The complex structure of the Mg II regions of 40 BeV stars
Danezis, E.; Lyratzi, E.; Theodossiou, E.; Nikolaidis, D.; Stathopoulou, M.; Drakopoulos, C.; Soulikias, A.
Abstract
In this paper we present a study of the UV Mg II resonance lines in 40 BeV stars' spectra. We used the model proposed by Danezis et al. (2002, 2003). This model is based on the idea of independent density layers in the regions where the spectral lines that present SACs (DACs) are created. We calculated the apparent rotation (Vrot) and expansion/contraction velocities (Vexp) of these density regions, as well as their ξ value, which is an expression of the optical depth. We also present the relation among these parameters and their evolutiona with the spectral subtype.