Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Line broadening and the solar opacity problem   The calculation of line widths constitutes theoretical and computational
challenges in the calculation of opacities of hot dense plasmas. Opacity models
use line broadening approximations that are untested at stellar interior
conditions. Moreover, calculations of atomic spectra of the sun, indicate a
large discrepancy in the K-shell line widths between several atomic codes and
the OP. In this work, the atomic code STAR is used to study the sensitivity of
solar opacities to line-broadening. Variations in the solar opacity profile,
due to an increase of the Stark widths resulting from discrepancies with OP,
are compared, in light of the solar opacity problem, with the required opacity
variations of the present day sun, as imposed by helioseismic and neutrino
observations. The resulting variation profile, is much larger than the
discrepancy between different atomic codes, agrees qualitatively with the
missing opacity profile, recovers about half of the missing opacity nearby the
convection boundary and has a little effect in the internal regions. Since it
is hard to estimate quantitatively the uncertainty in the Stark widths, we show
that an increase of all line widths by a factor of about 100 recovers
quantitatively the missing opacity. These results emphasize the possibility
that photoexcitation processes are not modeled properly, and more specifically,
highlight the need for a better theoretical characterization of the line
broadening phenomena at stellar interior conditions and of the uncertainty due
to the way it is implemented by atomic codes.

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The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
14
The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
19
The categories of this paper are: eess
15
The categories of this paper are: nucl-ex
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The categories of this paper are: stat
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph