Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the Eccentricity Excitation in Post-Main Sequence Binaries   Several classes of stellar binaries with post-main sequence (post-MS)
components - millisecond pulsars with the white dwarf companions (MSP+WD) and
periods P_b~30 d, binaries hosting post-asymptotic giant branch (post-AGB)
stars or barium stars with P_b~several yr - feature high eccentricities (up to
0.4) despite the expectation of their efficient tidal circularization during
the AGB phase. It was suggested that the eccentricities of these binaries can
be naturally excited by their tidal coupling to the circumbinary disk, formed
by the material ejected from the binary. Here we critically reassess this idea
using simple arguments rooted in the global angular momentum conservation of
the disk+binary system. Compared to previous studies we (1) fully account for
the viscous spreading of the circumbinary disk, (2) consider the possibility of
reaccretion from the disk onto the binary (in agreement with simulations and
empirical evidence), and (3) allow for the reduced viscosity after the disk
expands, cools, and forms dust. These ingredients conspire to significantly
lower the efficiency of eccentricity excitation by the disk tides. We find that
explaining eccentricities of the post-AGB binaries is difficult and requires
massive ($> 10^{-2}M_\odot$), long-lived ($> 10^5$ yr) circumbinary disks, that
do not reaccrete. Reaccretion is detrimental for the eccentricity growth also
in the MSP+WD systems. Reduced efficiency of the disk-driven excitation
motivates study of alternative mechanisms for producing the peculiar
eccentricities of the post-MS binaries.

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The categories of this paper are: supr-con
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
15
The categories of this paper are: nucl-ex
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The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
9
The categories of this paper are: nlin
14
The categories of this paper are: math-ph
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The categories of this paper are: solv-int
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The categories of this paper are: cmp-lg
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The categories of this paper are: adap-org
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-ex
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The categories of this paper are: plasm-ph
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The categories of this paper are: q-alg