Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gyrochronology and its usage for main sequence cool star ages   The construction of all age indicators consists of certain basic steps which
lead to the identification of the properties desirable for stellar age
indicators. Prior age indicators for main sequence field stars possess only
some of these properties. The measured rotation periods of cool stars are
particularly useful in this respect because they have well-defined dependencies
that allow stellar ages to be determined with ~20% errors. This method, called
gyrochronology, is explained informally in this talk, shown to have the desired
properties, compared to prior methods, and used to derive ages for samples of
main sequence field stars.

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The categories of this paper are: cond-mat
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The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-lat
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The categories of this paper are: cmp-lg
18
The categories of this paper are: econ
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The categories of this paper are: physics
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The categories of this paper are: patt-sol
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The categories of this paper are: stat
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The categories of this paper are: cs
34
The categories of this paper are: chem-ph
37
The categories of this paper are: supr-con
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The categories of this paper are: alg-geom
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The categories of this paper are: adap-org
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The categories of this paper are: quant-ph
0
The categories of this paper are: hep-ph