Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: K-Band Spectroscopy of (Pre-)Cataclysmic Variables: Are Some Donor Stars
  Really Carbon Poor?   We present a new sample of $K$-band spectral observations for CVs:
non-magnetic and magnetic as well as present day and pre CVs. The purpose of
this diverse sample is to address the recent claim that the secondary stars in
dwarf novae are carbon deficient, having become so through a far more evolved
evolution than the current paradigm predicts. Our new observations, along with
previous literature results, span a wide range of orbital period and CV type.
In general, dwarf novae in which the secondary star is seen show weak to no CO
absorption while polar and pre-CV donor stars appear to have normal CO
absorption for their spectral type. However, this is not universal. The
presence of normal looking CO absorption in the dwarf nova SS Aur and the
hibernating CV QS Vir and a complete lack of CO absorption in the long period
polar V1309 Ori cloud the issue. A summary of the literature pointing to
non-solar abundances including enhanced NV/CIV ratios is presented. It appears
that some CVs have non-solar abundance material accreting onto the white dwarf
suggesting an evolved secondary star while for others CO emission in the
accretion disk may play a role. However, the exact mechanism or combination of
factors causing the CO absorption anomaly in CVs is not yet clear.

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The categories of this paper are: adap-org
30
The categories of this paper are: q-alg
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The categories of this paper are: quant-ph
31
The categories of this paper are: ao-sci
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The categories of this paper are: cmp-lg
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The categories of this paper are: stat
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The categories of this paper are: alg-geom
2
The categories of this paper are: math
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The categories of this paper are: chao-dyn
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The categories of this paper are: eess
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The categories of this paper are: hep-th
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The categories of this paper are: hep-ex
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The categories of this paper are: atom-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: funct-an
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The categories of this paper are: supr-con