Kalin V. Staykov

Non-perturbative and self-consistent models of neutron stars in R-squared gravity

In the present paper we investigate non-perturbatively and self-consistently the structure of neutron stars in R-squared gravity by simultaneously solving the interior and exterior problem. The mass-radius relations are obtained for several equations of state and for wide range of the R-squared gravity parameter a. Even though the deviation from general relativity for nonzero values of a can be large, they are still comparable with the variations due to different modern realistic equations of state. That is why the current observations of the neutron star masses and radii alone can not put constraints on the value of the parameter a. We also compare our results with those obtained within the perturbative method and we discuss the differences between them.

Slowly rotating neutron and strange stars in R 2 gravity

In the present paper we investigate self-consistently slowly rotating neutron and strange stars in R-squared gravity. For this purpose we first derive the equations describing the structure of the slowly rotating compact stars in

Universal I-Q relations for rapidly rotating neutron and strange stars in scalar-tensor theories

f(R)

Moment of inertia -- compactness universal relations in scalar-tensor theories and

-gravity and then simultaneously solve the exterior and the interior problem. The structure of the slowly rotating neutron stars is studied for two different hadronic equations of state and a strange matter equation of state. The moment of inertia and its dependence on the stellar mass and the

\mathcal{R}^2

R

gravity

-squared gravity parameter

Gravitational wave asteroseismology of neutron and strange stars inR2gravity

a

Orbital and epicyclic frequencies around neutron and strange stars in R^2 gravity

is also examined in details. We find that the neutron star moment of inertia for large values of the parameter

Moment of inertia of neutron star crust in alternative and modified theories of gravity

a

Accretion disks around neutron and strange stars in

can be up to