Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Photoionization models of the Eskimo nebula: evidence for a binary
  central star?   The ionizing star of the planetary nebula NGC 2392 is too cool to explain the
high excitation of the nebular shell, and an additional ionizing source is
necessary. We use photoionization modeling to estimate the temperature and
luminosity of the putative companion. Our results show it is likely to be a
very hot (Teff ~ 250kK), dense white dwarf. If the stars form a close binary,
they may merge within a Hubble time, possibly producing a Type Ia supernova.

26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
25
The categories of this paper are: patt-sol
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg