Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Disc Instabilities in Soft X-ray Transients   I briefly review the theory of soft X-ray transient systems. Irradiation of
the accretion disc faces by the central X-ray source determines both the
occurrence and the nature of the outbursts, in particular forcing these to be
long viscous events and producing exponential decays at short orbital periods.
Soft X-ray transients constitute the majority of LMXBs, persistent systems
being largely confined to a subset of neutron-star LMXBs with periods P < 2 d.
It appears that LMXBs very frequently contain nuclear-evolved companions, even
at short orbital periods. In long-period transients (P > 20 d) the outburst
recurrence times must become extremely long (> 1500 yr). The outbursts are
highly super-Eddington, markedly reducing the accretion efficiency. Spinup of a
neutron-star primary to millisecond periods probably cannot occur for orbital
periods > 200 d, in agreement with observations of binary pulsars.

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The categories of this paper are: eess
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The categories of this paper are: q-fin
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The categories of this paper are: q-bio
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The categories of this paper are: bayes-an
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The categories of this paper are: mtrl-th
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The categories of this paper are: hep-th
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The categories of this paper are: gr-qc
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The categories of this paper are: acc-phys
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The categories of this paper are: supr-con
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The categories of this paper are: math-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: funct-an
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The categories of this paper are: physics
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The categories of this paper are: cs
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The categories of this paper are: nucl-ex
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The categories of this paper are: stat