Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Discovery of the Interstellar Chiral Molecule Propylene Oxide
  (CH$_3$CHCH$_2$O)   Life on Earth relies on chiral molecules, that is, species not superimposable
on their mirror images. This manifests itself in the selection of a single
molecular handedness, or homochirality, across the biosphere. We present the
astronomical detection of a chiral molecule, propylene oxide (CH$_3$CHCH$_2$O),
in absorption toward the Galactic Center. Propylene oxide is detected in the
gas phase in a cold, extended molecular shell around the embedded, massive
protostellar clusters in the Sagittarius B2 star-forming region. This material
is representative of the earliest stage of solar system evolution in which a
chiral molecule has been found.

24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
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The categories of this paper are: q-fin
2
The categories of this paper are: math
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
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The categories of this paper are: stat
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The categories of this paper are: nucl-th
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The categories of this paper are: math-ph
4
The categories of this paper are: cond-mat
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The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
33
The categories of this paper are: plasm-ph