Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: STIS Coronagraphic Imaging of Fomalhaut: Main Belt Structure and the
  Orbit of Fomalhaut b   We present new optical coronagraphic data of the bright star Fomalhaut
obtained with the HST in 2010/2012 using STIS. Fomalhaut b is recovered at both
epochs to high significance. The observations include the discoveries of
tenuous nebulosity beyond the main dust belt detected to at least 209 AU
projected radius and a ~50 AU wide azimuthal gap in the belt northward of Fom
b. The morphology of Fomalhaut b appears elliptical in the STIS detections. We
show that residual noise in the processed data can plausibly result in point
sources appearing extended. A MCMC analysis demonstrates that the orbit of Fom
b is highly eccentric, with e=0.8+/-0.1, a=177+/-68 AU, and q = 32+/-24 AU. Fom
b is apsidally aligned with the belt and 90% of allowed orbits have mutual
inclination 36 deg or less. Fomalhaut b's orbit is belt-crossing in projection,
but only 12% of possible orbits have nodes within a 25 AU wide belt annulus
(133-158 AU). The high e invokes a dynamical history where Fom b may have
experienced a significant dynamical interaction with a hypothetical planet
Fomalhaut c, and the current orbital configuration may be relatively
short-lived. The new value for the periastron distance diminishes the Hill
radius of Fom b and any weakly bound satellite system surrounding a planet
would be sheared and dynamically heated at periapse. We argue that Fom b's
minimum mass is that of a dwarf planet in order for a circumplanetary satellite
system to remain bound to a sufficient radius from the planet to be consistent
with the dust scattered light hypothesis. Fom b may be optically bright because
the recent passage through periapse and/or the ascending node has increased the
erosion rates of planetary satellites. In the coplanar case, Fomalhaut b will
collide with the main belt around 2032, and the subsequent emergent phenomena
may help determine its physical nature.

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The categories of this paper are: nucl-th
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The categories of this paper are: comp-gas
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex
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The categories of this paper are: physics
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The categories of this paper are: q-bio
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The categories of this paper are: cmp-lg
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The categories of this paper are: nlin
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The categories of this paper are: q-alg
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The categories of this paper are: patt-sol
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The categories of this paper are: mtrl-th
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The categories of this paper are: cs
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The categories of this paper are: adap-org
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The categories of this paper are: stat
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The categories of this paper are: eess
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The categories of this paper are: plasm-ph