A NEW BARYONIC EQUATION OF STATE AT SUB-NUCLEAR DENSITIES FOR CORE-COLLAPSE SIMULATIONS

Journal Article · Sat Sep 10 00:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/738/2/178; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21584856

Furusawa, Shun; Yamada, Shoichi ^[1]; Sumiyoshi, Kohsuke ^[2]; Suzuki, Hideyuki ^[3]

---

1. Department of Science and Engineering, Waseda University, 3-4-1 Okubo, Shinjuku, Tokyo 169-8555 (Japan)
2. Numazu College of Technology, Ooka 3600, Numazu, Shizuoka 410-8501 (Japan)
3. Faculty of Science and Technology, Tokyo University of Science, Yamazaki 2641, Noda, Chiba 278-8510 (Japan)

We calculate a new equation of state for baryons at sub-nuclear densities meant for the use in core-collapse simulations of massive stars. The abundances of various nuclei are obtained together with the thermodynamic quantities. The formulation is the nuclear statistical equilibrium description and the liquid drop approximation of nuclei. The model free energy to minimize is calculated by relativistic mean field theory for nucleons and the mass formula for nuclei with atomic number up to {approx}1000. We have also taken into account the pasta phase, thanks to which the transition to uniform nuclear matter in our equation of state (EOS) occurs in the conventional manner: nuclei are not dissociated into nucleons but survive right up to the transition to uniform nuclear matter. We find that the free energy and other thermodynamical quantities are not very different from those given in the H. Shen's EOS, one of the standard EOSs that adopt the single nucleus approximation. On the other hand, the average mass is systematically different, which may have an important ramification to the rates of electron captures and coherent neutrino scatterings on nuclei in supernova cores. It is also interesting that the root mean square of the mass number is not very different from the average mass number, since the former is important for the evaluation of coherent scattering rates on nuclei but has been unavailable so far. The EOS table is currently under construction, which will include the weak interaction rates.

• OSTI ID: 21584856
• Journal Information: Astrophysical Journal, Vol. 738, Issue 2; Other Information: DOI: 10.1088/0004-637X/738/2/178; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ABUNDANCE
EQUATIONS OF STATE
FREE ENERGY
MASS
MASS FORMULAE
MASS NUMBER
MEAN-FIELD THEORY
NEUTRINOS
NUCLEAR MATTER
NUCLEAR REACTIONS
NUCLEI
NUCLEONS
NUCLEOSYNTHESIS
SIMULATION
SUPERNOVAE
BARYONS
BINARY STARS
ELEMENTARY PARTICLES
ENERGY
EQUATIONS
ERUPTIVE VARIABLE STARS
FERMIONS
HADRONS
LEPTONS
MASSLESS PARTICLES
MATTER
PHYSICAL PROPERTIES
STARS
SYNTHESIS
THERMODYNAMIC PROPERTIES
VARIABLE STARS