Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The final fates of close hot subdwarf - white dwarf binaries: mergers
  involving He/C/O white dwarfs and the formation of unusual giant stars with
  C/O-dominated envelopes   Recently, a class of Roche-lobe-filling binary systems consisting of hot
subdwarf stars and white dwarfs with sub-hour periods has been discovered. At
present, the hot subdwarf is in a shell He burning phase and is transferring
some of its remaining thin H envelope to its white dwarf companion. As the
evolution of the hot subdwarf continues, it is expected to detach, leaving
behind a low mass C/O core white dwarf secondary with a thick He layer. Then,
on a timescale of $\sim 10$ Myr, gravitational wave radiation will again bring
the systems into contact. If the mass transfer is unstable and results in a
merger and a catastrophic thermonuclear explosion is not triggered, it creates
a remnant with a C/O-dominated envelope, but one still rich enough in He to
support an R Corona Borealis-like shell burning phase. We present evolutionary
calculations of this phase and discuss its potential impact on the cooling of
the remnant white dwarf.

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The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
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The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
36
The categories of this paper are: cmp-lg
2
The categories of this paper are: math
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The categories of this paper are: bayes-an
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The categories of this paper are: funct-an
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The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
4
The categories of this paper are: cond-mat
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The categories of this paper are: alg-geom
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The categories of this paper are: nucl-ex