A New Model for the Structure of the DACs and SACs Regions in the Oe and Be Stellar Atmospheres

Abstract

In this paper we present a new mathematical model for the density regions where a specific spectral line and its SACs/DACs are created in the Oe and Be stellar atmospheres. In the calculations of final spectral line function we consider that the main reasons of the line broadening are the rotation of the density regions creating the spectral line and its DACs/SACs, as well as the random motions of the ions. This line function is able to reproduce the spectral feature and it enables us to calculate some important physical parameters, such as the rotational, the radial and the random velocities, the Full Width at Half Maximum, the Gaussian deviation, the optical depth, the column density and the absorbed or emitted energy. Additionally, we can calculate the percentage of the contribution of the rotational velocity and the ions' random motions of the DACs/SACs regions to the line broadening. Finally, we present two tests and three short applications of the proposed model.

A study of the atmospheric structure of AX Mon (HD 45910)

“…Using the Gauss Rotation (GR) model (Danezis et al 1991(Danezis et al , 2007 we accomplished the best fit of the Al II (λ 1670.81Å), Al II (λλ 1854.722, 1867.782Å), Mg II (λλ 2795.523, 2802.698Å), Fe II (λ 2586.876Å), C II (λλ 1334.515, 1335.684Å) and Si IV (λλ 1393.73, 1402.73Å) spectral lines of HD 45910 (AX Mon). The complex structure of these spectral lines can be explained with Discrete Absorption components (DACs) and Satellite Absorption components (SACs, Danezis et al 2007).…”

DACs and SACs in the UV Spectrum of the Quasar PG 0946+301

“…These complex profiles are composed of a number of DACs or SACs which are created in the Broad Absorption Line Regions (BALR) that result from dynamical processes such as accretion, jets, ejection of matter etc. By applying the model proposed by Danezis et al [1] (GR model) we can accurately fit the observed complex profiles of both emission and absorption spectral lines. With this model we can calculate the apparent rotational and radial velocities, the random velocities of the ions, as well as the Full Width at Half Maximum (FWHM), the column density of the independent density regions of matter which produce the main and the satellite components of the studied spectral lines and the respective absorbed or emitted energy.…”

Studying the UV Mg II Resonance Lines in 20 Be Stars

“…Many researchers have observed the existence of absorption components shifted to the blue or red wing of the main spectral line (e.g., Doazan 1982;Danezis et al 1991;Doazan et al 1991;Lyratzi et al 2007;Danezis et al 2007). In this paper, using the GR model ), we analyze the UV Mg II resonanse lines at λ = 2795.523 and 2802.698Å in the spectra of 20 Be stars of different spectral subtypes and present the values of the rotational, radial and random velocities, as well as the FWHM and the absorbed energy, as a function of the effective temperature of the studied stars.…”