Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Halting Planet Migration in the Evacuated Centers of Protoplanetary
  Disks   Precise Doppler searches for extrasolar planets find a surfeit of planets
with orbital periods of 3-4 days, and no planets with orbital periods less than
3 days. The circumstellar distance, R_0, where small grains in a protoplanetary
disk reach sublimation temperature (~1500 K) corresponds to a period of ~6
days. Interior to R_0, turbulent accretion due to magneto-rotational
instability may evacuate the disk center. We suggest that planets with orbital
periods of 3-4 days are so common because migrating planets halt once this
evacuated region contains the sites of their exterior 2:1 Lindblad resonances.

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The categories of this paper are: adap-org
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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: acc-phys
1
The categories of this paper are: cs
4
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: alg-geom
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The categories of this paper are: dg-ga
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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: chem-ph
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The categories of this paper are: math
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The categories of this paper are: comp-gas
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The categories of this paper are: plasm-ph
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The categories of this paper are: nucl-ex