Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: NLTE Analysis of the Ultra-short Period White-dwarf Binary RX
  J0806.3+1527   RX J0806.3+1527 is suspected to be a double-degenerate white dwarf binary. We
present first results of our NLTE analysis of its optical spectrum. The
VLT/FORS1 data show a composite spectrum consisting of a blue continuum and
superimposed emission lines of the HeII Pickering series and, possibly, the H
Balmer series. Our models are based on hot white dwarf atmospheres and include
illumination effects onto the secondary star. The physical parameters and
chemical abundances derived from the comparison of the observed spectrum with a
grid of model atmospheres provide constraints on the true nature of this
enigmatic binary and on the models proposed so far.

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The categories of this paper are: q-fin
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The categories of this paper are: nlin
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The categories of this paper are: acc-phys
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
34
The categories of this paper are: chem-ph
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The categories of this paper are: hep-ex
1
The categories of this paper are: cs
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The categories of this paper are: stat
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The categories of this paper are: funct-an
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The categories of this paper are: chao-dyn
30
The categories of this paper are: q-alg
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The categories of this paper are: supr-con
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The categories of this paper are: plasm-ph
2
The categories of this paper are: math
35
The categories of this paper are: mtrl-th