Chemical composition of eight OB-type stars in the local Galactic environment


Ünal K. Ö., ELMASLI AKÇAR A.

Monthly Notices of the Royal Astronomical Society, cilt.548, sa.1, 2026 (SCI-Expanded, Scopus) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 548 Sayı: 1
  • Basım Tarihi: 2026
  • Doi Numarası: 10.1093/mnras/stag339
  • Dergi Adı: Monthly Notices of the Royal Astronomical Society
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Compendex, INSPEC, zbMATH, Directory of Open Access Journals
  • Anahtar Kelimeler: stars: abundances, stars: early-type, stars: fundamental parameters
  • Ankara Üniversitesi Adresli: Evet

Özet

We perform a non-local thermodynamic equilibrium spectroscopic analysis of eight OB-type stars in the solar neighbourhood, using high-resolution spectra obtained with the 0.8-m telescope at Ankara University Kreiken Observatory together with archival European Southern Observatory/Ultraviolet and Visual Echelle Spectrograph data. Stellar parameters were determined from hydrogen Balmer lines, silicon ionization equilibria, and helium line profiles, while chemical abundances were derived for He, C, N, O, Ne, Mg, Al, Si, S, and Fe. HD 37032 is newly identified as a He-rich peculiar star ([He/H] $\approx +0.33$ dex), with asymmetric H $\alpha$ and [O i] $\lambda$5577 features revealing the presence of circumstellar material. HD 46660, HD 46883, and HD 7694 likewise exhibit mild helium enrichment relative to the solar abundance. HD 29309 is found to be a double-lined spectroscopic binary hosting a Barium-star secondary. A Hertzsprung–Russell diagram analysis indicates that most of the stars are located close to the main sequence, whereas HD 46883 is classified as a blue supergiant with no strong signatures of CNO mixing. These findings provide new constraints of the chemical diversity and evolutionary pathways of early-type stars in the local Galactic environment.