Research Note

Stellar laboratories

V. The Xe vi ultraviolet spectrum and the xenon abundance in the hot DO-type white dwarf RE 0503−289^⋆,⋆⋆

¹ Institute for Astronomy and Astrophysics, Kepler Center for Astro and Particle Physics, Eberhard Karls University, Sand 1, 72076 Tübingen, Germany
e-mail: rauch@astro.uni-tuebingen.de
² Astrophysique et Spectroscopie, Université de Mons – UMONS, 7000 Mons, Belgium
³ IPNAS, Université de Liège, Sart Tilman, 4000 Liège, Belgium
⁴ Centro de Investigaciones Opticas (CIOp), CC 3, 1897 Gonnet, La Plata, Argentina

Received: 12 March 2015
Accepted: 8 April 2015

Abstract

Context. For the spectral analysis of spectra of hot stars with a high resolution and high signal-to-noise ratio (S/N), advanced non-local thermodynamic equilibrium (NLTE) model atmospheres are mandatory. These are strongly dependent on the reliability of the atomic data that are used for their calculation.

Aims. Reliable Xe vi oscillator strengths are used to identify Xe lines in the ultraviolet spectrum of the DO-type white dwarf RE 0503−289 and to determine its photospheric Xe abundance.

Methods. We publish newly calculated oscillator strengths that are based on a recently measured Xe vi laboratory line spectrum. These strengths were used to consider their radiative and collisional bound-bound transitions in detail in our NLTE stellar-atmosphere models to analyze Xe vi lines exhibited in high-resolution and high S/N UV observations of RE 0503−289.

Results. We identify three hitherto unknown Xe vi lines in the ultraviolet spectrum of RE 0503−289 and confirm the previously measured photospheric Xe abundance of this white dwarf (log  Xe = −4.2 ± 0.6 by mass).

Conclusions. Reliable measurements and calculations of atomic data are prerequisite for stellar-atmosphere modeling. Observed Xe vi line profiles in the ultraviolet spectrum of the white dwarf RE 0503−289 were well reproduced with the newly calculated Xe vi oscillator strengths.