered during 14 consecutive n ights and fully cover the orbital cycle of the binary. The orbital paramete rs that we derive from our data for the close binary are in full agreement with those found in 1995 by Tarasov et al. Our data does not offer a conclu sive test of the presence of the 4156-d period, With the CLEAN-method, we identify 5 periods in the intensity variations ac ross the line profiles, after the latter are corrected for the binary motio n: 5.300, 5.890, 6.250, 6.875, and 10.585 c d(-1). The results of our frequ ency analysis are consistent with previous ones based on the CLEAN algorith m. In terms of sinusoidal variations with constant phase, we thus find that the line-profile variations have a multiperiodic pattern. The Hipparcos ph otometry reveals yet another candidate frequency of 5.23280 c d(-1). It is not clear yet if this frequency is connected to those found in the spectra. With the PDM-method, we find some indications leading to the "super" period P-super - 1.(d)11878, as introduced by Harmanec (1999). On the other hand, many other periods between 1 and 3 days are equally likely than P-super. S ome of the frequencies found using CLEAN are integer submultiples of P-supe r. We do not have a sufficient amount of data to estimate the importance of ti dal effects for the line-profile variability near periastron for epsilon Pe rsei.