No abstract

No abstract

No abstract

Compact neutron stars (NSs) can consist of either hadronic matter or strange quark matter or exotic color superconducting matter. If the stars have a quark core and are surrounded by hadronic matter, they are called hybrid stars (HSs). The HS is a mixture of the hadron and exotic quark phases. Observational results suggest that magnetars are certain NSs having huge surface magnetic field. We calculate equation of states (EOSs) of hadronic and quark matter at high densities in the presence of strong magnetic field and then study the quark–hadron phase having mixed phase in between giving rise to hybrid star. The intermediate mixed phase is constructed based on the Glendenning conjecture. The magnetic field significantly affects the EOS of the matter if the field strength is above [Formula: see text]G. We also calculate HS structure parameters such as the maximum mass, radius, moment of inertia, fundamental period and surface redshift and compare them specially the maximum mass with the recent observation of pulsars PSR 1903+0327 and PSR J1614-2230. The observation restricts a severe constraint on the EOS of matter at extreme conditions.

Compact stars are classified into three categories: neutron stars (NSs), quark stars (QSs) and hybrid stars (HSs). Stars having only hadronic matter are NSs, QSs having only quark matter up to u, d and s quarks and stars having quark core surrounded by a mixed matter (hadronic matter and quark matter) followed by hadronic matter are HSs. The mixed matter is well distributed to both hadron and quark matters. A huge magnetic field is predicted in the core of the neutron star and is observed in the surface of the neutron star. We study the effect of such huge magnetic field in the matter inside the compact objects basically the equation of state (EOS) of the matters. Since matter inside the star are very dense both hadronic and quark matter, we consider relativistic mean field theory in the hadronic matter and simple MIT bag model in the quark matter in the presence of strong magnetic field. We calculate the phase transition between hadronic and quark phases, maximum mass and eigenfrequencies of radial pulsation of NS, HS and QS in the presence of such a huge magnetic field. The mixed phase is constructed by using Glendenning conjecture in between hadron and quark phases. We find in the presence of magnetic field, the EOS in both matter becomes soft. As a result, the maximum mass is reduced and the period of oscillation is changed significantly and there is a sudden dip in the period of oscillations in the HS, which signifies the transition from one to another matter.