Constraint on Properties of Rapidly Rotating Neutron Stars from Nuclear Symmetry Energy Slope

Key words: 
• symmetry energy /
• neutron star /
• rotation

Abstract: During the past decade, theoretical researches and terrestrial nuclear laboratory experiments have made impressive progresses on the researches of symmetry energy of the asymmetric nuclear matters, which is very important in understanding the equation of states and the structures of neutron stars. In this work, by making use of a conservative symmetry energy slope (SES) range (25 MeVare investigated. The constraint properties include the mass-radius relations, the moments of inertia, the redshift, the deformations of the rapid rotating stars, etc. According to the conservative SES range, it is shown that the radius of a canonical neutron star (with M = 1.4M⊙) can be constrained in a region of 10.28 s 13.43 km, which is consistent with one of the latest constraints on the radius of neutron star in observations. It is also shown that if a sub-millisecond pulsar with a lighter stellar mass is observed in the future, then a softer SES of the asymmetric nuclear matters is preferred. The universal property of the angular momentum provides a way to obtain the upper limit of the moment of inertia of a rapid rotating neutron star with observed mass. Moreover, the results also can provide a constraint on the lower mass limit (>1.5M⊙) of pulsar in low-mass X-ray binary EXO0748-676 if the observed redshift of this star is from the polar direction.