Stellar laboratories III. New Ba v, Ba vi, and Ba vii oscillator strengths and the barium abundance in the hot white dwarfs G191−B2B and RE 0503–289

• Published in: Astronomy and astrophysics (Berlin) Vol. 566; p. np
• Main Authors: Rauch, T, Werner, K, Quinet, P, Kruk, J W
• Format: Journal Article Web Resource
• Language: English
• Published: EDP Sciences 01.06.2014
• Subjects: Abundance; Astronomy; Aérospatiale, astronomie & astrophysique; Mathematical models; Oscillator strengths; Physical, chemical, mathematical & earth Sciences; Physics; Physique; Physique, chimie, mathématiques & sciences de la terre; Space science, astronomy & astrophysics; Spectra; Spectral lines; Thermodynamic equilibrium; White dwarf stars
• ISSN: 0004-6361; 1432-0746; 1432-0746
• DOI: 10.1051/0004-6361/201423878

For the spectral analysis of high-resolution and high-signal-to-noise (S/N) spectra of hot stars, state-of-the-art non-local thermodynamic equilibrium (NLTE) model atmospheres are mandatory. These are strongly dependent on the reliability of the atomic data that is used for their calculation. Reliable Ba V-VII oscillator strengths are used to identify Ba lines in the spectra of the DA-type white dwarf G191-B2B and the DO-type white dwarf RE 0503-289 and to determine their photospheric Ba abundances. Reliable measurements and calculations of atomic data are a pre-requisite for stellar-atmosphere modeling. Observed Ba VI-VII line profiles in two white dwarfs' (G191-B2B and RE 0503-289) far-ultraviolet spectra were well reproduced with our newly calculated oscillator strengths. This allowed to determine the photospheric Ba abundance of these two stars precisely.