Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Early B-type stars with resolved Zeeman split lines   Almost three decades ago, Mathys (1990) demonstrated the importance of
studying Ap stars showing resolved Zeeman split Fe II 6147.7 and 6149.2 lines.
Such Zeeman split lines can be seen in stars whose projected rotational
velocity is sufficiently small and whose magnetic field is strong enough to
exceed the rotational Doppler broadening. Observations of resolved Zeeman split
lines permit the diagnosis of the average of the modulus of the magnetic field
over the visible stellar hemisphere. Although Zeeman splitting is not expected
in faster rotating hot massive stars, we have recently been discovering early
B-type stars displaying magnetically split spectral lines.

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The categories of this paper are: hep-ex
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The categories of this paper are: eess
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: econ
31
The categories of this paper are: ao-sci
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The categories of this paper are: nlin
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The categories of this paper are: stat
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The categories of this paper are: cmp-lg
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The categories of this paper are: cs
32
The categories of this paper are: atom-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: chao-dyn
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex