Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A modified "Type I migration" model for propeller moons in Saturn's
  rings   We propose a mechanism for the observed non-keplerian motion (Tiscareno et
al. 2010, ApJL) of "propeller" moons embedded in Saturn's rings. Our mechanism,
in which radial variations in surface density -- external to, and unaffected
by, the embedded moon -- result in an equilibrium semimajor axis for the moon
due to "Type I" angular momentum exchange (Crida et al. 2010, AJ), provides a
good fit to the observations. Future observations should distinguish between
our model and others recently proposed.

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The categories of this paper are: cs
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The categories of this paper are: q-bio
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The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
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The categories of this paper are: stat
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The categories of this paper are: nucl-ex
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The categories of this paper are: solv-int
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The categories of this paper are: alg-geom
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The categories of this paper are: gr-qc
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The categories of this paper are: comp-gas
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The categories of this paper are: cond-mat
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The categories of this paper are: bayes-an
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The categories of this paper are: quant-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: supr-con
14
The categories of this paper are: math-ph