Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Lower limits on the maximum orbital frequency around rotating strange
  stars   Observations of kHz quasi-periodic oscillations (QPOs) in the X-ray fluxes of
low-mass X-ray binaries (LMXBs) have been used in attempts to constrain the
external metric of the compact members of these binaries, as well as their
masses and the equation of state of matter at supranuclear denisties. We
compute the maximum orbital frequency of stable circular motion around
uniformly rotating strange stars described by the MIT bag model. The
calculations are performed for both normal and supramassive constant baryon
mass sequences of strange stars rotating at all possible rates. We find the
lower limits on the maximum orbital frequency and discuss them for a range of
masses and for all rotational frequencies allowed in the model considered. We
show that for slowly and moderately rotating strange stars the maximum value of
orbital frequency can be a good indicator of the mass of the compact object.
However, for rapidly rotating strange stars the same value of orbital frequency
in the innermost stable circular orbit is obtained for stars with masses
ranging from that of a planetoid to about three solar masses. At sufficiently
high rotation rates of the strange star, the rotational period alone constrains
the stellar mass to a surprisingly narrow range.

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The categories of this paper are: physics
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The categories of this paper are: solv-int
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The categories of this paper are: chem-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-ph
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The categories of this paper are: stat
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-ex
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The categories of this paper are: nlin
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The categories of this paper are: atom-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-fin
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The categories of this paper are: cs
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The categories of this paper are: comp-gas
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The categories of this paper are: funct-an
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The categories of this paper are: math-ph