Using the model based on the Regge-like laws, new analytical formulas are obtained for the moment of inertia, the rotation frequency, and the radius of astronomical non-exotic objects (planets, stars, galaxies, and clusters of galaxies). The rotation frequency and moment of inertia of a neutron star and the observable Universe are estimated. The estimates of the average numbers of stars and galaxies in the observable Universe are given. The Darwin instability effect in the binary systems (di-planets, di-stars, and di-galaxies) is also analyzed.
With the recent measurement of GW170817 providing constraints on the tidal deformability (TD) of a neutron star, it is very important to understand what features of the equation of state (EoS) have the biggest effect on it. We therefore study the contribution of the crust to the TD and the moment of inertia (MoI) of a neutron star for a variety of well-known EoS. It is found that the contributions to these quantities from the low-density crust are typically quite small and as a result the determination of the TD provides an important constraint on the EoS of dense matter.
The properties of neutron star at temperatures 5 MeV, 10 MeV and 15 MeV are calculated by solving Tolmann–Oppenheimer–Volkoff (TOV) equation. The required equation of state of pure neutron matter is obtained using density dependent Sussex interaction. It is observed that maximum stable mass of the star corresponds to minimum gravitational radius for a given equation of state. Just like the limiting mass, limiting value of redshift, moment of inertia, Kepler frequency as well as Kepler period are observed in case of the neutron star. It is found that the star become somewhat 'massive' and 'fat' at higher temperatures. With the increase in temperature the moment of inertia and Kepler rotational period increase but redshift decreases and Kepler frequency slows down. We also predict that there is a possibility of pion condensation in pure neutron matter.
The moment of inertia of the neutron star PSR J0348+0432 and its proto neutron star
