Improved parameters of the hydrogen-deficient binary star KSPer

TL;DR

This study analyzes the optical spectrum of the hydrogen-deficient binary star KSPer, deriving its atmospheric parameters, chemical abundances, and spectral features, revealing a complex gaseous environment around the star.

Contribution

It provides improved parameters and detailed chemical composition of KSPer, enhancing understanding of hydrogen-deficient binary stars.

Findings

Hydrogen deficiency H/He=3x10^{-5}

High nitrogen abundance [N/Fe]=1.4

Complex NaI D doublet structure

Abstract

Using the high resolution spectral observations obtained with the Nasmyth Echelle Spectrograph NES of the 6m telescope we analysed the optical spectrum of the hydrogen-deficient binary star KSPer. The atmospheric parameters derived are: effective temperature Teff=9500+/-300 K, surface gravity log g=2.0+/-0.5, and microturbulent velocity Vt=9.5+/-0.5km/s. The hydrogen deficiency is H/He=3x10^{-5}, iron abundance is reduced by 0.8dex; nitrogen abundance is very high [N/Fe]=1.4, but carbon and oxygen abundances are low. The star luminosity is log L/Lo=3.3. A complex absorption and emission structure of the NaI D doublet was revealed. We suggest that the emission component forms in the circumbinary gaseous envelope.