Circumstellar envelope manifestations in the optical spectra of evolved stars

TL;DR

This paper studies the optical spectra of evolved stars with circumstellar envelopes, analyzing spectral line features and their relation to the envelope's properties and morphology.

Contribution

It provides a detailed analysis of spectral line peculiarities in evolved stars, linking them to the kinematic, chemical, and morphological characteristics of their circumstellar envelopes.

Findings

Spectral line profiles reveal envelope kinematics and chemistry.

Emission and absorption features correlate with envelope morphology.

Variability in line profiles indicates dynamic circumstellar environments.

Abstract

We consider the peculiarities of the optical spectra of far evolved stars with circumstellar gaseous-dusty envelopes: the time variability of the absorption-emission profiles of the H$\alpha$ line, the presence of stationary emission and absorption molecular bands, multicomponent complex profiles of the NaI D-doublet lines. We show that the peculiarities of the line profiles (the presence of an emission component in the NaI D-doublet lines, the specific type of the molecular features, the asymmetry or splitting of the profiles of strongest absorptions with low excitation potential of the low level) can be associated with the kinematic and chemical properties of the circumstellar envelope and its morphological type.