Long-term variability of the far-UV high velocity components in gammaCas (1978-1986).

Abstract

A synthesis of the authors' long term observations of γ Cas in the visual and in the far UV, combined with IUE archived spectra, shows that: (1) The occurrence of the high velocity components observed in the Si IV, C IV, and N V resonance lines exhibits a long term variability pattern, which is associated with the cyclic V/R variations of the Balmer emission-lines: they are frequently observed when V/R > 1, while they are absent/rarely present when V/R < 1. (2) During the present V/R > 1 half-cycle, the observed components do not fit the column density vs. velocity correlation derived by Henrichs et al. (1983). γ Cas is one more example of a Be star which exhibits associated far UV and visual long term variability patterns.