Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Bursting Behavior of 4U 1728-34: Parameters of a Neutron Star and
  Geometry of a NS-disk system   We analyze a set of Type I X-ray bursts from the low mass X-ray binary 4U
1728 -34, observed with Rossi X-ray Timing Explorer (RXTE). and we implement an
analytical model of X-ray spectral formation in the neutron star (NS)
atmosphere during a burst. We infer the dependence of the neutron star mass and
radius with respect to the assumed distance to the system using an analytical
model of X-ray burst spectral formation. The model behavior clearly indicates
that the burster atmosphere is helium-dominated. Our results strongly favor the
soft equation of state (EOS) of NS for 4U 1728-34. We find that distance to the
source should be within 4.5-5.0 kpc range. We obtain rather narrow constrains
for the NS radius in 8.7-9.7 km range and interval 1.2-1.6 solar masses for NS
mass for this particular distance range.
  We uncover a temporal behavior of red-shift corrected burst flux for the
radial expansion episodes and we put forth a dynamical evolution scenario for
the NS--accretion disk geometry during which an expanded envelope affects the
accretion disk and increases the area of the neutron star exposed to the Earth
observer. Our scenario enables us to explain the timing characteristics and
peak flux variation observed during the burst expansion stage, which is now
believed to be common phenomenon. In the framework of this scenario we provide
a new method for the estimation of the inclination angle which leads to the
value of 50 degrees for 4U 1728-34 .

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The categories of this paper are: chao-dyn
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The categories of this paper are: q-bio
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The categories of this paper are: stat
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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: chem-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: funct-an
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: eess
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-th
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The categories of this paper are: nlin
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The categories of this paper are: cs