Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The ionization structure of early-B supergiant winds   We present empirically determined ionization conditions for the winds of 106
luminous B0 to B5 stars observed by IUE. The UV wind lines are modelled to
extract products of mass-loss rates (Mdot) times ionization fractions (Mdot
q_i(w), where w = v/v_infty) for N V, C IV, Si IV, Si III, Al III and C II. We
describe the general behaviour of the Mdot q_i(w) and their ratios,
demonstrating that the wind ionization increases with distance from the star,
contrary to recent findings for O star winds. Using empirical mass-loss rates
(from H alpha observations) and model prescriptions, we derive mean q_i(w)
values integrated over the wind, <q_i>. These <q_i> are quite small, never
exceeding 15% for Al III or 2% for Si IV. This is surprising, since the <q_i>
for these ions clearly peak within the observed spectral range. We conclude
that the low <q_i> arise because the <Mdot q_i> are underestimated by the wind
models, which assume that the outflows are smooth when they are, in fact,
highly structured.

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The categories of this paper are: patt-sol
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The categories of this paper are: comp-gas
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The categories of this paper are: econ
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The categories of this paper are: alg-geom
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The categories of this paper are: math
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The categories of this paper are: funct-an
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The categories of this paper are: math-ph
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-alg
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The categories of this paper are: dg-ga
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The categories of this paper are: atom-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: plasm-ph
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The categories of this paper are: nlin