Nonrotating and rotating neutron stars in the extended field theoretical model

Abstract

We study the properties of non-rotating and rotating neutron stars for a new set of equations of state (EOSs) with different high density behaviour obtained using the extended field theoretical model. The high density behaviour for these EOSs are varied by varying the ω−meson self-coupling and hyperon-meson couplings in such a way that the quality of fit to the bulk nuclear observables, nuclear matter incompressibility coefficient and hyperon-nucleon potential depths remain practically unaffected. We find that the largest value for maximum mass for the non-rotating neutron star is 2.1M ⊙ . The radius for the neutron star with canonical mass is 12.8 − 14.1 km provided only those EOSs are considered for which maximum mass is larger than 1.6M ⊙ as it is the lower bound on the maximum mass measured so far. Our results for the very recently discovered fastest rotating neutron star indicate that this star is supra massive with mass 1.7 − 2.7M ⊙ and circumferential equatorial radius 12 − 19 km.

Constraining the symmetry energy content of nuclear matter from nuclear masses: A covariance analysis

“…The binding energy difference between the two Ne-nuclei is expected to cancel the pairing and the possible core-polarization effects arising from the two valence protons partially. In Fig.1 the binding energy difference between the four pairs of nuclei are plotted against ∆r np of 208 Pb, the ∆r np and the binding energies being calculated for seven models of BSR family [40,41], NL3 [42], FSU [8] and for seven models of Density Dependent Meson Exchange (DDME) family [43]. The correlation coefficient for the Ni-pair is seen to be only 0.012, for the Sn-pair, it has increased to 0.586.…”

Stable configurations of hybrid stars with color-flavor-locked core

“…The contributions of self-interaction of ρ-meson are ignored as they affect the ground state properties of heavy nuclei and compact stars only very marginally [39]. In our recent work [38] we have obtained several parameterizations of the extended FTRMF model in such a way that the bulk nuclear observables and nuclear matter incompressibility coefficient are fitted well. These different parameterizations produce different behavior for the EOS at high densities.…”

“…The contribution from the self-interaction of ω-mesons plays an important role in determining the high density behavior of EOS and consequently the structure properties of compact stars [38,39]. The contributions of self-interaction of ρ-meson are ignored as they affect the ground state properties of heavy nuclei and compact stars only very marginally [39].…”

The attribute of rotational profile to the hyperon puzzle in the prediction of heaviest compact star

“…[40][41][42][43][44][45] It is well known that the theoretical Mass-Radius relation depends on the rotation frequency and also the presence of an exotic core in massive neutron star. Within the present scenario, all neutron stars rotate and there are many millisecond pulsars with rotation frequency ≥ 500 Hz (10 accreting X-ray pulsars and 14 radio/gamma-ray pulsars).…”

“…In the interior of a neutron star, where the density is very high, other hadronic states are produced. [40][41][42][43][44][45] Thus, the considered model involves the full octet of baryons interacting through mesons. Finally, the truncated Lagrangian is given by…”