Stars and quark stars in bumblebee gravity

TL;DR

This paper explores how bumblebee gravity, a Lorentz symmetry breaking model, affects star structure, showing it can produce more massive stars than general relativity, especially with quark matter inside.

Contribution

It derives a modified TOV equation in bumblebee gravity and demonstrates increased star mass-radius relations due to Lorentz symmetry breaking effects.

Findings

Bumblebee gravity increases star mass limits beyond 2.5 solar masses.

Stars with quark matter can be more massive in this model.

The stability of quark stars is analyzed within the modified gravity context.

Abstract

In this work, the interior spacetime of stars is built in a Lorentz symmetry breaking model called bumblebee gravity. Firstly, we calculated the modified Tolman-Oppenheimer-Volkoff equation in this context of modified gravity. Then we show that the bumblebee field, responsible for the symmetry breaking, increases the star mass-radius relation when it assumes its vacuum expectation value. When compared to the general relativity mass-radius relation, a Lorentz symmetry breaking context, like the bumblebee gravity, could provide more massive stars, surpassing the $2.5 M_{\odot}$ limit as the interior of the star is described by quark matter with the MIT bag model. Also, we investigate the stability of the solution with the MIT bag equation of state in this context of modified gravity.