J/A+A/584/A103 Unified EoS for neutron stars (Sharma+, 2015)
Unified equation of state for neutron stars on a microscopic basis.
Sharma B.K., Centelles M., Vinas X., Baldo M., Burgio G.F.
<Astron. Astrophys. 584, A103 (2015)>
=2015A&A...584A.103S 2015A&A...584A.103S (SIMBAD/NED BibCode)
ADC_Keywords: Models ; Pulsars
Keywords: dense matter - equation of state - stars: neutron
Abstract:
We derive a new equation of state (EoS) for neutron stars (NS) from
the outer crust to the core based on modern microscopic calculations
using the Argonne v18 potential plus three-body forces computed with
the Urbana model. To deal with the inhomogeneous structures of matter
in the NS crust, we use a recent nuclear energy density functional
that is directly based on the same microscopic calculations, and which
is able to reproduce the ground-state properties of nuclei along the
periodic table. The EoS of the outer crust requires the masses of
neutron-rich nuclei, which are obtained through
Hartree-Fock-Bogoliubov calculations with the new functional when they
are unknown experimentally. To compute the inner crust, Thomas-Fermi
calculations in Wigner-Seitz cells are performed with the same
functional. Existence of nuclear pasta is predicted in a range of
average baryon densities between 0.067fm-3 and 0.0825fm-3, where the
transition to the core takes place. The NS core is computed from the
new nuclear EoS assuming non-exotic constituents (core of n-p-e-mu
matter). In each region of the star, we discuss the comparison of the
new EoS with previous EoSs for the complete NS structure, widely used
in astrophysical calculations. The new microscopically derived EoS
fulfills at the same time a NS maximum mass of 2 solar masses with a
radius of 10km, and a 1.5 solar mass NS with a radius of 11.6km.
Description:
A unified equation of state for neutron stars derived from microscopic
calculations is presented.
The composition and the EoS (mass-energy density, pressure, and
adiabatic index) are provided as functions of the baryon number
density for the outer crust, the inner crust, and the core of the
neutron star.
The composition is given as atomic number and mass number in the outer
crust and the inner crust, and as proton fraction, electron fraction,
and muon fraction in the core.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
crust1.dat 60 44 Composition and EoS for the outer crust (table 4)
crust2.dat 66 53 Composition and EoS for the inner crust (table 6)
core.dat 71 35 Composition and EoS for the core
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Byte-by-byte Description of file: crust1.dat
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Bytes Format Units Label Explanations
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1- 10 E10.4 fm-3 nb Baryon number density
15- 16 I2 --- Z Atomic number
21- 23 I3 --- A Mass number
28- 37 E10.4 Mg/m3 epsilon Mass-energy density (G1)
42- 51 E10.4 dPa P Pressure (G2)
56- 60 F5.3 --- Gamma Adiabatic index
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Byte-by-byte Description of file: crust2.dat
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Bytes Format Units Label Explanations
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1- 7 F7.5 fm-3 nb Baryon number density
12- 17 F6.3 --- Z Atomic number
22- 29 F8.3 --- A Mass number
34- 43 E10.4 Mg/m3 epsilon Mass-energy density (G1)
48- 57 E10.4 dPa P Pressure (G2)
62- 66 F5.3 --- Gamma Adiabatic index
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Byte-by-byte Description of file: core.dat
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Bytes Format Units Label Explanations
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1- 6 F6.4 fm-3 nb Baryon number density
11- 16 F6.3 --- xp Proton fraction
21- 26 F6.3 --- xe Electron fraction
31- 36 F6.3 --- xmu Muon fraction
41- 49 E9.4 Mg/m3 epsilon Mass-energy density (G1)
54- 62 E9.4 dPa P Pressure (G2)
67- 71 F5.3 --- Gamma Adiabatic index
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Global notes:
Note (G1): The SI unit Mg/m3 is equivalent to the CGS unit g/cm3.
Note (G2): The SI unit dPa is equivalent to the CGS unit erg/cm3.
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Acknowledgements:
Mario Centelles, mariocentelles(at)ub.edu
(End) Mario Centelles [Barcelona University], Patricia Vannier [CDS] 02-Nov-2015