Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Kinetic equilibrium of iron in the atmospheres of cool dwarf stars II.
  Weak Fe I lines in the solar spectrum   NLTE line formation calculations of FeI in the solar atmosphere are extended
to include weak optical lines. Previously established atomic models are used to
discriminate between different ways of treating collisional interaction
processes. To derive a common solar FeI abundance from both strong and weak
lines, fine-tuning of the microturbulence velocity parameter and the van-der-
Waals damping constants is required. The solar FeI abundances based on all
available f-values are dominated by the large scatter already found for the
stronger lines. In particular the bulk of the data from the work of May et al.
and O'Brian et al. is not adequate for accurate abundance work. Based on
f-values measured by the Hannover and Oxford groups alone, the FeI LTE
abundances are eps(FeI,Sun)=7.57 for the empirical and eps(FeI,Sun) = 7.48 ...
7.51 for the line-blanketed solar model. The solar Fe ionization equilibrium
obtained for different atomic and atmospheric models rules out NLTE atomic
models with a low efficiency of hydrogen collisions. At variance with Paper I,
it is now in better agreement with laboratory FeII f-values for all types of
line-blanketed models. Our final model assumptions consistent with a single
unique solar Fe abundance eps(Fe,Sun) = 7.48 ... 7.51 calculated from NLTE line
formation are (a) a line-blanketed solar model atmosphere, (b) an iron model
atom with hydrogen collision rates 0.5 < S_H < 5 times the standard value to
compensate for the large photoionization cross-sections, (c) a microturbulence
velocity xi = 1.0 kms, (d) van-der-Waals damping parameters decreased by
Delta(log C6) = -0.10...-0.15 as compared to Anstee & O'Mara's calculations,
depending on S_H, (e) FeII f-values as published by Schnabel et al., and (f)
FeI f-values published by the Hannover and Oxford groups.

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The categories of this paper are: alg-geom
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The categories of this paper are: acc-phys
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The categories of this paper are: econ
8
The categories of this paper are: hep-ex
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The categories of this paper are: stat
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The categories of this paper are: nucl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: physics
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The categories of this paper are: plasm-ph
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The categories of this paper are: math-ph
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The categories of this paper are: q-alg
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The categories of this paper are: nucl-ex
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-th
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The categories of this paper are: chao-dyn
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The categories of this paper are: gr-qc