Supergiants transiting towards white dwarf

TL;DR

This paper reviews the observational features and chemical compositions of evolved stars transitioning from the asymptotic giant branch to white dwarfs, highlighting new spectral peculiarities related to chemical enrichment.

Contribution

It reports the discovery of a new spectral peculiarity involving line splitting or asymmetry in post-AGB stars with enriched atmospheres.

Findings

Identification of spectral line splitting in post-AGB stars

Chemical composition analysis of evolved stars

Discussion of spectral peculiarities related to chemical enrichment

Abstract

Observational manifestations of far evolved stars at the asymptotic giants branch and their nearest descendants are briefly considered. Main results of their chemical composition determinations based on long term high resolution spectroscopy at the 6-m telescope are also briefly summed up. A new kind of peculiarity of optical spectra is found and discussed: splitting or asymmetry of strongest absorptions in the optical spectra of selected post-AGB stars with envelopes and atmospheres enriched in carbon and s-process heavy metals.