Statistical description of complex nuclear phases in supernovae and proto-neutron stars

Journal Article · Wed Dec 15 00:00:00 EST 2010 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.82.065801· OSTI ID:21499296

Raduta, Ad R ^[1]; Gulminelli, F ^[2]

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1. NIPNE, Bucharest-Magurele, POB-MG6 (Romania)
2. LPC - IN2P3-CNRS/Ensicaen et Universite, F-14076 Caen cedex (France)

We develop a phenomenological statistical model for dilute star matter at finite temperature, in which free nucleons are treated within a mean-field approximation and nuclei are considered to form a loosely interacting cluster gas. Its domain of applicability, that is, baryonic densities ranging from about {rho}>10{sup 8} g/cm{sup 3} to normal nuclear density, temperatures between 1 and 20 MeV, and proton fractions between 0.5 and 0, makes it suitable for the description of baryonic matter produced in supernovae explosions and proto-neutron stars. The first finding is that, contrary to the common belief, the crust-core transition is not first order, and for all subsaturation densities matter can be viewed as a continuous fluid mixture between free nucleons and massive nuclei. As a consequence, the equations of state and the associated observables do not present any discontinuity over the whole thermodynamic range. We further investigate the nuclear matter composition over a wide range of densities and temperatures. At high density and temperature our model accounts for a much larger mass fraction bound in medium nuclei with respect to traditional approaches as Lattimer-Swesty, with sizable consequences on the thermodynamic quantities. The equations of state agree well with the presently used EOS only at low temperatures and in the homogeneous matter phase, while important differences are present in the crust-core transition region. The correlation among the composition of baryonic matter and neutrino opacity is finally discussed, and we show that the two problems can be effectively decoupled.

• OSTI ID: 21499296
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 82, Issue 6; Other Information: DOI: 10.1103/PhysRevC.82.065801; (c) 2010 American Institute of Physics; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
APPROXIMATIONS
CORRELATIONS
DENSITY
EQUATIONS OF STATE
EXPLOSIONS
FLUIDS
MASS
MEAN-FIELD THEORY
MEV RANGE
NEUTRINOS
NEUTRON STARS
NUCLEAR MATTER
NUCLEI
OPACITY
PROTONS
STATISTICAL MODELS
SUPERNOVAE
BARYONS
BINARY STARS
CALCULATION METHODS
ELEMENTARY PARTICLES
ENERGY RANGE
EQUATIONS
ERUPTIVE VARIABLE STARS
FERMIONS
HADRONS
LEPTONS
MASSLESS PARTICLES
MATHEMATICAL MODELS
MATTER
NUCLEONS
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
STARS
VARIABLE STARS