Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The effects of surface fossil magnetic fields on massive star evolution:
  II. Implementation of magnetic braking in MESA and implications for the
  evolution of surface rotation in OB stars   The time evolution of angular momentum and surface rotation of massive stars
is strongly influenced by fossil magnetic fields via magnetic braking. We
present a new module containing a simple, comprehensive implementation of such
a field at the surface of a massive star within the Modules for Experiments in
Stellar Astrophysics (MESA) software instrument. We test two limiting scenarios
for magnetic braking: distributing the angular momentum loss throughout the
star in the first case, and restricting the angular momentum loss to a surface
reservoir in the second case. We perform a systematic investigation of the
rotational evolution using a grid of OB star models with surface magnetic
fields ($M_\star=5-60$ M$_\odot$, $\Omega/\Omega_{\rm crit} =0.2-1.0$, $B_{\rm
p} =1-20$ kG). We then employ a representative grid of B-type star models
($M_\star=5, 10, 15$ M$_\odot$, $\Omega/\Omega_{\rm crit} =0.2 , 0.5, 0.8$,
$B_{\rm p} = 1, 3 ,10, 30$ kG) to compare to the results of a recent
self-consistent analysis of the sample of known magnetic B-type stars. We infer
that magnetic massive stars arrive at the zero age main sequence with a range
of rotation rates, rather than with one common value. In particular, some stars
are required to have close-to-critical rotation at the ZAMS. However, magnetic
braking yields surface rotation rates converging to a common low value, making
it difficult to infer the initial rotation rates of evolved, slowly-rotating
stars.

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The categories of this paper are: atom-ph
7
The categories of this paper are: hep-th
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
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The categories of this paper are: adap-org
14
The categories of this paper are: math-ph
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
23
The categories of this paper are: solv-int
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The categories of this paper are: funct-an
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The categories of this paper are: comp-gas
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The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio