Compact stars in a cosmological background

Abstract

Compact stars, such as neutron stars, are dense celestial objects whose gravitational fields are so intense that they warp the spacetime around them, showcasing the cosmos’ profound connection between mass and gravity. The effect of cosmic expansion on local physics continues to be an open problem in astrophysics. Compact stars offer an ideal lab in which to test strong field physics. The underlying gravitational field equations governing compact stars can also be applied to cosmology. The growing tension in the standard model of cosmology in the cosmological context makes the need for more tests of these models all the more important. In this project, the local effects of cosmological models, such as the cosmological constant in standard model physics, will be probed using local physics such as the TolmanOppenhiemer-Volkoff equations where higher-order modified theories of gravity are employed. Through this work, a better understanding of the effect of cosmological evolution on astrophysical phenomena will be explored. Two different models of the higher modified theory of gravity - f(R) will be under observation, namely the Starobinsky model and the Hu-Sawicki model.