Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Stellar laboratories II. New Zn IV and Zn V oscillator strengths and
  their validation in the hot white dwarfs G191-B2B and RE0503-289   For the spectral analysis of high-resolution and high-signal-to-noise 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. In a recent
analysis of the ultraviolet (UV) spectrum of the DA-type white dwarf G191-B2B,
21 Zn IV lines were newly identified. Because of the lack of Zn IV data,
transition probabilities of the isoelectronic Ge VI were adapted for a first,
coarse determination of the photospheric Zn abundance.
  We performed new calculations of Zn IV and Zn V oscillator strengths to
consider their radiative and collisional bound-bound transitions in detail in
our NLTE stellar-atmosphere models for the analysis of the Zn IV - V spectrum
exhibited in high-resolution and high-S/N UV observations of G191-B2B and
RE0503-289.
  In the UV spectrum of G191-B2B, we identify 31 Zn IV and 16 Zn V lines. Most
of these are identified for the first time in any star. We can reproduce well
almost all of them at log Zn = -5.52 +/- 0.2 (mass fraction, about 1.7 times
solar). In particular, the Zn IV / Zn V ionization equilibrium, which is a very
sensitive indicator for the effective temperature, is well reproduced with the
previously determined Teff = 60000 +/- 2000 and log g = 7.60 +/- 0.05. In the
spectrum of RE0503-289, we identified 128 Zn V lines for the first time and
determined log Zn = -3.57 +/- 0.2 (155 times solar).
  Reliable measurements and calculations of atomic data are a pre-requisite for
stellar-atmosphere modeling. Observed Zn IV and Zn V line profiles in two white
dwarf (G191-B2B and RE0503-289) ultraviolet spectra were well reproduced with
our newly calculated oscillator strengths. This allowed us to determine the
photospheric Zn abundance of these two stars precisely.

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The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ex
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The categories of this paper are: quant-ph
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
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The categories of this paper are: comp-gas
2
The categories of this paper are: math
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The categories of this paper are: adap-org
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The categories of this paper are: econ
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The categories of this paper are: plasm-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: alg-geom
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The categories of this paper are: q-bio
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The categories of this paper are: nucl-th