Name: Monika Sinha
Affiliation: Indian Institute of Technology Jodhpur
Conference ID : ASI2022_848
Title : Effect of nuclear symmetry energy on neutron star properties
Authors : Monika Sinha
Abstract Type: Invited
Abstract Category : General Relativity and Cosmology
Abstract : The highly dense neutron star matter can not be produced in terrestrial laboratories. Still the properties of such highly dense matter can be extrapolated from the nuclear matter at nuclear saturation density and can be verified from the astrophysical observations of neutron stars. We study the effect of nuclear symmetry energy and its behaviour with density on the neutron star properties and attempt to constrain the matter properties at that much high density. We find that the symmetry energy and its slope with density have substantial effect on radius of stars. With the so far known range of symmetry energy and its slope, we find the theoretically obtained radius of star with only nucleons as well as with baryonic matter with exotic particles matches with the observational measurement of star radius. We also show that the values of symmetry energy and its slope are also consistent with the softness of matter as inferred from gravitational wave observations. However, recent measurement of nuclear symmetry energy and its slope by PREX2 data indicate that the star with only nucleons have larger radius than the observed. We conclude that the existence of hyperons and delta resonances within neutron star can be a possible scenario to fulfil both the nuclear physics and astrophysical data. The value of symmetry energy slope affects the threshold density of appearance hyperons and delta baryons. The symmetry energy and its slope have important influence on the relative abundances of nucleons. We find with new estimated values of these nuclear properties the proton fraction increases substantially making the direct URCA process possible even for the low mass stars. This opens up the possibility of rapid cooling in case of the most stars.