Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Radial pulsations and stability of protoneutron stars   Radial pulsations of newborn neutron stars (protoneutron stars) are studied
for a range of internal temperatures and entropies per baryon predicted by the
existing numerical simulations. Protoneutron star models are constructed using
a realistic equation of state of hot dense matter, and under various
assumptions concerning stellar interior (large trapped lepton number, zero
trapped lepton number, isentropic, isothermal). Under prevailing conditions,
linear oscillations of a protoneutron star can be treated as adiabatic, and
evolutionary effects can be neglected on dynamic timescale. The dynamic
behavior is governed by the adiabatic index, which in turn depends on the
physical state of the stellar interior. The eigenfrequencies of the lowest
radial modes of linear, adiabatic pulsations are calculated. Stability of
protoneutron stars with respect to small radial perturbations is studied, and
the validity of the static stability criteria is discussed.

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The categories of this paper are: gr-qc
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The categories of this paper are: chem-ph
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The categories of this paper are: q-bio
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The categories of this paper are: nlin
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The categories of this paper are: nucl-th
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The categories of this paper are: q-fin
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The categories of this paper are: dg-ga
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The categories of this paper are: stat
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The categories of this paper are: funct-an
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The categories of this paper are: adap-org
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The categories of this paper are: hep-lat
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The categories of this paper are: math
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The categories of this paper are: eess
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The categories of this paper are: ao-sci
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The categories of this paper are: mtrl-th
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The categories of this paper are: atom-ph