Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Galactic Habitable Zone and the Age Distribution of Complex Life in
  the Milky Way   We modeled the evolution of the Milky Way to trace the distribution in space
and time of four prerequisites for complex life: the presence of a host star,
enough heavy elements to form terrestrial planets, sufficient time for
biological evolution and an environment free of life-extinguishing supernovae.
We identified the Galactic habitable zone (GHZ) as an annular region between 7
and 9 kiloparsecs from the Galactic center that widens with time and is
composed of stars that formed between 8 and 4 billion years ago. This GHZ
yields an age distribution for the complex life that may inhabit our Galaxy. We
found that 75% of the stars in the GHZ are older than the Sun.

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The categories of this paper are: dg-ga
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
21
The categories of this paper are: adap-org
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The categories of this paper are: eess
16
The categories of this paper are: stat
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The categories of this paper are: bayes-an
31
The categories of this paper are: ao-sci
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
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The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
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The categories of this paper are: hep-lat
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph