Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Hydrogen Burning on Magnetar Surfaces   We compute the rate of diffusive nuclear burning for hydrogen on the surface
of a "magnetar" (Soft Gamma-Ray Repeater or Anomalous X-Ray Pulsar). We find
that hydrogen at the photosphere will be burned on an extremely rapid timescale
of hours to years, depending on composition of the underlying material.
Improving on our previous studies, we explore the effect of a maximally thick
"inert" helium layer, previously thought to slow down the burning rate. Since
hydrogen diffuses faster in helium than through heavier elements, we find this
helium buffer actually increases the burning rate for magnetars. We compute
simple analytic scalings of the burning rate with temperature and magnetic
field for a range of core temperature. We conclude that magnetar photospheres
are very unlikely to contain hydrogen. This motivates theoretical work on heavy
element atmospheres that are needed to measure effective temperature from the
observed thermal emission and constrains models of AXPs that rely on magnetar
cooling through thick light element envelopes.

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The categories of this paper are: nlin
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The categories of this paper are: quant-ph
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The categories of this paper are: q-alg
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The categories of this paper are: adap-org
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The categories of this paper are: cs
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The categories of this paper are: math
33
The categories of this paper are: plasm-ph
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-ex
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The categories of this paper are: stat
34
The categories of this paper are: chem-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: gr-qc
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The categories of this paper are: econ
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The categories of this paper are: cmp-lg
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The categories of this paper are: eess