Nuclear symmetry energy and core-crust transition in neutron stars: A critical study

¹ CFC, Department of Physics, University of Coimbra - P3004 - 516, Coimbra, Portugal, EU
² Institut de Physique Nucléaire, Université Paris-Sud, IN2P3-CNRS - F-91406 Orsay Cedex, France, EU

^a camille@tepr.fis.uc.pt

Received: 9 June 2010
Accepted: 20 July 2010

Abstract

The slope of the nuclear symmetry energy at saturation density L is pointed out as a crucial quantity to determine the mass and width of neutron-star crusts. This letter clarifies the relation between L and the core-crust transition. We confirm that the transition density is soundly correlated with L despite differences between models, and we propose a clear understanding of this correlation based on a generalised liquid-drop model. Using a large number of nuclear models, we evaluate the dispersion affecting the correlation between the transition pressure P_t and L. From a detailed analysis it is shown that this correlation is weak due to a cancellation between different terms. The correlation between the isovector coefficients K_sym and L plays a crucial role in this discussion.