Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Complete Evolution of a Neutron-Star Binary through a Common
  Envelope Phase Using 1D Hydrodynamic Simulations   Over forty years of research suggests that the common envelope phase, in
which an evolved star engulfs its companion upon expansion, is the critical
evolutionary stage forming short-period, compact-object binary systems, such as
coalescing double compact objects, X-ray binaries, and cataclysmic variables.
In this work, we adapt the one-dimensional hydrodynamic stellar evolution code,
MESA, to model the inspiral of a 1.4M$_{\odot}$ neutron star (NS) inside the
envelope of a 12$M_{\odot}$ red supergiant star. We self-consistently calculate
the drag force experienced by the NS as well as the back-reaction onto the
expanding envelope as the NS spirals in. Nearly all of the hydrogen envelope
escapes, expanding to large radii ($\sim$10$^2$ AU) where it forms an optically
thick envelope with temperatures low enough that dust formation occurs. We
simulate the NS orbit until only 0.8M$_{\odot}$ of the hydrogen envelope
remains around the giant star's core. Our results suggest that the inspiral
will continue until another $\approx$0.3M$_{\odot}$ are removed, at which point
the remaining envelope will retract. Upon separation, a phase of dynamically
stable mass transfer onto the NS accretor is likely to ensue, which may be
observable as an ultraluminous X-ray source. The resulting binary, comprised of
a detached 2.6M$_{\odot}$ helium-star and a NS with a separation of
3.3-5.7R$_{\odot}$, is expected to evolve into a merging double neutron-star,
analogous to those recently detected by LIGO/Virgo. For our chosen combination
of binary parameters, our estimated final separation (including the phase of
stable mass transfer) suggests a very high $\alpha_{\rm CE}$-equivalent
efficiency of $\approx$5.

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The categories of this paper are: chem-ph
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: hep-ex
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The categories of this paper are: eess
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The categories of this paper are: q-alg
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The categories of this paper are: funct-an
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The categories of this paper are: ao-sci
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The categories of this paper are: cs
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The categories of this paper are: cmp-lg
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The categories of this paper are: econ
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The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
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The categories of this paper are: gr-qc
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The categories of this paper are: quant-ph