Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Radio Observations of Masers in Post-AGB Stars   We present observations of 86 post-Asymptotic Giant Branch (post-AGB) stars
of OH maser transitions, taken with the Parkes Telescope between September 2002
and August 2003. Post-AGB stars are the precursors of planetary nebulae, which
have a wide range of morphologies that are not well explained. By studying the
circumstellar envelopes of post-AGB stars through the masers produced in them,
we hope to shed light on the origin of planetary nebula morphologies.

20
The categories of this paper are: acc-phys
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
5
The categories of this paper are: gr-qc
33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
8
The categories of this paper are: hep-ex
14
The categories of this paper are: math-ph
31
The categories of this paper are: ao-sci
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
24
The categories of this paper are: dg-ga
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th