TY - GEN

T1 - Shell effects in hot nuclei and their influence on nuclear composition in supernova matter

AU - Nishimura, Suguru

AU - Takano, Masatoshi

PY - 2014

Y1 - 2014

N2 - We calculate nuclear composition in supernova (SN) matter explicitly taking into account the temperature dependence of nuclear shell effects. The abundance of nuclei in SN matter is important in the dynamics of core-collapse supernovae and, in recently constructed equations of state (EOS) for SN matter, the composition of nuclei are calculated assuming nuclear statistical equilibrium wherein the nuclear internal free energies govern the composition. However, in these EOS, thermal effects on the shell energy are not explicitly taken into account. To address this shortfall, we calculate herein the shell energies of hot nuclei and examine their influence on the composition of SN matter. Following a simplified macroscopic-microscopic approach, we first calculate single-particle (SP) energies by using a spherical Woods-Saxon potential. Then we extract shell energies at finite temperatures using Strutinsky method with the Fermi distribution as the average occupation probability of the SP levels. The results show that at relatively low temperatures, shell effects are still important and magic nuclei are abundant. However, at temperatures above approximately 2 MeV, shell effects are almost negligible, and the mass fractions with shell energies including the thermal effect are close to those obtained from a simple liquid drop model at finite temperatures.

AB - We calculate nuclear composition in supernova (SN) matter explicitly taking into account the temperature dependence of nuclear shell effects. The abundance of nuclei in SN matter is important in the dynamics of core-collapse supernovae and, in recently constructed equations of state (EOS) for SN matter, the composition of nuclei are calculated assuming nuclear statistical equilibrium wherein the nuclear internal free energies govern the composition. However, in these EOS, thermal effects on the shell energy are not explicitly taken into account. To address this shortfall, we calculate herein the shell energies of hot nuclei and examine their influence on the composition of SN matter. Following a simplified macroscopic-microscopic approach, we first calculate single-particle (SP) energies by using a spherical Woods-Saxon potential. Then we extract shell energies at finite temperatures using Strutinsky method with the Fermi distribution as the average occupation probability of the SP levels. The results show that at relatively low temperatures, shell effects are still important and magic nuclei are abundant. However, at temperatures above approximately 2 MeV, shell effects are almost negligible, and the mass fractions with shell energies including the thermal effect are close to those obtained from a simple liquid drop model at finite temperatures.

KW - Strutinsky method

KW - equation of state

KW - nuclear statistical equilibrium

KW - shell effects

KW - supernova

UR - http://www.scopus.com/inward/record.url?scp=84903154571&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84903154571&partnerID=8YFLogxK

U2 - 10.1063/1.4874076

DO - 10.1063/1.4874076

M3 - Conference contribution

AN - SCOPUS:84903154571

SN - 9780735412286

T3 - AIP Conference Proceedings

SP - 239

EP - 244

BT - Origin of Matter and Evolution of Galaxies 2013 - Proceedings of the 12th International Symposium on Origin of Matter and Evolution of Galaxies, OMEG 2013

PB - American Institute of Physics Inc.

T2 - 12th International Symposium on Origin of Matter and Evolution of Galaxies, OMEG 2013

Y2 - 18 November 2013 through 21 November 2013

ER -