标题：Stellar laboratories - VII. New Kr iv – vii oscillator strengths and an improved spectral analysis of the hot, hydrogen-deficient DO-type white dwarf RE 0503−289
其他标题：VII. New Kr iv – vii oscillator strengths and an improved
spectral analysis of the hot, hydrogen-deficient DO-type white dwarf RE 0503−289⋆⋆⋆⋆⋆⋆⋆⋆⋆⋆†
摘要：Context. 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.
Aims. New Kr iv–vii oscillator strengths for a large number of
lines enable us to construct more detailed model atoms for our NLTE model-atmosphere
calculations. This enables us to search for additional Kr lines in observed spectra and to
improve Kr abundance determinations.
Methods. We calculated Kr iv–vii oscillator strengths to
consider radiative and collisional bound-bound transitions in detail in our NLTE
stellar-atmosphere models for the analysis of Kr lines that are exhibited in
high-resolution and high S/N ultraviolet (UV) observations of the hot white dwarf
RE 0503−289.
Results. We reanalyzed the effective temperature and surface gravity and
determined Teff =
70000 ± 2000 K and log
(g/ cm s-2) = 7.5 ± 0.1. We newly
identified ten Kr v lines and one Kr vi line in the spectrum of
RE 0503−289. We measured a Kr abundance of
−3.3 ± 0.3 (logarithmic mass
fraction). We discovered that the interstellar absorption toward RE 0503−289 has a multi-velocity structure within a
radial-velocity interval of −40 km
s-1
关键词：atomic data;line: identification;stars: abundances;stars:
individual: RE 0503;289;virtual observatory tools;stars:
individual: RE 0457;281
