J/A+A/665/A74 Equations of state of accreting neutron stars (Fantina+, 2022)
Accreting neutron stars from the nuclear energy-density functional theory.
II. Equation of state and global properties.
Fantina A.F., Zdunik, J.L., Chamel N., Pearson J.M., Suleiman, L.,
Goriely S.
<Astron. Astrophys. 665, A74 (2022)>
=2022A&A...665A..74F 2022A&A...665A..74F (SIMBAD/NED BibCode)
ADC_Keywords: Stars, neutron ; Models ; Accretion
Keywords: dense matter - equation of state - stars: neutron -
accretion, accretion disks -
nuclear reactions, nucleosynthesis, abundances
Abstract:
We study the impact of accretion on the equation of state and on the
global properties of neutron stars in the framework of the nuclear
energy-density functional theory.
Considering ashes made of 56Fe, we calculate the equations of state
using the Brussels-Montreal generalised Skyrme functionals BSk19,
BSk20, and BSk21, that have been already employed for determining the
crustal heating for the same ashes. Unified equations of state for
catalyzed neutron stars based on the same functionals are also
available. All regions of accreting neutron stars are treated in a
unified and thermodynamically consistent way. The equation of state of
accreted neutron-star crusts is found to be significantly stiffer than
that of catalyzed matter and, for this reason, accreting neutron stars
have larger radii. However, their crustal moment of inertia and their
tidal deformability are hardly changed provided density
discontinuities at the interface between adjacent crustal layers are
properly taken into account.
The enhancement of the stiffness of the equation of state of accreting
neutron stars is mainly a consequence of nuclear shell effects, thus
confirming the importance of a quantum treatment. With our previous
calculations of crustal heating using the same functionals, we have
thus obtained consistent microscopic inputs for simulations of
accreting neutron stars.
Description:
Three unified equations of state for accreting neutron-star matter,
reflecting the current lack of knowledge of the high-density matter,
are presented.
For each equation of state (BSk19, BSk20, and BSk21), the baryon
number density, the mass-energy density, and the pressure are given.
The equations of state are given up to the maximum baryon number
density consistent with causality (i.e. requiring that the speed of
sound remains lower than the speed of light).
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
eosbsk19.dat 50 1441 Baryon number and mass-energy densities, pressure
for equation of state BSk19
eosbsk20.dat 50 1121 Baryon number and mass-energy densities, pressure
for equation of state BSk20
eosbsk21.dat 50 1122 Baryon number and mass-energy densities, pressure
for equation of state BSk21
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Byte-by-byte Description of file: eosbsk*.dat
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Bytes Format Units Label Explanations
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1- 16 E16.8 1/fm3 nb Baryon number density
18- 33 E16.8 Mg/m3 rho Mass-energy density (1)
35- 50 E16.8 dPa Pres Pressure (2)
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Note (1): The SI unit Mg/m3 is equivalent to the CGS unit g/cm3.
Note (2): The SI unit dPa is equivalent to the CGS unit erg/cm3 or
equivalent to dyn/cm2.
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Acknowledgements:
Anthea F. Fantina,
References:
Goriely, Chamel, & Pearson, 2010PhRvC..82c5804G 2010PhRvC..82c5804G
Fantina, Zdunik, Chamel, Pearson, Haensel, & Goriely, 2018A&A...620A.105F 2018A&A...620A.105F
(End) Anthea F. Fantina [GANIL], Patricia Vannier [CDS] 28-Jul-2022