Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Synchronous Satellites of Venus   Synchronous satellites of Venus have long been thought unstable, but we use
Poincare's surface of section technique to show that synchronous
quasi-satellites orbiting just outside Venus' Hill sphere are quite stable, at
least for centuries. Such synchrosats always remain within a few degrees of
Venus' equator, and drift very slowly in longitude. These synchrosats could be
useful for continuous monitoring of points on Venus' surface, such as active
landforms or long-lived landers.

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The categories of this paper are: math
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The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
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The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-th
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ph
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The categories of this paper are: econ
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The categories of this paper are: eess
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The categories of this paper are: comp-gas
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The categories of this paper are: physics
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The categories of this paper are: bayes-an
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The categories of this paper are: funct-an
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The categories of this paper are: cond-mat