Mass of compact stars in f(T) gravity

TL;DR

This paper investigates how to accurately define and calculate the mass of compact stars within $f(T)$ gravity, proposing that the asymptotic mass is the most suitable measure in this alternative gravity theory.

Contribution

It compares different methods for determining the mass of compact objects in $f(T)$ gravity and advocates for the asymptotic mass as the most appropriate approach.

Findings

Asymptotic mass is likely the best measure in $f(T)$ gravity.

Different mass definitions yield varying results in $f(T)$ gravity.

Realistic equations of state are used in the models.

Abstract

The mass of compact objects in General Relativity (GR), which as is well known, is obtained via the Tolman - Oppenheimer - Volkov (TOV) equations, is a well defined quantity. However, in alternative gravity, this is not in general the case. In the particular case of $f(T)$ gravity, where $T$ is the scalar torsion, some authors consider that this is still an open question, since it is not guaranteed that the same equation used in TOV GR holds. In this paper we consider such an important issue and compare different ways to calculate the mass of compact objects in $f(T)$ gravity. In particular, we argue that one of them, the asymptotic mass, may be the most appropriate way to calculate mass in this theory. We adopt realistic equations of state in all the models presented in this article.